JP6421211B2 - Organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescence element.

  Organic electroluminescence devices using organic substances (hereinafter sometimes abbreviated as “organic EL devices”) are promising for use as solid light-emitting, inexpensive, large-area full-color display devices, and many developments have been made. ing. In general, an organic EL element is composed of a light emitting layer and a pair of counter electrodes sandwiching the light emitting layer. When an electric field is applied between both electrodes, electrons are injected from the cathode side and holes are injected from the anode side. Further, the electrons recombine with holes in the light emitting layer to generate an excited state, and energy is emitted as light when the excited state returns to the ground state.

  Conventional organic EL elements have a higher driving voltage and lower light emission luminance and light emission efficiency than inorganic light-emitting diodes. Moreover, characteristic deterioration was also remarkable. Although recent organic EL elements are gradually improved, further reduction in voltage, higher luminous efficiency, longer life, improved color reproducibility, and the like are required.

  The organic EL element described in Patent Document 1 includes a first light emitting layer and a second light emitting layer, and the first host material contained in the first light emitting layer is an amine derivative and is contained in the second light emitting layer. The second host material is any of a monoazine derivative, a diazine derivative, and a triazine derivative. In the organic EL element described in Patent Document 1, the two light emitting layers emit light in a well-balanced manner, and as a result, the organic EL element is driven at a low voltage and has good emission efficiency.

International Publication No. 2011/148909

  However, the organic EL element described in Patent Document 1 causes the two light-emitting layers to emit light in a well-balanced manner. The intensity of light emission of the two light-emitting layers is relatively adjusted so that the entire light-emitting color is desired. Adjustment to chromaticity is not described. As a method for changing the chromaticity, it is conceivable to change the film thickness of each light emitting layer or to change the dopant concentration of each light emitting layer. However, for example, when the thickness of the light emitting layer is reduced, there is a problem that the lifetime of the organic EL element is shortened. On the other hand, when the thickness of the light emitting layer is increased, there is a problem that the drive voltage of the organic EL element is increased. For example, if the dopant concentration is increased, concentration quenching may occur, and the light emission efficiency may be reduced.

  An object of this invention is to provide the organic electroluminescent element which is easy to adjust chromaticity when it makes it light-emit.

The organic electroluminescence device of the present invention is an organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The first host material is an amine derivative;
The second host material is a compound containing a nitrogen-containing six-membered heterocyclic group,
The first host material, the second host material, and the third host material satisfy the following formula (N-4).
μ (e) _H2 ≧ μ (e) _H3 > μ (e) _H1 (N-4)
However, in the formula (N-4), μ (e) _H1 is the electron mobility of the first host material, μ (e) _H2 is the electron mobility of the second host material, and μ (e ) _H3 is the electron mobility of the third host material.
The organic electroluminescence device of the present invention is an organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The second host material is a compound containing a nitrogen-containing six-membered heterocyclic group,
The third host material is a compound having a skeleton represented by the following formula (130),
The first host material, the second host material, and the third host material satisfy the following formula (N-4).
μ (e) _H2 ≧ μ (e) _H3 > μ (e) _H1 (N-4)
However, in the formula (N-4), μ (e) _H1 is the electron mobility of the first host material, μ (e) _H2 is the electron mobility of the second host material, and μ (e ) _H3 is the electron mobility of the third host material.

(In the formula (130), X represents an oxygen atom, a sulfur atom, or NR. ¹³⁰ Or CR ¹³¹ R ¹³² Represents.
R ¹³⁰ ~ R ¹³² Are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. R ¹³¹ And R ¹³² May be bonded to each other to form a ring structure. )
Moreover, in the organic electroluminescent element of the present invention, it is preferable that the third host material is represented by the following formula (16).

(In the formula (16),
L ¹⁰ Is a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, or these groups having 2 to 5 each other. Represents a group linked together.
X ¹ , X ² Independently represent a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.
Y ¹ ~ Y ⁴ Each independently represents a hydrogen atom, a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon. A haloalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 10 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 30 carbon atoms, a substituted or unsubstituted ring carbon number having 6 to 6 carbon atoms 30 aromatic hydrocarbon groups or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. Adjacent Y ¹ ~ Y ⁴ They may form a bond with each other to form a ring structure.
p and q are 4.
r and s are 3.
B ¹ And B ² Each independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. )
In the organic electroluminescence device of the present invention, the second host material is preferably a compound having a carbazole skeleton.
In the organic electroluminescence element of the present invention, the second host material is preferably represented by any one of the following formulas (21) to (26).

(In formulas (21) to (26), R _{101 to} R ₁₀₅ each independently represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, or an alkyl group.)
In the organic electroluminescence device of the present invention, the substituent in the case of “substituted or unsubstituted” is an aromatic hydrocarbon group, a heterocyclic group, a linear or branched alkyl group, a cycloalkyl group, a halogenated group. Alkyl group, alkenyl group, alkynyl group, alkylsilyl group, arylsilyl group, alkoxy group, halogenated alkoxy group, aralkyl group, aryloxy group, halogen atom, cyano group, hydroxyl group, nitro group, or carboxy group Is preferred.
In the organic electroluminescence device of the present invention, it is preferable that the first dopant material exhibits an emission peak of 570 nm or more, and the second dopant material exhibits an emission peak of less than 570 nm .
In the organic electroluminescence element of the present invention, it is preferable that the first light emitting layer is provided on the anode side with respect to the second light emitting layer .
The organic electroluminescence device of the present invention is an organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The first host material is an amine derivative;
The first host material, the second host material, and the third host material satisfy the formula (N-4).
The organic electroluminescence device of the present invention is an organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The third host material is a compound having a skeleton represented by the formula (130),
The first host material, the second host material, and the third host material satisfy the formula (N-4).

  The present invention can provide an organic electroluminescence device that easily adjusts chromaticity when light is emitted.

The figure which shows schematic structure of an example of the organic EL element in 1st embodiment which concerns on this invention. The figure which shows schematic structure of an example of the organic EL element in 2nd embodiment which concerns on this invention. The figure which shows schematic structure of an example of the organic EL element in 3rd embodiment which concerns on this invention. The figure which shows schematic structure of the organic EL element which concerns on the modification of this invention.

(Element structure of organic EL element)
Hereinafter, the element configuration of the organic EL element according to the present invention will be described.
The organic EL device of the present invention includes an organic compound layer between an anode and a cathode. This organic compound layer has a plurality of layers composed of an organic compound. The organic compound layer may contain an inorganic compound.
The organic compound layer has a plurality of light emitting layers including at least a first light emitting layer and a second light emitting layer. The third light emitting layer may be adjacent to the second light emitting layer.
In addition, you may have a layer employ | adopted by well-known organic EL elements, such as a positive hole injection layer, a positive hole transport layer, an electron injection layer, an electron carrying layer, a positive hole barrier layer, an electronic barrier layer, and a space layer. .

As an element structure of the organic EL element of the present invention,
(A) Anode / first light emitting layer / second light emitting layer / cathode (b) anode / hole injection / transport layer / first light emitting layer / second light emitting layer / cathode (c) anode / first light emitting layer / first Two light emitting layer / electron injection / transport layer / cathode (d) anode / hole injection / transport layer / first light emitting layer / second light emitting layer / electron injection / transport layer / cathode (e) anode / hole injection / transport Layer / first light emitting layer / barrier layer / second light emitting layer / electron injection / transport layer / cathode (f) anode / first light emitting layer / second light emitting layer / third light emitting layer / cathode (g) anode / hole Injection / transport layer / first emission layer / second emission layer / third emission layer / cathode (h) anode / third emission layer / first emission layer / second emission layer / electron injection / transport layer / cathode (i ) Anode / hole injection / transport layer / first light emitting layer / second light emitting layer / third light emitting layer / electron injection / transport layer / cathode (j) anode / hole injection / transport layer / first light emitting layer / first Two light emitting layer / barrier layer / electron injection Transporting layer / cathode (k) anode / hole injecting and transporting layer / first emitting layer / second emitting layer / barrier layer / third emitting layer / electron injecting · transporting layer / cathode structures, and the like.

Of the above, the configurations of (d), (e), (i), and (k) are preferably used, but of course not limited thereto.
The “light emitting layer” is an organic layer that generally employs a doping system and includes a host material and a dopant material. The host material generally promotes recombination of electrons and holes, and transmits excitation energy generated by the recombination to the dopant material. As the dopant material, a compound having a high quantum yield is preferred, and the dopant material that has received excitation energy from the host material exhibits high light emission performance.
The “hole injection / transport layer” means “at least one of a hole injection layer and a hole transport layer”, and “electron injection / transport layer” means “electron injection layer and electron transport layer”. It means “at least one of the layers”. Here, when it has a positive hole injection layer and a positive hole transport layer, it is preferable that the positive hole injection layer is provided in the anode side. Moreover, when it has an electron injection layer and an electron carrying layer, it is preferable that the electron injection layer is provided in the cathode side.
In the present invention, the term “electron transport layer” refers to an organic layer having the highest electron mobility among the electron injection transport layers existing between the light emitting layer and the cathode. When the electron injecting and transporting layer is composed of one layer, the layer is an electron transporting layer. Further, in the phosphorescent device, as shown in the configuration (i), a barrier layer that does not necessarily have high electron mobility is used between the light emitting layer and the electron transport layer in order to prevent diffusion of excitation energy generated in the light emitting layer. The organic layer adjacent to the light emitting layer does not necessarily correspond to the electron transport layer.

[First embodiment]
In FIG. 1, schematic structure of an example of the organic EL element in 1st embodiment of this invention is shown.
The organic EL element 1 includes a translucent substrate 2, an anode 3, a cathode 4, and a light emitting unit 5 disposed between the anode 3 and the cathode 4, and the light emitting unit 5 is in order from the anode 3 side. A hole transport layer 6, a first light emitting layer 51, a second light emitting layer 52, and an electron transport layer 7 are provided.

(Light emitting layer)
In the organic EL element 1 of the present embodiment, the first light emitting layer 51 includes a first host material and a first dopant material. The second light emitting layer 52 includes a second host material, a third host material, and a second dopant material.

<First light emitting layer>
[First host material]
The first host material is preferably selected from monoamine compounds, diamine compounds, triamine compounds, tetramine compounds, amine derivatives such as amine compounds substituted with a carbazole group, and compounds having a condensed aromatic ring. Among these, an amine compound substituted with a carbazole group or a compound having a condensed aromatic ring is preferable.
As the amine derivative, compounds represented by the following formulas (1) to (7) are preferable.

In formula (1), Ar _{1 to} Ar ₄ are each a substituted or unsubstituted aromatic hydrocarbon group having 6 to 40 ring carbon atoms or a substituted or unsubstituted aromatic group having 5 to 40 ring atoms. It is a heterocyclic group.
Examples of the aromatic hydrocarbon group include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a 9,9′-dimethylfluorene group, and a phenanthrene group.
Aromatic heterocyclic groups include thiophene monovalent residues, benzothiophene monovalent residues, dibenzothiophene monovalent residues, furan monovalent residues, benzofuran monovalent residues, dibenzofuran monovalent residues. Group and the like.
In formulas (2) to (7), Ar _{5 to} Ar ₁₆ are each a substituted or unsubstituted aromatic hydrocarbon group having 6 to 40 ring carbon atoms or a substituted or unsubstituted ring forming atom number of 5 to 40. An aromatic heterocyclic group. An aromatic amino group as a substituent, an aromatic hydrocarbon group having 8 to 40 ring carbon atoms which may further have a substituent, and an aromatic heterocyclic group as a substituent; Any of the aromatic hydrocarbon groups having 8 to 40 ring atoms which may have a substituent is preferable.
In the formulas (1) to (7), r1, r6 to r8, r11, r12, r19, r20, and r23 represent integers of 1 to 4, and r9, r10, r13 to r15, r18, r21, and r22 are 1. Represents an integer of ~ 3.
In Formulas (1) to (7), Ar _{1 to} Ar ₁₆ may be a ladder-type furan group.
In the formulas (1) to (7), Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ , Ar ₅ and Ar ₆ , Ar ₈ and Ar ₉ , Ar ₁₀ and Ar ₁₁ , Ar ₁₂ and Ar ₁₃ , Ar ₁₅ And Ar ₁₆ may be bonded to each other to form a ring.
In formulas (2), (4), (6), and (7), L _{1 to} L ₇ are a single bond or a linking group having 1 to 30 carbon atoms.
Here, for example, the case where L ₁ is a single bond is a structure in which an N atom and a phenylene ring are directly bonded.

In formulas (1) to (7), R _{1 to} R ₂₃ are each a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, or a substituted or unsubstituted ring forming atom number of 5 to 40. An aromatic heterocyclic group, a substituted or unsubstituted ring-forming aromatic hydrocarbon group having 6 to 40 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 20 carbon atoms, a substituted or unsubstituted carbon group having 2 to 40 carbon atoms Alkenyl group, substituted or unsubstituted alkylamino group having 1 to 40 carbon atoms, substituted or unsubstituted aralkylamino group having 7 to 60 carbon atoms, substituted or unsubstituted alkylsilyl group having 3 to 20 carbon atoms, substituted or unsubstituted Or an arylsilyl group having 8 to 40 carbon atoms, a substituted or unsubstituted aralkylsilyl group having 8 to 40 carbon atoms, and a substituted or unsubstituted alkyl halide group having 1 to 40 carbon atoms. It is either.
In formulas (4), (6), and (7), X _{1 to} X ₆ are any one of N atoms substituted with a sulfur atom, an oxygen atom, and a monoaromatic hydrocarbon group, respectively.
In Formula (1), the phenylene group directly bonded to the N atom directly bonded to Ar ₁ and Ar ₂ may be further directly bonded to Ar ₁ or Ar ₂ . In Formula (1), the phenylene group directly bonded to the N atom directly bonded to Ar ₃ and Ar ₄ may be further directly bonded to Ar ₃ or Ar ₄ .
In formula (1), Ar ₂ and Ar ₃ are preferably condensed aromatic hydrocarbons having 6 to 40 ring carbon atoms. Ar ₂ and Ar ₃ are preferably a naphthyl group.
In the formula (2), the phenylene group bonded via L ₁ to the N atom directly bonded to Ar ₅ and Ar ₆ may be further directly bonded to Ar ₅ or Ar ₆ .

In the present invention, “ring-forming carbon” means a carbon atom constituting a saturated ring, an unsaturated ring, or an aromatic ring. “Ring-forming atom” means a carbon atom and a hetero atom constituting a hetero ring (including a saturated ring, an unsaturated ring, and an aromatic ring).
Further, the “aromatic hydrocarbon group” includes not only a non-condensed aromatic hydrocarbon group but also a condensed aromatic hydrocarbon group unless otherwise specified. Unless otherwise specified, the “aromatic heterocyclic group” includes not only a non-condensed aromatic heterocyclic group but also a condensed aromatic heterocyclic group.

In the case of “substituted or unsubstituted”, examples of the substituent include aromatic hydrocarbon groups, heterocyclic groups, alkyl groups (straight chain or branched chain alkyl groups, cycloalkyl groups, alkyl halides). Group), alkenyl group, alkynyl group, alkylsilyl group, arylsilyl group, alkoxy group, halogenated alkoxy group, aralkyl group, aryloxy group, halogen atom, cyano group, hydroxyl group, nitro group, carboxy group, etc. Can be mentioned. Among the substituents mentioned here, an aromatic hydrocarbon group, a heterocyclic group, an alkyl group, a halogen atom, an alkylsilyl group, an arylsilyl group, and a cyano group are preferable, and more preferable in the description of each substituent. The specific substituents are preferred. Moreover, these substituents may be further substituted with the above-mentioned substituents.
“Unsubstituted” in the case of “substituted or unsubstituted” means that a hydrogen atom is substituted.
In the compound described below or a partial structure thereof, the case of “substituted or unsubstituted” is the same as described above.
In the present invention, the hydrogen atom includes isotopes having different numbers of neutrons, that is, light hydrogen (protium), deuterium (triuterium), and tritium.

  Among the amine derivatives represented by the general formulas (1) to (7), the amine derivatives represented by the general formulas (2) to (4) and (6) to (7) are preferable, and a compound having a carbazolyl group Is preferred. Examples of the amine derivative include the following compounds.

Examples of the compound having a condensed aromatic ring include a compound in which a substituted or unsubstituted condensed aromatic ring and a substituted or unsubstituted aromatic ring are linked.
As the compound having such a condensed aromatic ring, for example, a compound selected from the group consisting of polycyclic aromatic compounds represented by the following formulas (10A), (10B) and (10C) is preferable.

Ra-Ar ¹⁰¹ -Rb (10A)
Ra-Ar ¹⁰¹ -Ar ¹⁰² -Rb (10B)
Ra-Ar ¹⁰¹ -Ar ¹⁰² -Ar ¹⁰³ -Rb (10C)

In the general formulas (10A) to (10C), Ar ¹⁰¹ , Ar ¹⁰² , Ar ¹⁰³ , Ra and Rb are substituted or unsubstituted aromatic hydrocarbon groups having 6 to 60 ring carbon atoms.

Among them, Ar ¹⁰¹ , Ar ¹⁰² , Ar ¹⁰³ , Ra and Rb are substituted or unsubstituted benzene rings,
A substituted or unsubstituted naphthalene ring,
A substituted or unsubstituted chrysene ring,
A substituted or unsubstituted fluoranthene ring,
A substituted or unsubstituted phenanthrene ring,
Substituted or unsubstituted benzophenanthrene ring,
A substituted or unsubstituted dibenzophenanthrene ring,
A substituted or unsubstituted triphenylene ring,
A substituted or unsubstituted benzo [a] triphenylene ring,
A substituted or unsubstituted benzochrysene ring,
A substituted or unsubstituted benzo [b] fluoranthene ring,
A substituted or unsubstituted fluorene ring, and
It preferably represents a polycyclic aromatic skeleton selected from substituted or unsubstituted picene rings.
Further, the substituents for Ra and Rb are preferably not aromatic hydrocarbon groups, and Ar ¹⁰¹ , Ar ¹⁰² , Ar ¹⁰³ , Ra and Rb are preferably not simultaneously substituted or unsubstituted benzene rings.

  Further, in the general formulas (10A) to (10C), one or both of Ra and Rb are substituted or unsubstituted phenanthrene ring, substituted or unsubstituted benzo [c] phenanthrene ring, substituted or unsubstituted It is preferably selected from the group consisting of a triphenylene ring and a substituted or unsubstituted fluoranthene ring.

The compound having a condensed aromatic ring may be a compound in which a substituted or unsubstituted condensed aromatic ring and a substituted or unsubstituted condensed aromatic heterocyclic ring are linked.
Examples of the condensed aromatic heterocycle include a carbazole ring and a dibenzofuran ring.

  Specific examples of the compound having a condensed aromatic ring include the following compounds.

The triplet energy (Eg (T)) of the first host material is preferably 2.4 eV or more, and more preferably 2.5 eV or more. By setting the triplet energy of the first host material to 2.4 eV or more, the triplet energy of the first host material can be made larger than the triplet energy of the first dopant material. Thereby, the triplet energy of the first dopant material can be prevented from diffusing into the first host material and the like, and the light emission efficiency and the like can be improved.
On the other hand, the triplet energy (Eg (T)) of the first host material is smaller than the triplet energy (Eg (T)) of the hole transport material of the hole transport layer 6 adjacent to the first light emitting layer 51. preferable. Thereby, it is possible to avoid the triplet energy from diffusing into the hole transport layer 6 adjacent to the first light emitting layer 51, and to improve the light emission efficiency and the like.
In the present invention, the triplet energy means an energy difference between the lowest excited triplet state and the ground state.

  Further, the difference between Ip (ionization potential) of the first host material and Ip of the material of the hole transport layer 6 adjacent to the first light emitting layer 51 is preferably 0.2 eV or less, and 0.15 eV or less. More preferably, it is particularly preferably 0.10 eV or less. Since the difference in Ip between the first host material and the material of the hole transport layer 6 is 0.2 eV or less, the transportability of holes flowing from the hole transport layer 6 to the first light emitting layer 51 is improved. The number of holes flowing into the first light emitting layer 51 and the second light emitting layer 52 can be increased.

[First dopant material]
The first dopant material is a phosphorescent material, and is preferably a metal complex. The metal complex contains at least one of iridium (Ir), palladium (Pd), and platinum (Pt). It is preferable to include. The metal complex is more preferably an orthometalated complex represented by the formula (20).

In formula (20), A ³¹ is a ring bonded to A ³² and Q, and is a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group.
Here, as an aromatic hydrocarbon group, a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, etc. are preferable.
As the aromatic heterocyclic group, a thienyl group, a pyridyl group, a quinolyl group, an isoquinolyl group and the like are preferable.
Examples of the substituent substituted with the aromatic hydrocarbon group or the aromatic heterocyclic group include a halogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group, an alkoxycarbonyl group having 1 to 30 carbon atoms, and 1 to 30 carbon atoms. Of these, an alkoxy group, an aryloxy group, a dialkylamino group, a haloalkyl group, a cyano group and the like are preferable.
As the halogen atom, a fluorine atom or the like is preferable.
As a C1-C30 alkyl group, a methyl group, an ethyl group, etc. are preferable.
As the alkenyl group, a vinyl group and the like are preferable.
As the alkoxycarbonyl group having 1 to 30 carbon atoms, a methoxycarbonyl group, an ethoxycarbonyl group, and the like are preferable.
As an alkoxy group having 1 to 30 carbon atoms, a methoxy group, an ethoxy group, and the like are preferable.
As the aryloxy group, a phenoxy group, a benzyloxy group and the like are preferable.
As the dialkylamino group, a dimethylamino group, a diethylamino group and the like are preferable.
As the acyl group, an acetyl group and the like are preferable.
As the haloalkyl group, a trifluoromethyl group and the like are preferable.
A ³² is an aromatic heterocyclic group bonded to A ³¹ , and may contain nitrogen as an atom that forms the aromatic heterocyclic group, and may have a substituent.
As the aromatic heterocyclic group, a pyridyl group, pyrimidyl group, pyrazine group, triazine group, benzothiazole group, benzoxazole group, benzimidazole group, quinolyl group, isoquinolyl group, quinoxaline group, phenanthridine group and the like are preferable.
Examples of the substituent which is substituted on A ^32, the same as the substituent which is substituted to A ^31.
Ring containing ring and A ³² comprising A ³¹ is further coupled a ring structure at other sites between the ring, it may form a ring having one condensed ring or an unsaturated structure. Examples of such a condensed ring include a 7,8-benzoquinoline group.
Q is any one of palladium (Pd), iridium (Ir), and platinum (Pt).
L is a bidentate ligand. The bidentate ligand is preferably a β-diketo ligand such as acetylacetonate or pyromellitic acid.
In the formula (20), m and n represent an integer. When Q is a divalent metal, n = 2 and m = 0, and when Q is a trivalent metal, n = 3 and m = 0. Or n = 2 and m = 1.

  Examples of the orthometalated complex represented by the formula (20) include the following compounds.

In the present embodiment, the first dopant material preferably exhibits an emission peak of 570 nm or more. Here, the emission color showing an emission peak of 570 nm or more is, for example, red. Specifically, the above (K-15) to (K-22), Ir (pq) ₂ (acac), and Ir (tpiq) ₂ (acac) are preferable.

<Second light emitting layer>
The second light emitting layer includes a second host material, a third host material, and a second dopant material.

[Relationship between the first host material and the second host material]
In order to obtain light emission from both the first light emitting layer and the second light emitting layer, it is preferable to use an electron transporting host material for the second host material of the second light emitting layer.
The second host material preferably has a larger affinity and ionization potential than the first host material. When the second host material has a higher affinity than the first host material, the first light-emitting layer 51 can function as an electron barrier layer due to the difference in affinity. When the ionization potential of the second host material is larger than that of the first host material, the second light emitting layer 52 can also function as a hole barrier layer due to the difference in ionization potential.
As a result, excitons can be favorably generated near the interface between the first light-emitting layer 51 and the second light-emitting layer 52, and color shift can be suppressed even when the luminance is increased.

Affinity (Af, electron affinity) means the energy released or absorbed when one electron is given to the molecule of the host material, and is defined as positive in the case of emission and negative in the case of absorption. .
The affinity is defined by the ionization potential (Ip) and the singlet energy (Eg (S): energy difference between the lowest excited singlet state and the ground state) as follows.
Af = Ip-Eg (S)
Here, the ionization potential (Ip) means the energy required to remove the electrons from the host material compound and ionize it, and was measured by, for example, an ultraviolet photoelectron spectrometer (AC-3, Riken instrument). Value.
Singlet energy (Eg (S)) refers to the difference in optical energy between the conduction level and the valence level. For example, the long wavelength side tangent and the baseline (zero absorption) of the absorption spectrum of the diluted toluene solution of each host material This is obtained by converting the wavelength value of the intersection of to energy.

[Relationship between second host material and third host material]
It is preferable that the second host material and the third host material satisfy the following formula (N-1) and satisfy at least one of the following formulas (N-2) and (N-3).
Af _H2 ≧ Af _H3 (N−1)
μ (e) _H2 > μ (e) _H3 (N-2)
Eg (S) _H2 <Eg (S) _H3 (N-3)
However, in the formula (N-1), Af _H2 is the affinity of the second host material, and Af _H3 is the affinity of the third host material. In the formula (N-2), μ (e) _H2 is the electron mobility of the second host material, and μ (e) _H3 is the electron mobility of the third host material. In the formula (N-3), Eg (S) _H2 is singlet energy of the second host material, and Eg (S) _H3 is singlet energy of the third host material.

In order to obtain the desired chromaticity of the organic EL element, the emission intensity of the first light emitting layer and the second light emitting layer may be adjusted while obtaining light emission from the first light emitting layer and the second light emitting layer.
For example, in order to decrease the light emission intensity of the first light emitting layer and increase the intensity of the second light emitting layer, it is necessary to move the recombination region of holes and electrons to the second light emitting layer side. The recombination region can be moved to the second light emitting layer side by weakening the electron injection of the second light emitting layer.
In the second light emitting layer of the present embodiment, the affinity Af _H3 of the third host material is preferably not more than the affinity Af _H2 of the second host material, as shown in the formula (N-1). That is, the third host material preferably suppresses electron injection with respect to the second host material.

  The recombination region can be moved to the second light emitting layer side by weakening the electron transport property of the second light emitting layer. In order to weaken the electron transport property of the second light emitting layer, a third host material having an electron mobility lower than that of the second host material, that is, a third host material satisfying the formula (N-2) is used for the second light emitting layer. Add moderately. Thus, by adding the third host material satisfying the formula (N-1) and satisfying the formula (N-2) to the second light emitting layer, the change in the film thickness of each light emitting layer and the dopant concentration Without changing, the emission intensity of each layer can be adjusted, and an organic EL element having a desired chromaticity can be obtained.

  In addition, a third host material having a singlet energy larger than that of the second host material and a larger barrier to carriers, that is, a third host material satisfying the above formula (N-3) is appropriately added to the second light emitting layer. However, the recombination region can be moved to the second light emitting layer side. Thus, by adding the third host material satisfying the formula (N-1) and satisfying the formula (N-3) to the second light emitting layer, the change in the film thickness of each light emitting layer and the dopant concentration Without changing, the emission intensity of each layer can be adjusted, and an organic EL element having a desired chromaticity can be obtained.

Furthermore, the singlet energy Eg (S) _H2 of the second host material and the singlet energy Eg (S) _{H3 of} the third host material preferably satisfy the following formula (N-31).
ΔEg (S) = Eg (S) _H3 −Eg (S) _H2 > 0.2 [eV] (N−31)
Moreover, it is preferable that the electron mobility μ (e) _H2 of the second host material and the electron mobility μ (e) _{H3 of} the third host material satisfy the following formula (N-21).
Δμ (e) = μ (e) _H2 / μ (e) _H3 > 10 ² cm ² / Vs (N-21)

  Furthermore, in the second light emitting layer, if the third host material is large, the number of electrons flowing through the third host material increases, and the electron transport property of the second host material becomes weak. That is, since the electron transport property of the second host material is affected by the concentration of the third host material, the mass of the third host material relative to the total mass of the second host material and the third host material (of the third host material). By changing the (concentration), the electron transport property of the second host material can be changed, and thereby the chromaticity of the organic EL element can be adjusted.

  As a method for measuring mobility, several methods such as Time of Flight method are known. In the present invention, mobility is determined by impedance spectroscopy.

The mobility measurement by impedance spectroscopy will be described. A material for mobility measurement with a thickness of preferably about 100 nm to 200 nm is sandwiched between the anode and the cathode, and a minute AC voltage of 100 mV or less is applied while applying a bias DC voltage. The AC current value (absolute value and phase) flowing at this time is measured. This measurement is performed while changing the frequency of the AC voltage, and the complex impedance (Z) is calculated from the current value and the voltage value. At this time, the frequency dependence of the imaginary part (ImM) of the modulus M = iωZ (i: imaginary unit, ω: angular frequency) is obtained, and the reciprocal of the frequency ω at which ImM is the maximum value is conducted in the layer of the material to be measured. It is defined as the response time of the electron. Then, the mobility is calculated by the following formula.
Mobility = (film thickness of material layer to be measured) ² / (response time × voltage)

[Relationship between first host material, second host material and third host material]
The electron mobility μ (e) _H2 of the second host material and the electron mobility μ (e) _H3 of the third host material with respect to the electron mobility μ (e) _H1 of the first host material of the first light emitting layer are: It is preferable to satisfy the following formula (N-4).
μ (e) _H2 ≧ μ (e) _H3 > μ (e) _H1 (N-4)

  As described above, in order to obtain light emission from the first light-emitting layer and the second light-emitting layer, a hole-transporting host material is used for the first light-emitting layer, and an electron-transporting host material is used for the second light-emitting layer. It is preferable to use it. In this organic EL device, for example, in order to decrease the emission intensity of the first emission layer and increase the emission intensity of the second emission layer, the electron mobility is higher than that of the first host material and the second emission layer is increased. What is necessary is just to weaken the electron transport property of a 2nd light emitting layer using the 3rd host material whose electron mobility is lower than a host material.

When the hole mobility μ (h) _{H1 of} the first host material is 10 ⁻⁶ cm ² / Vs or more, the ionization potential Ip _H1 of the first host material and the ionization potential Ip _H3 of the third host material are expressed by the following formulas: It is preferable to satisfy (N-5).
Ip _H1 <Ip _H3 (N-5)
In this case, since the hole transportability of the first host material is high, the performance required for the third host material is considered to be control of the hole transport ability. On the other hand, it is desirable for the second host material to have a hole transport property.
Examples of the first host material having a hole mobility μ (h) _H1 of 10 ⁻⁶ cm ² / Vs or more include the amine derivatives described above.

When the hole mobility μ (h) _H1 of the first host material is smaller than 10 ⁻⁶ cm ² / Vs, the affinity Af _H1 of the first host material and the affinity Af _H3 of the third host material are expressed by the following formula (N −6) is preferably satisfied.
Af _H1 > Af _H3 (N-6)
In this case, the performance required for the third host material is to control electrons from the second host material to the first host material. For this reason, the third host material is preferably a compound having an electron blocking property, that is, a low affinity.
Examples of the first host material having a hole mobility μ (h) _H1 smaller than 10 ⁻⁶ cm ² / Vs include the compounds having the above-described condensed aromatic ring.

[Second host material]
In the present embodiment, the second host material is preferably an azine derivative. An azine derivative is a compound containing a six-membered ring containing one or more nitrogen atoms as a ring-forming atom (also called a nitrogen-containing six-membered heterocyclic group), a monoazine derivative, a diazine derivative, and a triazine derivative. It is preferable that it is either.
Since the second host material is any one of a monoazine derivative, a diazine derivative, and a triazine derivative, the electron transport property from the electron transport layer 7 to the first light emitting layer 51 is excellent.
As a 2nd host material, it is preferable that it is a compound shown, for example by Formula (21)-(26).

In formulas (21) to (26), R _{101 to} R ₁₀₅ are any one of a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, and an alkyl group.
As the substituent substituted by the aromatic hydrocarbon group, an aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a heterocyclic group having 5 to 30 carbon atoms, and an alkyl group having 1 to 20 carbon atoms are preferable.
As the substituent substituted by the heterocyclic group, an aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a heterocyclic group having 5 to 30 carbon atoms, and an alkyl group having 1 to 20 carbon atoms are preferable.

  The second host material is preferably a compound having a carbazole skeleton. Due to the second host material having a carbazole skeleton, the organic EL element 1 can be provided with no color shift and excellent durability.

  As a 2nd host material which has a carbazole skeleton, the compound (carbazole azine type compound) represented by the following general formula (BL-9) or (BL-10) is mentioned, for example.

  In formula (BL-9), Cz represents a carbazolyl group which may have a substituent or an azacarbazolyl group which may have a substituent. A is any group of a monoazine derivative, a diazine derivative, and a triazine derivative. m is an integer of 1-3.

In formula (BL-10), Cz represents an optionally substituted carbazolyl group or an optionally substituted azacarbazolyl group. A is any group of a monoazine derivative, a diazine derivative, and a triazine derivative. n is an integer of 1 to 3.
The second host material having a carbazole skeleton is preferably, for example, a compound represented by the following formula (27) or (28).

In formula (27), HAr ₃₁ is a substituted or unsubstituted nitrogen-containing 6-membered heterocyclic group. m is any one of integers 1 to 4, preferably any one of 1 to 3, and more preferably 1 or 2. n is one of integers 1 to 4. R ₃₁ is a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic hydrocarbon group. When R ₃₁ is a substituted or unsubstituted aromatic hydrocarbon group, a condensed ring structure in which R ₃₁ are bonded to each other and a benzene ring is condensed may be used.

In formula (28), HAr ₃₂ is a substituted or unsubstituted nitrogen-containing 6-membered heterocyclic group. m is any one of integers 1 to 4, preferably any one of 1 to 3, and more preferably 1 or 2. n is one of integers 1 to 4. R ₃₂ is a substituted or unsubstituted alkyl group or an aromatic hydrocarbon group. When R ₃₂ is a substituted or unsubstituted aromatic hydrocarbon group, a condensed ring structure in which R ₃₂ are bonded to each other and a benzene ring is condensed may be used.

  The second host material having a carbazole skeleton represented by the general formula (27) or (28) is a compound represented by the following formula (8) to (12A) or (29) to (32). preferable.

In formulas (8) to (11), Ar _{101 to} Ar ₁₀₄ are each a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 ring carbon atoms, and a substituted or unsubstituted ring forming atom. It is one of the heterocyclic groups of formula 5-60. However, in the formulas (8A), (9A), and (11A), not all of Ar _{101 to} Ar ₁₀₃ are hydrogen atoms, and in the formula (10A), all of Ar _{101 to} Ar ₁₀₄ are hydrogen atoms. There is no case.
R ₁₁₀ and R ₁₁₁ are the same as R ₁ described above.
n1 and n2 are any one of integers 1 to 4, and m is any one of integers 1 to 4. m is preferably any one of integers from 1 to 3, and more preferably 1 or 2. Note that the sum of n2 and m (n2 + m) has a relationship of 2 ≦ (n2 + m) ≦ 5.
In formulas (12) and (12A), X is an N atom or CH, and the number of N atoms is 1 to 4.
In formula (12), R _{121 to} R ₁₂₈ are each a hydrogen atom, an aromatic hydrocarbon group, an alkyl group, or a structure in which the skeleton of formula (12A) is linked.
The structures in which the skeleton of the formula (12A) is linked to R _{121 to} R ₁₂₈ are R ₁₂₁ and R ₁₂₂ , R ₁₂₂ and R ₁₂₃ , R ₁₂₃ and R ₁₂₄ , R ₁₂₅ and R ₁₂₆ , R ₁₂₆ and R ₁₂₇ , And at least one of R ₁₂₇ and R ₁₂₈ is bonded to the skeleton of the formula (12A).
In Formula (12A), R ₁₂₉ is any one of a hydrogen atom, an aromatic hydrocarbon group, and an alkyl group.

In formulas (29) to (32), Ar _{101 to} Ar ₁₀₄ , R ₁₁₀ , R ₁₁₁ , n1, n2, and m are the same as those in formulas (8) to (11).

  As the second host material of the formulas (29) to (32), for example, the following compounds are preferable.

  The second host material may be a compound represented by the following formula (13).

In formula (13), A ¹ is a substituted or unsubstituted nitrogen-containing six-membered heterocyclic group.
A ² is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted nitrogen-containing heterocyclic group having 5 to 30 ring atoms.
L ¹⁰ is a single bond or a linking group.
As the linking group,
A substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms,
It is a group derived from either a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, or a group in which these groups are linked to each other by 2 to 5 atoms.
The groups bonded to each other are the same or different from each other.
X ¹ and X ² are each independently a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. One of the ring groups.
The case where X ¹ is a single bond is a case where “A ¹ ” and “N” adjacent to X ¹ are directly bonded, and the case where X ² is a single bond is adjacent to X ² . In this case, “A ² ” and “N” are directly bonded.
Y ^{1 to} Y ⁴ are each independently a hydrogen atom, a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, Substituted or unsubstituted haloalkyl group having 1 to 20 carbon atoms, substituted or unsubstituted haloalkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted alkylsilyl group having 1 to 10 carbon atoms, substituted or unsubstituted carbon Either an arylsilyl group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. . In addition, adjacent Y ¹ to Y ⁴ may form a bond with each other to form a ring structure.
p and q are each an integer from 1 to 4, and r and s are each an integer from 1 to 3.
When p and q are any one of integers 2 to 4, and r and s are any integers 2 or 3, the plurality of Y ¹ to Y ⁴ may be the same or different.
At least ^{one of} A ¹ , A ² , X ¹ , X ² , and Y ^{1 to} Y ⁴ is a group derived from any of a monoazine derivative, a diazine derivative, and a triazine derivative.

  Here, the formula (13) is preferably the following formula (13A).

In the formula (13A), A ¹ , A ² , L ¹⁰ , X ¹ , X ² , Y ^{1 to} Y ⁴ , p, q, r, and s have the same meaning as the formula (13).

  Moreover, it is preferable that the said Formula (13) is a following formula (13C).

In the formula (13C), A ¹ , A ² , L ¹⁰ , X ¹ , X ² , Y ^{1 to} Y ⁴ , p, q, r, and s are as defined in the formula (13).

  Moreover, it is preferable that the said Formula (13) is a following formula (13D).

In the formula (13D), A ¹ , A ² , X ¹ , X ² , Y ^{1 to} Y ⁴ , p, q, r, and s have the same meaning as the formula (13).

  Examples of the second host material of the formula (13A) include the following compounds. The compound of the second host material of the formula (13A) includes exemplary compounds of the second host material of the following formula (13B).

  The second host material may be a compound represented by the following formula (14) or formula (15).

In formulas (14) and (15), X represents a CH or N atom, and at least one of X is an N atom. Ar ^{21 to} Ar ²³ are each independently a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group that is not a condensed ring structure.
Ar ²² or Ar ²³ may form a condensed ring with the ring containing X.

  As the second host material, particularly preferable compounds include, for example, the following compounds.

[Third host material]
The third host material of the present embodiment satisfies the relationship with the second host material described above, that is, satisfies the formula (N-1), and at least the formula (N-2) or (N-3). Any one satisfying either of them may be used. For example, among the materials described for the first host material and the materials described for the second host material, those satisfying the relationship with the second host material described above can be given. The third host material is preferably a compound containing a five-membered ring structure in the molecule. A compound having a skeleton represented by the following general formula (130) is also preferable.

In the general formula (130), X represents an oxygen atom, a sulfur atom, NR ¹³⁰ , or CR ¹³¹ R ¹³² .
R ^{130 to} R ¹³² are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. . A part of R ¹³¹ and R ¹³² may be bonded to form a ring structure.

  As the third host material, a compound having a skeleton represented by the above formula (130) is more preferable, and a compound having a carbazolyl group is more preferable. Particularly preferred is a biscarbazole derivative in which two carbazolyl groups are directly bonded. A preferred biscarbazole derivative as the third host material is represented by the following general formula (16).

In the general formula ^{(16), L 10, X} 1, X 2, Y 1 ~Y 4, p, q, r, s are as defined in the general formula (13). B ¹ and B ² are a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.

  Examples of preferable compounds as the third host material include the following compounds.

  In the second light emitting layer of this embodiment, the ratio of the second host material to the third host material is preferably 99: 1 to 1:99 by mass ratio, and 90:10 to 10:90. It is more preferable that the ratio is 80:20 to 20:80. Moreover, it is preferable that the ratio of the second host material and the third host material (that is, the total of the host materials in the second light emitting layer) and the second dopant material is 99: 1 to 50:50 by mass ratio.

[Second dopant material]
The second dopant material of this embodiment is preferably a phosphorescent metal complex. As a 2nd dopant material of this embodiment, the thing similar to what was demonstrated by the said 1st dopant material can be used. Specifically, (K-1) to (K-10), (K-12) to (K-14), (K-23) to (K-26), and Ir (Ph-ppy) _{3 above.} Is preferred.
The second dopant material preferably exhibits an emission peak of less than 570 nm, and more preferably exhibits an emission peak of 565 nm or less. The emission color showing an emission peak of less than 570 nm is, for example, green.

(substrate)
The organic EL element 1 of this embodiment is produced on a translucent substrate 2. This translucent substrate 2 is a substrate that supports an anode, an organic compound layer, a cathode, and the like that constitute an organic EL element, and is a smooth substrate having a light transmittance in the visible region of 400 nm to 700 nm of 50% or more. Is preferred.
Examples of the light-transmitting substrate include a glass plate and a polymer plate.
Examples of the glass plate include those using soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz and the like as raw materials.
Examples of the polymer plate include those using polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like as raw materials.

(Anode and cathode)
The anode of the organic EL element plays a role of injecting holes into the light emitting layer, and it is effective to have a work function of 4.5 eV or more.
Specific examples of the anode material include indium tin oxide alloy (ITO), tin oxide (NESA), indium zinc oxide, gold, silver, platinum, and copper.
When light emitted from the light-emitting layer is extracted from the anode side, it is preferable that the light transmittance in the visible region of the anode be greater than 10%. The sheet resistance of the anode is preferably several hundred Ω / □ (Ω / sq. Ohm per square) or less. Although the film thickness of the anode depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 nm to 200 nm.

As the cathode, a material having a small work function is preferable for the purpose of injecting electrons into the light emitting layer.
The cathode material is not particularly limited, and specifically, indium, aluminum, magnesium, magnesium-indium alloy, magnesium-aluminum alloy, aluminum-lithium alloy, aluminum-scandium-lithium alloy, magnesium-silver alloy and the like can be used.
Similarly to the anode, the cathode can be formed, for example, on the electron transport layer or the electron injection layer by a method such as vapor deposition. Moreover, the aspect which takes out light emission from a light emitting layer from a cathode side is also employable. When light emitted from the light emitting layer is extracted from the cathode side, it is preferable that the light transmittance in the visible region of the cathode be greater than 10%.
The sheet resistance of the cathode is preferably several hundred Ω / □ or less.
The thickness of the cathode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 50 nm to 200 nm.

(Hole injection / transport layer)
The hole injection / transport layer is a layer that assists hole injection into the light emitting layer and transports it to the light emitting region, and a compound having a high hole mobility and a low ionization energy is used.
As a material for forming the hole injecting / transporting layer, a material that transports holes to the light emitting layer with lower electric field strength is preferable. For example, an aromatic amine compound is preferably used.

(Electron injection / transport layer)
The electron injection / transport layer is a layer that assists injection of electrons into the light emitting layer and transports it to the light emitting region, and a compound having a high electron mobility is used.
As the compound used in the electron injecting / transporting layer, for example, an aromatic heterocyclic compound containing one or more hetero atoms in the molecule is preferably used, and a nitrogen-containing ring derivative is particularly preferable. As the nitrogen-containing ring derivative, a heterocyclic compound having a nitrogen-containing 6-membered ring or 5-membered ring skeleton is preferable.

  In the organic EL device of this embodiment, the organic compound layer other than the first light emitting layer 51 and the second light emitting layer 52 can be arbitrarily selected from the materials used in the conventional organic EL device in addition to the compounds exemplified above. These compounds can be selected and used.

(Layer formation method)
The method for forming each layer of the organic EL element of the present embodiment is not limited except as specifically mentioned above, but a dry film forming method such as a vacuum evaporation method, a sputtering method, a plasma method, an ion plating method, a spin method, Known methods such as a coating method, a dipping method, a flow coating method, and a wet film forming method such as an ink jet method can be employed.

(Manufacturing method of organic EL element)
In manufacturing the organic EL device of the present invention, that is, the organic EL device that can easily adjust the chromaticity, as described above, first, at least the first light emitting layer and the second light emitting layer are provided between the anode and the cathode. A first host material and a first dopant material are formed on the first light emitting layer, the second light emitting layer satisfies the above formula (N-1), and A third host material that satisfies at least one of the above formulas (N-2) and (N-3) and a second dopant material may be formed. At this time, the concentration of the third host material relative to the total mass of the second host material and the third host material in the second light emitting layer may be determined by the desired chromaticity of the organic EL element.

[Second Embodiment]
Next, the organic EL element in 2nd embodiment is demonstrated.
As shown in FIG. 2, the organic EL element 1A of the second embodiment further includes a charge barrier layer 8 and a third light emitting layer 53 between the second light emitting layer 52 and the electron transport layer 7 in the light emitting unit 5A. The point provided is different from the first embodiment.
The charge barrier layer 8 is continuously formed on the cathode 4 side of the second light emitting layer 52. The third light emitting layer 53 is continuously formed between the charge barrier layer 8 and the electron transport layer 7.
The charge barrier layer 8 is formed by providing an energy barrier of the HOMO level and the LUMO level between the adjacent second light emitting layer 52 and the third light emitting layer 53, so that the charge to the second light emitting layer 52 and the third light emitting layer 53 ( This is a layer for adjusting the injection of holes or electrons and adjusting the balance of charges injected into the second light emitting layer 52 and the third light emitting layer 53.
The 3rd light emitting layer 53 is a layer which shows blue fluorescence light emission, for example, and a peak wavelength is 450-500 nm. The third light emitting layer 53 contains a fourth host material and a fourth dopant material.
Examples of the fourth host material include compounds having a structure represented by the following formula (41) having an anthracene central skeleton.

In formula (41), A ₄₁ and A ₄₂ are each a group derived from a substituted or unsubstituted aromatic ring having 6 to 20 nuclear carbon atoms.
R _{41 to} R ₄₈ are each a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted heteroaromatic hydrocarbon group having 5 to 50 nuclear atoms, and a substituted group. Or an unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted carbon number 6 -50 aralkyl group, substituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms, substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl having 1 to 50 carbon atoms A group, a substituted or unsubstituted silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxyl group.

Examples of the substituent substituted on the aromatic ring of A ₄₁ and A ₄₂ include a substituted or unsubstituted aromatic hydrocarbon group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, A substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, a substituted or unsubstituted nucleus atom An aryloxy group having 5 to 50 atoms, a substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxyl group, Any of a halogen atom, a cyano group, a nitro group, and a hydroxyl group is mentioned.

  As the fourth dopant material, for example, arylamine compound, styrylamine compound, anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone, naphthaloperinone, diphenylbutadiene, tetraphenyl Butadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, imine, diphenylethylene, vinylanthracene, diaminocarbazole, pyran, thiopyran , Polymethine, merocyanine, imidazole chelated oxinoid compound, quinacridone, rubrene Fine fluorescent dye, and the like.

In the organic EL element 1 </ b> A, for example, a first dopant material that emits red light is used for the first light emitting layer 51, and a second dopant material that emits green light is used for the second light emitting layer 52. In this case, since the third light-emitting layer 53 that emits blue light is provided in addition to the light-emitting layers 51 and 52, the entire element can emit white light.
Therefore, the organic EL element 1A can be suitably used as a surface light source such as an illumination or a backlight.

[Third embodiment]
The organic EL element of the present invention can have a tandem element configuration having at least two light emitting units. In such a tandem element configuration, an intermediate layer is interposed between two light emitting units.
The intermediate layer is a layer serving as a supply source for injecting electrons or holes into the light emitting unit, and includes an intermediate conductive layer or a charge generation layer. In addition to the electric charge injected from the pair of electrodes, the electric charge supplied from the intermediate layer is injected into the light emitting unit. Therefore, by providing the intermediate layer, the luminous efficiency (current efficiency) with respect to the injected current is increased. improves.

In the present invention, at least one of the two or more light emitting units includes at least a hole transport layer, the first light emitting layer and the second light emitting layer in the present invention, and an electron transport layer. Of the two or more light emitting units, any light emitting unit other than the light emitting unit including the first light emitting layer and the second light emitting layer in the present invention may be used as long as it has at least one light emitting layer. .
Specific examples of the organic EL device of the present invention are shown below.
(14) Anode / first light emitting unit / intermediate layer / second light emitting unit / cathode (15) Anode / first light emitting unit / intermediate layer / second light emitting unit / intermediate layer / third light emitting unit / cathode

FIG. 3 shows an example of an organic EL element according to the third embodiment.
The organic EL element 1B includes an anode 3, a first light emitting unit 5B1, an intermediate layer 9, a second light emitting unit 5B2, and a cathode 4.
The first light emitting unit 5B1 includes, in order from the anode 3, a hole transport zone 6, a third light emitting layer 53, and an electron transport zone 7.
The hole transport zone 6 includes a first hole injection layer 61 and a first hole transport layer 62.
The third light emitting layer 53 includes a host material and a dopant material exhibiting fluorescent light having a main peak wavelength of 550 nm or less.
The electron transport zone 7 includes a barrier layer 71 adjacent to the third light emitting layer 53 and a first electron transport layer 72.
The second light emitting unit 5B2 is the same as the light emitting unit of the first embodiment, and in order from the anode 3 side, the second hole transport layer 63, the first light emitting layer 51, the second light emitting layer 52, and the second electrons. A transport layer 73.
The triplet energy (ETd) of the dopant material of the third light-emitting layer 53 is preferably larger than the triplet energy (ETh) of the host material, and the triplet energy (ETb) of the barrier layer 71 is preferably larger than ETh. . Triplet excitons are confined in the third light-emitting layer 53, and the TTF phenomenon (a phenomenon in which singlet excitons are generated by collisional fusion of two triplet excitons) is efficiently caused to increase the height of the fluorescent element. It is possible to achieve efficiency.
Here, the barrier layer 71 refers to a layer having a barrier function against triplet energy. Therefore, the hole barrier layer and the charge barrier layer have different functions.
Triplet energy can be measured using a commercially available apparatus F-4500 (manufactured by Hitachi). Conversion formula of triplet energy E ^T is as follows.
Conversion formula E ^T (eV) = 1239.85 / λ _edge
“Λ _edge ” means that when the phosphorescence spectrum is expressed by taking the phosphorescence intensity on the vertical axis and the wavelength on the horizontal axis, a tangent line is drawn with respect to the rising _{edge on} the short wavelength side of the phosphorescence spectrum. It means the wavelength value of the intersection (unit: nm).
Examples of the intermediate layer 9 include metals, metal oxides, metal oxide mixtures, composite oxides, and electron-accepting organic compounds. As the metal, a co-deposited film of Mg, Al, Mg or Ag is preferable. Examples of the metal oxide include ZnO, WO ₃ , MoO ₃ , and MoO ₂ . Examples of the metal oxide mixture include ITO, IZO, and ZnO: Al. Examples of the electron-accepting organic compound include organic compounds having a CN group as a substituent. As the organic compound containing a CN group, a triphenylene derivative, a tetracyanoquinodimethane derivative, an indenofluorene derivative, or the like is preferable. As the triphenylene derivative, hexacyanohexaazatriphenylene (HAT) is preferable. As the tetracyanoquinodimethane derivative, tetrafluoroquinodimethane and dicyanoquinodimethane are preferable. As the indenofluorene derivative, compounds shown in International Publication No. 2009/011327, International Publication No. 2009/069717 or International Publication No. 2010/064655 are preferable. The electron-accepting substance may be a single substance or a mixture with other organic compounds.
Specific examples of the compound that can be used for the electron transport zone, the host material, the dopant material, and the barrier layer in the tandem device configuration of the present invention include compounds described in Japanese Patent Application No. PCT / JP2010 / 003431. Examples of the compound that can be used in the hole transport zone include the same materials as the material of the hole transport layer of the first embodiment.
When the intermediate layer 9 is a charge generation layer, the third light-emitting layer 53 can easily receive electrons from the charge generation layer, so that a donor represented by an alkali metal is present in the vicinity of the charge generation layer interface in the electron transport zone 7. It is preferable to dope. As the donor, at least one of a donor metal, a donor metal compound, and a donor metal complex can be selected. Specific examples of compounds that can be used for such donor metal, donor metal compound, and donor metal complex include compounds described in Japanese Patent Application No. PCT / JP2010 / 003434.

[Modification of Embodiment]
Note that the present invention is not limited to the above description, and modifications within a range not departing from the gist of the present invention are included in the present invention.
In the first embodiment and the second embodiment, the configuration in which the hole transport layer is formed continuously with the anode is shown, but a hole injection layer may be further formed between the anode and the hole transport layer.
As a material for such a hole injection layer, it is preferable to use a porphyrin compound, an aromatic tertiary amine compound or a styrylamine compound, and in particular, an aromatic tertiary amine compound such as hexacyanohexaazatriphenylene (HAT). Is preferably used. When hexacyanohexaazatriphenylene is used, the adhesion between the anode and the hole transport layer can be improved and the durability can be improved.
Furthermore, by providing a hole injection layer and a hole transport layer between the anode and the first light-emitting layer, the hole transport property is compared with the case of transporting holes directly from the anode to the first light-emitting layer. Can be improved.
That is, by providing a hole injection layer and a hole transport layer, an ionization potential energy difference between the anode and the hole injection layer, an ionization potential energy difference between the hole injection layer and the hole transport layer, a hole The energy difference between the ionization potentials of the transport layer and the first light emitting layer can be reduced. Thereby, since the energy barrier at the time of a hole moving to each layer can be made small, hole transport property improves, and also luminous efficiency etc. can be improved.
Moreover, although the structure which forms an electron carrying layer continuously with a cathode was shown in 1st embodiment-3rd embodiment, you may further form an electron injection layer between a cathode and an electron carrying layer.
In the third embodiment, the configuration in which two light emitting units are formed is shown, but three or more light emitting units may be formed. In that case, a charge generation layer may be provided between the light emitting units.
The organic EL element 1B of the third embodiment may be the organic EL element 1C shown in FIG. The organic EL element 1C includes an anode 3, a second light emitting unit 5B2, an intermediate layer 9, a first light emitting unit 5B1, and a cathode 4 in this order. That is, it differs from the organic EL element 1B in that the second light emitting unit 5B2 is provided on the anode 3 side and the first light emitting unit 5B1 is provided on the cathode 4 side.
Moreover, you may utilize the organic EL element of 1st embodiment-3rd embodiment as a display other than surface light sources, such as illumination and a backlight.

  In addition, the specific structure and shape in the implementation of the present invention may be other structures as long as the object of the present invention is achieved.

Hereinafter, examples according to the present invention will be described, but the present invention is not limited to these examples.
The compounds used are as follows.

<Synthesis of compounds>
Synthesis Example 1 (Synthesis of Compound H3)
Synthesis Example 1-1-1 (Synthesis of Intermediate 1-1)

Under an argon stream, carbazole (56 g, 334 mmol) and N, N-dimethylformamide (250 mL) were added to a 1000 mL eggplant flask and cooled to −7 ° C. in an ice bath (sodium chloride added), and N-bromosuccinimide was added. A solution of (119 g, 668 mmol) in N, N-dimethylformamide (200 mL) was added dropwise, and the mixture was stirred at −7 ° C. for 4 hours.
After adding water to the reaction solution and raising the temperature to room temperature, the precipitated solid was filtered out. Intermediate 1-1 (71 g, yield 65%) was obtained by repeating recrystallization of the obtained solid with toluene. The intermediate body 1 was identified by analysis of FD-MS (field desorption mass spectrum).

Synthesis Example 1-1-2 (Synthesis of Intermediate 1-2)

In a 2000 mL eggplant flask under an argon stream, intermediate 1-1 (33 g, 102 mmol), phenylboronic acid (27 g, 221 mmol), tetrakis (triphenylphosphine) palladium (7.0 g, 6.1 mmol), 1, 2 -Dimethoxyethane (600 mL) and 2M aqueous sodium carbonate solution (200 mL) were sequentially added, and the mixture was heated to reflux for 8 hours.
After cooling the reaction solution to room temperature, the organic layer was separated, and the organic solvent was distilled off under reduced pressure. The obtained residue was purified by silica gel column chromatography to obtain Intermediate 1-2 (19 g, yield 58%). The powder was identified as Intermediate 1-2 by FD-MS (field desorption mass spectrum) analysis.

Synthesis Example 1-1-3 (Synthesis of Intermediate 1-3)

  In the synthesis of Intermediate 1-2, synthesis was performed in the same manner using 2,4,6-trichloropyrimidine instead of Intermediate 1-1. The powder was identified as Intermediate 1-3 by FD-MS (field desorption mass spectrum) analysis.

Synthesis Example 1-1-4 (Synthesis of Intermediate 1-4)

  In the synthesis of Intermediate 1-2, Intermediate 1-3 was used instead of Intermediate 1-1, and 4 ′-(4,4,5,5-tetramethyl-1,3, 3 was used instead of phenylboronic acid. Synthesis was performed in the same manner using 2-dioxaborolan-2-yl) biphenyl-4-carbonitrile. The powder was identified as Intermediate 1-4 by FD-MS (field desorption mass spectrum) analysis.

Synthesis Example 1-1-5 (Synthesis of Compound H3)

Under an argon stream, intermediate 1-2 (2.3 g, 7.2 mmol), intermediate 1-4 (3.2 g, 8.6 mmol), tris (dibenzylideneacetone) dipalladium (0.26 g, 0.29 mmol) ), Tri-t-butylphosphonium tetrafluoroborate (0.21 g, 0.72 mmol), sodium t-butoxy (1.4 g, 14 mmol), and anhydrous xylene (40 mL) were sequentially added, and the mixture was heated to reflux for 8 hours.
After cooling the reaction solution to room temperature, the organic layer was separated, and the organic solvent was distilled off under reduced pressure. The obtained residue was purified by silica gel column chromatography to obtain 3.6 g of a yellowish white solid (H3).
About the obtained compound, FD-MS (field desorption mass spectrum), fluorescence emission maximum wavelength FL (PhMe, λex = 325 nm) in a toluene solution; λmax are shown below.
FDMS, calcd for C47H30N4 = 650, found m / z = 650 (M +)
FL (PhMe, λex = 325nm); λmax, 471nm

<Evaluation of compound>
First, physical properties of the compounds H1, H2, and H3 used in this example were measured. The measurement method and calculation method are shown below, and the measurement results and calculation results are shown in Table 1.

-Ionization potential It measured using the atmospheric photoelectron spectrometer (the Riken Keiki Co., Ltd. product: AC-1). Specifically, the measurement was performed by irradiating the material with light and measuring the amount of electrons generated by charge separation at that time.

・ Singlet energy Eg (S)
The sample to be measured was deposited on a quartz substrate to prepare a sample, and the absorption spectrum of this sample was measured at room temperature (300K). The film thickness of the sample was 100 nm. In the absorption spectrum, the vertical axis represents absorbance and the horizontal axis represents wavelength. A tangent line was drawn with respect to the fall of the absorption spectrum on the long wavelength side, and a wavelength value λ edge [nm] at the intersection of the tangent line and the horizontal axis was obtained. A value obtained by converting this wavelength value into an energy value by the following conversion formula was defined as EgS.
Conversion formula: Eg (S) [eV] = 1239.85 / λedge
A spectrophotometer U3310 manufactured by Hitachi, Ltd. was used for the measurement of the absorption spectrum.

In addition, the tangent with respect to the fall of the long wavelength side of an absorption spectrum was drawn as follows. When moving on the spectrum curve in the long wavelength direction from the maximum value on the longest wavelength side among the maximum values of the absorption spectrum, the tangent at each point on the curve is considered. This tangent repeats as the curve falls (ie, as the value on the vertical axis decreases), the slope decreases and then increases. The tangent drawn at the point where the slope value takes the minimum value on the long wavelength side (except when the absorbance is 0.1 or less) is taken as the tangent to the fall on the long wavelength side of the absorption spectrum.
In addition, the maximum point whose absorbance value is 0.2 or less was not included in the maximum value on the longest wavelength side.

-Triplet energy Eg (T)
Each compound was measured by a known phosphorescence measurement method (for example, “the world of photochemistry” (edited by the Chemical Society of Japan, 1993), page 50). Specifically, each compound is dissolved in a solvent (sample 10 [μmol / liter], EPA (diethyl ether: isopentane: ethanol = 5: 5: 2 (volume ratio), each solvent is a spectroscopic grade), and phosphorescence measurement is performed. The phosphorescence measurement sample placed in the quartz cell was cooled to 77 [K], the excitation light was irradiated onto the phosphorescence measurement sample, and the phosphorescence intensity was measured while changing the wavelength. Is the phosphorescence intensity, and the horizontal axis is the wavelength.
A tangent line was drawn with respect to the rising edge of the phosphorescence spectrum on the short wavelength side, and a wavelength value λ edge [nm] at the intersection of the tangent line and the horizontal axis was obtained. A value obtained by converting this wavelength value into an energy value by the following conversion formula was defined as EgT.
Conversion formula: Eg (T) [eV] = 1239.85 / λedge
For phosphorescence measurement, an F-4500 type spectrofluorometer main body manufactured by Hitachi High-Technology Co., Ltd. and optional equipment for low temperature measurement were used. Note that the measurement device is not limited to this, and the measurement may be performed by combining a cooling device and a cryogenic container, an excitation light source, and a light receiving device.

・ Affinity Af
It calculated from the measured value of ionization potential Ip and singlet energy Eg (S). The calculation formula is as follows.
Af = Ip-Eg (S)
Singlet energy Eg (S) was measured from the absorption edge of the absorption spectrum in benzene. Specifically, the absorption spectrum was measured using a commercially available visible / ultraviolet spectrophotometer, and calculated from the wavelength at which the spectrum started to rise.

-Electron mobility μ (e) and hole mobility μ (h)
Mobility evaluation was performed using impedance spectroscopy. A single carrier device as described below was manufactured, and a complex modulus was measured by applying a DC voltage on which an alternating voltage of 100 mV was applied. When the frequency at which the imaginary part of the modulus is the maximum is f _max (Hz), the response time T (seconds) is calculated as T = 1/2 / π / f _{max and} the electric field strength of the mobility is calculated using this value. Dependency was determined. The single carrier devices used for the measurement of hole mobility μ (h) and electron mobility μ (e) are described below.

μ (h): Al / measurement target compound (150) / ET (5) / LiF (1) / Al
μ (e): ITO / HT (5) / Measurement target compound (100) / Al
(Numerical values in parentheses are film thickness. Unit: nm).

Example 1
A glass substrate with an ITO transparent electrode (anode) having a thickness of 25 mm × 75 mm × 1.1 mm (manufactured by Geomatic Co., Ltd.) was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes, and then UV ozone cleaning was performed for 30 minutes.
First, the cleaned glass substrate with a transparent electrode line is mounted on a substrate holder of a vacuum deposition apparatus, and the compound electrode HI is formed by resistance heating vapor deposition so as to cover the transparent electrode on the surface on which the transparent electrode line is formed. Were laminated. Thereby, a hole injection layer adjacent to the anode having a thickness of 20 nm was formed.
On this hole injection layer, compound HT was laminated | stacked by resistance heating vapor deposition. Thereby, a hole transport layer having a thickness of 30 nm was formed.
On this hole transport layer, the compound H1 as the first host material and the compound D1 as the first dopant material were co-evaporated by resistance heating. This formed the 10 nm-thick 1st light emitting layer which shows red light emission. In addition, the density | concentration of compound D1 was 8 mass%.
Further, a compound H2 as a second host material, a compound H3 as a third host material, and a compound D2 as a second dopant material were co-deposited on the first light emitting layer by resistance heating. This formed the 30 nm-thick 2nd light emitting layer which shows green light emission. In addition, the density | concentration of compound D2 was 15 mass%. Further, the mass (concentration) of the third host material with respect to the total mass of the second host material and the third host material in the second light emitting layer was 5 mass%.
On this green light emitting layer, the compound ET was laminated by resistance heating vapor deposition. Thereby, an electron transport layer having a thickness of 35 nm was formed.
Furthermore, LiF was vapor-deposited on the electron transport layer to form an electron injection layer having a thickness of 1 nm. Furthermore, metal Al was vapor-deposited on the electron injection layer to form a cathode having a thickness of 80 nm.

-Examples 2-4 and Comparative Examples 1-3
In Examples 2 to 4 and Comparative Examples 1 to 3, in Example 1, the film thickness of the first light emitting layer, the film thickness of the second light emitting layer, the concentration of the third host material, the concentration of the third host material, etc. are shown in Table 2. An organic EL device was produced in the same manner as in Example 1 except that the changes were made as shown.

[Evaluation of organic EL elements]
In the organic EL devices produced in Examples 1 to 4 and Comparative Examples 1 to 3, the driving voltage, CIE 1931 chromaticity, current efficiency L / J, power efficiency η, and current density when the current density is 3.00 mA / cm ² The life LT90 was evaluated. The results are shown in Table 3.

-Drive voltage The voltage (unit: V) when electricity was supplied between ITO and Al so that a current density might be set to 3.00 mA / cm < ² > was measured.

CIE1931 chromaticity CIE1931 chromaticity coordinates (x, y) when a voltage is applied to the element so that the current density is 3.00 mA / cm ² is measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta). did.
・ Current efficiency L / J and power efficiency η
The spectral radiance spectrum when a voltage was applied to the device so that the current density was 3.00 mA / cm ² was measured with the above spectral radiance meter, and the current efficiency (unit: cd) was obtained from the obtained spectral radiance spectrum. / A) and power efficiency η (unit: lm / W) were calculated.
・ Lifetime LT90
A voltage was applied to the device so that the current density was 50 mA / cm ^2, and the time until the luminance became 90% with respect to the initial luminance (unit: hr) was measured.

  As can be seen from Table 2 and Table 3, in Examples 1 to 4 in which the second light-emitting layer contains the third host material H3, the third host can be used without changing the film thickness of the first light-emitting layer and the second light-emitting layer. The chromaticity CIE can be changed simply by changing the concentration of the material H3. On the other hand, in Comparative Examples 1 to 3 in which the second light emitting layer does not include the third host material H3, the chromaticity CIE is changed by changing the film thickness. However, in Comparative Example 2 in which the film thickness of the second light emitting layer is increased compared to Comparative Example 1, the voltage is significantly increased as compared to Comparative Example 1. Further, in Comparative Example 3 in which the film thickness of the first light emitting layer was made thinner than that in Comparative Example 1, no change was observed in the chromaticity CIE even though the film thickness was halved.

  The organic EL element of the present invention can be used as a light emitting element in a display device or a lighting device.

1,1A, 1B, 1C Organic EL device (organic electroluminescence device)
2 Substrate 3 Anode 4 Cathode 51 First light emitting layer (light emitting layer)
52 Second Light-Emitting Layer 6 Hole Transport Layer (Hole Transport Band)
61 1st hole injection layer 62 1st hole transport layer 63 2nd hole transport layer 7 Electron transport layer (electron transport zone)
72 First Electron Transport Layer 73 Second Electron Transport Layer

Claims (12)

An organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material ,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The first host material is an amine derivative;
The second host material, Ri compound der containing nitrogen-containing six-membered heterocyclic group,
Said 1st host material, said 2nd host material, and said 3rd host material satisfy | fill following formula (N-4), The organic electroluminescent element characterized by the above-mentioned.
μ (e) _H2 ≧ μ (e) _H3 > μ (e) _H1 (N-4)
However, in the formula (N-4), μ (e) _H1 is the electron mobility of the first host material, μ (e) _H2 is the electron mobility of the second host material, and μ (e ) _H3 is the electron mobility of the third host material. An organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The second host material is a compound containing a nitrogen-containing six-membered heterocyclic group,
The third host material is a compound having a skeleton represented by the following formula (130),
Said 1st host material, said 2nd host material, and said 3rd host material satisfy | fill following formula (N-4), The organic electroluminescent element characterized by the above-mentioned.
μ (e) _H2 ≧ μ (e) _H3 > Μ (e) _H1         (N-4)
However, in the formula (N-4), μ (e) _H1 Is the electron mobility of the first host material, μ (e) _H2 Is the electron mobility of the second host material, μ (e) _H3 Is the electron mobility of the third host material.
(In the formula (130), X represents an oxygen atom, a sulfur atom, or NR. ¹³⁰ Or CR ¹³¹ R ¹³² Represents.
R ¹³⁰ ~ R ¹³² Are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. R ¹³¹ And R ¹³² May be bonded to each other to form a ring structure. ) The organic electroluminescence device according to claim 2,
Said 3rd host material is represented by following formula (16), The organic electroluminescent element characterized by the above-mentioned.
(In the formula (16),
L ¹⁰ Is a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, or these groups having 2 to 5 each other. Represents a group linked together.
X ¹ , X ² Independently represent a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.
Y ¹ ~ Y ⁴ Each independently represents a hydrogen atom, a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon. A haloalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 10 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 30 carbon atoms, a substituted or unsubstituted ring carbon number having 6 to 6 carbon atoms 30 aromatic hydrocarbon groups or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. Adjacent Y ¹ ~ Y ⁴ They may form a bond with each other to form a ring structure.
p and q are 4.
r and s are 3.
B ¹ And B ² Each independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. ) In the organic electroluminescent element according to any one of claims 1 to 3 ,
The organic electroluminescent element, wherein the second host material is a compound having a carbazole skeleton. In the organic electroluminescent element according to any one of claims 1 to 4 ,
Said 2nd host material is represented by either of following formula (21)-(26), The organic electroluminescent element characterized by the above-mentioned.
(In formulas (21) to (26), R _{101 to} R ₁₀₅ each independently represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, or an alkyl group.) In the organic electroluminescent element according to claim 2, claim 3, or claim 5,
In the case of “substituted or unsubstituted”, the substituent may be an aromatic hydrocarbon group, a heterocyclic group, a linear or branched alkyl group, a cycloalkyl group, a halogenated alkyl group, an alkenyl group, an alkynyl group, an alkylsilyl group. An organic electroluminescent device, which is a group, arylsilyl group, alkoxy group, halogenated alkoxy group, aralkyl group, aryloxy group, halogen atom, cyano group, hydroxyl group, nitro group, or carboxy group. In the organic electroluminescent element according to any one of claims 1 to 6 ,
The first dopant material exhibits an emission peak of 570 nm or more,
Said 2nd dopant material shows the light emission peak below 570 nm, The organic electroluminescent element characterized by the above-mentioned. In the organic electroluminescent element according to any one of claims 1 to 7 ,
The organic electroluminescence element, wherein the first light emitting layer is provided on the anode side with respect to the second light emitting layer. An organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The first host material is an amine derivative;
Said 1st host material, said 2nd host material, and said 3rd host material satisfy | fill following formula (N-4), The organic electroluminescent element characterized by the above-mentioned.
μ (e) _H2 ≧ μ (e) _H3 > Μ (e) _H1         (N-4)
However, in the formula (N-4), μ (e) _H1 Is the electron mobility of the first host material, μ (e) _H2 Is the electron mobility of the second host material, μ (e) _H3 Is the electron mobility of the third host material. An organic electroluminescence device comprising at least a first light emitting layer and a second light emitting layer between an anode and a cathode,
The first light emitting layer includes a first host material and a first dopant material,
The second light emitting layer includes a second host material, a third host material, and a second dopant material,
The third host material is a compound having a skeleton represented by the following formula (130),
Said 1st host material, said 2nd host material, and said 3rd host material satisfy | fill following formula (N-4), The organic electroluminescent element characterized by the above-mentioned.
μ (e) _H2 ≧ μ (e) _H3 > Μ (e) _H1         (N-4)
However, in the formula (N-4), μ (e) _H1 Is the electron mobility of the first host material, μ (e) _H2 Is the electron mobility of the second host material, μ (e) _H3 Is the electron mobility of the third host material.
(In the formula (130), X represents an oxygen atom, a sulfur atom, or NR. ¹³⁰ Or CR ¹³¹ R ¹³² Represents.
R ¹³⁰ ~ R ¹³² Are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. R ¹³¹ And R ¹³² May be bonded to each other to form a ring structure. ) In the organic electroluminescent element according to claim 10,
Said 3rd host material is represented by following formula (16), The organic electroluminescent element characterized by the above-mentioned.
(In the formula (16),
L ¹⁰ Is a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, or these groups having 2 to 5 each other. Represents a group linked together.
X ¹ , X ² Independently represent a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.
Y ¹ ~ Y ⁴ Each independently represents a hydrogen atom, a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon. A haloalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 10 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 30 carbon atoms, a substituted or unsubstituted ring carbon number having 6 to 6 carbon atoms 30 aromatic hydrocarbon groups or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. Adjacent Y ¹ ~ Y ⁴ They may form a bond with each other to form a ring structure.
p and q are 4.
r and s are 3.
B ¹ And B ² Each independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. ) In the organic electroluminescence device according to claim 10 or 11,
In the case of “substituted or unsubstituted”, the substituent may be an aromatic hydrocarbon group, a heterocyclic group, a linear or branched alkyl group, a cycloalkyl group, a halogenated alkyl group, an alkenyl group, an alkynyl group, an alkylsilyl group. An organic electroluminescent device, which is a group, arylsilyl group, alkoxy group, halogenated alkoxy group, aralkyl group, aryloxy group, halogen atom, cyano group, hydroxyl group, nitro group, or carboxy group.