JP2007043130A - Composite material, light emitting element using same, light emitting device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite material comprising an organic compound and an inorganic compound; excellent in conductivity and the properties of carrier injection to the organic compound, and having low contact resistance with metal, a light emitting element operating at a low driving voltage due to the application of the composite material to a current excitation type light emitting element, and a light emitting device with low power consumption by manufacturing the light emitting device using the light emitting element. <P>SOLUTION: A composite material contains an organic compound having an oxidation peak potential to the oxidation-reduction potential of ferrocene in dimethylformamide (DMF) at room temperature located within the range of 0 V and 1.5 V (vs. Fc/Fc<SP>+</SP>), preferably within the range of 0.1 V and 1.0 V(vs. Fc/Fc<SP>+</SP>) and a metal oxide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a composite material in which an organic compound and an inorganic compound are combined, and the composite material is excellent in carrier transport property and carrier injection property to an organic compound. The present invention also relates to a current excitation type light emitting element using the composite material. In addition, the present invention relates to a light-emitting device and an electronic device each having a light-emitting element.

In recent years, research and development of light-emitting elements using light-emitting organic compounds have been actively conducted. The basic structure of these light-emitting elements is such that a layer containing a light-emitting organic compound is sandwiched between a pair of electrodes. By applying a voltage to this element, electrons and holes are injected from the pair of electrodes into the layer containing a light-emitting organic compound, and current flows. Then, these carriers (electrons and holes) recombine, whereby the light-emitting organic compound forms an excited state, and emits light when the excited state returns to the ground state. Due to such a mechanism, such a light-emitting element is referred to as a current-excitation light-emitting element.

Note that the excited states formed by the organic compound can be singlet excited state or triplet excited state. Light emission from the singlet excited state is called fluorescence, and light emission from the triplet excited state is called phosphorescence. ing.

Such a light-emitting element is formed of an organic thin film having a thickness of, for example, about 0.1 μm. In addition, since the time from the injection of the carrier to the light emission is about 1 μsec or less, one of the features is that the response speed is very fast. These characteristics are considered suitable for flat panel displays.

In addition, since these light-emitting elements are formed in a film shape, planar light emission can be easily obtained by forming a large-area element. This is a feature that is difficult to obtain with a point light source typified by an incandescent bulb or LED, or a line light source typified by a fluorescent lamp, and therefore has a high utility value as a surface light source applicable to illumination or the like.

  By the way, display devices to be incorporated into various information processing devices that have been rapidly developed in recent years have a particularly high demand for low power consumption. In order to achieve this, attempts have been made to reduce the driving voltage of light-emitting elements. Yes. In view of commercialization, it is important not only to lower the driving voltage but also to extend the life of the light emitting element, and the development of light emitting elements to achieve this is underway.

  For example, in Patent Document 1, a low driving voltage of a light emitting element is achieved by using a metal oxide having a high work function such as molybdenum oxide for an anode. In addition, the effect of extending the life is also obtained.

However, in particular, regarding the extension of the lifetime, it cannot be said that the means disclosed in Patent Document 1 alone is sufficient, and it is necessary to develop a technology for achieving a longer lifetime.
JP-A-9-63771

  Therefore, an object of the present invention is to provide a composite material in which an organic compound and an inorganic compound are combined and has excellent conductivity. It is another object of the present invention to provide a composite material having excellent carrier injection properties into an organic compound. It is another object of the present invention to provide a composite material having low contact resistance with a metal.

  It is another object of the present invention to provide a light-emitting element with a low driving voltage by applying the composite material to a current-excitation light-emitting element. Another object is to provide a light-emitting device with low power consumption by manufacturing a light-emitting device using the light-emitting element.

  As a result of intensive studies, the present inventors have found that the problem can be solved by applying a composite material containing an organic compound and an inorganic compound.

That is, one of the composite materials of the present invention has an oxidation peak potential with respect to an Ag / Ag ⁺ electrode in dimethylformamide (DMF) at room temperature within a range of 0 V to 1.5 V (vs. Ag / Ag ⁺ ). An organic compound and a metal oxide are included.

One of the composite materials of the present invention has an oxidation peak potential with respect to an Ag / Ag ⁺ electrode in dimethylformamide (DMF) at room temperature within a range of 0.2 V to 1.1 V (vs. Ag / Ag ⁺ ). An organic compound and a metal oxide are included.

One of the composite materials of the present invention is an organic compound in which the oxidation peak potential with respect to the oxidation-reduction potential of ferrocene in dimethylformamide (DMF) at room temperature is in the range of 0 V to 1.5 V (vs. Fc / Fc ⁺ ) And a metal oxide.

One of the composite materials of the present invention has an oxidation peak potential with respect to the oxidation-reduction potential of ferrocene in dimethylformamide (DMF) at room temperature within a range of 0.1 V to 1.0 V (vs. Fc / Fc ⁺ ). An organic compound and a metal oxide are included.

  One of the composite materials of the present invention includes an organic compound having an ionization potential of 4.8 eV or more and 6.4 eV or less in a dimethylformamide (DMF) solution at room temperature, and a metal oxide.

  One of the composite materials of the present invention includes an organic compound having an ionization potential of 5.0 eV or more and 6.0 eV or less in a dimethylformamide (DMF) solution at room temperature, and a metal oxide.

One of the composite materials of the present invention is a half-wave potential [V vs. V in a dimethylformamide (DMF) solution. Ag / Ag ⁺ ] is 0.2 to 0.9 [V vs. Ag / Ag ⁺ ] is included, and a metal oxide is included.

One of the composite materials of the present invention is a half-wave potential [V vs. V in a dimethylformamide (DMF) solution. Fc / Fc ⁺ ] is 0.1 to 0.8 [V vs. Fc / Fc ⁺ ] is included, and a metal oxide is included.

  In the above structure, the organic compound is an aromatic amine compound.

  The organic compound is a carbazole derivative.

  The organic compound is an aromatic hydrocarbon.

  The organic compound is a metal complex.

  The organic compound is an organometallic complex.

  The organic compound is a polymer compound.

  In the above structure, the metal oxide has an electron accepting property with respect to the organic compound.

  In the above structure, the metal oxide is preferably a transition metal oxide. In particular, an oxide of a metal belonging to Groups 4 to 8 in the periodic table is preferable. More preferably, one or more of vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable.

  Further, the composite material of the present invention can be used for a light-emitting element. Therefore, the light-emitting element of the present invention includes a layer containing a light-emitting substance between a pair of electrodes, and the layer containing a light-emitting substance has a layer containing the above composite material.

  In the above structure, the layer containing the composite material of the present invention may be provided so as to be in contact with an electrode functioning as an anode of the pair of electrodes, or may be provided so as to be in contact with an electrode functioning as a cathode. Good. One layer may be provided so as to be in contact with each of the pair of electrodes.

  One of the light-emitting elements of the present invention has a layer containing a light-emitting substance of n (n is an arbitrary natural number of 2 or more) between a pair of electrodes, and the m-th layer (m is an arbitrary natural number). The layer including the above-described composite material is provided between the layer including the light-emitting substance of 1 ≦ m <n and the layer including the (m + 1) th light-emitting substance.

  The present invention also includes a light emitting device having the above-described light emitting element. The light-emitting device in this specification includes an image display device, a light-emitting device, or a light source (including a lighting device). Also, a panel in which a light emitting element is formed and a connector, for example, a FPC (Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) tape, a printed wiring board on the end of a TAB tape or TCP The light-emitting device also includes a module provided with an IC or an IC (integrated circuit) directly mounted on a light-emitting element by a COG (Chip On Glass) method.

  An electronic device using the light-emitting element of the present invention for the display portion is also included in the category of the present invention. Therefore, an electronic device according to the present invention includes a display portion, and the display portion includes the above-described light emitting element and a control unit that controls light emission of the light emitting element.

  By implementing the present invention, it is possible to provide a composite material in which an organic compound and an inorganic compound are combined, which is excellent in carrier transportability and carrier injectability into the organic compound.

  Further, by applying the composite material of the present invention to a light emitting element, low voltage driving and low current driving can be realized.

  In addition, by applying the composite material of the present invention to a light-emitting device, a light-emitting device with low power consumption can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

(Embodiment 1)

The composite material of the present invention has an oxidation peak potential with respect to an Ag / Ag ⁺ electrode in dimethylformamide (DMF) at room temperature of 0 V to 1.5 V (vs. Ag / Ag ⁺ ), preferably 0.2 V to 1.1 V. It is characterized by containing an organic compound located within the range of (vs. Ag ^/ Ag ⁺ ) below and a metal oxide. The oxidation peak potential with respect to the redox potential of ferrocene in dimethylformamide (DMF) at room temperature is 0 V or more and 1.5 V or less (vs. Fc / Fc ⁺ ), preferably 0.1 V or more and 1.0 V or less (vs. Fc). / Fc ⁺ ), an organic compound located in the range, and a metal oxide. And an organic compound having an ionization potential in a dimethylformamide (DMF) solution at a room temperature of 4.8 eV to 6.4 eV, preferably 5.0 eV to 6.0 eV, and a metal oxide. It is said.

With such a configuration, the organic compound is easily oxidized by the metal oxide in the composite material of the present invention. In other words, in the composite material of the present invention, radical cations of organic compounds are easily generated. As a result, the conductivity of the composite material can be improved as compared with a single organic compound. In addition, carrier injectability (particularly hole injectability) into the organic compound can be improved. Moreover, the electrical barrier with various metals can be eased and the contact resistance with metals can be reduced.

  Examples of the organic compound used for the composite material of the present invention include the above-described oxidation peak potentials such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, metal complexes, organometallic complexes, and polymer compounds (oligomers, dendrimers, polymers, etc.). Various compounds located within the range can be used. As long as it is such a compound, both a hole transporting compound and an electron transporting compound can be used, but a hole transporting organic compound is particularly preferable. Below, the organic compound which can be used for the composite material of this invention is enumerated concretely.

  For example, as an aromatic amine compound, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4′-bis [N- (3-methylphenyl) ) -N-phenylamino] biphenyl (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″- And tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA).

  Further, N, N′-di (p-tolyl) -N, N′-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4′-bis [N- (4-diphenylaminophenyl) -N— Phenylamino] biphenyl (abbreviation: DPAB), 4,4′-bis (N- {4- [N- (3-methylphenyl) -N-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD) ), 1,3,5-tris [N- (4-diphenylaminophenyl) -N-phenylamino] benzene (abbreviation: DPA3B), and the like.

  Specific examples of the carbazole derivative that can be used in the present invention include 3- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3 , 6-Bis [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3- [N- (1-naphthyl) -N- (9- Phenylcarbazol-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1) and the like.

  Alternatively, 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB), or the like can be used.

Examples of aromatic hydrocarbons that can be used in the present invention include 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), anthracene, and 9,10-diphenyl. Anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra (tert-butyl) perylene and the like can be mentioned. In addition, pentacene, coronene, and the like can also be used. Thus, it is more preferable to use an aromatic hydrocarbon having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or more and having 14 to 42 carbon atoms.

  The aromatic hydrocarbon that can be used in the present invention may have a vinyl skeleton. As the aromatic hydrocarbon having a vinyl group, for example, 4,4′-bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), 9,10-bis [4- (2,2- Diphenylvinyl) phenyl] anthracene (abbreviation: DPVPA) and the like.

  Examples of the metal complex that can be used in the present invention include tris (8-quinolinolato) aluminum (abbreviation: Alq), bis (8-quinolinolato) zinc (abbreviation: Znq), and the like.

Examples of the organometallic complex that can be used in the present invention include tris (2-phenylpyridinato) iridium (III) (abbreviation: Ir (ppy) ₃ ), tris [N- (2-pyridyl) pyrazolato] cobalt. (III) (abbreviation: Co (ppz) ₃ ) and the like.

Alternatively, a high molecular compound such as poly (N-vinylcarbazole) (abbreviation: PVK) or poly (4-vinyltriphenylamine) (abbreviation: PVTPA) can be used.

  Moreover, as an inorganic compound used for the composite material of the present invention, a transition metal oxide is preferable. In addition, an oxide of a metal belonging to Groups 4 to 8 in the periodic table is preferable. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because of their high electron accepting properties. Among these, molybdenum oxide is particularly preferable because it is stable in the air and easy to handle.

  In addition, the manufacturing method of the composite material of this invention may use what kind of method regardless of a wet method and a dry method. For example, the composite material of the present invention can be manufactured by co-evaporation of the organic compound and the inorganic compound described above. Moreover, it can also obtain by apply | coating and baking the solution containing the organic compound and metal alkoxide which were mentioned above. Molybdenum oxide is easy to evaporate in a vacuum and is preferable from the viewpoint of the manufacturing process.

(Embodiment 2)
The light-emitting element of the present invention has a plurality of layers between a pair of electrodes. The plurality of layers have a high carrier injection property and carrier transport so that a light emitting region is formed at a position away from the electrode, that is, a carrier (carrier) is recombined at a position away from the electrode. The layers are formed by combining layers made of highly specific materials.

  One embodiment of a light-emitting element of the present invention is described below with reference to FIG.

  In this embodiment, the light-emitting element includes a first electrode 102, a first layer 103, a second layer 104, a third layer 105, and a fourth layer 106 that are sequentially stacked over the first electrode 102. And a second electrode 107 provided thereon. Note that in this embodiment mode, the first electrode 102 functions as an anode and the second electrode 107 functions as a cathode.

  The substrate 101 is used as a support for the light emitting element. As the substrate 101, for example, glass or plastic can be used. Note that other materials may be used as long as they function as a support in the process for manufacturing the light-emitting element.

  As the first electrode 102, various metals, alloys, electrically conductive compounds, and mixtures thereof can be used. For example, indium tin oxide (ITO), indium tin oxide containing silicon, IZO (Indium Zinc Oxide) in which 2 to 20 wt% zinc oxide (ZnO) is mixed with indium oxide, gold ( Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), titanium (Ti), copper (Cu), palladium ( Pd), aluminum (Al), aluminum-silicon (Al-Si), aluminum-titanium (Al-Ti), aluminum-silicon-copper (Al-Si-Cu), or a nitride of metal material (TiN), etc. In the case where the first electrode is used as an anode, a material having a high work function (among others) ( It is preferably formed thing function 4.0eV or higher) and the like.

  Note that in the light-emitting element of the present invention, the first electrode 102 is not limited to a material having a high work function, and a material having a low work function can also be used.

  The first layer 103 is a layer including the composite material described in Embodiment 1.

The second layer 104 is formed using a substance having a high hole-transport property, such as 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB) or N, N′-bis ( 3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenyl) Aromatic amines such as amino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA) That is, it is a layer made of a compound (having a benzene ring-nitrogen bond). The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used. Note that the second layer 104 is not limited to a single layer, and may be a stack of two or more layers including any of the above substances.

  The third layer 105 is a layer including a substance having a high light-emitting property. For example, a highly luminescent substance such as N, N′-dimethylquinacridone (abbreviation: DMQd) or 3- (2-benzthiazoyl) -7-diethylaminocoumarin (abbreviation: coumarin 6) and tris (8-quinolinolato) aluminum (abbreviation) : Alq) and 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), etc., which are freely combined with a material having high carrier transportability and good film quality (that is, difficult to crystallize). However, since Alq and DNA are substances having high light-emitting properties, a structure in which these substances are used alone may be used as the third layer 105.

The fourth layer 106 is formed using a substance having a high electron-transport property, such as tris (8-quinolinolato) aluminum (abbreviation: Alq), tris (5-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10− Hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), and other metals having a quinoline skeleton or a benzoquinoline skeleton It is a layer made of a complex or the like. In addition, bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) -benzothiazolate] zinc (abbreviation: Zn ( A metal complex having an oxazole-based or thiazole-based ligand such as BTZ) ₂ ) can also be used. In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5 -(P-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 2,2 ′, 2 ″-(1,3,5-benzene Triyl) tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBi), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1,2,4-triazole (Abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4-triazole (abbreviation: p-EtTAZ), batho Phenanthroline (abbreviation: B) hen), basocuproin (abbreviation: BCP), or the like can also be used. The substances mentioned here are mainly substances having an electron mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that a substance other than the above substances may be used for the fourth layer 106 as long as it has a property of transporting more electrons than holes. The fourth layer 106 is not limited to a single layer, and may be a stack of two or more layers formed using the above substances.

  As a material for forming the second electrode 107, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a low work function (a work function of 3.8 eV or less) can be used. Specific examples of such a cathode material include elements belonging to Group 1 or Group 2 of the periodic table of elements, that is, alkali metals such as lithium (Li) and cesium (Cs), and magnesium (Mg), calcium (Ca), Examples thereof include alkaline earth metals such as strontium (Sr) and alloys containing them (Mg: Ag, Al: Li). However, by providing a layer having a function of promoting electron injection between the second electrode 107 and the fourth layer 106 so as to be stacked with the second electrode, Al can be obtained regardless of the work function. Various conductive materials such as Ag, ITO, and ITO containing silicon can be used for the second electrode 107.

Note that as a layer having a function of promoting electron injection, an alkali metal or alkaline earth metal compound such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), or the like is used. Can do. In addition, a layer made of a substance having an electron transporting property containing an alkali metal or an alkaline earth metal, for example, a layer containing magnesium (Mg) in Alq can be used.

  As a method for forming the first layer 103, the second layer 104, the third layer 105, and the fourth layer 106, various methods such as an evaporation method, an ink-jet method, or a spin coating method can be used. Moreover, you may form using the different film-forming method for each electrode or each layer.

  The light-emitting element of the present invention having the above structure is a third layer that contains a highly light-emitting substance because a current flows due to a potential difference generated between the first electrode 102 and the second electrode 107. In the layer 105, holes and electrons recombine to emit light. That is, a light emitting region is formed in the third layer 105. However, it is not necessary that all of the third layer 105 functions as a light emitting region. For example, the light emitting region is formed only on the second layer 104 side or the fourth layer 106 side of the third layer 105. It may be anything.

  Light emission is extracted outside through one or both of the first electrode 102 and the second electrode 107. Therefore, one or both of the first electrode 102 and the second electrode 107 is formed using a light-transmitting substance. In the case where only the first electrode 102 is formed using a light-transmitting substance, light emission is extracted from the substrate side through the first electrode 102 as illustrated in FIG. In the case where only the second electrode 107 is formed using a light-transmitting substance, light emission is extracted from the side opposite to the substrate through the second electrode 107 as illustrated in FIG. In the case where both the first electrode 102 and the second electrode 107 are made of a light-transmitting substance, light is emitted from the first electrode 102 and the second electrode 107 as shown in FIG. And is taken out from both the substrate side and the opposite side of the substrate.

  Note that the structure of the layers provided between the first electrode 102 and the second electrode 107 is not limited to the above. In this configuration, a region where holes and electrons are recombined is provided at a site away from the first electrode 102 and the second electrode 107 so that quenching caused by the proximity of the light emitting region and the metal is reduced. As long as it has a layer containing the composite material shown in Embodiment Mode 1, other than the above may be used.

In other words, there is no particular limitation on the layered structure of the layers, and a substance having a high electron-transport property or a substance having a high hole-transport property, a substance having a high electron-injection property, a substance having a high hole-injection property, The layer made of the substance having a high transportability) may be freely combined with the layer containing the composite material of the present invention. Further, the position of carrier recombination may be controlled by providing a layer formed of a silicon oxide film or the like over the first electrode 102.

  A light-emitting element illustrated in FIG. 2 includes a first layer 303 formed using a substance having a high electron-transport property, a second layer 304 containing a substance having a high light-emitting property, and a hole transport over the first electrode 302 functioning as a cathode. A third layer 305 made of a highly conductive substance, a fourth layer 306 which is a layer containing the composite material of the present invention, and a second electrode 307 functioning as an anode are stacked in this order. Reference numeral 301 denotes a substrate.

  In this embodiment mode, a light-emitting element is manufactured over a substrate made of glass, plastic, or the like. A passive light-emitting device can be manufactured by manufacturing a plurality of such light-emitting elements over one substrate. In addition to a substrate made of glass, plastic, or the like, a light emitting element may be manufactured on a thin film transistor (TFT) array substrate, for example. Thus, an active matrix light-emitting device in which driving of the light-emitting element is controlled by the TFT can be manufactured. Note that the structure of the TFT is not particularly limited. A staggered TFT or an inverted staggered TFT may be used. Also, the driving circuit formed on the TFT array substrate may be composed of N-type and P-type TFTs, or may be composed of only one of N-type and P-type. Further, there is no particular limitation on the crystallinity of the semiconductor used for the TFT, and an amorphous semiconductor or a crystalline semiconductor may be used.

In the light-emitting element of the present invention, the oxidation peak potential with respect to the Ag / Ag ⁺ electrode in the dimethylformamide (DMF) at room temperature is 0 V to 1.5 V (vs. Ag / Ag). ⁺ ), Preferably in a dimethylformamide (DMF) at room temperature, or a composite material containing an organic compound located within a range of 0.2 V to 1.1 V (vs. Ag ^/ Ag ⁺ ) and a metal oxide The oxidation peak potential with respect to the oxidation-reduction potential of ferrocene is 0 V or more and 1.5 V or less (vs. Fc / Fc ⁺ ), preferably 0.1 V or more and 1.0 V or less (vs. Fc / Fc ⁺ ). Ionization potential in a dimethylformamide (DMF) solution at room temperature is 4.8 eV or more in a composite material containing an organic compound and a metal oxide .4eV less, preferably has a layer containing an organic compound is less than 5.0 eV 6.0 eV, a composite material comprising a metal oxide. The composite material of the present invention has high electrical conductivity due to the intrinsic generation of carriers, and thus low voltage driving of the light emitting element can be realized.

  Further, by increasing the thickness of the layer containing the composite material, it is possible to improve color purity by optical design without increasing the driving voltage.

  Further, by increasing the thickness of the layer containing the composite material, a short circuit due to dust, impact, or the like can be prevented; thus, a highly reliable light-emitting element can be obtained. For example, the film thickness between electrodes of a normal light emitting element is 100 nm to 150 nm, whereas the film thickness between electrodes of a light emitting element using a layer containing a composite material is 100 nm to 500 nm, preferably 200 nm to 500 nm. It can be.

  In addition, the layer containing the composite material used for the light-emitting element of the present invention can be in ohmic contact with the electrode and has low contact resistance with the electrode. Therefore, the electrode material can be selected without considering the work function or the like. That is, the choice of electrode material is expanded.

(Embodiment 3)
In this embodiment, a light-emitting element having a structure different from that described in Embodiment 2 will be described with reference to FIGS. In the structure described in this embodiment mode, a layer containing the composite material of the present invention can be provided so as to be in contact with an electrode functioning as a cathode.

  FIG. 5A shows an example of the structure of the light-emitting element of the present invention. A first layer 411, a second layer 412, and a third layer 413 are stacked between the first electrode 401 and the second electrode 402. In this embodiment, the case where the first electrode 401 functions as an anode and the second electrode 402 functions as a cathode is described.

  The same structure as that in Embodiment 2 can be applied to the first electrode 401 and the second electrode 402. The first layer 411 is a layer containing a substance having high light-emitting properties. The second layer 412 is a layer including one compound selected from electron donating substances and a compound having a high electron-transport property, and the third layer 413 includes the composite material described in Embodiment 1. Is a layer. The electron donating substance contained in the second layer 412 is preferably an alkali metal or alkaline earth metal and oxides or salts thereof. Specifically, lithium, cesium, calcium, lithium oxide, calcium oxide, barium oxide, cesium carbonate, and the like can be given.

  With this configuration, as shown in FIG. 5A, by applying a voltage, electrons are exchanged near the interface between the second layer 412 and the third layer 413, and the electrons and Holes are generated and the second layer 412 transports electrons to the first layer 411, while the third layer 413 transports holes to the second electrode 402. In other words, the second layer 412 and the third layer 413 together serve as a carrier generation layer. In addition, it can be said that the third layer 413 has a function of transporting holes to the second electrode 402.

  In addition, the third layer 413 exhibits extremely high hole injecting property and hole transporting property. Therefore, the drive voltage can be reduced. In addition, when the third layer 413 is thickened, an increase in driving voltage can be suppressed.

  Further, even if the third layer 413 is thickened, an increase in driving voltage can be suppressed. Therefore, the thickness of the third layer 413 can be set freely, and light emission from the first layer 411 can be extracted. Efficiency can be improved. In addition, the thickness of the third layer 413 can be set so that the color purity of light emission from the first layer 411 is improved.

Further, taking FIG. 5A as an example, when the second electrode 402 is formed by sputtering, damage to the first layer 411 containing a light-emitting substance can be reduced.

  Note that the light-emitting element of this embodiment also has various variations by changing materials of the first electrode 401 and the second electrode 402. The schematic diagram is shown in FIG. 5 (b), FIG. 5 (c) and FIG. In FIG. 5B, FIG. 5C, and FIG. 6, the reference numerals in FIG. Reference numeral 400 denotes a substrate carrying the light emitting element of the present invention.

  FIG. 5 shows an example in which the first layer 411, the second layer 412, and the third layer 413 are configured in this order from the substrate 400 side. At this time, the first electrode 401 is made light transmissive and the second electrode 402 is made light-shielding (particularly reflective) so that light is emitted from the substrate 400 side as shown in FIG. Become. In addition, the first electrode 401 is made light-shielding (particularly reflective) and the second electrode 402 is made light-transmissive so that light is emitted from the opposite side of the substrate 400 as shown in FIG. It becomes. Further, by making both the first electrode 401 and the second electrode 402 light transmissive, light is emitted to both the substrate 400 side and the opposite side of the substrate 400 as shown in FIG. Configuration is also possible.

  FIG. 6 shows an example in which the third layer 413, the second layer 412, and the first layer 411 are configured in this order from the substrate 400 side. At this time, the first electrode 401 is made light-shielding (particularly reflective), and the second electrode 402 is made light-transmissive so that light is extracted from the substrate 400 side as shown in FIG. . In addition, the first electrode 401 is made light transmissive and the second electrode 402 is made light-shielding (particularly reflective), whereby light is extracted from the opposite side of the substrate 400 as shown in FIG. 6B. Become. Further, by making both the first electrode 401 and the second electrode 402 light transmissive, light is emitted to both the substrate 400 side and the opposite side of the substrate 400 as shown in FIG. Configuration is also possible.

  Note that in the case of manufacturing the light-emitting element in this embodiment, various methods can be used regardless of a wet method or a dry method.

  Further, as illustrated in FIG. 5, after the first electrode 401 is formed, the first layer 411, the second layer 412, and the third layer 413 are sequentially stacked to form the second electrode 402. Alternatively, as shown in FIG. 6, after the second electrode 402 is formed, the third layer 413, the second layer 412, and the first layer 411 are sequentially stacked to form the first electrode 401. May be.

  Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 4)
In this embodiment, a light-emitting element having a structure different from those described in Embodiments 2 and 3 will be described with reference to FIGS. In the structure described in this embodiment mode, a layer including the composite material of the present invention can be provided so as to be in contact with two electrodes of the light-emitting element.

  FIG. 3A shows an example of the structure of the light-emitting element of the present invention. A first layer 211, a second layer 212, a third layer 213, and a fourth layer 214 are stacked between the first electrode 201 and the second electrode 202. In this embodiment, the case where the first electrode 201 functions as an anode and the second electrode 202 functions as a cathode is described.

  The first electrode 201 and the second electrode 202 can have the same structure as that in Embodiment 2. The first layer 211 is a layer including the composite material described in Embodiment 1, and the second layer 212 is a layer including a substance having a high light-emitting property. The third layer 213 is a layer including an electron-donating substance and a compound having a high electron-transport property, and the fourth layer 214 is a layer including the composite material described in Embodiment 1. The electron donating substance contained in the third layer 213 is preferably an alkali metal or alkaline earth metal and oxides or salts thereof. Specifically, lithium, cesium, calcium, lithium oxide, calcium oxide, barium oxide, cesium carbonate, and the like can be given.

  With such a configuration, as shown in FIG. 3A, when a voltage is applied, electrons are transferred near the interface between the third layer 213 and the fourth layer 214, and the electrons and Holes are generated and the third layer 213 transports electrons to the second layer 212, while the fourth layer 214 transports holes to the second electrode 202. That is, the third layer 213 and the fourth layer 214 together serve as a carrier generation layer. In addition, it can be said that the fourth layer 214 has a function of transporting holes to the second electrode 202. Note that a tandem light-emitting element can be obtained by stacking the second layer and the third layer again between the fourth layer 214 and the second electrode 202.

In addition, the first layer 211 and the fourth layer 214 exhibit extremely high hole injecting property and hole transporting property. Therefore, the driving voltage of the light emitting element can be reduced.
In addition, when the first layer 211 and the fourth layer 214 are thickened, an increase in driving voltage can be suppressed.

  Further, even if the first layer 211 and the fourth layer 214 are thickened, an increase in driving voltage can be suppressed. Therefore, the thicknesses of the first layer 211 and the fourth layer 214 can be freely set. In addition, the extraction efficiency of light emission from the second layer 212 can be improved. In addition, the thickness of the first layer 211 or the fourth layer 214 can be set so that the color purity of light emission from the second layer 212 is improved.

In addition, the light emitting element of this embodiment can make the anode side and the cathode side of the second layer responsible for the light emitting function very thick, and can effectively prevent a short circuit of the light emitting element. Further, taking FIG. 3A as an example, when the second electrode 202 is formed by sputtering, damage to the second layer 212 containing a light-emitting substance can be reduced. Furthermore, by configuring the first layer 211 and the fourth layer 214 with the same material, layers composed of the same material can be provided on both sides of the layer responsible for the light emitting function, thereby suppressing stress strain. Can also be expected.

  Note that the light-emitting element of this embodiment also has various variations by changing materials of the first electrode 201 and the second electrode 202. The schematic diagram is shown in FIG. 3 (b), FIG. 3 (c) and FIG. In FIGS. 3B, 3C, and 4, the reference numerals in FIG. 3A are cited. Reference numeral 200 denotes a substrate carrying the light emitting element of the present invention.

  FIG. 3 shows an example in which the first layer 211, the second layer 212, the third layer 213, and the fourth layer 214 are configured in this order from the substrate 200 side. At this time, the first electrode 201 is light-transmitting and the second electrode 202 is light-shielding (particularly reflective) so that light is emitted from the substrate 200 side as shown in FIG. Become. Further, the first electrode 201 is made light-shielding (particularly reflective), and the second electrode 202 is made light-transmissive so that light is emitted from the opposite side of the substrate 200 as shown in FIG. It becomes. Further, by making both the first electrode 201 and the second electrode 202 light transmissive, light is emitted to both the substrate 200 side and the opposite side of the substrate 200 as shown in FIG. Configuration is also possible.

  FIG. 4 shows an example in which the fourth layer 214, the third layer 213, the second layer 212, and the first layer 211 are configured in this order from the substrate 200 side. At this time, the first electrode 201 is made light-shielding (particularly reflective), and the second electrode 202 is made light-transmissive so that light is extracted from the substrate 200 side as shown in FIG. . Further, the first electrode 201 is made light-transmitting and the second electrode 202 is made light-shielding (particularly reflective), whereby light is extracted from the opposite side of the substrate 200 as shown in FIG. Become. Furthermore, by making both the first electrode 201 and the second electrode 202 light transmissive, light is emitted to both the substrate 200 side and the opposite side of the substrate 200 as shown in FIG. Configuration is also possible.

  Note that the first layer 211 includes one compound selected from an electron-donating substance and a compound having a high electron-transport property, the second layer 212 includes a light-emitting substance, and the third layer. Reference numeral 213 denotes a layer including the composite material described in Embodiment 1, and the fourth layer 214 includes one compound selected from electron-donating substances and a compound having a high electron-transport property. It is also possible.

  Note that in the case of manufacturing the light-emitting element in this embodiment, various methods can be used regardless of a wet method or a dry method.

  Further, as illustrated in FIG. 3, after the first electrode 201 is formed, the first layer 211, the second layer 212, the third layer 213, and the fourth layer 214 are sequentially stacked. 4, or after forming the second electrode 202, as shown in FIG. 4, the fourth layer 214, the third layer 213, the second layer 212, and the first layer The layer 211 may be sequentially stacked to form the first electrode.

  Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 5)
In this embodiment, a light-emitting element having a structure different from the structures shown in Embodiments 2 to 4 will be described. The structure described in this embodiment is a structure in which the composite material of the present invention is applied as a charge generation layer of a light-emitting element having a structure in which a plurality of light-emitting units are stacked.

  In this embodiment, a light-emitting element having a structure in which a plurality of light-emitting units are stacked (hereinafter referred to as a tandem element) will be described. That is, the light-emitting element has a plurality of light-emitting units between the first electrode and the second electrode. FIG. 66 shows a tandem element in which two light emitting units are stacked.

  In FIG. 66, a first light emitting unit 511 and a second light emitting unit 512 are stacked between a first electrode 501 and a second electrode 502. A charge generation layer 513 is formed between the first light emitting unit 511 and the second light emitting unit 512.

  Various materials can be used for the first electrode 501 and the second electrode 502.

  The first light-emitting unit 511 and the second light-emitting unit 512 can have various configurations.

  The charge generation layer 513 includes the composite material of the present invention described in Embodiment Mode 1. Since the composite material of the present invention is excellent in carrier injecting property and carrier transporting property, low voltage driving and low current driving can be realized.

  Note that the charge generation layer 513 may be formed by combining the composite material of the present invention with another material. For example, as shown in Embodiment Mode 3, a layer made of the composite material of the present invention and a layer containing one compound selected from electron donating substances and a compound having a high electron transporting property are combined. It may be formed. Moreover, you may form combining the layer which consists of a composite material of this invention, and a transparent conductive film.

  Although the light-emitting element having two light-emitting units has been described in this embodiment mode, the material of the present invention can also be applied to a light-emitting element in which three or more light-emitting units are stacked. For example, a light emitting element in which three light emitting units are stacked is stacked in the order of a first light emitting unit, a first charge generating layer, a second light emitting unit, a second charge generating layer, and a third light emitting unit. However, the composite material of the present invention may be contained only in any one of the charge generation layers, or may be contained in all the charge generation layers.

  Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 6)
In this embodiment mode, optical design of a light-emitting element will be described.

In the light-emitting elements described in any of Embodiments 2 to 5, at least one of the thicknesses of each layer excluding the first electrode and the second electrode is different for each light-emitting element that emits each emission color. Thus, the light extraction efficiency for each emission color can be increased.

For example, as illustrated in FIG. 10, a light-emitting element that emits a red color (R), a green color (G), and a blue color (B) includes a first electrode 1101 that is a reflective electrode, and a light-transmitting property. And the second layer 1101R, 1111G, 1111B, the second layer 1112R, 1112G, 1112B, the third layer 1113R, 1113G, 1113B, the fourth layer 1114R, 1114G and 1114B. Then, the thicknesses of the first layers 1111R, 1111G, and 1111B are made different for each emission color.

Note that in the light-emitting element illustrated in FIG. 10, when voltage is applied so that the potential of the first electrode 1101 is higher than the potential of the second electrode 1102, holes are transferred from the first layer 1111 to the second layer 1112. Is injected. Electrons are transferred in the vicinity of the interface between the third layer 1113 and the fourth layer 1114, electrons and holes are generated, and the third layer 1113 transports electrons to the second layer 1112, and at the same time, The fourth layer 1114 transports holes to the second electrode 1102. Holes and electrons recombine in the second layer 1112 to bring the light-emitting substance into an excited state. The excited luminescent material emits light when returning to the ground state.

As shown in FIG. 10, by making the first layers 1111R, 1111G, and 1111B different for each emission color, the first layer 1111R, 1111G, 1111B are directly recognized through the second electrode, and the second layer is reflected by the first electrode. It is possible to prevent the light extraction efficiency from being lowered due to the difference in the optical path between the case of recognition through the electrode.

Specifically, when light is incident on the first electrode, phase inversion occurs in the reflected light, resulting in a light interference effect. As a result, the optical distance between the light emitting region and the reflective electrode, that is, the refractive index × distance is (2m−1) / 4 times the emission wavelength (m is an arbitrary positive integer), that is, 1/4 of the emission wavelength, When the ratio is 3/4, 5/4,..., The light extraction efficiency is increased. On the other hand, when m / 2 times (m is an arbitrary positive integer), that is, 1/2, 1, 3/2.

Therefore, in the light emitting device of the present invention, the optical distance between the light emitting region and the reflective electrode, that is, the refractive index × distance is (2m−1) / 4 times the emission wavelength (m is an arbitrary positive integer). The film thickness of any of the first to fourth layers is made different for each light emitting element.

In particular, in the first layer to the fourth layer, the thickness of the layer between the layer where the electrons and holes are recombined and the reflective electrode may be different, but from the layer where the electrons and holes are recombined. The film thickness between the light-transmitting electrodes may be different. Furthermore, the film thicknesses of both may be different. As a result, the emitted light can be efficiently extracted outside.

In order to change the film thickness of any of the first layer to the fourth layer, it is necessary to increase the thickness of the layer. The light-emitting element of the present invention is characterized in that the layer including the composite material described in Embodiment Mode 1 is used for the layer to be thickened.

In general, when the thickness of the light emitting element layer is increased, the driving voltage increases, which is not preferable. However, when the composite material described in Embodiment 1 is used for the layer to be thickened, the driving voltage itself can be lowered, and an increase in driving voltage due to the thickening can be suppressed.

  In FIG. 10, the optical distance between the light emitting region of the red light emitting element (R) and the reflective electrode is 1/4 times the light emitting wavelength, and the light emitting region of the green light emitting element (G) and the reflective electrode The optical distance is 3/4 times the emission wavelength, and the optical distance between the light emitting region of the blue light emitting element (B) and the reflective electrode is 5/4 times the emission wavelength. Note that the present invention is not limited to this value, and the value of m can be set as appropriate. As shown in FIG. 10, the value of m, which is (2m−1) / 4 times the emission wavelength, may be different for each light emitting element.

Further, by increasing the thickness of any of the first to fourth layers, the first electrode and the second electrode can be prevented from being short-circuited, and mass productivity can be improved. preferable.

As described above, in the light-emitting element of the present invention, the film thicknesses of at least the first layer to the fourth layer can be made different for each emission color. At this time, it is preferable that the film thickness of the layer between the layer where the electrons and holes are recombined and the reflective electrode be different for each emission color. Further, the layer that needs to be thicker is preferably a layer containing the composite material described in Embodiment Mode 1 because the driving voltage is not increased.

  Note that although this embodiment mode is described using the light-emitting element having the structure described in Embodiment Mode 4, it can be combined with any other embodiment mode as appropriate.

(Embodiment 7)
In this embodiment mode, a light-emitting device having the light-emitting element of the present invention will be described.

  In this embodiment mode, a light-emitting device having the light-emitting element of the present invention in a pixel portion will be described with reference to FIGS. 7A is a top view illustrating the light-emitting device, and FIG. 7B is a cross-sectional view taken along lines A-A ′ and B-B ′ in FIG. 7A. Reference numeral 601 indicated by a dotted line denotes a driving circuit portion (source side driving circuit), 602 denotes a pixel portion, and 603 denotes a driving circuit portion (gate side driving circuit). Reference numeral 604 denotes a sealing substrate, reference numeral 605 denotes a sealing material, and the inside surrounded by the sealing material 605 is a space 607.

  Note that the routing wiring 608 is a wiring for transmitting a signal input to the source side driving circuit 601 and the gate side driving circuit 603, and a video signal, a clock signal, an FPC (flexible printed circuit) 609 serving as an external input terminal, Receives start signal, reset signal, etc. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

  Next, a cross-sectional structure will be described with reference to FIG. A driver circuit portion and a pixel portion are formed over the element substrate 610. Here, a source-side driver circuit 601 that is a driver circuit portion and one pixel in the pixel portion 602 are illustrated.

  Note that the source side driver circuit 601 is a CMOS circuit in which an n-channel TFT 623 and a p-channel TFT 624 are combined. The TFT forming the driving circuit may be formed by various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment mode, a driver integrated type in which a driver circuit is formed over a substrate is shown; however, this is not always necessary, and the driver circuit can be formed outside the substrate.

  The pixel portion 602 is formed by a plurality of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. Here, a positive photosensitive acrylic resin film is used.

  In order to improve the coverage, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when positive photosensitive acrylic is used as a material for the insulator 614, it is preferable that only the upper end portion of the insulator 614 has a curved surface with a curvature radius (0.2 μm to 3 μm). As the insulator 614, either a negative type that becomes insoluble in an etchant by light irradiation or a positive type that becomes soluble in an etchant by light irradiation can be used.

  Over the first electrode 613, a layer 616 containing a light-emitting substance and a second electrode 617 are formed. Here, as a material used for the first electrode 613 functioning as an anode, a material having a high work function is preferably used. For example, an ITO film or an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt% zinc oxide, a single layer film such as a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film In addition, a stack of a titanium nitride film and a film containing aluminum as a main component, a three-layer structure including a titanium nitride film, a film containing aluminum as a main component, and a titanium nitride film can be used. Note that with a stacked structure, resistance as a wiring is low, good ohmic contact can be obtained, and a function as an anode can be obtained.

  The layer 616 containing a light-emitting substance is formed by various methods such as an evaporation method using an evaporation mask, an inkjet method, and a spin coating method. The layer 616 containing a light-emitting substance includes the layer containing the composite material described in Embodiment 1. In addition, the other material forming the layer 616 containing a light-emitting substance may be a low molecular material, a medium molecular material (including an oligomer or a dendrimer), or a high molecular material. In addition, as a material used for a layer containing a light-emitting substance, an organic compound is usually used in a single layer or a stacked layer. I will do it.

Further, as a material used for the second electrode 617 formed over the light-emitting substance-containing layer 616 and functioning as a cathode, a material having a low work function (Al, Ag, Li, Ca, or an alloy or compound thereof, MgAg, or the like) MgIn, AlLi, CaF ₂ , LiF or calcium nitride) is preferably used. Note that in the case where light generated in the layer 616 containing a light-emitting substance passes through the second electrode 617, the second electrode 617 includes a thin metal film and a transparent conductive film (ITO, 2 to 20 wt. % Of indium oxide containing zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), or the like is preferably used.

  Further, the sealing substrate 604 is bonded to the element substrate 610 with the sealant 605, whereby the light-emitting element 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. Yes. Note that the space 607 is filled with a filler, and may be filled with a sealant 605 in addition to an inert gas (such as nitrogen or argon).

  Note that an epoxy-based resin is preferably used for the sealant 605. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), Mylar, polyester, acrylic, or the like can be used as a material for the sealing substrate 604.

  As described above, a light-emitting device having the light-emitting element of the present invention can be obtained.

  Since the light-emitting device of the present invention includes the layer including the composite material described in Embodiment Mode 1, driving voltage can be reduced and power consumption can be reduced.

  In addition, the light-emitting device of the present invention can suppress an increase in driving voltage even if the layer containing the composite material is thickened. Therefore, the layer containing the composite material can be thickened to prevent a short circuit of the light-emitting element. In addition, it is possible to realize an improvement in the efficiency of taking out emitted light by optical design. Thus, a light-emitting device with low power consumption and high reliability can be obtained.

  As described above, in this embodiment mode, an active light-emitting device that controls driving of a light-emitting element using a transistor has been described; A passive light emitting device may be used. FIG. 8 is a perspective view of a passive light emitting device manufactured by applying the present invention. In FIG. 8, a layer 955 containing a light-emitting substance is provided between the electrode 952 and the electrode 956 over the substrate 951. An end portion of the electrode 952 is covered with an insulating layer 953. A partition layer 954 is provided over the insulating layer 953. The side wall of the partition wall layer 954 has an inclination such that the distance between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross section in the short side direction of the partition wall layer 954 has a trapezoidal shape, and the bottom side (side facing the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is the top side (surface of the insulating layer 953). The direction is the same as the direction and is shorter than the side not in contact with the insulating layer 953. In this manner, by providing the partition layer 954, defects in the light-emitting element due to static electricity or the like can be prevented. A passive light emitting device can also be driven with low power consumption by including the light emitting element of the present invention that operates at a low driving voltage.

(Embodiment 8)
In this embodiment mode, electronic devices of the present invention which include the light-emitting device described in Embodiment Mode 7 as a part thereof will be described. An electronic device of the present invention includes a layer including the composite material described in Embodiment 1 and includes a display portion with low power consumption. In addition, by providing a thick layer including the composite material described in Embodiment 1, an electronic device including a highly reliable display portion in which a short circuit due to a minute foreign matter or an external impact is suppressed is provided. It is also possible.

As an electronic device manufactured using the light emitting device of the present invention, a video camera, a digital camera, a goggle type display, a navigation system, a sound reproducing device (car audio, audio component, etc.), a computer, a game device, a portable information terminal (mobile) Display device capable of playing back a recording medium such as a computer, a mobile phone, a portable game machine, or an electronic book) and a recording medium (specifically, a digital versatile disc (DVD)) and displaying the image And the like). Specific examples of these electronic devices are shown in FIGS.
FIG. 9A illustrates a television device according to the present invention, which includes a housing 9101, a supporting base 9102, a display portion 9103, a speaker portion 9104, a video input terminal 9105, and the like. In this television device, the display portion 9103 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 2 to 6 in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to a minute foreign matter or an external impact. Since the display portion 9103 including the light-emitting elements has similar features, this television set has little deterioration in image quality and low power consumption. With such a feature, the deterioration compensation function and the number of power supply circuits can be significantly reduced or reduced in the television device, so that the housing 9101 and the support base 9102 can be reduced in size and weight. In the television device according to the present invention, low power consumption, high image quality, and reduction in size and weight are achieved, so that a product suitable for a living environment can be provided.

  FIG. 9B illustrates a computer according to the present invention, which includes a main body 9201, a housing 9202, a display portion 9203, a keyboard 9204, an external connection port 9205, a pointing mouse 9206, and the like. In this computer, the display portion 9203 includes light-emitting elements similar to those described in Embodiment Modes 2 to 6, arranged in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to a minute foreign matter or an external impact. The display portion 9203 which includes the light-emitting elements has similar features. Therefore, in this computer, image quality is hardly deteriorated and low power consumption is achieved. With such a feature, the number of deterioration compensation functions and power supply circuits can be significantly reduced or reduced in the computer, so that the main body 9201 and the housing 9202 can be reduced in size and weight. In the computer according to the present invention, low power consumption, high image quality, and reduction in size and weight are achieved; therefore, a product suitable for the environment can be provided. Further, the computer can be carried, and a computer having a display portion that is resistant to external shocks when being carried can be provided.

  FIG. 9C illustrates a mobile phone according to the present invention, which includes a main body 9401, a housing 9402, a display portion 9403, an audio input portion 9404, an audio output portion 9405, operation keys 9406, an external connection port 9407, an antenna 9408, and the like. . In this cellular phone, the display portion 9403 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 2 to 6 in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to a minute foreign matter or an external impact. Since the display portion 9403 including the light-emitting elements has similar features, the cellular phone has little deterioration in image quality and low power consumption. With such a feature, the number of deterioration compensation functions and power supply circuits can be significantly reduced or reduced in the mobile phone, so that the main body 9401 and the housing 9402 can be reduced in size and weight. Since the cellular phone according to the present invention has low power consumption, high image quality, and reduced size and weight, a product suitable for carrying can be provided. In addition, a product having a display portion that is resistant to impact when carried can be provided.

  FIG. 9D illustrates a camera according to the present invention, which includes a main body 9501, a display portion 9502, a housing 9503, an external connection port 9504, a remote control receiving portion 9505, an image receiving portion 9506, a battery 9507, an audio input portion 9508, and operation keys 9509. , And an eyepiece 9510. In this camera, the display portion 9502 includes light-emitting elements similar to those described in Embodiment Modes 2 to 6, arranged in a matrix. The light-emitting element has characteristics that light emission efficiency is high, a driving voltage is low, and a short circuit due to a minute foreign matter or an external impact can be prevented. Since the display portion 9502 including the light-emitting elements has similar features, this camera has little deterioration in image quality and low power consumption. With such a feature, the number of deterioration compensation functions and power supply circuits in the camera can be significantly reduced or reduced, so that the main body 9501 can be reduced in size and weight. Since the camera according to the present invention has low power consumption, high image quality, and small size and light weight, a product suitable for carrying can be provided. In addition, a product having a display portion that is resistant to impact when carried can be provided.

  As described above, the applicable range of the light-emitting device of the present invention is so wide that the light-emitting device can be applied to electronic devices in various fields. By using the light-emitting device of the present invention, an electronic device having a display portion with low power consumption and high reliability can be provided.

  In addition, the light-emitting device of the present invention includes a light-emitting element with high emission efficiency, and can also be used as a lighting device. One mode of using the light-emitting element of the present invention as a lighting device will be described with reference to FIGS.

  FIG. 11 illustrates an example of a liquid crystal display device using the light-emitting device of the present invention as a backlight. The liquid crystal display device illustrated in FIG. 11 includes a housing 901, a liquid crystal layer 902, a backlight 903, and a housing 904, and the liquid crystal layer 902 is connected to a driver IC 905. The backlight 903 uses the light-emitting device of the present invention, and a current is supplied from a terminal 906.

  By using the light-emitting device of the present invention as a backlight of a liquid crystal display device, a backlight with reduced power consumption can be obtained. Further, the light-emitting device of the present invention is a surface-emitting illumination device and can have a large area, so that the backlight can have a large area and a liquid crystal display device can have a large area. Further, since the light emitting device is thin and has low power consumption, the display device can be thinned and the power consumption can be reduced.

  In this example, a measurement example of oxidation characteristics of an organic compound that can be used for the composite material of the present invention is shown. The oxidation characteristics were examined by cyclic voltammetry (CV) measurement. For the measurement, an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model 600A) was used.

As a solution in CV measurement, dehydrated dimethylformamide (DMF) (manufactured by Aldrich, 99.8%, catalog number: 22705-6) was used as a solvent, and tetra-n-butylammonium perchlorate (supporting electrolyte) ( n-Bu ₄ NClO ₄ ) (manufactured by Tokyo Chemical Industry Co., Ltd., catalog number: T0836) is dissolved to a concentration of 100 mmol / L, and the measurement target is further dissolved to a concentration of 1 mmol / L. did. In addition, as a working electrode, a platinum electrode (manufactured by BAS Co., Ltd., PTE platinum electrode), and as an auxiliary electrode, a platinum electrode (manufactured by BAS Inc., Pt counter electrode for VC-3 ( 5 cm)), and Ag / Ag ⁺ electrode (manufactured by BAS Co., Ltd., RE5 non-aqueous solvent system reference electrode) was used as a reference electrode. In addition, the measurement was performed at room temperature (20-25 degreeC).

(CV measurement of standard substance)
First, the oxidation-reduction potential of ferrocene (Fc) as a standard substance was measured by CV measurement. Ferrocene is oxidized to become ferrocenium ion (Fc ⁺ ), but when ferrocenium ion is reduced, it is reversibly returned to ferrocene. Therefore, in the present invention, the redox potential “Fc / Fc ⁺ ” (defined as an intermediate potential between the oxidation peak potential and the reduction peak potential) is used as a reference value.

The measurement results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.34 V to 0.80 V and then from 0.80 V to −0.34 V. The scanning speed was set to 0.1 V / s. From FIG. 12, the oxidation peak potential (E _pa ) of ferrocene is 0.12 V, and the reduction peak potential (E _pc ) of ferrocenium ion, which is an ferrocene oxide, is 0.05 V. Therefore, the oxidation-reduction potential of ferrocene is (0.12 + 0.05) /2≈0.09 [V vs. Ag / Ag ⁺ ].

(Measurement Example 1: NPB)
In Measurement Example 1, the oxidation peak potential of NPB that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.20 to 0.80 V and then from 0.80 V to −0.20 V. The scanning speed was set to 0.1 V / s. From FIG. 13, the oxidation peak potential (E _pa ) of NPB is 0.45 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of NPB is 0 .36 [V vs. Fc / Fc ⁺ ].

(Measurement Example 2: DNTPD)
In this measurement example 2, the oxidation peak potential of DNTPD that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.05 V to 1.20 V and then from 1.20 V to −0.05 V. The scanning speed was set to 0.1 V / s. From FIG. 14, the oxidation peak potential (E _pa ) of DNTPD is 0.26 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of DNTPD is 0 .17 [V vs. Fc / Fc ⁺ ].

(Measurement Example 3; PCzPCA1)
In Measurement Example 3, the oxidation peak potential of PCzPCA1 that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.16 V to 0.50 V and then from 0.50 V to −0.16 V. The scanning speed was set to 0.1 V / s. From FIG. 15, the oxidation peak potential (E _pa ) of _PCzPCA1 is 0.27 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of PCzPCA1 is 0 18 [V vs. Fc / Fc ⁺ ].

(Measurement Example 4: PCzPCN1)
In Measurement Example 4, the oxidation peak potential of PCzPCN1 that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.20 V to 0.50 V and then from 0.50 V to −0.20 V. The scanning speed was set to 0.1 V / s. From FIG. 16, the oxidation peak potential (E _pa ) of PCzPCN1 is 0.26 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of PCzPCN1 is 0 .17 [V vs. Fc / Fc ⁺ ].

(Measurement Example 5: CBP)
In Measurement Example 5, the oxidation peak potential of CBP that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.20 V to 1.20 V and then from 1.20 V to −0.20 V. The scanning speed was set to 0.1 V / s. From FIG. 17, the oxidation peak potential (E _pa ) of CBP is 1.00 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of CBP is 0. .91 [V vs. Fc / Fc ⁺ ].

(Measurement Example 6; for t-BuDNA)
In Measurement Example 6, the oxidation peak potential of t-BuDNA that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.30 V to 1.20 V and then from 1.20 V to −0.30 V. The scanning speed was set to 0.1 V / s. FIG. 18 shows that the oxidation peak potential (E _pa ) of t-BuDNA is 0.89 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of t-BuDNA is , 0.80 [V vs. Fc / Fc ⁺ ].

(Measurement Example 7; DPVBi)
In Measurement Example 7, the oxidation peak potential of DPVBi that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.10 V to 1.10 V and then from 1.10 V to −0.10 V. The scanning speed was set to 0.1 V / s. From FIG. 19, the oxidation peak potential (E _pa ) of DPVBi is 1.00 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of DPVBi is 0 .91 [V vs. Fc / Fc ⁺ ].

(Measurement Example 8; in the case of Alq)
In Measurement Example 8, the oxidation peak potential of Alq that can be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.52 V to 1.20 V and then from 1.20 V to −0.52 V. The scanning speed was set to 0.1 V / s. From FIG. 20, the oxidation peak potential (E _pa ) of Alq is 0.82 [V vs. Ag / Ag ⁺ ].

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of Alq is 0 .73 [V vs. Fc / Fc ⁺ ].
(Comparative measurement example 1: BCP)
In this comparative measurement example 1, the oxidation peak potential of BCP that cannot be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.20 V to 2.00 V and then from 2.00 V to −0.20 V. The scanning speed was set to 0.1 V / s. In FIG. 21, the amount of current exceeds the upper limit of the measuring range of the measuring device between 1.60 and 2.00 V, but at least the oxidation peak potential of BCP is −0.20 to 1.60 [V vs. [Ag / Ag ⁺ ] was not observed.

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of BCP is − 0.29 to 1.51 [V vs. Fc / Fc ⁺ ] was found not to exist.

(Comparative measurement example 2; in the case of OXD-7)
In this comparative measurement example 2, the oxidation peak potential of OXD-7 that cannot be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.47 V to 2.00 V and then from 2.00 V to −0.47 V. The scanning speed was set to 0.1 V / s. In FIG. 22, the amount of current exceeds the upper limit of the measuring range of the measuring instrument between 1.60 and 2.00 V, but at least the oxidation peak potential of OXD-7 is −0.47 to 1.60 [V. vs. [Ag / Ag ⁺ ] was not observed.

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of OXD-7 is , −0.56 to 1.51 [V vs. Fc / Fc ⁺ ] was found not to exist.

(Comparative measurement example 3; for TPBi)
In this comparative measurement example 3, the oxidation peak potential of TPBi that cannot be used for the composite material of the present invention was measured by CV measurement. The results are shown in FIG. The measurement was performed by scanning the potential of the working electrode with respect to the reference electrode from −0.40 V to 2.00 V and then from 2.00 V to −0.40 V. The scanning speed was set to 0.1 V / s. In FIG. 23, the amount of current exceeds the upper limit of the measurement range of the measuring device between 1.60 and 2.00 V, but at least the oxidation peak potential of TPBi is −0.40 to 1.60 [V vs. [Ag / Ag ⁺ ] was not observed.

Therefore, when the oxidation-reduction potential of ferrocene (= 0.09 [V vs. Ag ^/ Ag ⁺ ]) measured in the above (CV measurement of standard substance) is used as a reference value (0 V), the oxidation peak potential of TPBi is − 0.49 to 1.51 [V vs. Fc / Fc ⁺ ] was found not to exist.

The above results are summarized in Table 1 below. As shown in Table 1, the organic compound that can be used in the composite material of the present invention has an oxidation peak potential (vs. Ag ^/ Ag ⁺ ) in dimethylformamide (DMF) at room temperature in the range of 0V to 1.5V. Is located. Further, the oxidation peak potential (vs. Fc / Fc ⁺ ) in dimethylformamide (DMF) at room temperature is in the range of 0V to 1.5V. On the other hand, it can be seen that an organic compound that cannot be used in the composite material of the present invention does not have an oxidation peak potential observed within the above range.

Next, using the organic compound measured in Example 1, a light-emitting element was manufactured and the characteristics were evaluated. The results are shown in the following examples.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown. The effects of the present invention will be described with comparative examples.

(Light emitting element 1)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then NPB, molybdenum oxide (VI), and rubrene are co-evaporated on the first electrode, whereby the layer containing the composite material of the present invention is formed. Formed. The film thickness was 120 nm, and the ratio of NPB, molybdenum oxide (VI) and rubrene was adjusted to be 2: 0.75: 0.04 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber. Further, although rubrene is added in this embodiment, rubrene is not always necessary, and almost the same characteristics can be obtained by using only NPB and molybdenum oxide (VI).

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a light emitting element 1 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm using a resistance heating vapor deposition method. did.

(Comparative light emitting element 1)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, only NPB was formed to a thickness of 60 nm on the first electrode by a vapor deposition method using resistance heating.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on NPB. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a comparative light-emitting element 1 was manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm by using a resistance heating vapor deposition method.

FIG. 24 shows current-voltage characteristics of the light-emitting element 1 and the comparative light-emitting element 1 of the present invention. In addition, FIG. 25 shows luminance-voltage characteristics. In the light-emitting element 1 of the present invention, the voltage necessary for obtaining a luminance of 990 cd / m ² was 5.8 V, and the current flowing at that time was 0.351 mA (current density was 8.78 mA / cm ² ). . Moreover, the current efficiency at this time was 11 cd / A, and the power efficiency was 6.1 lm / W. On the other hand, in the comparative light-emitting element 1, the voltage required to obtain a luminance of 1000 cd / m ² is 9.0 V, and the current flowing at that time is 0.363 mA (current density is 9.07 mA / cm ² ). It was. At this time, the current efficiency was 11 cd / A, and the power efficiency was 3.9 lm / W.

Therefore, in the case where the light-emitting element emits light with a luminance of about 1000 cd / m ² , the book using the layer containing the composite material of the present invention is used as compared with the comparative light-emitting element 1 in which the layer using only the organic compound is formed as the layer in contact with the electrode It can be seen that the light-emitting element 1 of the invention is reduced in both driving voltage and power consumption.

From the above results, it was found that the driving voltage can be reduced by using the composite material of the present invention for a light emitting element. It was also found that power consumption can be reduced.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown. The effects of the present invention will be described with comparative examples.

(Light emitting element 2)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, DNTPD, molybdenum oxide (VI), and rubrene are co-evaporated on the first electrode, whereby the layer containing the composite material of the present invention is formed. Formed. The film thickness was 120 nm, and the weight ratio of DNTPD, molybdenum oxide (VI), and rubrene was adjusted to 1: 0.5: 0.02. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber. Further, although rubrene is added in this embodiment, rubrene is not always necessary, and almost the same characteristics can be obtained by using only NPB and molybdenum oxide (VI).

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a light emitting element 2 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm using a resistance heating vapor deposition method. did.

(Comparative light emitting element 2)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, DNTPD was deposited on the first electrode so as to have a film thickness of 50 nm by an evaporation method using resistance heating.

  Thereafter, NPB was formed to a thickness of 10 nm on DNTPD by a vapor deposition method using resistance heating.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on NPB. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a comparative light-emitting element 2 was manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm by using a resistance heating vapor deposition method.

FIG. 26 shows current-voltage characteristics of the light-emitting element 2 and the comparative light-emitting element 2 of the present invention. In addition, FIG. 27 shows luminance-voltage characteristics. 26 and 27, in the light-emitting element 2 of the present invention, the voltage necessary to obtain a luminance of 950 cd / m ² is 5.8 V, and the current that flows at that time is 0.267 mA (current density is 6.66 mA). / Cm ² ). Moreover, the current efficiency at this time was 14 cd / A, and the power efficiency was 7.7 lm / W. On the other hand, in the comparative light-emitting element 2, the voltage necessary to obtain a luminance of 1000 cd / m ² is 5.8 V, and the current flowing at that time is 0.331 mA (current density is 8.27 mA / cm ² ). It was. At this time, the current efficiency was 12 cd / A, and the power efficiency was 6.6 lm / W.

Therefore, in the case where the light emitting element is made to emit light with a luminance of about 1000 cd / m ² , the book using the layer containing the composite material of the present invention is used as compared with the comparative light emitting element 2 in which the layer using only the organic compound is formed as the layer in contact with the electrode. The light-emitting element 2 of the invention was almost the same as the comparative light-emitting element 2 with respect to the driving voltage, but it can be seen that the power consumption is reduced as a result of the improvement in current efficiency.

From the above results, it was found that power consumption can be reduced by using the composite material of the present invention for a light-emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown. The effects of the present invention will be described with comparative examples.

(Light emitting element 3)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed by co-evaporating PCzPCA1 and molybdenum oxide (VI) on the first electrode. did. The film thickness was 120 nm and the weight ratio of PCzPCA1 to molybdenum oxide (VI) was adjusted to 1: 0.5. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a light emitting element 3 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm using a resistance heating vapor deposition method. did.

(Comparative light emitting element 3)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, PCzPCA1 was formed to a thickness of 50 nm on the first electrode by a vapor deposition method using resistance heating.

  Thereafter, NPB was formed to a thickness of 10 nm on PCzPCA1 by a vapor deposition method using resistance heating.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on NPB. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a comparative light-emitting element 3 was manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm by using a resistance heating vapor deposition method.

FIG. 28 shows current-voltage characteristics of the light-emitting element 3 and the comparative light-emitting element 3 of the present invention. In addition, FIG. 29 shows luminance-voltage characteristics. 28 and 29, in the light-emitting element 3 of the present invention, the voltage necessary to obtain a luminance of 1000 cd / m ² is 5.4 V, and the current flowing at that time is 0.269 mA (current density is 6.73 mA). / Cm ² ). At this time, the current efficiency was 15 cd / A, and the power efficiency was 8.9 lm / W. On the other hand, in the comparative light-emitting element 3, the voltage necessary to obtain a luminance of 1000 cd / m ² is 5.8 V, and the current flowing at that time is 0.282 mA (current density is 7.1 mA / cm ² ). It was. Moreover, the current efficiency at this time was 14 cd / A, and the power efficiency was 7.6 lm / W.

Therefore, in the case where the light-emitting element emits light with a luminance of about 1000 cd / m ² , the book using the layer containing the composite material of the present invention is used as compared with the comparative light-emitting element 3 in which a layer using only an organic compound is formed as a layer in contact with the electrode It can be seen that the light-emitting element 3 of the invention is reduced in both driving voltage and power consumption.

From the above results, it was found that the driving voltage can be reduced by using the composite material of the present invention for a light emitting element. It was also found that power consumption can be reduced.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown. The effects of the present invention will be described with comparative examples.

(Light emitting element 4)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, a layer containing the composite material of the present invention is formed by co-evaporating PCzPCN1 and molybdenum oxide (VI) on the first electrode. did. The film thickness was 120 nm and the weight ratio of PCzPCN1 to molybdenum oxide (VI) was adjusted to 1: 0.5. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a light emitting element 4 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm using a resistance heating vapor deposition method. did.

(Comparative light emitting element 4)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, PCzPCN1 was formed to a thickness of 50 nm on the first electrode by an evaporation method using resistance heating.

  Thereafter, NPB was formed to a thickness of 10 nm on PCzPCN1 by a vapor deposition method using resistance heating.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on NPB. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a comparative light-emitting element 4 was manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm by using a resistance heating vapor deposition method.

FIG. 30 shows current-voltage characteristics of the light-emitting element 4 and the comparative light-emitting element 4 of the present invention. Further, FIG. 31 shows luminance-voltage characteristics. 30 and 31, in the light-emitting element 4 of the present invention, the voltage necessary to obtain a luminance of 890 cd / m ² is 5.6 V, and the current flowing at that time is 0.267 mA (current density is 6.67 mA). / Cm ² ). Moreover, the current efficiency at this time was 13 cd / A, and the power efficiency was 7.5 lm / W. On the other hand, in the comparative light-emitting element 4, the voltage required to obtain a luminance of 950 cd / m ² is 6.0 V, and the current flowing at that time is 0.336 mA (current density is 8.40 mA / cm ² ). It was. Moreover, the current efficiency at this time was 11 cd / A, and the power efficiency was 5.9 lm / W.

Therefore, in the case where the light-emitting element emits light with a luminance of about 1000 cd / m ² , the book using the layer containing the composite material of the present invention is used as compared with the comparative light-emitting element 4 in which the layer using only the organic compound is formed as the layer in contact with the electrode. It can be seen that the light-emitting element 4 of the invention is reduced in both driving voltage and power consumption.

From the above results, it was found that the driving voltage can be reduced by using the composite material of the present invention for a light emitting element. It was also found that power consumption can be reduced.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown. The effects of the present invention will be described with comparative examples.

(Light emitting element 5)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed on the first electrode by co-evaporation of CBP and molybdenum oxide (VI). did. The film thickness was 120 nm, and the ratio of CBP to molybdenum oxide (VI) was adjusted to be 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, the light emitting element 5 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm using a resistance heating vapor deposition method. did.

(Comparative light-emitting element 5)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, CBP was deposited on the first electrode so as to have a film thickness of 50 nm by vapor deposition using resistance heating.

  Thereafter, NPB was formed to a thickness of 10 nm on CBP by a vapor deposition method using resistance heating.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on NPB. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a comparative light-emitting element 5 was manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm using a vapor deposition method using resistance heating.

FIG. 32 shows current-voltage characteristics of the light-emitting element 5 and the comparative light-emitting element 5 of the present invention. In addition, FIG. 33 shows luminance-voltage characteristics. 32 and 33, in the light-emitting element 5 of the present invention, the voltage necessary to obtain a luminance of 890 cd / m ² is 5.4 V, and the current that flows at that time is 0.301 mA (current density is 7.52 mA). / Cm ² ). Moreover, the current efficiency at this time was 12 cd / A, and the power efficiency was 6.9 lm / W. On the other hand, in the comparative light-emitting element 5, the voltage required to obtain a luminance of 1000 cd / m ² was 18 V, and the current that flowed at that time was 0.386 mA (current density was 9.65 mA / cm ² ). Moreover, the current efficiency at this time was 11 cd / A, and the power efficiency was 1.9 lm / W.

Therefore, in the case where the light-emitting element emits light with a luminance of about 1000 cd / m ² , the book using the layer containing the composite material of the present invention is used as compared with the comparative light-emitting element 5 in which the layer using only the organic compound is formed as the layer in contact with the electrode It can be seen that the light-emitting element 5 of the invention is reduced in both driving voltage and power consumption.

From the above results, it was found that the driving voltage can be reduced by using the composite material of the present invention for a light emitting element. It was also found that power consumption can be reduced.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown. The effects of the present invention will be described with comparative examples.

(Light emitting element 6)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, t-BuDNA and molybdenum oxide (VI) are co-evaporated on the first electrode, whereby the layer containing the composite material of the present invention is formed. Formed. The film thickness was 120 nm, and the ratio of t-BuDNA to molybdenum oxide (VI) was adjusted to 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a light emitting element 6 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm using a resistance heating vapor deposition method. did.

(Comparative light emitting element 6)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, t-BuDNA was deposited on the first electrode to a thickness of 50 nm by a vapor deposition method using resistance heating.

  Thereafter, NPB was formed to a thickness of 10 nm on t-BuDNA by a vapor deposition method using resistance heating.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on NPB. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a comparative light-emitting element 6 was fabricated by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm by using a resistance heating vapor deposition method.

FIG. 34 shows current-voltage characteristics of the light-emitting element 6 and the comparative light-emitting element 6 of the present invention. In addition, FIG. 35 shows luminance-voltage characteristics. 34 and 35, in the light-emitting element 6 of the present invention, the voltage necessary to obtain a luminance of 970 cd / m ² is 5.4 V, and the current flowing at that time is 0.304 mA (current density is 7.59 mA). / Cm ² ). Moreover, the current efficiency at this time was 13 cd / A, and the power efficiency was 7.4 lm / W. On the other hand, in the comparative light-emitting element 6, the voltage necessary to obtain a luminance of 1000 cd / m ² is 17.5 V, and the current flowing at that time is 0.369 mA (current density is 9.22 mA / cm ² ). It was. At this time, the current efficiency was 11 cd / A, and the power efficiency was 2.0 lm / W.

Therefore, in the case where the light-emitting element emits light with a luminance of about 1000 cd / m ² , the book using the layer containing the composite material of the present invention is used as compared with the comparative light-emitting element 6 in which the layer using only the organic compound is formed as the layer in contact with the electrode. It can be seen that the light-emitting element 6 of the invention is reduced in both driving voltage and power consumption.

From the above results, it was found that the driving voltage can be reduced by using the composite material of the present invention for a light emitting element. It was also found that power consumption can be reduced.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown. The effects of the present invention will be described with comparative examples.

(Light emitting element 7)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, DPVBi and molybdenum oxide (VI) are co-evaporated on the first electrode to form a layer containing the composite material of the present invention. did. The film thickness was 120 nm, and the ratio of DPVBi to molybdenum oxide (VI) was adjusted to 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a light emitting element 7 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm by using a resistance heating vapor deposition method. did.

(Comparative light-emitting element 7)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, DPVBi was formed to a thickness of 50 nm on the first electrode by a vapor deposition method using resistance heating.

  Thereafter, NPB was formed to a thickness of 10 nm on DPVBi by a vapor deposition method using resistance heating.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 37.5 nm on NPB. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was formed on the light emitting layer so as to have a film thickness of 37.5 nm to form an electron transporting layer.

  Furthermore, on the electron transport layer, calcium fluoride was formed to a thickness of 1 nm by a resistance heating vapor deposition method to form an electron injection layer.

  Finally, a comparative light-emitting element 7 was fabricated by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm using an evaporation method using resistance heating.

FIG. 36 shows current-voltage characteristics of the light-emitting element 7 and the comparative light-emitting element 7 of the present invention. In addition, FIG. 37 shows luminance-voltage characteristics. 36 and 37, in the light-emitting element 7 of the present invention, the voltage necessary for obtaining a luminance of 1100 cd / m ² is 5.6 V, and the current that flows is 0.381 mA (current density is 9.53 mA). / Cm ² ). Moreover, the current efficiency at this time was 11 cd / A, and the power efficiency was 6.3 lm / W. On the other hand, in the comparative light-emitting element 7, the voltage necessary to obtain a luminance of 960 cd / m ² is 24.6 V, and the current flowing at that time is 1.11 mA (current density is 27.8 mA / cm ² ). It was. At this time, the current efficiency was 3.5 cd / A, and the power efficiency was 0.44 lm / W.

Therefore, in the case where the light emitting element is made to emit light with a luminance of about 1000 cd / m ² , the book using the layer containing the composite material of the present invention is used as compared with the comparative light emitting element 7 in which the layer using only the organic compound is formed as the layer in contact with the electrode. It can be seen that the light-emitting element 7 of the invention is reduced in both driving voltage and power consumption.

From the above results, it was found that the driving voltage can be reduced by using the composite material of the present invention for a light emitting element. It was also found that power consumption can be reduced.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 8)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed on the first electrode by co-evaporation of Alq and molybdenum oxide (VI). did. The film thickness was 50 nm, and the ratio of Alq to molybdenum oxide (VI) was adjusted to be 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 30 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a light emitting element 8 of the present invention is manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm using a resistance heating vapor deposition method. did.

FIG. 38 shows current-voltage characteristics of the light-emitting element 8 of the present invention. Further, FIG. 39 shows luminance-voltage characteristics. 38 and 39, in the light-emitting element 8 of the present invention, the voltage at which light emission of 1 cd / m ² or more is obtained is 5.2 V, and the voltage at which light emission of 0.1 cd / m ² or more is obtained is 3.2 V. Met.

When attention is paid to the light emission start voltage (voltage at which light emission of 0.1 cd / m ² or more is obtained), the light emitting element 8 is the light emitting elements 1 to 7 of the present invention described above (light emission start voltage is 2.4 to 2.6 V). There is no inferiority. Therefore, as in this example, the present invention relates to a compound in which an oxidation peak potential as shown in the measurement example of Example 1 is observed even if it is an electron transporting compound such as Alq. It was found that it can be used for composite materials. It was also found that the light-emitting element can be operated sufficiently using the composite material.
(Comparative light emitting element 11)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed by co-evaporating BCP and molybdenum oxide (VI) on the first electrode. did. The film thickness was 50 nm, and the ratio of BCP to molybdenum oxide (VI) was adjusted to 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 30 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a comparative light-emitting element 11 was manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm by using a resistance heating vapor deposition method.

A current-voltage characteristic of the comparative light-emitting element 11 is shown in FIG. In addition, FIG. 41 shows luminance-voltage characteristics. 40 and 41 that the comparative light-emitting element needs a high voltage to obtain light emission with a constant luminance. Specifically, in the comparative light-emitting element 11, the voltage at which light emission of 1 cd / m ² or more was obtained was 34V, and the voltage at which light emission of 0.1 cd / m ² or more was obtained (light emission start voltage) was 30V. .

Thus, it was found that it was difficult to use the compound in which the oxidation peak potential was not observed as shown in the comparative measurement example of Example 1 for the composite material of the present invention. It was also found that it is difficult to sufficiently operate the light-emitting element using the composite material.

(Comparative light emitting element 12)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, OXD-7 and molybdenum oxide (VI) are co-evaporated on the first electrode, whereby the layer containing the composite material of the present invention is formed. Formed. The film thickness was 50 nm, and the ratio of OXD-7 to molybdenum oxide (VI) was adjusted to 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 30 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a comparative light-emitting element 12 was fabricated by forming a second electrode by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm by using a resistance heating vapor deposition method.

A current-voltage characteristic of the comparative light emitting element 12 is shown in FIG. In addition, FIG. 43 shows luminance-voltage characteristics. 42 and 43 that the comparative light-emitting element requires a high voltage to obtain light emission with a constant luminance. Specifically, in the comparative light emitting element 12, the voltage at which light emission of 1 cd / m ² or more was obtained was 19V, and the voltage at which light emission of 0.1 cd / m ² or more was obtained (light emission start voltage) was 16V. .

Thus, it was found that it was difficult to use the compound in which the oxidation peak potential was not observed as shown in the comparative measurement example of Example 1 for the composite material of the present invention. It was also found that it is difficult to sufficiently operate the light-emitting element using the composite material.

(Comparative light-emitting element 13)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed on the first electrode by co-evaporation of TPBi and molybdenum oxide (VI). did. The film thickness was 50 nm, and the ratio of TPBi to molybdenum oxide (VI) was adjusted to be 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 30 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a comparative light-emitting element 13 was manufactured by forming a second electrode by depositing aluminum on the electron injection layer so as to have a film thickness of 200 nm using an evaporation method using resistance heating.

FIG. 44 shows current-voltage characteristics of the comparative light-emitting element 13. In addition, FIG. 45 shows luminance-voltage characteristics. 44 and 45 that the comparative light-emitting element needs a high voltage in order to obtain light emission with a constant luminance. Specifically, in the comparative light-emitting element 11, the voltage at which light emission of 1 cd / m ² or more was obtained was 20 V, and the voltage at which light emission of 0.1 cd / m ² or more was obtained (light emission start voltage) was 17 V. .

Thus, it was found that it was difficult to use the compound in which the oxidation peak potential was not observed as shown in the comparative measurement example of Example 1 for the composite material of the present invention. It was also found that it is difficult to sufficiently operate the light-emitting element using the composite material.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 21)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed by co-evaporating DNTPD and molybdenum oxide (VI) on the first electrode. did. The film thickness was 50 nm, and the ratio of DNTPD to molybdenum oxide (VI) was adjusted to be 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the Alq layer.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 30 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a second electrode was formed by depositing aluminum on the electron injection layer so as to have a thickness of 200 nm using a vapor deposition method using resistance heating. The light-emitting element manufactured in this example is referred to as a light-emitting element 21 of the present invention.

FIG. 46 shows current-voltage characteristics of the light-emitting element 21 of the present invention. In addition, FIG. 47 shows luminance-voltage characteristics. 46 and 47, in the light-emitting element 21 of the present invention, the voltage necessary to obtain a luminance of 1100 cd / m ² is 5.8 V, and the current flowing at that time is 0.346 mA (current density is 8.66 mA). / Cm ² ). Moreover, the current efficiency at this time was 13 cd / A, and the power efficiency was 6.8 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 22)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed by co-evaporating PCzPCA1 and molybdenum oxide (VI) on the first electrode. did. The film thickness was 50 nm and the weight ratio of PCzPCA1 to molybdenum oxide (VI) was adjusted to 1: 0.5. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 30 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a second electrode was formed by depositing aluminum to a thickness of 200 nm on the electron injection layer using a resistance heating vapor deposition method. The light-emitting element manufactured in this example is referred to as a light-emitting element 22 of the present invention.

FIG. 48 shows current-voltage characteristics of the light-emitting element 22 of the present invention. Further, FIG. 49 shows luminance-voltage characteristics. 48 and 49, in the light-emitting element 22 of the present invention, the voltage required to obtain a luminance of 1200 cd / m ² is 5.0 V, and the current that flows is 0.396 mA (current density is 9.90 mA). / Cm ² ). Moreover, the current efficiency at this time was 12 cd / A, and the power efficiency was 7.7 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 23)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, a layer containing the composite material of the present invention is formed by co-evaporating PCzPCN1 and molybdenum oxide (VI) on the first electrode. did. The film thickness was 50 nm and the weight ratio of PCzPCN1 to molybdenum oxide (VI) was adjusted to 1: 0.5. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 30 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a second electrode was formed by depositing aluminum to a thickness of 200 nm on the electron injection layer using a resistance heating vapor deposition method. The light-emitting element manufactured in this example is referred to as a light-emitting element 23 of the present invention.

FIG. 50 shows current-voltage characteristics of the light-emitting element 23 of the present invention. In addition, FIG. 51 shows luminance-voltage characteristics. 50 and 51, in the light-emitting element 23 of the present invention, the voltage necessary for obtaining a luminance of 1200 cd / m ² is 5.0 V, and the current flowing at that time is 0.300 mA (current density is 7.51 mA). / Cm ² ). At this time, the current efficiency was 16 cd / A, and the power efficiency was 9.9 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 24)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, copper phthalocyanine (CuPc) was formed on the first electrode so as to have a thickness of 20 nm by an evaporation method using resistance heating.

  Next, NPB was formed to a thickness of 40 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.003 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 10 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Next, a layer containing the composite material of the present invention was formed by co-evaporation of NPB and molybdenum oxide (VI). The film thickness was 20 nm, and the ratio of NPB to molybdenum oxide (VI) was adjusted to be 4: 0.25 by weight.

  After forming a layer containing a light emitting substance formed by laminating a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a layer containing the composite material of the present invention in this way. The second electrode is formed by sputtering or vapor deposition. In this example, the second electrode was formed by depositing aluminum so as to have a thickness of 200 nm on the layer containing the composite material of the present invention using an evaporation method by resistance heating. The light-emitting element manufactured in this example is referred to as a light-emitting element 24 of the present invention.

FIG. 52 shows current-voltage characteristics of the light-emitting element 24 of the present invention. In addition, FIG. 53 shows luminance-voltage characteristics. 52 and 53 that the layer containing the composite material of the present invention functions as a light-emitting element even when it is provided in contact with an electrode functioning as a cathode. Specifically, in the light-emitting element 24 of the present invention, a voltage necessary for obtaining a luminance of 1200 cd / m ² is 7.8 V, and a current flowing at that time is 0.346 mA (current density is 8.66 mA / cm). ² ). At this time, the current efficiency was 14 cd / A, and the power efficiency was 5.6 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 25)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed on the first electrode by co-evaporation of NPB and molybdenum oxide (VI). did. The film thickness was 50 nm, and the weight ratio of NPB and molybdenum oxide (VI) was adjusted to 4: 1. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 10 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Next, a layer containing the composite material of the present invention was formed by co-evaporation of NPB and molybdenum oxide (VI). The film thickness was 10 nm, and the weight ratio of NPB and molybdenum oxide (VI) was adjusted to 4: 1.

  Thus, a layer containing a luminescent substance formed by laminating a layer containing the composite material of the present invention, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a layer containing the composite material of the present invention. After forming the second electrode, a second electrode is formed by a sputtering method or an evaporation method. In this example, the second electrode was formed by depositing aluminum so as to have a thickness of 200 nm on the layer containing the composite material of the present invention using an evaporation method by resistance heating. The light-emitting element manufactured in this example is referred to as a light-emitting element 25 of the present invention.

FIG. 54 shows current-voltage characteristics of the light-emitting element 25 of the present invention. In addition, FIG. 55 shows luminance-voltage characteristics. 54 and 55 that the layer containing the composite material of the present invention functions as a light-emitting element even when it is provided in contact with both electrodes of the light-emitting element. Specifically, in the light-emitting element 25 of the present invention, the voltage necessary for obtaining a luminance of 1000 cd / m ² is 5.4 V, and the current flowing at that time is 0.435 mA (current density is 10.9 mA / cm). ² ). At this time, the current efficiency was 9.3 cd / A, and the power efficiency was 5.4 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 26)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed by co-evaporating DNTPD and molybdenum oxide (VI) on the first electrode. did. The film thickness was 50 nm, and the ratio of DNTPD to molybdenum oxide (VI) was adjusted to be 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 10 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Next, a layer containing the composite material of the present invention was formed by co-evaporation of DNTPD and molybdenum oxide (VI). The film thickness was 20 nm and the weight ratio of DNTPD to molybdenum oxide (VI) was adjusted to 1: 0.5.

  Thus, a layer containing a luminescent substance formed by laminating a layer containing the composite material of the present invention, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a layer containing the composite material of the present invention. After forming the second electrode, a second electrode is formed by a sputtering method or an evaporation method. In this example, the second electrode was formed by depositing aluminum so as to have a thickness of 200 nm on the layer containing the composite material of the present invention using an evaporation method by resistance heating. The light-emitting element manufactured in this example is referred to as a light-emitting element 26 of the present invention.

FIG. 56 shows current-voltage characteristics of the light-emitting element 26 of the present invention. In addition, FIG. 57 shows luminance-voltage characteristics. 56 and 57 that the layer including the composite material of the present invention functions as a light-emitting element even when it is provided in contact with both electrodes of the light-emitting element. Specifically, in the light-emitting element 26 of the present invention, a voltage necessary for obtaining a luminance of 1100 cd / m ² is 5.8 V, and a current that flows at that time is 0.322 mA (current density is 8.05 mA / cm). ² ). At this time, the current efficiency was 13 cd / A, and the power efficiency was 7.3 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 27)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed by co-evaporating PCzPCA1 and molybdenum oxide (VI) on the first electrode. did. The film thickness was 50 nm and the weight ratio of PCzPCA1 to molybdenum oxide (VI) was adjusted to 1: 0.5. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 10 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Next, a layer containing the composite material of the present invention was formed by co-evaporation of PCzPCA1 and molybdenum oxide (VI). The film thickness was 20 nm, and the ratio of PCzPCA1 to molybdenum oxide (VI) was adjusted to 1: 0.5 by weight.

  Thus, a layer containing a luminescent substance formed by laminating a layer containing the composite material of the present invention, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a layer containing the composite material of the present invention. After forming the second electrode, a second electrode is formed by a sputtering method or an evaporation method. In this example, the second electrode was formed by depositing aluminum so as to have a thickness of 200 nm on the layer containing the composite material of the present invention using an evaporation method by resistance heating. The light-emitting element manufactured in this example is referred to as a light-emitting element 27 of the present invention.

FIG. 58 shows current-voltage characteristics of the light-emitting element 27 of the present invention. In addition, FIG. 59 shows luminance-voltage characteristics. 58 and 59 that the layer containing the composite material of the present invention functions as a light-emitting element even when it is provided in contact with both electrodes of the light-emitting element. Specifically, in the light-emitting element 27 of the present invention, the voltage necessary to obtain a luminance of 1200 cd / m ² is 5.6 V, and the current that flows is 0.388 mA (current density is 9.70 mA / cm). ² ). At this time, the current efficiency was 12 cd / A, and the power efficiency was 6.8 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 28)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, a layer containing the composite material of the present invention is formed by co-evaporating PCzPCN1 and molybdenum oxide (VI) on the first electrode. did. The film thickness was 50 nm and the weight ratio of PCzPCN1 to molybdenum oxide (VI) was adjusted to 1: 0.5. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 10 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Next, a layer containing the composite material of the present invention was formed by co-evaporation of PCzPCN1 and molybdenum oxide (VI). The film thickness was 20 nm and the weight ratio of PCzPCN1 to molybdenum oxide (VI) was adjusted to 1: 0.5.

  Thus, a layer containing a luminescent substance formed by laminating a layer containing the composite material of the present invention, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a layer containing the composite material of the present invention. After forming the second electrode, a second electrode is formed by a sputtering method or an evaporation method. In this example, the second electrode was formed by depositing aluminum so as to have a thickness of 200 nm on the layer containing the composite material of the present invention using an evaporation method by resistance heating. The light-emitting element manufactured in this example is referred to as a light-emitting element 28 of the present invention.

FIG. 60 shows current-voltage characteristics of the light-emitting element 28 of the present invention. In addition, FIG. 61 shows luminance-voltage characteristics. 60 and 61 that the layer containing the composite material of the present invention functions as a light-emitting element even when it is provided in contact with both electrodes of the light-emitting element. Specifically, in the light-emitting element 28 of the present invention, the voltage necessary to obtain a luminance of 1200 cd / m ² is 5.6 V, and the current that flows is 0.354 mA (current density is 8.85 mA / cm). ² ). Moreover, the current efficiency at this time was 13 cd / A, and the power efficiency was 7.4 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  In this example, a light-emitting element using the composite material of the present invention is specifically shown.

(Light emitting element 29)
First, indium tin oxide containing silicon oxide was formed over a glass substrate by a sputtering method to form a first electrode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. Thereafter, the inside of the vacuum apparatus is evacuated, the pressure is reduced to about 10 ⁻⁴ Pa, and then a layer containing the composite material of the present invention is formed on the first electrode by co-evaporation of CBP and molybdenum oxide (VI). did. The film thickness was 50 nm, and the ratio of CBP to molybdenum oxide (VI) was adjusted to 1: 0.5 by weight. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm by a vapor deposition method using resistance heating to form a hole transport layer.

  Further, Alq and coumarin 6 were co-evaporated to form a light emitting layer having a thickness of 40 nm on the hole transport layer. Here, the weight ratio of Alq to coumarin 6 was adjusted to be 1: 0.01 (= Alq: coumarin 6). As a result, the coumarin 6 is dispersed in the layer made of Alq.

  Thereafter, using an evaporation method by resistance heating, Alq was deposited on the light emitting layer so as to have a thickness of 10 nm to form an electron transporting layer.

  Further, an electron injection layer having a thickness of 10 nm was formed on the electron transport layer by co-evaporation of Alq and lithium. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Next, a layer containing the composite material of the present invention was formed by co-evaporation of CBP and molybdenum oxide (VI). The film thickness was 20 nm, and the ratio between CBP and molybdenum oxide (VI) was adjusted to 1: 0.5 by weight.

  Thus, a layer containing a luminescent substance formed by laminating a layer containing the composite material of the present invention, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a layer containing the composite material of the present invention. After forming the second electrode, a second electrode is formed by a sputtering method or an evaporation method. In this example, the second electrode was formed by depositing aluminum so as to have a thickness of 200 nm on the layer containing the composite material of the present invention using an evaporation method by resistance heating. The light-emitting element manufactured in this example is referred to as a light-emitting element 29 of the present invention.

FIG. 62 shows current-voltage characteristics of the light-emitting element 29 of the present invention. In addition, FIG. 63 shows luminance-voltage characteristics. 62 and 63 that the layer including the composite material of the present invention functions as a light-emitting element even when it is provided in contact with both electrodes of the light-emitting element. Specifically, in the light-emitting element 29 of the present invention, a voltage necessary to obtain a luminance of 1100 cd / m ² is 5.8 V, and a current flowing at that time is 0.424 mA (current density is 10.6 mA / cm). ² ). Moreover, the current efficiency at this time was 11 cd / A, and the power efficiency was 5.7 lm / W.

Thus, it can be seen that low voltage driving and low power consumption are possible by using the composite material of the present invention for a light emitting element.

  An embodiment of the present invention will be described with reference to FIG.

  An indium tin oxide film was formed over the glass substrate 1300 to form a layer 1301 made of indium tin oxide. A sputtering method was used for film formation. The film thickness was 110 nm.

  Next, on the layer 1301 made of indium tin oxide, NPB and molybdenum oxide are formed by a co-evaporation method so as to have a weight ratio of 1: 0.25 (= NPB: molybdenum oxide). A layer 1302 containing NPB and molybdenum oxide was formed. The film thickness was set to 50 nm. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources.

  Next, NPB was formed by a vapor deposition method over the layer 1302 containing NPB and molybdenum oxide, whereby a layer 1303 made of NPB was formed. The film thickness was 10 nm.

  Next, Alq, rubrene, and DCJTI are deposited on the layer 1303 made of NPB by a co-evaporation method so that the weight ratio is 1: 1: 0.02 (= Alq: rubrene: DCJTI). A layer 1304 containing Alq, rubrene, and DCJTI was formed. The film thickness was 37.5 nm.

  Next, Alq was deposited by a vapor deposition method over the layer 1304 containing Alq, rubrene, and DCJTI, whereby a layer 1305 made of Alq was formed. The film thickness was 27.5 nm.

  Next, BCP and lithium (Li) are deposited on the Alq layer 1305 by a co-evaporation method so as to have a weight ratio of 1: 0.005 (= BCP: lithium). A layer 1306 containing lithium was formed. The film thickness was 10 nm.

  Next, NPB and molybdenum oxide are formed over the layer 1306 containing BCP and lithium by a co-evaporation method so as to have a weight ratio of 1: 0.25 (= NPB: molybdenum oxide). A layer 1307 containing NPB and molybdenum oxide was formed. The film thickness was set to 50 nm.

  Next, NPB was deposited by a vapor deposition method over the layer 1307 containing NPB and molybdenum oxide, whereby a layer 1308 made of NPB was formed. The film thickness was 10 nm.

  Next, Alq and coumarin 6 are formed on the layer 1308 made of NPB by a co-evaporation method so as to have a weight ratio of 1: 0.005 (= Alq: coumarin 6). A layer 1309 containing The film thickness was 37.5 nm.

  Next, Alq was deposited by a vapor deposition method over the layer 1309 containing Alq and coumarin 6 to form a layer 1310 made of Alq. The film thickness was 27.5 nm.

  Next, BCP and lithium (Li) are formed on the Alq layer 1310 by a co-evaporation method so as to have a weight ratio of 1: 0.005 (= BCP: lithium). 1311 containing lithium was formed. The film thickness was 10 nm.

  Next, NPB and molybdenum oxide are formed over the layer 1311 containing BCP and lithium by a co-evaporation method so that the weight ratio is 1: 0.25 (= NPB: molybdenum oxide). A layer 1312 containing NPB and molybdenum oxide was formed. The film thickness was set to 50 nm.

  Next, NPB was formed by a vapor deposition method over the layer 1312 containing NPB and molybdenum oxide, whereby a layer 1313 made of NPB was formed. The film thickness was 10 nm.

  Next, t-BuDNA was deposited on the layer 1313 made of NPB by vapor deposition to form a layer 1314 made of t-BuDNA. The film thickness was 37.5 nm.

  Next, Alq was deposited on the layer 1314 made of t-BuDNA by an evaporation method to form a layer 1315 made of Alq. The film thickness was 27.5 nm.

  Next, BCP and lithium (Li) are formed on the Alq layer 1315 by a co-evaporation method so as to have a weight ratio of 1: 0.005 (= BCP: lithium). A layer 1316 containing lithium was formed. The film thickness was 10 nm.

  Next, aluminum was formed over the layer 1316 containing BCP and lithium by an evaporation method, so that a layer 1317 made of aluminum was formed. The film thickness was set to 200 nm.

  In the light-emitting element manufactured as described above, the layer 1301 made of indium tin oxide functions as an anode, and the layer 1317 made of aluminum functions as a cathode.

  The layer 1302 containing NPB and molybdenum oxide has a function of injecting holes into the layer 1303 made of NPB. The layer 1307 containing NPB and molybdenum oxide has a function of injecting holes into the layer 1308 made of NPB. The layer 1312 containing NPB and molybdenum oxide has a function of injecting holes into the layer 1313 made of NPB.

  The layer 1303 made of NPB has a function of transporting the injected holes to the layer 1304 containing Alq, rubrene, and DCJTI. Further, the layer 1308 made of NPB has a function of transporting the injected holes to the layer 1309 containing Alq and coumarin 6. The layer 1313 made of NPB transports the injected holes to the layer 1314 made of t-BuDNA, and functions as a hole transport layer.

  The layer 1306 containing BCP and lithium has a function of injecting electrons into the layer 1305 made of Alq. The layer 1311 containing BCP and lithium has a function of injecting electrons into the layer 1310 made of Alq. The layer 1316 containing BCP and lithium has a function of injecting electrons into the layer 1315 made of Alq.

  The layer 1305 made of Alq has a function of transporting injected electrons to the layer 1304 containing Alq, rubrene, and DCJTI. The layer 1310 made of Alq has a function of transporting injected electrons to the layer 1309 containing Alq and coumarin 6. The layer 1315 made of Alq transports electrons injected from the layer 1316 containing BCP and lithium to the layer 1314 made of t-BuDNA, and functions as an electron transport layer.

  In the layers 1302, 1307, and 1312 containing NPB and molybdenum oxide, molybdenum oxide functions as an electron acceptor. Further, in the layers 1306, 1311, and 1316 containing BCP and lithium, lithium functions as an electron donor.

  In the light-emitting element as described above, when a voltage is applied to the layer 1301 made of indium tin oxide and the layer 1317 made of aluminum, a current flows between the layer 1301 made of indium tin oxide and the layer 1317 made of aluminum. . Thus, the layer 1304 containing Alq, rubrene, and DCJTI exhibits light emission having a peak in the wavelength region of 600 to 680 nm, and the layer 1309 containing Alq and coumarin 6 exhibits light emission having a peak in the wavelength region of 500 to 550 nm. , T-BuDNA layer 1314 emits light having a peak in the wavelength range of 420 nm to 480 nm. These light emissions are emitted to the outside through the layer 1301 made of indium tin oxide. As can be seen from the above description, in the light-emitting element of this example, the layer 1317 made of aluminum has a layer that emits light at a wavelength shorter than 420 nm to 480 nm than a layer that emits light at a longer wavelength from 600 nm to 680 nm. It is provided so as to be close to a layer with high reflectivity. Therefore, interference between the emitted light and the reflected light generated by reflecting the emitted light by the aluminum layer 1317 can be reduced.

FIG. 65 shows an emission spectrum when the light-emitting element manufactured in this example emits light. In FIG. 65, the horizontal axis represents wavelength (nm) and the vertical axis represents emission intensity (arbitrary unit). FIG. 65 shows that the light-emitting element manufactured in this example emits light in the wavelength region of 450 nm to 620 nm. The CIE chromaticity coordinate at 0.979 mA (current density was 24.5 mA / cm ² ) was (x, y) = (0.33, 0.46), and the luminance was 1900 cd / m ² . This indicates that the light-emitting element manufactured in this example exhibits white light emission.

  By manufacturing a tandem light-emitting element as described above, a light-emitting element with high current efficiency can be obtained. Further, as in this embodiment, white light emission having a broad spectrum in the visible light region can be obtained. Further, a light-emitting element which is less deteriorated due to moisture mixing can be obtained by using a material having low water absorption such as molybdenum oxide as in this embodiment. Furthermore, since the light emitting element of this embodiment has little interference between the emitted light and the reflected light, it is easy to adjust the chromaticity of the emitted light.

  In this example, the current-voltage characteristics of the layer containing the composite material of the present invention were measured.

(Element 1)

  First, indium tin oxide containing silicon oxide (ITSO) was formed over a glass substrate by a sputtering method to form a first electrode. The electrode size was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

  Thereafter, the inside of the vacuum apparatus was evacuated and decompressed, and then a layer made of the composite material of the present invention was formed by co-evaporating NPB and molybdenum oxide (VI) on the first electrode. The film thickness was 200 nm. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber. The ratio of NPB to molybdenum oxide (VI) was adjusted to be 4: 1 by weight.

An element 1 was manufactured by forming a second electrode by depositing aluminum (Al) on the layer containing the composite material of the present invention by vapor deposition by resistance heating.
(Element 2)

  First, indium tin oxide containing silicon oxide (ITSO) was formed over a glass substrate by a sputtering method to form a first electrode. The electrode size was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

  Thereafter, the inside of the vacuum apparatus was evacuated and decompressed, and then a layer of the composite material of the present invention was formed by co-evaporating DNTPD and molybdenum oxide (VI) on the first electrode. The film thickness was 200 nm. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber. The ratio of DNTPD to molybdenum oxide (VI) was adjusted to be 4: 2 by weight.

An element 2 was fabricated by forming a second electrode by depositing aluminum (Al) on the layer containing the composite material of the present invention by vapor deposition by resistance heating.

(Element 3)

  First, indium tin oxide containing silicon oxide (ITSO) was formed over a glass substrate by a sputtering method to form a first electrode. The electrode size was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

  Thereafter, the inside of the vacuum apparatus was evacuated and decompressed, and then PCzPCN1 and molybdenum oxide (VI) were co-evaporated on the first electrode to form a layer made of the composite material of the present invention. The film thickness was 200 nm. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber. The ratio of PCzPCN1 to molybdenum oxide (VI) was adjusted to be 4: 2 by weight.

An element 3 was fabricated by forming a second electrode by depositing aluminum (Al) on the layer containing the composite material of the present invention by vapor deposition using resistance heating.
(Element 4)

  First, indium tin oxide containing silicon oxide (ITSO) was formed over a glass substrate by a sputtering method to form a first electrode. The electrode size was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

  Thereafter, the inside of the vacuum apparatus was evacuated and decompressed, and t-BuDNA and molybdenum oxide (VI) were co-evaporated on the first electrode to form a layer made of the composite material of the present invention. The film thickness was 200 nm. Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in one processing chamber. The ratio of t-BuDNA to molybdenum (VI) oxide was adjusted to be 4: 2 by weight.

An element 4 was fabricated by forming a second electrode by depositing aluminum (Al) on the layer containing the composite material of the present invention by vapor deposition using resistance heating.

(Comparative element 5)

  First, indium tin oxide containing silicon oxide (ITSO) was formed over a glass substrate by a sputtering method to form a first electrode. The electrode size was 2 mm × 2 mm.

  Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

  Thereafter, the inside of the vacuum apparatus was evacuated and decompressed, and a layer made of t-BuDNA was formed on the first electrode. The film thickness was 200 nm.

  On the layer made of t-BuDNA, a comparative electrode 5 was fabricated by forming a second electrode by depositing aluminum (Al) using a resistance heating vapor deposition method.

The current-voltage characteristics were measured by the two-terminal method with ITSO as the anode and Al as the cathode as the forward direction, and ITSO as the cathode and Al as the anode as the reverse direction.

  The results of current-voltage characteristics at 25 ° C. for elements 1 to 3 are shown in FIG. It can be seen that in elements 1 to 3, current flows in both the forward and reverse directions, and the current-voltage characteristics are symmetric about the origin. It is considered that the interface between the electrode and the layer containing the composite material of the present invention is not a Schottky contact because it has symmetry despite using electrodes different from ITSO and Al.

  In addition, FIG. 68 shows the results of current-voltage characteristics of the element 4 and the comparison element 5. Note that FIG. 68B is an enlarged view of a portion where the voltage value in FIG. 68A is −2V to 2V. It can be seen that the element 4 having the layer having the composite material of the present invention is easier to inject carriers from the electrode and has higher conductivity than the comparative element 5 having the layer made of only the organic compound. Further, similarly to the elements 1 to 3, the element 4 also has a current flowing in both the forward direction and the reverse direction, and the current-voltage characteristics are symmetric about the origin. Therefore, it is considered that the interface between the electrode and the layer containing the composite material of the present invention is not a Schottky contact because it has symmetry despite using electrodes different from ITSO and Al.

  In this example, the ionization potential of each substance was calculated by converting the value of the oxidation peak potential of each substance measured in Example 1 into electron volts [eV].

First, the number of electron volts corresponding to the potential energy of the reference electrode potential used in Example 1 was calculated. That is, the ionization potential of the Ag / Ag ⁺ electrode was calculated. The redox potential of ferrocene in methanol is +0.610 [V vs. SHE] (reference: Christian R. Goldsmith et al., J. Am. Chem. Soc., Vol. 124, No. 1, 83-96, 2002). The standard hydrogen electrode potential is known to be 4.44 eV (reference: Toshihiro Onishi and Tamami Koyama, polymer EL material (Kyoritsu Shuppan), p. 64-67). From these facts, it can be seen that the potential energy of the oxidation-reduction potential of ferrocene in methanol is 5.05 eV.

On the other hand, when the oxidation-reduction potential of ferrocene in methanol was determined using the reference electrode used in Example 1, it was +0.20 V [vs. Ag / Ag ⁺ ]. Therefore, when the potential energy of the reference electrode used in Example 1 is E _R [eV], E _R + 0.20 = 0.05 [eV]. Therefore, the potential _{E R} of the reference electrode used in Example 1 was calculated to be 5.05-0.20 = 4.85 [eV].

Here, the ionization potential I _p of each substance in the DMF solution can be calculated by I _p = E _R + E _pa = 4.85 + E _pa [eV]. Therefore, using the results of Table 1, the ionization potential I _p of each substance is as shown in Table 2 below. Note that no ionization potential was observed in the range of 4.85 [eV] to 6.35 [eV] for BCP, OXD-7, and TPBi used in the comparative measurement examples. Therefore, the ionization potential of the organic compound that can be used for the composite material of the present invention is 4.8 [eV] to 6.4 [eV]. Moreover, from the result of Table 2, Preferably it is 5.0 [eV]-6.0 [eV].

  In this example, the half-wave potential was calculated from the value of the oxidation peak potential of each substance measured in Example 1.

In Example 1, the oxidation peak potential (E _pa ) of an oxidation reaction in which a neutral organic compound emits electrons to become a cation was measured. The reduction reaction in which the cation receives an electron and returns to the neutral organic compound. By using the value of the reduction peak potential (E _pc ), the potential of the electron transfer equilibrium state (ie, the formula potential) can be obtained. It can be considered that the formula potential is almost equal to an intermediate value (that is, a half-wave potential) between the oxidation peak potential (E _pa ) and the reduction peak potential (E _pc ), and is not affected by temperature or scanning speed. Table 3 shows the reduction peak potential (E _pc ) of each substance measured in Example 1 and the half-wave potential (E _1/2 ) converted from the measured value of Example 1. For the calculation, the measured value of Example 1 (3 digits after the decimal point) was used, and in Table 3, the calculated result was expressed as 2 significant digits after the decimal point. In Table 3, half-wave potential [vs. The value of [Fc / Fc ⁺ ] was determined by conversion in the same manner as in the case of the oxidation peak potential (E _pa ).

From Table 3, the half-wave potential [V vs. V] of the organic compound that can be used for the composite material of the present invention is shown. Ag / Ag ⁺ ] is 0.2 to 0.9 [V vs. It can be seen that [Ag / Ag ⁺ ]. In addition, the half-wave potential [vs. Fc / Fc ⁺ ] is 0.1 to 0.8 [vs. It can be seen that Fc / Fc ⁺ ].

4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B each illustrate an electronic device using a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B each illustrate an electronic device using a light-emitting device of the present invention. The figure which shows the CV measurement result of ferrocene. The figure which shows the CV measurement result of NPB. The figure which shows the CV measurement result of DNTPD. The figure which shows the CV measurement result of PCzPCA1. The figure which shows the CV measurement result of PCzPCN1. The figure which shows the CV measurement result of CBP. The figure which shows the CV measurement result of t-BuDNA. The figure which shows the CV measurement result of DPVBi. The figure which shows the CV measurement result of Alq. The figure which shows the CV measurement result of BCP. The figure which shows the CV measurement result of OXD-7. The figure which shows the CV measurement result of TPBi. FIG. 6 shows current-voltage characteristics of a light-emitting element and a comparative light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element and the comparative light-emitting element of the present invention. FIG. 6 shows current-voltage characteristics of a light-emitting element and a comparative light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element and the comparative light-emitting element of the present invention. FIG. 6 shows current-voltage characteristics of a light-emitting element and a comparative light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element and the comparative light-emitting element of the present invention. FIG. 6 shows current-voltage characteristics of a light-emitting element and a comparative light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element and the comparative light-emitting element of the present invention. FIG. 6 shows current-voltage characteristics of a light-emitting element and a comparative light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element and the comparative light-emitting element of the present invention. FIG. 6 shows current-voltage characteristics of a light-emitting element and a comparative light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element and the comparative light-emitting element of the present invention. FIG. 6 shows current-voltage characteristics of a light-emitting element and a comparative light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element and the comparative light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 13 shows current-voltage characteristics of comparative light-emitting elements. FIG. 14 shows luminance-voltage characteristics of comparative light-emitting elements. FIG. 13 shows current-voltage characteristics of comparative light-emitting elements. FIG. 14 shows luminance-voltage characteristics of comparative light-emitting elements. FIG. 13 shows current-voltage characteristics of comparative light-emitting elements. FIG. 14 shows luminance-voltage characteristics of comparative light-emitting elements. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. FIG. 4 shows current-voltage characteristics of the light-emitting element of the present invention. FIG. 5 shows luminance-voltage characteristics of the light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. FIG. 9 shows an emission spectrum of the light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. FIG. 26 shows current-voltage characteristics of the element manufactured in Example 20. FIG. 26 shows current-voltage characteristics of the element manufactured in Example 20.

Explanation of symbols

101 substrate 102 first electrode 103 first layer 104 second layer 105 third layer 106 fourth layer 107 second electrode 200 substrate 201 first electrode 202 second electrode 211 first layer 212 2nd layer 213 3rd layer 214 4th layer 302 1st electrode 303 1st layer 304 2nd layer 305 3rd layer 306 4th layer 307 2nd electrode 400 substrate 401 1st Electrode 402 Second electrode 411 First layer 412 Second layer 413 Third layer 501 First electrode 502 Second electrode 511 First light emitting unit 512 Second light emitting unit 513 Charge generation layer 601 Source side Drive circuit 602 Pixel portion 603 Gate side drive circuit 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 609 FPC (flexible printed circuit)
610 Element substrate 611 TFT for switching
612 Current control TFT
613 First electrode 614 Insulator 616 Layer containing light emitting substance 617 Second electrode 618 Light emitting element 623 n-channel TFT
624 p-channel TFT
901 Case 902 Liquid crystal layer 903 Backlight 904 Case 905 Driver IC
906 Terminal 951 Substrate 952 Electrode 953 Insulating layer 954 Partition layer 955 Layer 995 containing luminescent material Electrode 1101 First electrode 1102 Second electrode 1111 First layer 1112 Second layer 1113 Third layer 1114 Fourth layer 1300 Substrate 1301 Layer 1302 made of indium tin oxide 1302 Layer made of NPB and molybdenum oxide 1303 Layer made of NPB 1304 Layer made of Alq, rubrene and DCJTI 1305 Layer made of Alq 1306 Layer made of BCP and lithium 1307 NPB and Layer 1308 comprising molybdenum oxide 1308 Layer comprising NPB 1309 Layer comprising Alq and coumarin 6 1310 Layer comprising Alq 1311 Layer comprising BCP and lithium 1312 Layer comprising NPB and molybdenum oxide 1313 Layer comprising NPB 1314 t- BuDNA Layer 1315 Alq layer 1316 BCP and lithium layer 1317 Aluminum layer 9101 Housing 9102 Support base 9103 Display unit 9104 Speaker unit 9105 Video input terminal 9201 Body 9202 Housing 9203 Display unit 9204 Keyboard 9205 External connection Port 9206 Pointing mouse 9401 Main body 9402 Case 9403 Display unit 9404 Audio input unit 9405 Audio output unit 9405 Operation key 9407 External connection port 9408 Antenna 9501 Main unit 9502 Display unit 9503 Case 9504 External connection port 9505 Remote control receiving unit 9506 Image receiving unit 9507 Battery 9508 Voice input unit 9509 Operation key 9510 Eyepiece unit

Claims (23)

An organic compound having an oxidation peak potential with respect to an Ag / Ag ⁺ electrode in dimethylformamide (DMF) at room temperature in a range of 0 V to 1.5 V (vs. Ag / Ag ⁺ ) and a metal oxide A composite material characterized by An organic compound having an oxidation peak potential with respect to an Ag / Ag ⁺ electrode in dimethylformamide (DMF) at room temperature within a range of 0.2 V to 1.1 V (vs. Ag / Ag ⁺ ), and a metal oxide A composite material characterized by comprising. An organic compound having an oxidation peak potential with respect to a redox potential of ferrocene in dimethylformamide (DMF) at room temperature within a range of 0 V to 1.5 V (vs. Fc / Fc ⁺ ) and a metal oxide A composite material characterized by An organic compound having an oxidation peak potential with respect to a redox potential of ferrocene in dimethylformamide (DMF) at room temperature in a range of 0.1 V to 1.0 V (vs. Fc / Fc ⁺ ), and a metal oxide A composite material characterized by comprising. A composite material comprising an organic compound having an ionization potential of 4.8 eV or more and 6.4 eV or less in a dimethylformamide (DMF) solution at room temperature and a metal oxide. A composite material comprising an organic compound having an ionization potential of 5.0 eV or more and 6.0 eV or less in a dimethylformamide (DMF) solution at room temperature and a metal oxide. The composite material according to claim 1, wherein the organic compound is an aromatic amine compound. The composite material according to any one of claims 1 to 6, wherein the organic compound is a carbazole derivative. The composite material according to any one of claims 1 to 6, wherein the organic compound is an aromatic hydrocarbon. The composite material according to any one of claims 1 to 6, wherein the organic compound is a metal complex. 7. The composite material according to claim 1, wherein the organic compound is an organometallic complex. The composite material according to claim 1, wherein the organic compound is a polymer compound. 13. The composite material according to claim 1, wherein the metal oxide exhibits an electron accepting property with respect to the organic compound. The composite material according to any one of claims 1 to 12, wherein the metal oxide is a transition metal oxide. 13. The composite material according to claim 1, wherein the metal oxide is an oxide of a metal belonging to Group 4 to Group 8 of the periodic table. The metal oxide according to any one of claims 1 to 12, wherein the metal oxide is one or more of vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide. A composite material characterized by A light-emitting material having a layer containing a light-emitting substance between a pair of electrodes, wherein the layer containing the light-emitting substance has a layer containing the composite material according to any one of claims 1 to 16. element. The light-emitting element according to claim 17, wherein the layer including the composite material is provided so as to be in contact with an electrode functioning as an anode of the pair of electrodes. The light-emitting element according to claim 17, wherein the layer including the composite material is provided so as to be in contact with an electrode functioning as a cathode of the pair of electrodes. 18. The light-emitting element according to claim 17, wherein the layer including the composite material is provided one by one so as to be in contact with each of the pair of electrodes. Between the pair of electrodes, n (n is an arbitrary natural number greater than or equal to 2) layers including a light emitting substance,
The layer according to any one of claims 1 to 16, wherein the layer includes a light-emitting substance in an m-th layer (m is an arbitrary natural number, 1 ≦ m <n) and a layer containing a light-emitting substance in the (m + 1) th layer. A light emitting element comprising a layer containing the composite material according to claim 1. A light-emitting device comprising: the light-emitting element according to any one of claims 17 to 21; Having a display,
An electronic apparatus comprising: the light emitting element according to any one of claims 17 to 21; and a control unit that controls light emission of the light emitting element.

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