JP2008273861A - Anthracene derivative, organic electroluminescent element, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anthracene derivative suitably used as a green-colored light-emitting material in an organic electroluminescent element, and also constituting the excellent organic electroluminescent element having a high light-emitting efficiency and excellent in life characteristics. <P>SOLUTION: This anthracene derivative is expressed by general formula (1). As a specific example, the compound wherein Ar<SB>1</SB>to Ar<SB>4</SB>are phenyl groups, and A and B are hydrogen atoms can be cited. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an anthracene derivative suitably used as an organic material for an organic electroluminescent element, an organic electroluminescent element using the anthracene derivative, and a display device using the element.

  In recent years, a display device using an organic electroluminescent element (so-called organic EL element) has attracted attention as a flat panel display with low power consumption, high response speed, and no viewing angle dependency.

  In general, an organic electroluminescent element has an organic layer sandwiched between a cathode and an anode, and holes and electrons injected from the anode and the cathode, respectively, recombine in the organic layer. Emits light. As the organic layer, for example, a structure in which a hole transport layer, a light emitting layer containing a light emitting material, and an electron transport layer are laminated in order from the anode side, and further, a light emitting material is included in the electron transport layer so as to have an electron transporting property. A structure having a light emitting layer has been developed.

  By the way, the organic electroluminescent element having the above configuration is a self-luminous element. When a display device is configured using the organic electroluminescent element, it is most important to extend the life of the organic electroluminescent element and to ensure the reliability. It becomes one of the important issues. For this reason, research on organic materials constituting organic electroluminescent elements is being pursued.

  In particular, regarding a light emitting material that controls light emission, various studies have been made on red, green, and blue light emitting materials corresponding to the three primary colors. In addition to the indices specific to compounds such as heat resistance and fluorescence quantum yield, the physical properties required of luminescent materials are required to be materials that can solve element characteristics such as color purity and luminance in devices, as well as luminescence lifetime. .

  For example, green light-emitting materials have been actively developed since the past, and typical examples thereof include aluminum quinolinol complexes such as Alq3 and further coumarin derivatives (see Patent Document 1 below). In addition, anthracene derivatives substituted at the 9 and 10 positions with a diarylamino group (see Patent Document 6 and Non-Patent Document 1 below) are known.

  In recent years, light-emitting materials having anthracene as a main skeleton have attracted attention as light-emitting materials other than green light-emitting materials as chemical means for improving the light-emitting efficiency of organic materials. For example, it has been reported that an amino group is introduced into an anthracene skeleton with a specific aromatic hydrocarbon group interposed therebetween to provide a material exhibiting high blue light emission (Patent Documents 4 and 5 below).

JP 2000-182772 A JP-A-8-53397 Japanese Patent Laid-Open No. 2006-199628 Japanese Patent Laid-Open No. 2006-199629 “Chemistry of Materials”, (USA), 2002, Volume 14, p. 3598-3963

  However, an aluminum quinolinol complex typified by Alq3 emits good green light, but a single light emitting layer has low efficiency and a short light emission lifetime. For this reason, aluminum quinolinol complexes are now used for hosts in light-emitting systems having a host / dopant binary configuration rather than forming a light-emitting layer alone.

  In addition, coumarin derivatives are good green dopant materials, but in general, concentration quenching occurs unless the doping concentration is less than 1% with respect to the host, and high concentration doping cannot be performed. For this reason, the process control is a difficult problem because it is necessary to control at a low doping concentration.

  Furthermore, anthracene derivatives that have attracted attention as light-emitting materials in addition to green light-emitting materials as a means to improve the light-emitting efficiency of organic materials have been used mainly for molecular design as blue materials. Is only a derivative in which the 9,10-position of anthracene is directly substituted with an arylamino group, and when this is used as a light emitting material to form a green organic electroluminescent device, it can obtain a high luminance life although high efficiency is obtained. could not.

  Accordingly, an object of the present invention is to provide an anthracene derivative that can be used as an excellent green light-emitting material, and to provide an organic electroluminescent element and a display device using the anthracene derivative.

The present invention for achieving such an object is an anthracene derivative suitably used as an organic material constituting an organic electroluminescent element, and is represented by the following general formula (1).

Ar _{1 to} Ar ₄ in the general formula (1) each independently represent a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms.

  A and B in the general formula (1) are each independently hydrogen, halogen, hydroxyl group, a substituted or unsubstituted carbonyl group having 20 or less carbon atoms, or a substituted or unsubstituted carbonyl ester group having 20 or less carbon atoms. Substituted or unsubstituted alkyl group having 20 or less carbon atoms, substituted or unsubstituted alkenyl group having 20 or less carbon atoms, substituted or unsubstituted alkoxyl group having 20 or less carbon atoms, cyano group, nitro group, 30 or less carbon atoms A substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms.

  Furthermore, this invention is also an organic electroluminescent element using the anthracene derivative shown by the said General formula (1). This organic electroluminescent element includes an organic layer having at least a light emitting layer between an anode and a cathode, and an anthracene derivative having the above-described structure is used for the organic layer. In particular, this anthracene derivative is preferably used as a material constituting the light emitting layer.

  The anthracene derivative represented by the general formula (1) as described above is characterized in that a specific diarylamino group is provided at positions 2 and 6 of the anthracene skeleton. In an organic electroluminescence device using such an anthracene derivative as a light emitting material, it was confirmed that green light emission was obtained. In addition, since the anthracene derivative represented by the general formula (1) is also an amine compound, the charge transportability is excellent and good light emission efficiency is obtained. Accordingly, it was confirmed that the luminance and the light emission lifetime were excellent as compared with the light emitting material having an aryl group bonded to the 9th and 10th positions of the anthracene skeleton.

  The present invention is also a display device including the organic electroluminescent element having the above-described configuration, and particularly preferably, the organic electroluminescent element having the above-described configuration is provided as a green light-emitting element in some of the plurality of pixels. Suppose that

  As described above, by forming the organic layer of the organic electroluminescent element using the anthracene derivative represented by the general formula (1) of the present invention, it becomes possible to improve the light emission efficiency and the light emission lifetime, In particular, the light emission efficiency can be improved in the green light emission region. In addition, since a display device is configured using an organic electroluminescent element capable of emitting green light with high luminous efficiency and excellent lifetime characteristics as a green light emitting element, it is combined with other red light emitting elements and blue light emitting elements. As a result, full color display with high color reproducibility and reliability becomes possible.

  Hereinafter, embodiments of the present invention will be described in the order of an anthracene derivative, an organic electroluminescent element using the anthracene derivative, and a display device.

≪Anthracene derivative≫
A more specific example of the anthracene derivative of the present invention represented by the following general formula (1) will be described.

  The anthracene derivative represented by the general formula (1) is an anthracene derivative that is preferably used in the organic layer of the organic electroluminescence device, and is independently bonded to amino groups at the 2nd and 6th positions of the anthracene skeleton.

And Ar < ₁ > -Ar < ₄ > in General formula (1) shows an aryl group or a heterocyclic group each independently. These aryl groups or heterocyclic groups have 30 or less carbon atoms and may be further substituted with other groups or may be unsubstituted.

  A and B in the general formula (1) are each independently hydrogen, halogen, hydroxyl group, carbonyl group, carbonyl ester group, alkyl group, alkenyl group, alkoxyl group, cyano group, nitro group, silyl group, aryl A group or a heterocyclic group; Among these, the carbonyl group, the carbonyl ester group, the alkyl group, the alkenyl group, and the alkoxyl group have 20 or less carbon atoms, and may be further substituted or unsubstituted. In addition, the silyl group, aryl group, and heterocyclic group have 30 or less carbon atoms, and may be further substituted or unsubstituted.

  The carbonyl group includes an aldehyde group, a ketone group, and a carboxyl group. The alkyl group includes a linear alkyl group, a branched alkyl group, and a cyclic alkyl group.

The aryl group constituting Ar _{1 to} Ar ₄ is preferably composed of 30 or less carbon atoms. For example, a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a fluorenyl group, a 1-anthryl group, 2- Anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group, 1- Pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 1-chrycenyl group, 6-chrycenyl group, 2-fluoranthenyl group, 3-fluoranthenyl group, 2-biphenylyl group, 3-biphenylyl group, 4 -Biphenylyl group, o-tolyl group, m-tolyl group, p-tolyl group, pt-butylphenyl group and the like can be mentioned.

Ar _{1 to} Ar ₄ may be the same as Ar ₁ and Ar _3, and Ar ₂ and Ar ₄ may be the same when considering the simplicity in synthesizing the anthracene derivative of the general formula (1). preferable.

The heterocyclic group constituting Ar _{1 to} Ar ₄ is preferably one having 30 or less carbon atoms, for example, 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl. Group, 3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl Group, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group Group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzo Ranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group 7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolyl group 1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group Nansridinyl group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinyl group, etc. are mentioned.

Among the groups shown as Ar _{1 to} Ar ₄ and A and B, the substituents for the group which may further have a substituent include a halogen, a hydroxyl group, a carbonyl group, and a carbonyl ester group. , A cyclic alkyl group, an alkenyl group, an alkoxy group, an aryl group, a heterocyclic group, a cyano group, a nitro group, or a silyl group.

  Tables 1-1 and 1-2 below show exemplary structures of the above general formula (1), but the anthracene derivatives of the present invention are limited to the structures illustrated here as long as they are included in the above-described range. It is not a thing.

  The anthracene derivative of the present invention shown as an example above can be synthesized by various methods, and examples include the following methods a) to c).

a) A synthesis method in which a halogenated anthracene is coupled by a Grignard reaction using magnesium.
b) A method in which a halogenated anthracene is coupled by the Ullmann reaction in the presence of a copper catalyst.
c) A method of synthesizing boronic acid or boronic esterified anthracene and halogenated anthracene by a transition metal catalyst typified by palladium (so-called Suzuki coupling reaction).

  The anthracene derivative of the present invention is used as a material constituting the organic layer of the organic electroluminescent element, and it is preferable to increase the purity before being subjected to the manufacturing process of the organic electroluminescent element. It should be 95% or more, more preferably 99% or more. As a method for obtaining such a high-purity anthracene derivative, in addition to a recrystallization method, a reprecipitation method, or a column purification using silica or alumina, which is a purification after the synthesis of an anthracene derivative, a known method by sublimation purification or zone melt method is used. High purity methods can be used.

  Further, by repeating these purification methods or combining different purification methods, the mixture of unreacted anthracene derivatives, reaction by-products, catalyst residues, or residual solvents in the present invention is reduced, and more It is possible to obtain an organic electroluminescent element having excellent device characteristics.

  Further, this compound is composed of the organic light-emitting material, particularly by suppressing the deterioration reaction from the oxidation and decomposition by taking the following storage methods a) to c) from the external factors such as light and oxygen. In the organic electroluminescence device, not only provides superior light emission characteristics, but also exhibits an effect in reducing the load on the manufacturing apparatus.

a) After synthesizing the organic light emitting material, immediately leave it in a cool place. The storage temperature is preferably in the range of -100 ° C to 100 ° C, more preferably in the temperature range of -50 ° C to 50 ° C.
b) After synthesizing the organic light emitting material, immediately store it in a light-shielding container.
c) After synthesizing the organic light emitting material, the synthesized organic light emitting material is stored in an inert gas atmosphere such as nitrogen, carbon dioxide, argon or the like.

  The anthracene derivative of the present invention exemplified by the general formula (1) and the structural formulas (1) to (27) having the configuration described above has a configuration in which an arylamino group is provided at positions 2 and 6 of the anthracene skeleton.

  Thereby, in the organic electroluminescent element described below using this anthracene derivative as a light emitting material, green light emission having high color purity peculiar to anthracene can be obtained. In addition, the molecular weight ensures a sufficient amount of heat resistance, ensuring good thermal properties, excellent external force and thermal durability, and stable voltage fluctuation. It has sex.

  In addition, since the anthracene derivative having the above structure is also an amine compound having an anthracene skeleton, it has excellent charge transportability and good light emission efficiency can be obtained.

  Furthermore, the anthracene derivative according to the present invention has both electron transport performance and hole transport performance. For this reason, as will be described in detail below, among the organic layers of the organic electroluminescent device, it can be used as a light emitting layer also serving as an electron transporting layer or as a light emitting layer also serving as a hole transporting layer. . It is also possible to adopt a structure in which the anthracene derivative according to the present invention is sandwiched between the electron transport layer and the hole transport layer as a light emitting layer.

≪Organic electroluminescent element≫
FIG. 1 is a cross-sectional view schematically showing an organic electroluminescent element of the present invention. The organic electroluminescent element 11 shown in this figure is formed by laminating an anode 13, an organic layer 14, and a cathode 15 in this order on a substrate 12. Among these, the organic layer 14 is formed by laminating, for example, a hole injection layer 14a, a hole transport layer 14b, a light emitting layer 14c, and an electron transport layer 14d in this order from the anode 13 side.

  Next, the detailed structure of each part which comprises this organic electroluminescent element 11 is demonstrated in an order from the board | substrate 12 side.

<Board>
The substrate 12 is a support on which the organic electroluminescent elements 11 are arranged and formed on one main surface side, and may be a known substrate, for example, a film or sheet made of quartz, glass, metal foil, or resin. Of these, quartz and glass are preferable. In the case of resin, methacrylic resin represented by polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), poly Examples thereof include polyesters such as butylene naphthalate (PBN), polycarbonate resins, and the like, but it is necessary to perform a laminated structure and surface treatment that suppress water permeability and gas permeability.

<Anode>
The anode 13 has a large work function from the vacuum level of the electrode material in order to inject holes efficiently, for example, aluminum (Al), chromium (Cr), molybdenum (Mo), tungsten (W), copper (Cu), silver (Ag), gold (Au) metals and alloys thereof, oxides of these metals and alloys, or alloys of tin oxide (SnO2) and antimony (Sb), ITO (indium tin) Oxide), InZnO (indium zinc oxide), alloys of zinc oxide (ZnO) and aluminum (Al), and oxides of these metals and alloys are used alone or in a mixed state.

  Further, the anode 13 may have a laminated structure of a first layer having excellent light reflectivity and a second layer having a light transmittance and a high work function provided thereon.

  The first layer is made of an alloy containing aluminum as a main component. The subcomponent may include at least one element having a work function relatively smaller than that of aluminum as a main component. As such a subcomponent, a lanthanoid series element is preferable. Although the work function of the lanthanoid series elements is not large, the inclusion of these elements improves the stability of the anode and also satisfies the hole injection property of the anode. In addition to lanthanoid series elements, elements such as silicon (Si) and copper (Cu) may be included as subcomponents.

  The content of subcomponents in the aluminum alloy layer constituting the first layer is preferably about 10 wt% or less in total for Nd, Ni, Ti, or the like that stabilizes aluminum. Thereby, while maintaining the reflectance in the aluminum alloy layer, the aluminum alloy layer can be stably maintained in the manufacturing process of the organic electroluminescent element, and further, processing accuracy and chemical stability can be obtained. In addition, the conductivity of the anode 13 and the adhesion to the substrate 12 can be improved.

  Examples of the second layer include a layer made of at least one of an oxide of an aluminum alloy, an oxide of molybdenum, an oxide of zirconium, an oxide of chromium, and an oxide of tantalum. Here, for example, when the second layer is an oxide layer of an aluminum alloy containing a lanthanoid element as a subcomponent (including a natural oxide film), the oxide of the lanthanoid element has a high transmittance, so that this is included. The transmittance of the second layer is improved. For this reason, it is possible to maintain a high reflectance on the surface of the first layer. Further, the second layer may be a transparent conductive layer such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). These conductive layers can improve the electron injection characteristics of the anode 13.

  Further, the anode 13 may be provided with a conductive layer for improving the adhesion between the anode 13 and the substrate 12 on the side in contact with the substrate 11. Examples of such a conductive layer include transparent conductive layers such as ITO and IZO.

  When the driving method of the display device configured using the organic electroluminescent element 11 is an active matrix method, the anode 13 is patterned for each pixel and connected to a driving thin film transistor provided on the substrate 12. It is provided in the state that was done. Further, in this case, although not shown here, an insulating film is provided on the anode 13, and the surface of the anode 13 of each pixel is exposed from the opening of the insulating film. And

<Hole injection layer / hole transport layer>
The hole injection layer 14a and the hole transport layer 14b are for increasing the efficiency of hole injection into the light emitting layer 14c. Examples of the material for the hole injection layer 14a or the hole transport layer 14b include benzine, styrylamine, triphenylamine, porphyrin, triphenylene, azatriphenylene, tetracyanoquinodimethane, triazole, imidazole, and oxadiazole. , Polyarylalkanes, phenylenediamines, arylamines, oxazoles, anthracenes, fluorenones, hydrazones, stilbenes or their derivatives, or heterocyclic conjugated systems such as polysilane compounds, vinylcarbazole compounds, thiophene compounds or aniline compounds Monomers, oligomers or polymers of can be used.

  Further, as specific materials for the hole injection layer 14a or the hole transport layer 14b, α-naphthylphenylphenylenediamine, porphyrin, metal tetraphenylporphyrin, metal naphthalocyanine, hexacyanoazatriphenylene, 7,7,8 , 8-tetracyanoquinodimethane (TCNQ), 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (F4-TCNQ), tetracyano 4,4,4-tris (3-methylphenylphenylamino) triphenylamine, N, N, N ′, N′-tetrakis (p-tolyl) p-phenylenediamine, N, N, N ′, N′-tetraphenyl-4,4 ′ -Diaminobiphenyl, N-phenylcarbazole, 4-di-p-tolylaminostilbene, poly (paraphenylene vinyle ), Poly (thiophene vinylene), poly (2,2'-thienylpyrrole), and including without being limited thereto.

<Light emitting layer>
The light emitting layer 14c is a region in which holes and electrons are injected from each of the anode 13 and the cathode 15 when a voltage is applied by the anode 13 and the cathode 15, and these are recombined. An organic light emitting material such as a molecular fluorescent dye, a fluorescent polymer, or a metal complex is used. In the present embodiment, the light-emitting layer 14c contains the anthracene derivatives represented by the general formula (1) and the structural formulas (1) to (27).

  These anthracene derivatives are added as a light emitting guest material in the light emitting layer 14c. In this case, the addition amount of the anthracene derivative in the light emitting layer 14c is 1% by volume to 99% by volume, preferably 1% by volume to 50% by volume, and more preferably 20% by volume or less.

  The host material when an anthracene derivative is used as a guest material is an aromatic hydrocarbon compound composed of a phenylene nucleus, a naphthalene nucleus, an anthracene nucleus, a pyrene nucleus, a naphthacene nucleus, a chrysene nucleus, or a perylene nucleus. Specifically, 9,10-diphenylanthracene, 9,10-di (1-naphthyl) anthracene, 9,10-di (2-naphthyl) anthracene, 1,6-diphenylpyrene, 1,6-di (1-naphthyl) ) Pyrene, 1,6-di (2-naphthyl), 1,8-diphenylpyrene, 1,8-di (1-naphthyl) pyrene, 1,8-di (2-naphthyl) pyrene, rubrene, 6,12 -Diphenylchrysene, 6,12-di (1-naphthyl) chrysene, 6,12-di (2-naphthyl) chrysene and the like can be suitably used.

  A small amount of other guest material may be added to the light emitting layer 14c for the purpose of controlling the emission spectrum of the light emitting layer 14c. As such other guest materials, organic substances such as naphthalene derivatives, anthracene derivatives, pyrene derivatives, naphthacene derivatives, berylene derivatives, coumarin derivatives, and pyran dyes are used, and among these aromatic tertiary amine compounds. Are preferably used.

  In the above description, the case where the light emitting layer 14c is configured using the anthracene derivative of the present invention as a guest material has been described. However, in the case where the light emitting layer 14c is formed using the anthracene derivative of the present invention, the light emitting layer 14c made of a simple substance of the anthracene derivative of the present invention may be formed. Moreover, you may use the anthracene derivative of this invention as a host material. In this case, the guest material is configured using a material having high luminous efficiency, for example, an organic light emitting material such as a low molecular fluorescent dye, a fluorescent polymer, or a metal complex.

  Examples of the light-emitting guest material when the anthracene derivative of the present invention is used as a host material include anthracene, naphthalene, indene, phenanthrene, pyrene, naphthacene, triphenylene, anthracene, perylene, picene, fluoranthene, acephenanthrylene, Pentaphen, pentacene, coronene, butadiene, coumarin, acridine, stilbene, or derivatives thereof, tris (8-quinolinolato) aluminum complex, bis (benzoquinolinolato) beryllium complex, tri (dibenzoylmethyl) phenanthroline europium complex ditoluyl vinyl Biphenyl can be used.

<Electron transport layer>
The electron transport layer 14d is for transporting electrons injected from the cathode 15 to the light emitting layer 14c. Examples of the material for the electron transport layer 14d include quinoline, perylene, bisstyryl, pyrazine, triazole, oxazole, oxadiazole, fluorenone, and derivatives thereof. Specific examples include tris (8-hydroxyquinoline) aluminum (abbreviated as Alq3), anthracene, naphthalene, phenanthrene, pyrene, anthracene, perylene, butadiene, coumarin, acridine, stilbene, or derivatives thereof.

  As mentioned above, each said layers 14a-14d which comprise the organic layer 14 can be formed by methods, such as a vacuum evaporation method and a spin coat method, for example. However, in particular, when a small amount of a guest material is added to the light emitting layer 14c in addition to the anthracene derivative of the present invention for the purpose of controlling the emission spectrum of the light emitting layer 14c, the formation of the light emitting layer 14c Co-evaporation of guest materials.

  The organic layer 14 is not limited to such a layer structure, and has at least the light emitting layer 14c and the hole transport layer 14a or the hole injection layer 14b between the anode 13 and the light emitting layer 14c. If it is a structure, the laminated structure as needed can be selected. The light emitting layer 14c may be provided in the organic electroluminescence device 11 as a hole transporting light emitting layer, an electron transporting light emitting layer, or a charge transporting light emitting layer.

  Furthermore, each layer constituting the organic layer 14, for example, the hole injection layer 14a, the hole transport layer 14b, the light emitting layer 14c, and the electron transport layer 14d may have a laminated structure including a plurality of layers.

<Cathode>
The cathode 15 has, for example, a two-layer structure in which a first layer 15a and a second layer 15b are sequentially stacked from the organic layer 14 side.

  The first layer 15a is made of a material having a small work function and good light transmittance. As such a material, for example, lithium oxide (Li2O) which is an oxide of lithium (Li), cesium oxide (Cs2O) which is an oxide of cesium (Cs), or a mixture of these oxides is used. Can do. Further, the first layer 15a is not limited to such a material. For example, alkaline earth metals such as calcium (Ca) and barium (Ba), alkali metals such as lithium and cesium, and indium ( In), magnesium (Mg), or other low work function metals, or oxides of these metals may be used alone or as a mixture or alloy of these metals and oxides with increased stability. .

  The second layer 15b is constituted by a thin film using a light-transmitting layer such as MgAg. The second layer 15b may be a mixed layer containing an organic light emitting material such as an aluminum quinoline complex, a styrylamine derivative, or a phthalocyanine derivative. In this case, a layer having optical transparency such as MgAg may be additionally provided as the third layer.

  Each layer constituting the cathode 15 can be formed by a technique such as vacuum deposition, sputtering, or plasma CVD. Further, when the driving method of the display device configured using the organic electroluminescent element 11 is an active matrix method, the cathode 15 is formed by an organic layer 14 and the above-described insulating film, which is not shown here, by an anode. 13 is formed in a solid film shape on the substrate 12 in an insulated state and used as a common electrode of each pixel.

  Needless to say, the cathode 15 is not limited to the laminated structure as described above, and an optimum combination and laminated structure may be adopted according to the structure of the device to be manufactured. For example, the configuration of the cathode 15 of the above embodiment includes an inorganic layer (first layer 15a) that promotes functional separation of each electrode layer, that is, electron injection into the organic layer 14, and an inorganic layer (second layer 15b) that controls the electrode. Is a laminated structure in which and are separated. However, the inorganic layer that promotes electron injection into the organic layer 14 may also serve as the inorganic layer that controls the electrode, and these layers may be configured as a single layer structure. Moreover, it is good also as a laminated structure which formed transparent electrodes, such as ITO, on this single layer structure.

  The current applied to the organic electroluminescent element 11 having the above-described configuration is usually a direct current, but a pulse current or an alternating current may be used. The current value and the voltage value are not particularly limited as long as the element is not destroyed. However, considering the power consumption and life of the organic electroluminescent element, it is desirable to efficiently emit light with as little electric energy as possible.

  Moreover, in the organic electroluminescent light emitting element 11 shown in FIG. 1, the structure which takes out light from upper and lower sides by using the transparent electrode which consists of ITO etc. for the anode 13 may be sufficient.

  When the organic electroluminescent element 11 has a cavity structure, the total film thickness of the organic layer 14 and the electrode layer (cathode 15 in the present embodiment) made of a transparent material or a semi-transparent material is the emission wavelength. And is set to a value derived from the multiple interference calculation. When the display device using the organic electroluminescent element 11 has a so-called TAC (Top Emitting Adoptive Current drive) structure in which a top emission type organic electroluminescent element is provided on a substrate on which a TFT is formed, By positively using the cavity structure, it is possible to improve the light extraction efficiency to the outside and control the emission spectrum.

  According to the organic electroluminescent element 11 having the configuration described above, the light emitting layer 14c of the organic layer 14 is configured using the anthracene derivative described using the general formula (1). Thereby, the durability and stability of the organic layer 14 can be improved, and high-purity green electroluminescence based on the high fluorescence characteristic of anthracene can be obtained. As a result, as will be described in the following examples, an organic electroluminescent device having high luminous efficiency and excellent lifetime characteristics can be configured.

  In the above embodiment, the anthracene derivative of the present invention is used as a constituent material of the light emitting layer 14c (including an electron transporting light emitting layer, a hole transporting light emitting layer, and a charge transporting light emitting layer). Only explained that. However, the anthracene derivative of the present invention is excellent in durability as described in the embodiment of the anthracene derivative, and since it is an amine compound, it has an electron transport property and a hole transport property. The anthracene derivative of the present invention can also be used as a material constituting a layer other than the light emitting layer 14c, such as the electron transport layer 14d, the hole transport layer 14b, and the hole injection layer 14a. It becomes possible to improve durability.

  Further, the organic electroluminescent device of the present invention is not limited to the top emission type, and is not limited to the application to the TAC structure using the same, and the organic layer having at least a light emitting layer is sandwiched between the anode and the cathode. The present invention can be widely applied to the configuration. Therefore, in order from the substrate side, the cathode, the organic layer, and the anode are laminated in sequence, and the electrode located on the substrate side (lower electrode as the cathode or anode) is made of a transparent material and located on the opposite side of the substrate It is also applicable to a so-called bottom emission type organic electroluminescence device in which light (external electrode as a cathode or anode) is made of a reflective material so that light is extracted only from the lower electrode side. Even if it is such a structure, it is possible to acquire the same effect by using the organic luminescent material demonstrated using General formula (1) for an organic layer.

  Furthermore, the organic electroluminescent element of the present invention may be an element formed by a pair of electrodes (anode and cathode) and an organic layer sandwiched between the electrodes. For this reason, it is not limited to what comprised only a pair of electrode and organic layer, and other components (for example, an inorganic compound layer and an inorganic component) coexist in the range which does not impair the effect of this invention. Is not to be excluded.

≪Display device≫
FIG. 2 is a schematic circuit configuration diagram for explaining a configuration example of a display device using the organic electroluminescence element, a so-called organic EL display device. Here, an embodiment in which the present invention is applied to an active matrix display device 10 using an organic electroluminescent element 11 will be described.

  As shown in this figure, a display area 12 a and its peripheral area 12 b are set on the substrate 12 of the display device 20. In the display area 12a, a plurality of scanning lines 21 and a plurality of signal lines 23 are wired vertically and horizontally, and configured as a pixel array section in which one pixel is provided corresponding to each intersection. In the peripheral region 12b, a scanning line driving circuit 25 that scans and drives the scanning line 23 and a signal line driving circuit 27 that supplies a video signal (that is, an input signal) corresponding to luminance information to the signal line 23 are arranged. Yes.

  A pixel circuit provided at each intersection of the scanning line 21 and the signal line 23 includes, for example, a switching thin film transistor Tr 1, a driving thin film transistor Tr 2, a storage capacitor Cs, and the organic electroluminescence element 11. Then, the video signal written from the signal line 23 via the switching thin film transistor Tr1 is held in the holding capacitor Cs by driving by the scanning line driving circuit 25, and a current corresponding to the held signal amount is supplied to the driving thin film transistor. The organic electroluminescent element 11 is supplied from Tr2 to the organic electroluminescent element 11, and the organic electroluminescent element 11 emits light with a luminance corresponding to the current value. The driving thin film transistor Tr2 and the storage capacitor Cs are connected to a common power supply line (Vcc) 29.

  Note that the configuration of the pixel circuit as described above is merely an example, and a capacitor element may be provided in the pixel circuit as necessary, or a plurality of transistors may be provided to configure the pixel circuit. Further, a necessary drive circuit is added to the peripheral region 12b according to the change of the pixel circuit.

  In the display device 20 of the present invention, the organic electroluminescent element 11 of the present invention described with reference to FIG. 1 is provided as a green (G) organic electroluminescent element in one pixel, and further the blue (B) organic A pixel provided with an electroluminescent element and a pixel provided with a red (R) organic electroluminescent element are each formed as one sub-pixel. A plurality of pixels each having a set of three sub-pixels are arranged on the substrate 12 so that full color display is performed.

  Further, in the display device 20 including the organic electroluminescent element 11 having such a configuration, a treatment such as forming a sealing film for preventing deterioration of the organic electroluminescent element 11 due to moisture or oxygen in the atmosphere. It is preferable to apply.

  For example, as shown in FIG. 3, it may be a module having a sealed configuration. In this case, for example, a sealing portion 31 is provided so as to surround the display region 12a which is a pixel array portion, and the sealing portion 31 is used as an adhesive and is attached to a facing portion (sealing substrate 32) such as transparent glass. Applicable display module. The transparent sealing substrate 32 may be provided with a color filter, a protective film, a light shielding film, and the like.

  The substrate 12 as a display module in which the display area 12a as described above is formed may be provided with a flexible printed circuit board 33 for inputting / outputting signals to / from the display area 12a (pixel array portion) from the outside. good.

  In the display device 20 having the above-described configuration, the display device is configured using an organic electroluminescence element capable of emitting green light with high light emission efficiency and excellent lifetime characteristics as described above. In combination with a red organic electroluminescent element, full color display with high color reproducibility and reliability becomes possible.

≪Application example≫
The display device according to the present invention described above is input to various electronic devices shown in FIGS. 4 to 8, such as digital cameras, notebook personal computers, portable terminal devices such as mobile phones, and video cameras. The video signal generated or the video signal generated in the electronic device can be applied to a display device of an electronic device in any field for displaying as an image or a video. An example of an electronic device to which the present invention is applied will be described below.

  FIG. 4 is a perspective view showing a television to which the present invention is applied. The television according to this application example includes a video display screen unit 101 including a front panel 102, a filter glass 103, and the like, and is created by using the display device according to the present invention as the video display screen unit 101.

  5A and 5B are diagrams showing a digital camera to which the present invention is applied. FIG. 5A is a perspective view seen from the front side, and FIG. 5B is a perspective view seen from the back side. The digital camera according to this application example includes a light emitting unit 111 for flash, a display unit 112, a menu switch 113, a shutter button 114, and the like, and is manufactured by using the display device according to the present invention as the display unit 112.

  FIG. 6 is a perspective view showing a notebook personal computer to which the present invention is applied. A notebook personal computer according to this application example includes a main body 121 including a keyboard 122 that is operated when characters and the like are input, a display unit 123 that displays an image, and the like. It is produced by using.

  FIG. 7 is a perspective view showing a video camera to which the present invention is applied. The video camera according to this application example includes a main body 131, a lens 132 for shooting an object on a side facing forward, a start / stop switch 133 at the time of shooting, a display unit 134, and the like. It is manufactured by using such a display device.

  FIG. 8 is a view showing a mobile terminal device to which the present invention is applied, for example, a mobile phone, in which (A) is a front view in an opened state, (B) is a side view thereof, and (C) is in a closed state. (D) is a left side view, (E) is a right side view, (F) is a top view, and (G) is a bottom view. The mobile phone according to this application example includes an upper housing 141, a lower housing 142, a connecting portion (here, a hinge portion) 143, a display 144, a sub display 145, a picture light 146, a camera 147, and the like. And the sub display 145 is manufactured by using the display device according to the present invention.

  Next, a synthesis example of the anthracene derivative of the present invention and an example of the organic electroluminescence device of the present invention using this anthracene derivative will be specifically described. Here, first, synthesis examples 1 to 4 of the anthracene derivative of the present invention will be described, and then a procedure for producing an organic electroluminescent element using these anthracene derivatives and an organic electroluminescent element of a comparative example, and further, an evaluation result thereof Will be explained.

<Synthesis Example 1>
According to the following reaction formula (1), 2,6-bis (N, N′-diphenylamino) anthracene [Structural Formula (1) in Table 1-1], which is one of the anthracene derivatives of the present invention, is converted into a compound ( As 1), it was synthesized as follows.

  A 500 ml three-necked flask equipped with a mechanical stirrer was thoroughly replaced with nitrogen, and then N, N′-diphenylamine (17.0 g, 100 mmol), 2,6-dibromoanthracene (16.8 g, 50 mmol), sodium-tert -Butoxide (5 g, 50 mmol) was dissolved in 100 mL toluene.

  The mixed solution was bubbled with nitrogen for 10 minutes to sufficiently exhaust the dissolved oxygen in the solution. Subsequently, palladium acetate (1.1 g, 5 mmol) was added all at once as a palladium catalyst component, and tri (t-butylphosphine) (4.0 g, 20 mmol) dissolved in 20 ml of toluene was added dropwise with stirring. After the addition was completed, the temperature was raised and the reaction was carried out at the reflux temperature for 6 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, the insoluble part was separated with celite, the organic layer was washed 5 times with water, and the organic layer was dried over magnesium sulfate. The solution was concentrated and then passed through a silica column with a mixed solvent of hexane / toluene to obtain 12 g (yield 46%) of a yellow solid.

  The obtained solid was measured by 1H-NMR, 13C-NMR, and FD-MS, and confirmed to be 2,6-bis (N, N′-diphenylamino) anthracene, which was the target product.

<Synthesis Example 2>
This is one of the anthracene derivatives of the present invention, which is carried out under the same reaction conditions as in Synthesis Example 1 except that bis (4-isopropylphenyl) amine is used as a raw material instead of N, N′-diphenylamine in Synthesis Example 1. Compound (2) was obtained. The obtained solid was measured by 1H-NMR, 13C-NMR, and FD-MS to confirm that it was the target product.

<Synthesis Example 3>
This is one of the anthracene derivatives of the present invention, which is carried out under the same reaction conditions as in Synthesis Example 1 except that N-phenylnaphthalen-1-amine is used as a raw material instead of N, N′-diphenylamine in Synthesis Example 1. Compound (3) [Structural Formula (19) in Table 1-2] was obtained. The obtained solid was measured by 1H-NMR, 13C-NMR, and FD-MS to confirm that it was the target product.

<Synthesis Example 4>
This is one of the anthracene derivatives of the present invention, which is carried out under the same reaction conditions as in Synthesis Example 1 except that N-phenylnaphthalen-2-amine is used in place of N, N′-diphenylamine as a raw material in Synthesis Example 1. Compound (4) [Structural Formula (22) in Table 1-2] was obtained. The obtained solid was measured by 1H-NMR, 13C-NMR, and FD-MS to confirm that it was the target product.

  As shown in Synthesis Examples 1 to 4 above, it was confirmed that the anthracene derivative of the present invention can be synthesized from a simple route.

<Preparation of organic electroluminescent element: Examples 1 to 4>
Using the compounds (1) to (4) obtained in Synthesis Example 1, organic electroluminescent elements of Examples 1 to 4 (see FIG. 1) were produced as follows.

  First, an organic electroluminescence device for top emission, in which a 12.5 nm ITO transparent electrode is laminated on an Ag alloy (reflection layer) having a film thickness of 190 nm as an anode 13 on a substrate 12 made of a glass plate of 30 mm × 30 mm. A cell was prepared.

Next, as the hole injection layer 14a, a film made of the following m-MTDATA was formed by vapor deposition at a film thickness of 20 nm (deposition rate: 0.2 to 0.4 nm / sec.).

Next, as the hole transport layer 14b, a film made of the following α-NPD was deposited at a thickness of 20 nm (deposition rate: 0.2 to 0.4 nm / sec.).

  Next, as the light emitting layer 14c, each compound (1)-(4) obtained like the said synthesis example was vapor-deposited with a film thickness of 20 nm, respectively.

Next, as the electron transport layer 14d, the following Alq3 (8-hydroxyquinoline aluminum) was deposited to a thickness of 20 nm.

After the above, a film made of Li ₂ O was deposited as the first layer 15a of the cathode 15 with a film thickness of about 0.3 nm (deposition rate 0.01 nm / sec.).

  Finally, as the second layer 15b of the cathode 15, a film made of MgAg was deposited to a thickness of about 10 nm.

  As described above, organic electroluminescent elements of Examples 1 to 4 using the compounds (1) to (4) were produced.

<Comparative example>
Instead of the compound used to form the light-emitting layer 14c in Examples 1 to 4, the following is reported in US Chemistry of Materials, 2002, Vol. 14, pages 3958 to 3963 (Non-patent Document 1). Organic electroluminescent elements were produced in exactly the same manner as in Examples 1 to 4, except that 9,10-diphenylaminoanthracene was used.

<Evaluation result 1>
The organic electroluminescent elements of Examples 1 to 4 and Comparative Example produced as described above were subjected to direct current voltage driving, and the driving voltage, light emission luminance, light emission color, and light emission lifetime up to half the luminance were measured. The results are shown in Table 2. Note that the light emission lifetime is a value when driving at a constant current with an initial luminance of 300 cd / m ² .

  As shown in Table 2, the organic electroluminescent elements of Examples 1 to 4 in which the light emitting layer 14c is configured using the compounds (1) to (4) which are anthracene derivatives of the present invention are green as in the comparative example. Color development was confirmed. Moreover, the light emission luminance and the light emission lifetime in the organic electroluminescent elements of Examples 1 to 4 were both higher than those of the comparative examples, and in particular, the light emission lifetime was twice or more.

  From this result, it was confirmed that the light emission luminance and the light emission lifetime of the organic electroluminescence device are increased by forming the light emitting layer using the anthracene derivative of the present invention.

<Preparation of organic electroluminescent element: Examples 5 to 8>
An organic electroluminescent element was prepared in the same manner as in Example 3 except that the compound (3) synthesized in Synthesis Example 3 was used as a guest material in the formation of the light emitting layer 14c in the production procedure described in Example 3. Produced.

  Here, in the formation of the light emitting layer 14c, the following 9,10-di (2-naphthyl) anthracene (ADN) is used as a host material, and the compound (3) synthesized in Synthesis Example 3 is used as a guest material, 4%, A film doped with a guest material was deposited by a relative film thickness ratio of 10%, 30%, and 60%.

<Evaluation result 2>
The organic electroluminescent elements of Examples 5 to 8 produced as described above were subjected to direct current voltage driving, and the driving voltage, light emission luminance, light emission color, and light emission lifetime up to half the luminance were measured. The results are shown in Table 3. In Table 3, the evaluation results of Example 3 are also shown. Note that the light emission lifetime is a value when driving at a constant current with an initial luminance of 300 cd / m ² .

  As shown in Table 3, when the light emitting layer 14c is formed using the compound (3) which is an anthracene derivative of the present invention, the compound (3) is doped as a guest material rather than being used at a composition ratio of 100%. It can be seen that the light emission luminance and the light emission lifetime are further improved by using the compound.

In particular, when the doping concentration is 30% by volume (ratio of film thickness) or less, the emission luminance is 2100 cd / m ² or more at a voltage of about 5 V, and the emission lifetime is 2100 hours or more.

  From this result, when the light emitting layer is formed using the anthracene derivative of the present invention, the light emission luminance and light emission lifetime of the organic electroluminescence device can be improved by setting the dopant concentration to 60% by volume or less, more preferably 30% by volume or less. It was confirmed that it can be effectively increased.

It is sectional drawing of the organic electroluminescent element of embodiment. It is a figure which shows an example of the circuit structure of the display apparatus of embodiment. It is a block diagram which shows the module-shaped display apparatus of the sealed structure to which this invention is applied. It is a perspective view which shows the television to which this invention is applied. It is a figure which shows the digital camera to which this invention is applied, (A) is the perspective view seen from the front side, (B) is the perspective view seen from the back side. 1 is a perspective view showing a notebook personal computer to which the present invention is applied. It is a perspective view which shows the video camera to which this invention is applied. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the portable terminal device to which this invention is applied, for example, a mobile telephone, (A) is the front view in the open state, (B) is the side view, (C) is the front view in the closed state , (D) is a left side view, (E) is a right side view, (F) is a top view, and (G) is a bottom view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Organic electroluminescent element, 12 ... Board | substrate, 13 ... Anode, 14 ... Organic layer, 14c ... Light emitting layer, 15 ... Cathode, 20 ... Display apparatus

Claims (8)

Anthracene derivatives represented by the following general formula (1).

[However, in the general formula (1),
Ar _{1 to} Ar ₄ each independently represent a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms.
A and B are each independently hydrogen, halogen, hydroxyl group, substituted or unsubstituted carbonyl group having 20 or less carbon atoms, substituted or unsubstituted carbonyl ester group having 20 or less carbon atoms, and having 20 or less carbon atoms. Substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group having 20 or less carbon atoms, substituted or unsubstituted alkoxyl group having 20 or less carbon atoms, cyano group, nitro group, substituted or unsubstituted having 30 or less carbon atoms A silyl group, a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms is shown. ] The anthracene derivative according to claim 1, wherein
Ar _{1 to} Ar ₄ in the general formula (1) have a phenyl nucleus, a biphenyl nucleus, or a naphthyl nucleus. The anthracene derivative according to claim 1, wherein
An anthracene derivative characterized in that Ar ₁ and Ar ₃ in the general formula (1) are the same, and Ar ₂ and Ar ₄ are the same. In an organic electroluminescent device comprising an organic layer having at least a light emitting layer between an anode and a cathode,
The organic layer is composed of an anthracene derivative represented by the following general formula (1).

[However, in the general formula (1),
Ar _{1 to} Ar ₄ each independently represent a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms.
A and B are each independently hydrogen, halogen, hydroxyl group, substituted or unsubstituted carbonyl group having 20 or less carbon atoms, substituted or unsubstituted carbonyl ester group having 20 or less carbon atoms, and having 20 or less carbon atoms. Substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group having 20 or less carbon atoms, substituted or unsubstituted alkoxyl group having 20 or less carbon atoms, cyano group, nitro group, substituted or unsubstituted having 30 or less carbon atoms A silyl group, a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms is shown. ] The organic electroluminescent device according to claim 4, wherein
The said anthracene derivative is used as a material which comprises the said light emitting layer. The organic electroluminescent element characterized by the above-mentioned. The organic electroluminescent device according to claim 5, wherein
The light-emitting layer contains at least one kind of the anthracene derivative as a light-emitting guest material. In a display device in which a plurality of organic electroluminescent elements formed by sandwiching an organic layer having at least a light emitting layer between an anode and a cathode are formed on a substrate,
In at least one of the organic electroluminescent elements, the organic layer is configured using an anthracene derivative represented by the following general formula (1).

[However, in the general formula (1),
Ar _{1 to} Ar ₄ each independently represent a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms.
A and B are each independently hydrogen, halogen, hydroxyl group, substituted or unsubstituted carbonyl group having 20 or less carbon atoms, substituted or unsubstituted carbonyl ester group having 20 or less carbon atoms, and having 20 or less carbon atoms. Substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group having 20 or less carbon atoms, substituted or unsubstituted alkoxyl group having 20 or less carbon atoms, cyano group, nitro group, substituted or unsubstituted having 30 or less carbon atoms A silyl group, a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms is shown. ] The display device according to claim 7, wherein
An organic electroluminescent element in which the organic layer is formed using the anthracene derivative is provided as a green light emitting element in a part of a plurality of pixels.

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