JP5441634B2 - Organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescent element (hereinafter sometimes referred to as an organic EL element) that can be effectively used for a surface light source such as a full-color display, a backlight, and an illumination light source, and a light source array such as a printer.

  Today, research and development on various display elements are active. In particular, organic EL elements are attracting attention as promising display elements because they can emit light with high luminance at a low voltage.

  The organic EL element is composed of a light emitting layer or a plurality of organic layers including a light emitting layer and a counter electrode sandwiching the organic layer. In the organic EL element, electrons injected from the cathode and holes injected from the anode are recombined in the organic layer, emitted light from the generated excitons, and other molecules generated by energy transfer from the excitons. It is an element for obtaining light emission using at least one of light emission from the excitons.

The organic EL element is also characterized in that it is possible to emit various emission colors by mixing colors combining a plurality of emission colors.
Among the luminescent colors, the need for white light emission is particularly high. White light emission can be used as power saving in general lighting, an in-vehicle display, or a backlight. Furthermore, it can be divided into blue, green, and red pixels using a color filter, and a full-color display device is also possible.

For example, it is disclosed that the light emitting layer contains two or more different light emitting materials, and at least one of the light emitting materials is an orthometalated complex (for example, see Patent Document 1).
However, there is a problem that light emitting materials having different exciton energies cause quenching or a change in emission color due to energy transfer due to interaction.

For example, it has been proposed that two layers of a blue light emitting layer that emits short wavelength light and a red light emitting layer that emits long wavelength light are stacked to obtain white light emission as a mixed color of both light emitting layers ( For example, see Patent Document 2).
However, even in such a configuration in which the light emitting layers are laminated, the excitons generated in the respective layers diffuse to the adjacent layers, so that the light emission color changes and the light emission efficiency decreases.

JP 2001-319780 A JP-A-7-142169

  An object of the present invention is to provide an organic electroluminescent device having a low driving voltage and high luminous efficiency. In particular, an organic electroluminescence device useful as a white light-emitting device is provided.

The above object of the present invention is achieved by the following means.
<1> An organic electroluminescent device having a pair of electrodes and at least one organic layer between the electrodes on a substrate, wherein the organic layer comprises at least two light emitting layers and at least two light emitting layers. Each of the at least two light emitting layers contains a phosphorescent material, and the phosphorescent material has a blue phosphorescent material having an emission peak at 420 nm or more and less than 500 nm, 500 nm or more The phosphorescence which is at least one selected from the group consisting of a green phosphorescent material having an emission peak at less than 570 nm and a red phosphorescent material having an emission peak from 570 nm to 650 nm and contained in each layer of the light emitting layer An organic electroluminescent device, wherein the light emitting material has different emission peaks, and the intermediate layer contains a binder material.

<2> The organic electroluminescence according to <1>, wherein the at least two light emitting layers include a layer containing the blue phosphorescent material and a layer containing the green phosphorescent material and the red phosphorescent material. element.

<3> The at least two light emitting layers are, in order from the substrate side, a layer containing the blue phosphorescent light emitting material, a layer containing the green phosphorescent light emitting material, and a layer containing the red phosphorescent light emitting material, A first intermediate layer between the layer containing the blue phosphorescent material and the layer containing the green phosphorescent material, and a layer containing the green phosphorescent material and a layer containing the red phosphorescent material Organic electroluminescent element as described in <1> which has a 2nd intermediate | middle layer in between.

<4> The at least two light emitting layers are a layer containing the green phosphorescent light emitting material, a layer containing the blue phosphorescent light emitting material, and a layer containing the red phosphorescent light emitting material in this order from the substrate side. A first intermediate layer is provided between the layer containing the green phosphorescent material and the blue phosphorescent material, and a first intermediate layer is provided between the layer containing the blue phosphorescent material and the layer containing the red phosphorescent material. The organic electroluminescent element as described in <1> which has 2 intermediate | middle layers.

<5> The organic electroluminescent element according to any one of <1> to <4>, wherein the binder material is a compound represented by the following general formula (1).

(In General Formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or aryl. Group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano group, ester group, amide group, halogen atom, perfluoroalkyl group having 1 to 6 carbon atoms, Represents a silyl group, and at least one of R _{1 to} R ₄ is a group having a double bond or a triple bond, X _{1 to} X ₁₂ each independently represents a hydrogen atom, an alkyl having 1 to 6 carbon atoms; Group, alkenyl group having 2 to 6 carbon atoms, alkynyl group having 2 to 6 carbon atoms, aryl group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano group ,ester , An amide group, a halogen atom, a perfluoroalkyl group having 1 to 6 carbon atoms, a silyl group.)

<6> The organic electroluminescent element according to any one of <1> to <4>, wherein the binder material is a hydrocarbon compound having an alkyl group having 7 or more carbon atoms.
<7> The organic electroluminescence device according to <6>, wherein the hydrocarbon compound having an alkyl structure having 7 or more carbon atoms is a linear saturated hydrocarbon compound.
<8> The organic electroluminescence device according to <6> or <7>, wherein the hydrocarbon compound having an alkyl structure having 7 or more carbon atoms is solid at room temperature.

<9> The organic electroluminescent element according to any one of <1> to <4>, wherein the binder material is a compound represented by the following general formula (2).
General formula (2) L- (Ar) m
(In general formula (2), Ar represents a group represented by the following general formula (3), L represents a trivalent or higher benzene skeleton, and m represents an integer of 3 or higher.)

(In General Formula (3), R ¹ represents a substituent, and when a plurality of R ¹ are present, they may be the same or different from each other. N1 represents an integer of 0 to 9.)

<10> The organic electroluminescent element according to any one of <1> to <4>, wherein the binder material is a compound represented by the following general formula (4).

(In General Formula (4), R ² represents a substituent, and when ^two or more R ² are present, they may be the same or different from each other. N2 represents an integer of 0 to 20.)

<11> The organic electroluminescent element according to any one of <1> to <10>, wherein the intermediate layer has a thickness of 0.1 nm or more and less than 5 nm.

ADVANTAGE OF THE INVENTION According to this invention, an organic electroluminescent element with a low drive voltage and high luminous efficiency is provided. In particular, an organic electroluminescent device useful as a white light emitting device is provided.
In the organic EL device of the present invention, the light emitting layers having different emission colors are partitioned by the intermediate layer. The intermediate layer is a layer containing an electrically inactive binder material. The binder material in the present invention is an electrically inactive organic compound. The energy difference (expressed as Eg) between the highest occupied orbital and the lowest unoccupied orbital is 4.0 eV or more, the triplet lowest excited level (T1 and (Noted) is 2.7 eV or more, electric affinity (denoted Ea) is 2.3 eV or less, and ionization potential (denoted Ip) is 6.1 eV or more. Thereby, diffusion of excitons generated in the light emitting layer can be prevented. Accordingly, excitons generated in each light-emitting layer are confined in each layer, and excitons having different excitation energies do not interact with each other and can emit light effectively in the layer, thereby improving the light emission efficiency. . Furthermore, since each light emitting layer emits light efficiently, high-luminance white light emission can be obtained by mixing these colors.
In addition, since the intermediate layer of the present invention can function as a thin layer, it is possible to maintain a high driving durability without increasing the driving voltage.

It is a conceptual diagram which shows the cross-sectional structure of the organic EL element of this invention. It is a conceptual diagram which shows the cross-sectional structure of another aspect of the organic EL element of this invention. It is a conceptual diagram which shows the cross-sectional structure of another aspect of the organic EL element of this invention. It is a conceptual diagram which shows the cross-sectional structure of another aspect of the organic EL element of this invention.

Hereinafter, the organic electroluminescent device will be described in detail.
The organic EL device in the present invention has a cathode and an anode on a substrate, and an organic layer including an organic light emitting layer (hereinafter sometimes simply referred to as “light emitting layer”) between both electrodes. In view of the properties of the light emitting element, at least one of the anode and the cathode is preferably transparent in the visible light region.
The organic layer in the present invention may be either a single layer or a laminate. As an aspect in the case of lamination, an aspect in which a hole transport layer, a light emitting layer, and an electron transport layer are laminated in this order from the anode side is preferable. Further, a charge blocking layer or the like may be provided between the hole transport layer and the light-emitting layer, or between the light-emitting layer and the electron transport layer. A hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer. Each layer may be divided into a plurality of secondary layers.

  The organic EL device of the present invention is preferably a white organic electroluminescent device having a pair of electrodes and at least one organic layer between the electrodes on the substrate, and the organic layer comprises at least two light emitting layers and the light emitting layer. The at least two light emitting layers contain phosphorescent materials having different emission colors, and the intermediate layer contains an electrically inactive binder material.

  In the present invention, the intermediate layer is preferably represented by a compound represented by the general formula (1), a hydrocarbon compound having an alkyl structure having 7 or more carbon atoms, or a general formula (2) as a binder material. The compound or the compound represented by General formula (4) is contained. More preferably, 50% by mass or more of the intermediate layer is a compound represented by the general formula (1), a hydrocarbon compound having an alkyl structure having 7 or more carbon atoms, a compound represented by the general formula (2), or It is a compound represented by General formula (4), The content rate of these compounds becomes like this. More preferably, it is 80 mass% or more, More preferably, it is 90 mass% or more, Most preferably, it is 100 mass%. As the intermediate layer, one kind of material may be used, or a plurality of kinds of materials may be mixed and used. When a mixture of a plurality of types of binder materials is used, the mixing ratio is preferably in the range of 1:99 to 50:50, more preferably in the range of 20:80 to 50:50. By using a mixture of a plurality of binder materials, it is possible to improve the luminous efficiency, drive durability, and suppress crystallization in addition to suppressing exciton migration.

  In the present invention, the intermediate layer is preferably a thin layer having a thickness of 0.1 nm or more and less than 5 nm. More preferably, they are 0.1 nm or more and 4 nm or less, More preferably, they are 0.5 nm or more and 3 nm or less. If the thickness of the intermediate layer is 5 nm or more, it is not preferable because the drive voltage increases and the light emission efficiency decreases. Further, if the thickness of the intermediate layer is less than 0.1 nm, the effect of the layer in the present invention cannot be exhibited, which is not preferable.

The configuration of the organic EL device of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing a cross-sectional configuration of the organic EL element of the present invention. A first phosphor containing a blue light emitting (B light emitting) phosphorescent material having an anode 2, a hole injection layer 3, and a hole transport layer 4 on a substrate 1 and having an emission peak at 420 nm or more and less than 500 nm. 1 light emitting layer 5-1, intermediate layer 9, phosphorescent material emitting green light (G light emission) having an emission peak in the range of 500 nm to less than 570 nm and phosphorescent light emitting red light (R emission) having an emission peak in the range of 570 nm to 650 nm And a second light-emitting layer 5-2 containing the material. An electron transport layer 6, an electron injection layer 7, and a cathode 8 are provided on the light emitting layer 5-2. When a voltage is applied to the element having such a structure, excitons are generated in the first light-emitting layer 5-1 and the second light-emitting layer 5-2, and light is emitted by recombination in each layer. The excitons generated in each layer are isolated by the intermediate layer 9 and do not diffuse and mix with each other, so that light is emitted in each layer. Therefore, inefficiency due to color shift or extinction due to energy transfer or the like is prevented, and high luminous efficiency is achieved. Further, the intermediate layer 9 is a layer made of an inert binder, and may have a thickness necessary for preventing diffusion of excitons to an adjacent layer, and a preferable compound used in the present invention is used. Therefore, an ultrathin layer of about 0.1 nm to 5 nm can sufficiently fulfill its function. Therefore, the drive voltage is not increased by introducing the intermediate layer, and the durability is not deteriorated.

  As shown in FIG. 3, the light emitting layer has a structure in which the first light emitting layer 25-1 has a green phosphorescent light emitting material having an emission peak at 500 nm to less than 570 nm and a red light having an emission peak at 570 nm to 650 nm. The second light emitting layer 25-2 may be a layer containing a blue light emitting phosphorescent material having an emission peak at 420 nm or more and less than 500 nm. In this case, the intermediate layer 29 is provided between the first light emitting layer 25-1 and the second light emitting layer 25-2.

  FIG. 2 is a conceptual diagram showing a cross-sectional configuration of an organic EL element according to another aspect of the present invention. A first phosphor containing a blue light emitting (B light emitting) phosphorescent material having an anode 2, a hole injection layer 3, and a hole transport layer 4 on a substrate 1 and having an emission peak at 420 nm or more and less than 500 nm. A first light emitting layer 15-1, a first intermediate layer 19-1, a second light emitting layer 15-2 containing a green light emitting (G light emitting) phosphorescent light emitting material having an emission peak at 500 nm or more and less than 570 nm, a second light emitting layer 15-2 And a third light emitting layer 15-3 containing a red light emitting (R light emitting) phosphorescent light emitting material having an emission peak at 570 nm to 650 nm. An electron transport layer 6, an electron injection layer 7, and a cathode 8 are provided on the light emitting layer 15-3.

  Also in the configuration of FIG. 2, light is emitted in each light emission color in each light emitting layer. Therefore, inefficiency due to color shift or extinction due to energy transfer or the like is prevented, and high luminous efficiency is achieved. Since the intermediate layer can perform its function sufficiently with an ultra-thin layer, the introduction of the intermediate layer does not increase the driving voltage nor deteriorate the durability.

As shown in FIG. 4, the light emitting layer is configured such that the first light emitting layer 35-1 is a green phosphorescent light emitting material having an emission peak at 500 nm or more and less than 570 nm, and the second light emitting layer 35-2. Is a layer containing a blue-emitting phosphorescent material having an emission peak at 420 nm or more and less than 500 nm, and the third light-emitting layer 35-3 is a red-emitting phosphorescent material having an emission peak at 570 nm or more and 650 nm or less. It may be a layer containing. In this case, the first intermediate layer 39-1 is disposed between the first light emitting layer 35-1 and the second light emitting layer 35-2, and the second light emitting layer 35-2 and the third light emitting layer 35 are disposed. -3 is disposed between the second intermediate layer 39-2.
Alternatively, although not illustrated, the first light-emitting layer 35-1 is a red light-emitting phosphorescent material having an emission peak at 570 nm to 650 nm, and the second light-emitting layer 35-2 is 420 nm to less than 500 nm. The third light emitting layer 35-3 is a layer containing a green light emitting phosphorescent material having an emission peak at 500 nm or more and less than 570 nm. Also good.

The binder used in the intermediate layer of the present invention preferably has an energy difference (expressed as Eg) of 4.0 eV or more between the highest occupied orbit and the lowest unoccupied orbit. More preferably, Eg is 4.1 eV or more, and still more preferably 4.2 eV or more.
The binder used in the intermediate layer of the present invention preferably has a triplet lowest excitation level (denoted as T1) of 2.7 eV or more. More preferably, it is 2.8 eV or more, and still more preferably 2.9 eV or more.
The binder used in the intermediate layer of the present invention preferably has an electric affinity (denoted as Ea) of 2.3 eV or less. More preferably, it is 2.4 eV or more, and still more preferably 2.5 eV or more.
The binder used in the intermediate layer of the present invention preferably has an ionization potential (denoted Ip) of 6.1 eV or more. More preferably, it is 6.2 eV or more, More preferably, it is 6.3 eV or more.

As the binder material used for the intermediate layer in the present invention, one type of material may be used, or a plurality of types of materials may be used. When a mixture of a plurality of types of binder materials is used, the mixing ratio is preferably in the range of 1:99 to 50:50, more preferably in the range of 20:80 to 50:50. By using a mixture of a plurality of binder materials, in addition to suppressing exciton migration, it is possible to improve luminous efficiency, drive durability, and crystallization.
The binder used for the intermediate layer is preferably a compound represented by the general formula (1), and as another preferred embodiment, a hydrocarbon compound having an alkyl structure. More preferably, the hydrocarbon compound having an alkyl structure is a saturated hydrocarbon compound not containing a double bond and having an ethylene (—CH ₂ CH ₂ —) structure. More preferably, the hydrocarbon compound having an alkyl structure is a linear saturated hydrocarbon compound.
Preferably, the hydrocarbon compound having an alkyl structure is solid at room temperature.
The intermediate layer in the present invention is a layer that prevents the diffusion of excitons to the adjacent layer, and by using the above-mentioned preferred compound, an extremely thin layer of about 0.1 nm to 5 nm can sufficiently perform its function. Can do.

  Although the specific example of the binder material which concerns on this invention is given to the following, it is not limited to these.

(Adamantane compounds)
Examples of the electrically inactive material constituting the intermediate layer of the organic electroluminescent element according to the present invention include an adamantane compound represented by the following general formula (1).

In the general formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or an aryl group. , Heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano group, ester group, amide group, halogen atom, perfluoroalkyl group having 1 to 6 carbon atoms, silyl Represents a group, and at least one of R _{1 to} R ₄ is a group having a double bond or a triple bond. X _{1 to} X ₁₂ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group, a heteroaryl group, or a carbon number. 1 to 6 alkoxy groups, acyl groups, acyloxy groups, amino groups, nitro groups, cyano groups, ester groups, amide groups, halogen atoms, perfluoroalkyl groups having 1 to 6 carbon atoms, and silyl groups.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl (that is, 2 -Butyl), isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.

Examples of the alkenyl group having 2 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include vinyl, allyl (that is, 1- (2-propenyl)), 1- (1- Propenyl), 2-propenyl, 1- (1-butenyl), 1- (2-butenyl), 1- (3-butenyl), 1- (1,3-butadienyl), 2- (2-butenyl), 1 -(1-pentenyl), 5- (cyclopentadienyl), 1- (1-cyclohexenyl) and the like.

Examples of the alkynyl group having 2 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include ethynyl, propargyl (that is, 1- (2-propynyl)), 1- (1- Propynyl), 1-butadiynyl, 1- (1,3-pentadiynyl) and the like.

Examples of the aryl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include phenyl, o-tolyl (that is, 1- (2-methylphenyl)), m-tolyl, p-tolyl, 1- (2,3-dimethylphenyl), 1- (3,4-dimethylphenyl), 2- (1,3-dimethylphenyl), 1- (3,5-dimethylphenyl), 1- (2,5 -Dimethylphenyl), p-cumenyl, mesityl, 1-naphthyl, 2-naphthyl, 1-anthranyl, 2-anthranyl, 9-anthranyl, and 4-biphenylyl (ie, 1- (4-phenyl) phenyl), 3 -Biphenylyls such as biphenylyl, 2-biphenylyl, 4-p-terphenylyl (i.e. 1-4- (4-biphenylyl) phenyl), 4-m-terphenylyl (i.e. Terphenylyls such as 1-4- (3-biphenylyl) phenyl).

Examples of the heteroaryl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include a nitrogen atom, an oxygen atom, a sulfur atom, and the like as the hetero atom contained therein. Specifically, Examples include imidazolyl, pyrazolyl, pyridyl, pyrazyl, pyrimidyl, triazinyl, quinolyl, isoquinolinyl, pyrrolyl, indolyl, furyl, thienyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl, azepinyl and the like.

Examples of the alkoxy group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include methoxy, ethoxy, isopropoxy, cyclopropoxy, n-butoxy, tert-butoxy, cyclohexyloxy , Phenoxy and the like.

Examples of the acyl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include acetyl, benzoyl, formyl, and pivaloyl.

Examples of the acyloxy group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include acetoxy, benzoyloxy, and the like.

Examples of the amino group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, pyrrolidino, piperidino, morpholino and the like. Can be mentioned.

Examples of the ester group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include methyl ester (that is, methoxycarbonyl), ethyl ester, isopropyl ester, phenyl ester, benzyl ester, and the like.

Examples of the amide group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include N, N-dimethylamide (that is, dimethylaminocarbonyl) and N-phenylamide linked by a carbon atom of the amide. N, N-diphenylamide, N-methylacetamide (that is, acetylmethylamino), N-phenylacetamide, N-phenylbenzamide and the like linked by a nitrogen atom of the amide.

Examples of the halogen atom represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the perfluoroalkyl group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include trifluoromethyl, pentafluoroethyl, 1-perfluoropropyl, and 2-perfluoro. Examples include propyl and perfluoropentyl.

Examples of the silyl group having 1 to 18 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include trimethylsilyl, triethylsilyl, triisopropylsilyl, triphenylsilyl, methyldiphenylsilyl, dimethylphenylsilyl. , Tert-butyldimethylsilyl, tert-butyldiphenylsilyl, and the like.

Said R < ₁ > -R < ₄ > and X < ₁ > -X < ₁₂ > may be further substituted by another substituent. For example, examples of the alkyl group substituted with an aryl group include benzyl, 9-fluorenyl, 1- (2-phenylethyl), 1- (4-phenyl) cyclohexyl, etc., and the aryl group substituted with a heteroaryl group Examples thereof include 1- (4-N-carbazolyl) phenyl, 1- (3,5-di (N-carbazolyl)) phenyl, 1- (4- (2-pyridyl) phenyl) and the like.

R _{1 to} R ₄ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an amino group, an ester group, or a silyl group, and more preferably a hydrogen atom. , An alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an amino group, and a silyl group, and particularly preferably a hydrogen atom, an alkyl group, and an aryl group.

X _{1 to} X ₁₂ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an amino group, an ester group, or a silyl group, and more preferably a hydrogen atom. , An alkyl group and an aryl group, particularly preferably a hydrogen atom.

The alkyl group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclopentyl, and cyclohexyl are more preferable, and methyl, ethyl, tert-butyl, n-hexyl, and cyclohexyl are more preferable, and methyl and ethyl are particularly preferable.

The aryl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ is preferably phenyl, o-tolyl, 1- (3,4-dimethylphenyl), 1- (3,5-dimethylphenyl). , 1-naphthyl, 2-naphthyl, 9-anthranyl, and biphenylyls and terphenylyls, more preferably phenyl, biphenylyls, and terphenylyls, and more preferably phenyl.

The hydrogen atom represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ may be a deuterium atom, and is preferably a deuterium atom.

  Part or all of the hydrogen atoms contained in the compound represented by the general formula (1) may be substituted with deuterium atoms.

At least one of R _{1 to} R ₄ is a double bond or a group having a triple bond. Examples of the double bond include C═C, C═O, C═S, C═N, N = N, S = O, P = O, etc., preferably C = C, C = O, C = N, S = O, P = O, more preferably C = C, C = O, C = N, particularly preferably C = C. Examples of the triple bond include C≡C and C≡N, and preferably C≡C.

As the group having a double bond or triple bond of R _{1 to} R ₄ , an aryl group is preferable, and among them, a phenyl group, a biphenylyl group, and a terphenylyl group represented by the following are preferable, and a phenyl group is particularly preferable.

At least one of R _{1 to} R ₄ is a group having a double bond or a triple bond, but the number of R _{1 to} R ₄ having a double bond or a triple bond is preferably 2 to 4, 3 -4 is more preferable, and 4 is particularly preferable.

When the number of R _{1 to} R ₄ having a double bond or triple bond is 1 to 3, R ^{1 to} R ⁴ consisting of only the remaining single bond is a hydrogen atom, an alkyl group, an alkoxy group, or a silyl group. Preferably, a hydrogen atom, an alkyl group, and a silyl group are preferable, and a hydrogen atom and an alkyl group are particularly preferable.

R _{1 to} R ₄ and X _{1 to} X ₁₂ may be linked to each other to form a ring structure. For example, as described below, X ₂ , X ₃ , and X ₉ may be linked to each other to form a diamantane structure, and X ₄ , X ₅ , and X ₁₂ are linked to each other to form a triamantane structure. May be formed. These diamantane structure and triamantane structure may be further substituted with a substituent.

  In the present invention, the compound represented by the general formula (1) is preferably mixed and contained. Preferably, compounds having different groups having a double bond, or compounds having different numbers of substitution can be used in combination. Examples of the group having a double bond include the above phenyl group, biphenylyl group, and terphenylyl group, and compounds having 1 to 4 substitutions thereof. For example, a mono-substituted product having a substitution number of 1 and a tetra-substitution product having a substitution number of 4 can be used.

  Specific examples of the adamantane compound represented by the general formula (1) used in the present invention are shown below, but the compound of the present invention is not limited thereto.

  The adamantane compound represented by the general formula (1) has characteristics that Eg and Ip are large and Ea is small, and does not contribute to electron transport, hole transport, exciton quenching, and exciton dissipation. It is considered that the effect of suppressing energy transfer between the light emitting materials via the host material is exhibited.

(Hydrocarbon compound having an alkyl group)
A hydrocarbon compound having an alkyl group can also be used as an electrically inactive material contained in the intermediate layer. Such a hydrocarbon compound having an alkyl group is a saturated hydrocarbon compound that does not contain a double bond and contains an ethylene (—CH ₂ CH ₂ —) structure, from the viewpoint of forming a film at a relatively low temperature by vapor deposition. It is preferably a linear saturated hydrocarbon compound. Moreover, it is preferable that it is solid at room temperature (25 degreeC) from a viewpoint which comprises an intermediate | middle layer after film-forming.
Preferably, it is a hydrocarbon compound having an alkyl group having 7 or more carbon atoms.
Specifically, those represented by the following structural formula are preferable.

As the electrically inactive material contained in the intermediate layer, aromatic hydrocarbons represented by the following general formula (2) or general formula (4) can also be preferably used.
General formula (2) L- (Ar) m
In general formula (2), Ar represents a group represented by the following general formula (3), L represents a trivalent or higher benzene skeleton, and m represents an integer of 3 or higher.

In General Formula (3), R ¹ represents a substituent, and when a plurality of R ¹ are present, they may be the same as or different from each other. n1 represents the integer of 0-9.

In General Formula (4), R ² represents a substituent, and when a plurality of R ² are present, they may be the same as or different from each other. n2 represents an integer of 0 to 20.

First, the general formula (2) will be described in detail.
L contained in the general formula (2) represents a trivalent or higher benzene skeleton. Ar represents a group represented by the general formula (3), and m represents an integer of 3 or more. m is preferably 3 or more and 6 or less, and more preferably 3 or 4.

Next, the group represented by the general formula (3) will be described.
R ¹ contained in the general formula (3) represents a substituent. Here, examples of the substituent include an alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms such as methyl, ethyl, iso-propyl, tert. -Butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms such as vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl groups (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably carbon atoms). 2 to 10, for example, propargyl, 3-pentynyl, etc.), aryl group (preferably carbon number) 30, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyl, p- methylphenyl, naphthyl, anthranyl),

An amino group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino; Etc.), an alkoxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc. An aryloxy group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy). Etc.), heteroaryloxy groups (preferably having 1 to 30 carbon atoms, more preferred) Has 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, and the like, acyl groups (preferably 1 to 30 carbon atoms, more preferably 1 carbon atoms). To 20, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl, pivaloyl, etc., alkoxycarbonyl groups (preferably 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, especially Preferably it is C2-C12, for example, a methoxycarbonyl, ethoxycarbonyl etc. are mentioned, Aryloxycarbonyl group (Preferably C7-30, More preferably C7-20, Especially preferably C7 To 12 and examples thereof include phenyloxycarbonyl).

An acyloxy group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy and benzoyloxy), an acylamino group (preferably having 2 carbon atoms) To 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino, and alkoxycarbonylamino groups (preferably 2 to 30 carbon atoms, more preferably Has 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, and examples thereof include methoxycarbonylamino and the like, and aryloxycarbonylamino group (preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms). Particularly preferably, it has 7 to 12 carbon atoms, such as phenyloxycarbonylamino Mentioned are),

A sulfonylamino group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino, benzenesulfonylamino, etc.), a sulfamoyl group (preferably Is a carbon number of 0-30, more preferably a carbon number of 0-20, particularly preferably a carbon number of 0-12, for example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc.). A carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), an alkylthio group (Preferably 1-30 carbon atoms, more preferred Or having 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio, and arylthio groups (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly Preferably it is C6-C12, for example, phenylthio etc. are mentioned, for example, Preferably it is C1-C30, More preferably, it is C1-C20, Most preferably, it is C1-C12. For example, pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like),

A sulfonyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms such as mesyl and tosyl), a sulfinyl group (preferably having 1 to 1 carbon atoms). 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl and the like, ureido group (preferably 1 to 30 carbon atoms, more preferably carbon numbers) 1 to 20, particularly preferably 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido and the like, phosphoric acid amide group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms) Particularly preferably, it has 1 to 12 carbon atoms, and examples thereof include diethyl phosphate amide and phenyl phosphate amide)

  Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic ring Group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and having a hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom, etc., specifically, for example, imidazolyl, pyridyl, quinolyl, Furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, especially Preferably it has 3 to 24 carbon atoms, such as trimethylsilyl, trif Nirushiriru and the like, and the like).

When a plurality of R ¹ are present, they may be the same as or different from each other, and these may be bonded to each other to form a ring. R ¹ may be further substituted.

  n1 represents an integer of 0 to 9. n1 is preferably an integer of 0 to 6, and more preferably 0 to 3.

Next, general formula (4) will be described.
R ² in the general formula (4) represents a substituent. The substituent R ² is synonymous with the substituent R ^{1 including} preferred embodiments.
n2 represents an integer of 0 to 20. The preferable range of n2 is 0 to 10, more preferably 0 to 5.

  Although the specific example of a compound represented by General formula (2) or General formula (4) below is shown, this invention is not limited to these.

(Light emitting layer)
The organic light emitting layer receives holes from the anode, the hole injection layer, or the hole transport layer when an electric field is applied, receives electrons from the cathode, the electron injection layer, or the electron transport layer, and recombines holes and electrons. It is a layer having a function of providing a field to emit light.
The light emitting layer in the present invention has at least two light emitting layers and an intermediate layer between the light emitting layers.
The at least two light emitting layers contain phosphorescent materials having different emission colors, and preferably each contain a host material.
The light emitting layer may be two layers, three layers, or more layers. In the case of two layers, it is preferable that the emission colors are complementary to each other, and it is preferable to form a white color by mixing light emission from the respective emission layers. In the case of three layers, it is desirable that the three layers be made of a light emitting material exhibiting light emission colors of the three primary colors of red (R), green (G), and blue (B).
Alternatively, in the case of a two-layer structure or a three-layer structure, if there is a color that is insufficient for white formation, it is also preferable to add a light-emitting material that compensates for it and introduce it into any of the light-emitting layers.

The light emitting layer in the present invention preferably contains a host material.
The host material is a compound mainly responsible for charge injection and transport in the light-emitting layer, and is a compound that itself does not substantially emit light. In this specification, “substantially no light emission” means that the light emission amount from the substantially non-light emitting compound is preferably 5% or less, more preferably 3% or less of the total light emission amount of the entire device. More preferably, it means 1% or less.
When the phosphorescent material in the present invention is electron transporting, the host material is preferably a hole transporting material, and conversely, the phosphorescent material in the present invention is a hole transporting material. The host material is preferably an electron transporting material.

In the present invention, the concentration (content) of the material constituting the light-emitting layer 5-1 in FIG. 1 or the light-emitting layer 25-2 in FIG. 3 varies depending on the type of the material, but the production stability, suppression of energy transfer, color From the viewpoint of balance and the like, the blue phosphorescent material having an emission peak at 420 nm or more and less than 500 nm is 5% by mass to 30% by mass, the host material concentration is 70% by mass to 95% by mass, the light emitting layer 5-2 or the light emitting layer The concentration (content) of each material constituting 25-1 is a green phosphorescent material having an emission peak at 500 nm to less than 570 nm, and a red color having an emission peak at 0.2% to 15% by mass and 570 nm to 650 nm. The phosphorescent material is preferably contained in an amount of 0.2% to 15% by mass, and the host material concentration is 70% to 99% by mass.
The thickness of each light emitting layer is preferably 5 nm or more and 100 nm or less, more preferably 5 nm or more and 70 nm or less, and further preferably 5 nm or more and 50 nm or less for the light emitting layer 5-1 or the light emitting layer 25-2. preferable. The light emitting layer 5-2 or the light emitting layer 25-1 is preferably 5 nm to 50 nm, more preferably 5 nm to 40 nm, and still more preferably 5 nm to 30 nm.

In the present invention, the concentration (content) of the material constituting the light-emitting layer 15-1 in FIG. 2 or the light-emitting layer 35-2 in FIG. 4 varies depending on the type of the material, but the production stability, suppression of energy transfer, color From the viewpoint of balance and the like, the blue phosphorescent material having an emission peak at 420 nm or more and less than 500 nm is 5% by mass to 30% by mass, the host material concentration is 70% by mass to 95% by mass, the light emitting layer 15-2 or the light emitting layer The concentration (content) of each material constituting 35-1 is 5% by mass to 30% by mass for a green phosphorescent light emitting material having an emission peak at 500 nm to less than 570 nm, and the host material concentration is 70% by mass to 95% by mass. The concentration (content) of the material constituting the light emitting layer 15-3 or the light emitting layer 35-3 is 0 for a red phosphorescent light emitting material having an emission peak at 570 nm or more and 650 nm or less. 15 wt% 2 wt% or more or less, the host material concentration is 85% by mass to 99% by weight or less, in it preferably contains, respectively.
The thickness of each light emitting layer is preferably 5 nm or more and 100 nm or less, more preferably 5 nm or more and 70 nm or less, and further preferably 5 nm or more and 50 nm or less for the light emitting layer 15-1 or the light emitting layer 35-2. preferable. The light emitting layer 5-2 or the light emitting layer 35-1 is preferably 5 nm to 50 nm, more preferably 5 nm to 40 nm, and still more preferably 5 nm to 30 nm. The light emitting layer 5-3 or the light emitting layer 35-3 is preferably 5 nm to 50 nm, more preferably 5 nm to 40 nm, and still more preferably 5 nm to 30 nm.
In addition, the light emitting layer in the present invention may contain an electrically inactive binder material.

-Phosphorescent material-
Examples of the phosphorescent light-emitting material contained in the light-emitting layer include complexes containing transition metal atoms or lanthanoid atoms.
Although it does not specifically limit as a transition metal atom, Preferably, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum are mentioned, More preferably, they are rhenium, iridium, and platinum.
Examples of lanthanoid atoms include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these lanthanoid atoms, neodymium, europium, and gadolinium are preferable.

Examples of the ligand of the complex include G.I. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H.C. Examples include ligands described in Yersin's "Photochemistry and Photophysics of Coordination Compounds" published by Springer-Verlag 1987, Akio Yamamoto "Organic Metal Chemistry-Fundamentals and Applications-" .
Specific ligands are preferably halogen ligands (preferably chlorine ligands), nitrogen-containing heterocyclic ligands (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, phenanthroline, etc.), diketones Ligand (for example, acetylacetone), carboxylic acid ligand (for example, acetic acid ligand), carbon monoxide ligand, isonitrile ligand, cyano ligand, more preferably nitrogen-containing Heterocyclic ligand. The complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.

  Among these, as specific examples of the light emitting material, for example, US6303238B1, US6097147, WO00 / 57676, WO00 / 70655, WO01 / 08230, WO01 / 39234A2, WO01 / 41512A1 Gazette, WO02 / 02714A2, WO02 / 15645A1, WO02 / 44189A1, JP2001-247859, JP2002-302671, JP2002-117978, JP2002-225352 JP, 2002-233506, JP 2003-133074, JP 2002-170684, EP 12112257, JP 2002-226495, JP 2002-23 No. 894, JP-A No. 2001-247859, JP-A No. 2001-298470, JP-A No. 2002-173684, JP-A No. 2002-203678, JP-A No. 2002-203679, JP-A No. 2004-357791 And phosphorescent compounds described in JP-A-2006-256999.

The phosphorescent light-emitting material used in the present invention preferably has an electron transport property with an electron affinity (Ea) of 2.5 eV or more and 3.5 eV or less and an ionization potential (Ip) of 5.7 eV or more and 7.0 eV or less. It is a phosphorescent material.
Specifically, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, platinum, gold, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and Examples include a ruthenium complex, more preferably a ruthenium, rhodium, palladium, rhenium, iridium, or platinum complex, and most preferably an iridium or platinum complex.

  The phosphorescent material used in the present invention is particularly preferably a metal complex having a tridentate or higher ligand. The metal complex having a tridentate or higher ligand in the present invention will be described.

1) Metal ion Although the atom coordinated to a metal ion in the metal complex having a tridentate or higher ligand is not particularly limited, an oxygen atom, a nitrogen atom, a carbon atom, a sulfur atom or a phosphorus atom is preferable, and an oxygen atom, A nitrogen atom or a carbon atom is more preferable, and a nitrogen atom or a carbon atom is still more preferable.

  The metal ion in the metal complex is not particularly limited, but is preferably a transition metal ion or a rare earth metal ion from the viewpoint of improving luminous efficiency, improving durability, and lowering driving voltage, iridium ion, platinum ion, gold ion, Rhenium ion, tungsten ion, rhodium ion, ruthenium ion, osmium ion, palladium ion, silver ion, copper ion, cobalt ion, zinc ion, nickel ion, lead ion, aluminum ion, gallium ion, or rare earth metal ion (for example, europium) An iridium ion, a platinum ion, a gold ion, a rhenium ion, a tungsten ion, a palladium ion, a zinc ion, an aluminum ion, a gallium ion, and the like. , Europium ion, cadolinium ion or terbium ion, more preferably iridium ion, platinum ion, rhenium ion, tungsten ion, europium ion, kadolinium ion or terbium ion, more preferably iridium ion. Platinum ion, palladium ion, zinc ion, aluminum ion, or gallium ion, and most preferably platinum ion.

2) Coordination number The metal complex having a tridentate or higher ligand is preferably a metal complex having a tridentate or higher and hexadentate ligand from the viewpoint of improving luminous efficiency and durability. In the case of a metal ion that easily forms a hexacoordination complex represented by, a metal complex having a tridentate, tetradentate, or hexadentate ligand is more preferable, and a tetracoordination represented by a platinum ion. In the case of a metal ion that easily forms a type complex, a metal complex having a tridentate or tetradentate ligand is more preferable, and a metal complex having a tetradentate ligand is more preferable.

3) Ligand From the viewpoint of improving luminous efficiency and durability, the ligand of the metal complex is preferably a chain or a ring, and is represented by a central metal (for example, represented by the general formula (A) described later). In the case of a compound to be represented, M ¹¹ represents nitrogen-containing heterocycles coordinated with nitrogen (for example, pyridine ring, quinoline ring, pyrimidine ring, pyrazine ring, pyrrole ring, imidazole ring, pyrazole ring, oxazole). A ring, a thiazole ring, an oxadiazole ring, a thiadiazole ring, or a triazole ring). The nitrogen-containing heterocycle is more preferably a nitrogen-containing 6-membered heterocycle or a nitrogen-containing 5-membered heterocycle. These heterocycles may form condensed rings with other rings.

  In addition, that the ligand of a metal complex is a chain | strand means that the ligand of a metal complex does not take a cyclic structure (for example, a terpyridyl ligand etc.). Further, that the ligand of the metal complex is cyclic means that a plurality of ligands in the metal complex are bonded to each other to form a closed structure (for example, phthalocyanine ligand, crown ether coordination). Etc.).

4) Preferred Metal Complex Structure The metal complex used as the phosphorescent material in the present invention is preferably an organic compound represented by the general formula (A) described in detail below.

In the general formula (A), M ¹¹ represents a metal ion, and L ^{11 to} L ¹⁵ each represents a ligand coordinated to M ¹¹ . An atomic group may further exist between L ¹¹ and L ¹⁴ to form a cyclic ligand. L ¹⁵ may combine with both L ¹¹ and L ¹⁴ to form a cyclic ligand.
Y ¹¹ , Y ¹² and Y ¹³ each represent a linking group, a single bond or a double bond. When Y ¹¹ , Y ¹² , or Y ¹³ is a linking group, L ¹¹ and Y ¹² , Y ¹² and L ¹² , L ¹² and Y ¹¹ , Y ¹¹ and L ¹³ , L ¹³ and Y ¹³ , Y ¹³ And the bond between L ¹⁴ each independently represents a single bond or a double bond. n ¹¹ represents the 0-4. The bond between M ¹¹ and L ^{11 to} L ¹⁵ may be any of a coordination bond, an ionic bond, and a covalent bond.

In the general formula (A), the metal ion represented by M ¹¹ is not particularly limited, but a divalent or trivalent metal ion is preferable. The divalent or trivalent metal ion is preferably a gold ion, platinum ion, iridium ion, rhenium ion, palladium ion, rhodium ion, ruthenium ion, copper ion, europium ion, gadolinium ion, or terbium ion, and platinum ion, iridium. Ions or europium ions are more preferable, platinum ions and iridium ions are more preferable, and platinum ions are particularly preferable.

In general formula (A), L ¹¹ , L ¹² , L ¹³ , and L ¹⁴ each independently represent a ligand that coordinates to M ¹¹ . The atoms contained in L ¹¹ , L ¹² , L ¹³ , and L ¹⁴ and coordinated to M ¹¹ are preferably a nitrogen atom, an oxygen atom, a sulfur atom, a carbon atom, or a phosphorus atom. An atom, a sulfur atom, or a carbon atom is more preferable, and a nitrogen atom, an oxygen atom, or a carbon atom is still more preferable.

The bonds formed by M ¹¹ and L ¹¹ , L ¹² , L ¹³ , and L ¹⁴ may each independently be a covalent bond, an ionic bond, or a coordinate bond. For convenience of explanation, the ligand in the present invention shall be used not only in the case of a coordination bond but also in the case of being formed by other ionic bonds or covalent bonds.
The ligand consisting of L ¹¹ , Y ¹² , L ¹² , Y ¹¹ , L ¹³ , Y ¹³ , and L ¹⁴ is an anionic ligand (a ligand in which at least one anion binds to a metal). Is preferred. 1-3 are preferable, as for the number of anions in an anionic ligand, 1-2 are more preferable, and 2 is more preferable.

L ¹¹ , L ¹² , L ¹³ , and L ¹⁴ coordinated to M ¹¹ by a carbon atom are not particularly limited, but are each independently an imino ligand, an aromatic carbocyclic ligand (for example, a benzene ligand). , Naphthalene, anthracene, or phenanthracene ligands), heterocyclic ligands (eg, thiophene ligands, pyridine ligands, pyrazine ligands, pyrimidine ligands, thiazole ligands) Ligands, oxazole ligands, pyrrole ligands, imidazole ligands, pyrazole ligands, and condensed rings containing them (eg, quinoline ligands, benzothiazole ligands, etc.) and their tautomers Sex body).

L ¹¹ , L ¹² , L ¹³ , and L ¹⁴ coordinated to M ¹¹ by a nitrogen atom are not particularly limited, but each independently includes a nitrogen-containing heterocyclic ligand (eg, pyridine ligand, pyrazine coordination). Ligand, pyrimidine ligand, pyridazine ligand, triazine ligand, thiazole ligand, oxazole ligand, pyrrole ligand, imidazole ligand, pyrazole ligand, triazole ligand, oxadi Azole ligands, thiadiazole ligands, and condensed rings containing them (for example, quinoline ligands, benzoxazole ligands, benzimidazole ligands, etc.) and tautomers thereof (note that In the present invention, in addition to the usual isomers, the following examples are also defined as tautomers, for example, the 5-membered heterocyclic ligand of the compound (24) described later and the 5-membered terminal of the compound (64). Arocyclic ligands, 5-membered heterocyclic ligands of the compound (145) are also defined as pyrrole tautomers, etc.) amino ligands (alkylamino ligands (preferably having 2 to 30 carbon atoms, More preferably, it has 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include methylamino.), Arylamino ligands (for example, phenylamino), acylamino ligands (Preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino ligands (preferably Has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 12 carbon atoms, and examples thereof include methoxycarbonylamino. ), An aryloxycarbonylamino ligand (preferably having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonylamino). Sulfonylamino ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino, benzenesulfonylamino, etc.), imino. These ligands may be further substituted.

L ¹¹ , L ¹² , L ¹³ , and L ¹⁴ coordinated to M ¹¹ with an oxygen atom are not particularly limited, but are independently an alkoxy ligand (preferably having 1 to 30 carbon atoms, more preferably having carbon atoms). 1 to 20, particularly preferably 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy, 2-ethylhexyloxy), aryloxy ligands (preferably 6 to 30 carbon atoms, more preferably Has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyloxy, 1-naphthyloxy, 2-naphthyloxy and the like, and a heterocyclic oxy ligand (preferably having 1 carbon atom). To 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridyloxy, pyrazyloxy, pyrimidyloxy, Noryloxy, etc.), acyloxy ligands (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy, benzoyloxy and the like. ), A silyloxy ligand (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyloxy and triphenylsilyloxy). , Carbonyl ligands (eg, ketone ligands, ester ligands, amide ligands, etc.), ether ligands (eg, dialkyl ether ligands, diaryl ether ligands, furyl ligands, etc.) Can be mentioned.

Although it does not specifically limit as L < ¹¹ >, L < ¹² >, L <^13> , and L < ¹⁴ > coordinated to M < ¹¹ > by a sulfur atom, Each is independently alkylthio ligand (preferably C1-C30, More preferably, carbon number. 1 to 20, particularly preferably 1 to 12 carbon atoms, for example, methylthio, ethylthio, etc.), an arylthio ligand (preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably Has 6 to 12 carbon atoms, for example, phenylthio and the like, and a heterocyclic thio ligand (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms). And examples thereof include pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio), and thiocarbo. Le ligands (e.g. thioketone ligand, etc. thioester ligands), or thioether ligands (e.g. dialkyl thioether ligands, diaryl thioether ligands, etc. thiofuryl ligand), and the like. These substituted ligands may be further substituted.

L ¹¹ , L ¹² , L ¹³ , and L ¹⁴ coordinated to M ¹¹ with a phosphorus atom are not particularly limited, but each independently includes a dialkylphosphino group, a diarylphosphino group, a trialkylphosphine, a triarylphosphine, And a phosphinin group. These groups may be further substituted.

L ¹¹ and L ¹⁴ are each independently an aromatic carbocyclic ligand, alkyloxy ligand, aryloxy ligand, ether ligand, alkylthio ligand, arylthio ligand, alkylamino coordination Ligand, arylamino ligand, acylamino ligand, nitrogen-containing heterocyclic ligand (eg pyridine ligand, pyrazine ligand, pyrimidine ligand, pyridazine ligand, triazine ligand, thiazole ligand) Ligands, oxazole ligands, pyrrole ligands, imidazole ligands, pyrazole ligands, triazole ligands, oxadiazole ligands, thiadiazole ligands, or condensed ligand bodies containing them (For example, a quinoline ligand, a benzoxazole ligand, a benzimidazole ligand, or the like, or a tautomer thereof) is preferable, and an aromatic carbocyclic ligand Aryloxy ligands, arylthio ligands, arylamino ligands, and pyridine ligands, pyrazine ligands, imidazole ligands, or condensed ligand bodies containing them (for example, quinoline ligands) , A quinoxaline ligand, a benzimidazole ligand, or the like, or a tautomer thereof, an aromatic carbocyclic ligand, an aryloxy ligand, an arylthio ligand, or an arylamino coordination A child is further preferred, and an aromatic carbocyclic ligand or an aryloxy ligand is particularly preferred.

L ¹² and ^{L 13} each ^{independently} ligands preferably form a coordinate bond with ^{M 11,} as ligands forming a coordination bond with ^{M 11,} a pyridine ring, a pyrazine ring, a pyrimidine ring, Triazine ring, thiazole ring, oxazole ring, pyrrole ring, triazole ring, and condensed ring containing them (for example, quinoline ring, benzoxazole ring, benzimidazole ring, or indolenine ring) and their tautomerism Pyridine ring, pyrazine ring, pyrimidine ring, pyrrole ring, and condensed ring containing them (for example, quinoline ring, benzpyrrole, etc.) and tautomers thereof are more preferable, pyridine ring, More preferred are a pyrazine ring, a pyrimidine ring, and a condensed ring containing them (for example, a quinoline ring, etc.), a pyridine ring, and A condensed ring containing a pyridine ring (for example, a quinoline ring) is particularly preferable.

In the general formula (A), L ¹⁵ represents a ligand coordinated to M ¹¹ . L ¹⁵ is preferably a 1-4-dentate ligand, more preferably a 1-4-dentate anionic ligand. Although it does not specifically limit as an anionic ligand of 1-4 tetradentate, The monoanionic property containing a halogen ligand, a 1, 3- diketone ligand (for example, acetylacetone ligand etc.), and a pyridine ligand Bidentate ligand (eg, picolinic acid ligand, 2- (2-hydroxyphenyl) -pyridine ligand, etc.), L ¹¹ , Y ¹² , L ¹² , Y ¹¹ , L ¹³ , Y ¹³ , L ¹⁴ And a monoanionic bidentate ligand containing a 1,3-diketone ligand (for example, an acetylacetone ligand) or a pyridine ligand (for example, a picolinic acid ligand). A tetradentate ligand formed by L ¹¹ , Y ¹² , L ¹² , Y ¹¹ , L ¹³ , Y ¹³ , L ¹⁴ , and the like. Preferably, 1,3-diketone Ligands (eg, acetylacetone ligand), monoanionic bidentate ligands containing pyridine ligand (eg, picolinic acid ligand, 2- (2-hydroxyphenyl) -pyridine ligand, etc.) Are more preferable, and a 1,3-diketone ligand (for example, an acetylacetone ligand) is particularly preferable. The number of coordination sites and the number of ligands do not exceed the coordination number of the metal. However, L ¹⁵ does not combine with both L ¹¹ and L ¹⁴ to form a cyclic ligand.

In General Formula (A), Y ¹¹ , Y ¹² , and Y ¹³ each independently represent a linking group, a single bond, or a double bond. Although it does not specifically limit as a coupling group, For example, the coupling group comprised including the atom selected from a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, and a phosphorus atom is preferable. Specific examples of such a linking group include the following.

When Y ¹¹ , Y ¹² , or Y ¹³ is a linking group, L ¹¹ and Y ¹² , Y ¹² and L ¹² , L ¹² and Y ¹¹ , Y ¹¹ and L ¹³ , L ¹³ and Y ¹³ , Y ¹³ And the bond between L ¹⁴ each independently represents a single bond or a double bond.

Y ¹¹ , Y ¹² , and Y ¹³ are each independently preferably a single bond, a double bond, a carbonyl linking group, an alkylene linking group, or an alkenylene group. Y ¹¹ is more preferably a single bond or an alkylene group, and still more preferably an alkylene group. Y ¹² and Y ¹³ are more preferably a single bond or an alkenylene group, and even more preferably a single bond.

Ring formed by Y ¹² , L ¹¹ , L ¹² , and M ¹¹ , Ring formed by Y ¹¹ , L ¹² , L ¹³ , and M ¹¹ , Formed by Y ¹³ , L ¹³ , L ¹⁴ , and M ¹¹ The ring to be formed preferably has 4 to 10 ring members, more preferably 5 to 7 ring members, and further preferably 5 or 6 ring members.

In the general formula ^{(A), n 11} represents 0 to 4. If M ¹¹ is a metal coordination number ^{4, n 11} is ^0, when ^{M 11} is a metal coordination number ^{6, n 11} is 1, 2 is preferable, and more preferably 1. When M ¹¹ is coordination number 6 and n ¹¹ is 1, L ¹⁵ represents a bidentate ligand, and when M ¹¹ is coordination number 6 and n ¹¹ is 2, L ¹⁵ represents a monodentate ligand. When M ¹¹ is a metal having a coordination number of 8, n ¹¹ is preferably 1 to 4, more preferably 1, 2, and more preferably 1. When M ¹¹ is coordination number 8 and n ¹¹ is 1, L ¹⁵ represents a tetradentate ligand, and when M ¹¹ is coordination number 8 and n ¹¹ is 2, L ¹⁵ represents a bidentate ligand. When n ¹¹ is plural, a plurality of L ¹⁵ may be different even in the same.
Specific examples of the phosphorescent material that can be used in the present invention will be given below, but the invention is not limited thereto.

  Examples of the iridium complex as the phosphorescent material are shown below, but the present invention is not limited thereto.

  Among these, examples of the blue phosphorescent light emitting material having an emission peak at 420 nm or more and less than 500 nm include, but are not limited to, the following.

  Examples of the green phosphorescent material having an emission peak at 500 nm or more and less than 570 nm include, but are not limited to, the following.

  Examples of the red phosphorescent light emitting material having an emission peak at 570 nm or more and 650 nm or less include, but are not limited to, the following.

-Host material-
The host material used in the present invention is preferably a hole transporting host material when an electron transporting light emitting material is used, and preferably an electron transporting host material when a hole transporting light emitting material is used.
<Hole transportable host material>
The hole transporting host material used in the light emitting layer of the present invention preferably has an ionization potential Ip of 5.1 eV or more and 6.4 eV or less from the viewpoint of improving durability and lowering driving voltage. More preferably, it is 0.2 eV or less, and further preferably 5.6 eV or more and 6.0 eV or less. Further, from the viewpoint of improving durability and lowering driving voltage, the electron affinity Ea is preferably 1.2 eV or more and 3.1 eV or less, more preferably 1.4 eV or more and 3.0 eV or less, and 1.8 eV or more. More preferably, it is 2.8 eV or less.

Specific examples of such hole transporting host materials include pyrrole, indole, carbazole, azaindole, azacarbazole, pyrazole, imidazole, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, and amino-substituted Chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidin compound, porphyrin compound, polysilane compound, poly (N-vinylcarbazole), aniline Examples thereof include polymers, conductive polymer oligomers such as thiophene oligomer thiophene oligomers and polythiophenes, organic silanes, carbon films, and derivatives thereof.
Among them, indole derivatives, carbazole derivatives, azaindole derivatives, azacarbazole derivatives, aromatic tertiary amine compounds, and thiophene derivatives are preferable. Those having a plurality of at least one of tertiary amine skeletons are preferred.
Specific examples of such a hole transporting host material include, but are not limited to, the following compounds. D represents deuterium.

<Electron transporting host material>
The electron transporting host material used in the present invention preferably has an electron affinity Ea of 2.5 eV or more and 3.5 eV or less, from the viewpoint of improving durability and lowering driving voltage, and 2.6 eV or more and 3.4 eV or less. It is more preferable that it is 2.8 eV or more and 3.3 eV or less. Further, from the viewpoint of improving durability and reducing driving voltage, the ionization potential Ip is preferably 5.7 eV or more and 7.5 eV or less, more preferably 5.8 eV or more and 7.0 eV or less, and 5.9 eV or more. More preferably, it is 6.5 eV or less.
A preferable lowest triplet excited level (hereinafter referred to as T1) is preferably 2.2 eV or more and 3.7 eV or less, more preferably 2.4 eV or more and 3.7 eV or less, and most preferably 2.4 eV or more and 3. 4 eV or less.

  Specific examples of such electron transporting host materials include pyridine, pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole, oxadiazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, and thiopyran dioxide. , Carbodiimide, fluorenylidenemethane, distyrylpyrazine, fluorine-substituted aromatic compounds, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanines, and derivatives thereof (may form condensed rings with other rings) ), Metal complexes of 8-quinolinol derivatives, metal phthalocyanines, various metal complexes represented by metal complexes having benzoxazole or benzothiazole as a ligand, and the like.

The electron transporting host material is preferably a metal complex, an azole derivative (benzimidazole derivative, imidazopyridine derivative, etc.), or an azine derivative (pyridine derivative, pyrimidine derivative, triazine derivative, etc.). From the viewpoint, a metal complex compound is preferable. The metal complex compound is more preferably a metal complex having a ligand having at least one nitrogen atom, oxygen atom or sulfur atom coordinated to the metal.
The metal ion in the metal complex is not particularly limited, but is preferably beryllium ion, magnesium ion, aluminum ion, gallium ion, zinc ion, indium ion, tin ion, platinum ion, or palladium ion, more preferably beryllium ion, Aluminum ion, gallium ion, zinc ion, platinum ion or palladium ion, and more preferably aluminum ion, zinc ion, platinum ion or palladium ion.

  There are various known ligands contained in the metal complex. For example, “Photochemistry and Photophysics of Coordination Compounds”, Springer-Verlag, H.C. Examples include the ligands described in Yersin, published in 1987, “Organometallic Chemistry: Fundamentals and Applications”, Sakai Hanafusa, Yamamoto Akio, published in 1982, and the like.

The ligand is preferably a nitrogen-containing heterocyclic ligand (preferably having 1 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 3 to 15 carbon atoms, and a monodentate ligand. Alternatively, it may be a bidentate or higher ligand, preferably a bidentate or higher and a hexadentate or lower ligand, or a bidentate or higher and lower 6 or lower ligand and a monodentate mixed ligand. preferable.
Examples of the ligand include an azine ligand (for example, pyridine ligand, bipyridyl ligand, terpyridine ligand, etc.), a hydroxyphenylazole ligand (for example, hydroxyphenylbenzimidazole coordination). And a hydroxyphenyl benzoxazole ligand, a hydroxyphenyl imidazole ligand, a hydroxyphenylimidazopyridine ligand, etc.), an alkoxy ligand (preferably having 1 to 30 carbon atoms, more preferably 1 carbon atom). To 20, particularly preferably 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy, 2-ethylhexyloxy), aryloxy ligands (preferably 6 to 30 carbon atoms, more preferably 6-20 carbon atoms, particularly preferably 6-12 carbon atoms, for example phenyl Carboxymethyl, 1-naphthyloxy, 2-naphthyloxy, 2,4,6-trimethylphenyl oxy, and 4-biphenyloxy and the like.),

Heteroaryloxy ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, and quinolyloxy. ), An alkylthio ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio), arylthio ligands (Preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio), heteroarylthio ligand (preferably 1 carbon atom) To 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridylthio , 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio, etc.), a siloxy ligand (preferably having 1 to 30 carbon atoms, more preferably 3 to 25 carbon atoms). Particularly preferably, it has 6 to 20 carbon atoms, and examples thereof include a triphenylsiloxy group, a triethoxysiloxy group, and a triisopropylsiloxy group.), An aromatic hydrocarbon anion ligand (preferably having 6 carbon atoms) To 30, more preferably 6 to 25 carbon atoms, particularly preferably 6 to 20 carbon atoms, such as a phenyl anion, a naphthyl anion, an anthranyl anion, etc.), an aromatic heterocyclic anion ligand (preferably Has 1 to 30 carbon atoms, more preferably 2 to 25 carbon atoms, and particularly preferably 2 to 20 carbon atoms. Pyrrole anion, pyrazole anion, pyrazole anion, triazole anion, oxazole anion, benzoxazole anion, thiazole anion, benzothiazole anion, thiophene anion, benzothiophene anion, etc.), indolenine anion ligand, etc. , Preferably a nitrogen-containing heterocyclic ligand, aryloxy ligand, heteroaryloxy group, or siloxy ligand, more preferably a nitrogen-containing heterocyclic ligand, aryloxy ligand, siloxy coordination Or an aromatic hydrocarbon anion ligand or an aromatic heterocyclic anion ligand.

  Examples of the metal complex electron transporting host material include, for example, JP-A-2002-235076, JP-A-2004-214179, JP-A-2004-221062, JP-A-2004-221665, JP-A-2004-221068. And the compounds described in JP 2004-327313 A and the like.

  Specific examples of such an electron transporting host material include, but are not limited to, the following materials.

  Next, elements other than the light emitting layer and the intermediate layer constituting the light emitting device of the present invention will be described in detail.

(substrate)
The substrate used in the present invention is preferably a substrate that does not scatter or attenuate light emitted from the organic layer. Specific examples include zirconia-stabilized yttrium (YSZ), inorganic materials such as glass, polyesters such as polyethylene terephthalate, polybutylene phthalate, and polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, and polycycloolefin. , Norbornene resins, and organic materials such as poly (chlorotrifluoroethylene).
For example, when glass is used as the substrate, alkali-free glass is preferably used as the material in order to reduce ions eluted from the glass. Moreover, when using soda-lime glass, it is preferable to use what gave barrier coatings, such as a silica. In the case of an organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.

  There is no restriction | limiting in particular about the shape of a board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. In general, the shape of the substrate is preferably a plate shape. The structure of the substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.

  The substrate may be colorless and transparent or colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the organic light emitting layer.

The substrate can be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
As a material for the moisture permeation preventive layer (gas barrier layer), inorganic materials such as silicon nitride and silicon oxide are preferably used. The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.
When a thermoplastic substrate is used, a hard coat layer, an undercoat layer, or the like may be further provided as necessary.

(anode)
The anode usually only needs to have a function as an electrode for supplying holes to the organic layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials. As described above, the anode is usually provided as a transparent anode.

  Suitable examples of the material for the anode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof. Specific examples of the anode material include conductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Metals such as oxides, gold, silver, chromium, nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene, polypyrrole, etc. Organic conductive materials, and a laminate of these and ITO. Among these, conductive metal oxides are preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.

  The anode is composed of, for example, a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as a CVD and a plasma CVD method. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material to be processed. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.

  In the organic electroluminescent element of the present invention, the formation position of the anode is not particularly limited and can be appropriately selected according to the use and purpose of the light emitting element, but it is preferably formed on the substrate. In this case, the anode may be formed on the entire one surface of the substrate, or may be formed on a part thereof.

  The patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching such as laser, or vacuum deposition or sputtering with a mask overlapped. It may be performed by a lift-off method or a printing method.

  The thickness of the anode can be appropriately selected depending on the material constituting the anode and cannot be generally defined, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.

The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less. When the anode is transparent, it may be colorless and transparent or colored and transparent. In order to take out light emission from the transparent anode side, the transmittance is preferably 60% or more, and more preferably 70% or more.

  The transparent anode is described in detail in the book “New Development of Transparent Electrode Films” published by CMC (1999), supervised by Yutaka Sawada, and the matters described here can be applied to the present invention. In the case of using a plastic substrate having low heat resistance, a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

(cathode)
The cathode usually has a function as an electrode for injecting electrons into the organic layer, and there is no particular limitation on the shape, structure, size, etc., and it is known depending on the use and purpose of the light-emitting element. The electrode material can be selected as appropriate.

  Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, LI, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium and ytterbium. These may be used alone, but two or more can be suitably used in combination from the viewpoint of achieving both stability and electron injection.

Among these, as a material constituting the cathode, an alkali metal or an alkaline earth metal is preferable from the viewpoint of electron injecting property, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy). Etc.).

  The materials for the cathode are described in detail in JP-A-2-15595 and JP-A-5-121172, and the materials described in these public relations can also be applied in the present invention.

There is no restriction | limiting in particular about the formation method of a cathode, According to a well-known method, it can carry out.
For example, the cathode described above is configured from a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method. It can be formed according to a method appropriately selected in consideration of suitability with the material. For example, when a metal or the like is selected as the cathode material, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.

  Patterning when forming the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or by vacuum deposition or sputtering with the mask overlaid. It may be performed by a lift-off method or a printing method.

In the present invention, the cathode forming position is not particularly limited, and may be formed on the entire organic layer or a part thereof.
A dielectric layer made of an alkali metal or alkaline earth metal fluoride, oxide or the like may be inserted between the cathode and the organic layer in a thickness of 0.1 nm to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer. The dielectric layer can be formed by, for example, vacuum deposition, sputtering, or ion plating.

The thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be generally defined, but is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm.
Further, the cathode may be transparent or opaque. The transparent cathode can be formed by depositing a thin cathode material to a thickness of 1 nm to 10 nm and further laminating a transparent conductive material such as ITO or IZO.

(Organic layer)
The other organic layer in this invention is demonstrated.
The organic EL device of the present invention has at least two light-emitting layers and an intermediate layer between the light-emitting layers, the at least two light-emitting layers contain phosphorescent materials having different emission colors, and the intermediate layer contains a binder. It is a layer to contain.
Examples of the organic layer other than the light emitting layer include a hole transport layer, an electron transport layer, a charge block layer (hole block layer, electron block layer), a hole injection layer, and an electron injection layer.

  In the organic EL device of the present invention, each layer constituting the organic layer can be suitably formed by any of dry film forming methods such as vapor deposition and sputtering, wet coating methods, transfer methods, printing methods, and ink jet methods. it can.

<Hole injection layer, hole transport layer>
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side.
The material that can be used for the hole injection layer and the hole transport layer in the present invention may be a low molecular compound or a high molecular compound.
Specifically, pyrrole derivatives, carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styryl Anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organosilane derivatives, or carbon And the like.

  The hole-injecting layer or the hole-transporting layer can contain an electron-accepting dopant. As the electron-accepting dopant introduced into the hole-injecting layer or the hole-transporting layer, an inorganic compound or an organic compound can be used as long as it has an electron-accepting property and oxidizes an organic compound.

  Specifically, examples of the inorganic compound include metal halides such as ferric chloride, aluminum chloride, gallium chloride, indium chloride, and antimony pentachloride, metal oxides such as vanadium pentoxide, and molybdenum trioxide.

In the case of an organic compound, a compound having a nitro group, halogen, cyano group, trifluoromethyl group or the like as a substituent, a quinone compound, an acid anhydride compound, fullerene, or the like can be preferably used.
In addition, JP-A-6-212153, JP-A-11-111463, JP-A-11-251067, JP-A-2000-196140, JP-A-2000-286054, JP-A-2000-315580 JP, JP-A-2001-102175, JP-A-2001-160493, JP-A-2002-252085, JP-A-2002-56985, JP-A-2003-157981, JP-A-2003-217862 JP-A 2003-229278, JP-A 2004-342614, JP-A 2005-72012, JP-A 2005-166637, JP-A 2005-209643, etc., described in the present invention The hole transporting host material can be suitably used.

  These electron-accepting dopants may be used alone or in combination of two or more. Although the usage-amount of an electron-accepting dopant changes with kinds of material, it is preferable that it is 0.01 mass%-50 mass% with respect to hole transport layer material, and it is 0.05 mass%-20 mass%. It is further more preferable and it is especially preferable that it is 0.1 mass%-10 mass%.

The thicknesses of the hole injection layer and the hole transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the thickness of the hole injection layer is preferably 0.1 nm to 200 nm, more preferably 0.5 nm to 100 nm, and still more preferably 1 nm to 100 nm.
The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the materials described above, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .

<Electron injection layer, electron transport layer>
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side.

The electron injection material and the electron transport material used for the electron transport layer in the present invention may be a low molecular compound or a high molecular compound.
Specifically, pyridine derivatives, quinoline derivatives, pyrimidine derivatives, pyrazine derivatives, phthalazine derivatives, phenanthroline derivatives, triazine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone Derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthalene, perylene and other aromatic ring tetracarboxylic acid anhydrides, phthalocyanine derivatives, 8-quinolinol derivative metal complexes, Metal phthalocyanines, various metal complexes represented by metal complexes with benzoxazole and benzothiazole as ligands, organosilane derivatives represented by siloles Body, or the like is preferably a layer containing.

The thicknesses of the electron injection layer and the electron transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the thickness of the electron injection layer is preferably 0.1 nm to 200 nm, more preferably 0.2 nm to 100 nm, and still more preferably 0.5 nm to 50 nm.
The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

<Hole blocking layer>
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic layer adjacent to the light emitting layer on the cathode side.
Examples of the compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like.
The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

<Electronic block layer>
The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side. In the present invention, an electron blocking layer can be provided as an organic layer adjacent to the light emitting layer on the anode side.
As examples of the compound constituting the electron blocking layer, for example, those mentioned as the hole transport material described above can be applied.
The thickness of the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

(Protective layer)
In the present invention, the entire organic EL element may be protected by a protective layer.
As a material contained in the protective layer, any material may be used as long as it has a function of preventing materials that promote device deterioration such as moisture and oxygen from entering the device.
Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, and Fe _2. Metal oxide such as O ₃ , Y ₂ O ₃ , or TiO ₂ , metal nitride such as SiN _x , SiN _x O _y , metal fluoride such as MgF ₂ , LiF, AlF ₃ , or CaF ₂ , polyethylene, polypropylene Polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one comonomer. Copolymer obtained by copolymerizing monomer mixture containing And a fluorine-containing copolymer having a cyclic structure in the copolymer main chain, a water-absorbing substance having a water absorption of 1% or more, and a moisture-proof substance having a water absorption of 0.1% or less.

  The method for forming the protective layer is not particularly limited, and for example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, or transfer method can be applied.

(Sealing)
Furthermore, the organic electroluminescent element of this invention may seal the whole element using a sealing container.
Further, a moisture absorbent or an inert liquid may be sealed in a space between the sealing container and the light emitting element. Although it does not specifically limit as a moisture absorber, For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, calcium chloride, magnesium chloride, copper chloride Cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide, and the like. The inert liquid is not particularly limited, and examples thereof include paraffins, liquid paraffins, fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether, chlorinated solvents, and silicone oils. Can be mentioned.

(Drive)
The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Can be obtained.
The driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234585, The driving methods described in each publication of Japanese Patent No. 8-24047, Japanese Patent No. 2784615, US Pat. No. 5,828,429, Japanese Patent No. 6023308, and the like can be applied.

  The light-emitting element of the present invention can improve the light extraction efficiency by various known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate / ITO layer / organic layer, controlling the film thickness of the substrate / ITO layer / organic layer, etc. It is possible to improve light extraction efficiency and external quantum efficiency.

  The light emitting device of the present invention may be a bottom emission method in which light emission is extracted from the anode side, and may be a top emission method in which light emission is extracted from the cathode side.

(Use of the present invention)
The organic electroluminescence device of the present invention can be suitably used for display devices, displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, reading light sources, signs, signboards, interiors, optical communications, and the like.

The present invention will be specifically described using examples, but the present invention is not limited to these examples.
1. Production of organic EL element (production of element 1 of the present invention)
A glass substrate having a thickness of 0.5 mm and a square of 2.5 cm was placed in a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. The following layers were deposited on this transparent anode by vacuum deposition. The vapor deposition rate in the examples of the present invention is 0.2 nm / second unless otherwise specified. The deposition rate was measured using a quartz resonator. The film thicknesses described below were also measured using a crystal resonator.
-Anode: ITO (Indium Tin Oxide) was deposited on a glass substrate to a thickness of 100 nm.
Hole injection layer: 4,4 ′, 4 ″ -Tris (N- (2-naphthyl) -N-phenyl-amino) -triphenylamine (abbreviated as 2-TNATA) and 2 on the anode (ITO) , 3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (abbreviated as F4-TCNQ) and the ratio of F4-TCNQ to 2-TNATA is 1.0 mass. The film thickness was 160 nm.
-Hole transport layer: α-NPD (Bis [N- (1-naphthyl) -N-pheny] benzidine) was deposited on the hole injection layer to a thickness of 10 nm.
First light emitting layer: 1,3-bis (N-carbazol-9-yl) benzene (abbreviated as mCP) on the hole transport layer, and 15% by mass of platinum complex 1 (light emission) with respect to mCP (Peak wavelength: 457 nm, blue light emission) was co-evaporated. The thickness was 20 nm.
Intermediate layer: Compound AD1 was formed to a thickness of 0.5 nm on the first light-emitting layer.
Second light-emitting layer: On the intermediate layer, mCP, 15% by mass of platinum complex 2 (emission peak wavelength: 506 nm, green light emission) and 0.5% by mass of Ir (piq) ₃ (emission peak) Three-way vapor deposition was performed at a wavelength of 621 nm (red light emission). The thickness was 10 nm.
Electron transport layer: Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum (III) (abbreviated as BAlq) was deposited on the light-emitting layer to a thickness of 39 nm.
Electron injection layer: Bathocuproin (abbreviated as BCP) was deposited on the electron transport layer to a thickness of 1 nm.
Cathode: LiF was deposited on the electron injection layer to a thickness of 1 nm, and then a patterned mask (a mask having a light emitting area of 2 mm × 2 mm) was placed, and metal aluminum was deposited to 100 nm to form a cathode.

  The produced laminate was put in a glove box substituted with argon gas, and sealed using a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.).

(Production of elements 2 and 3 of the present invention)
In the production of the element 1 of the present invention, the thickness of the intermediate layer was changed to 1 nm and 2 nm, respectively, and the other elements 2 and 3 of the present invention were produced in the same manner as the production of the element 1 of the present invention.

(Production of Comparative Element A)
In the production of the element 1 of the present invention, a comparative element A was produced in the same manner as in the production of the element 1 of the present invention except for the intermediate layer.

  The structure of the material used in the examples is shown below.

2. Performance Evaluation The performance of the obtained device of the present invention and comparative device was evaluated according to the following.
1) Driving voltage Using a source measure unit 2400 manufactured by Toyo Technica Co., Ltd., a DC voltage was applied to each element to emit light. The voltage when the luminance was 1000 cd / m ² was measured as the driving voltage.
2) External quantum efficiency Using a source measure unit 2400 manufactured by Toyo Technica Co., Ltd., a direct current voltage was applied to each element to emit light. The brightness was measured using a luminance meter BM-8 manufactured by Topcon Corporation. The emission spectrum and emission wavelength were measured using a spectrum analyzer PMA-11 manufactured by Hamamatsu Photonics. Based on these numerical values, the external quantum efficiency at a luminance of 1000 cd / m ² was calculated by a luminance conversion method.
3) Driving durability Using a source measure unit 2400 manufactured by Toyo Technica Co., Ltd., a direct current voltage was applied to each element to emit light so that the luminance was 1000 cd / m ² . Luminescence was continued under the current-voltage conditions, and the luminance half-life for which the luminance decreased to 500 cd / m ² was measured. The relative element 1 is expressed as a relative value, assuming that the half time of the element 1 is 1.
The obtained results are shown in Table 1.

  From the results shown in Table 1, the devices 1 to 3 of the present invention having an intermediate layer between the light emitting layers had a lower driving voltage, higher external quantum efficiency, and better driving durability than the comparative device A. The thickness of the intermediate layer is most preferably a thin layer of 0.5 nm, and as the thickness increases to 2 nm, the driving voltage slightly increases and the external quantum efficiency and driving durability tend to decrease slightly. Indicated.

Example 2
1. Fabrication of organic EL elements

(Preparation of element 10 of the present invention)
In the production of the element 1 of the present invention of Example 1, the same procedure as for the element 1 of the present invention was performed except that the first to third light emitting layers and the third light emitting layer having the following constitution were used as the light emitting layer and the intermediate layer. The element 10 of the present invention was produced.
A first light-emitting layer, an intermediate layer 1, a second light-emitting layer, an intermediate layer 2, and a third light-emitting layer were provided in this order from the hole transport layer side.
On the first light-emitting layer :: hole transport layer, mCP and 15% by mass of platinum complex 1 with respect to mCP were co-evaporated. The thickness was 20 nm.
Intermediate layer 1: Compound AD1 was formed to a thickness of 0.5 nm on the first light emitting layer.
Second light-emitting layer: mCP and platinum complex 2 were co-deposited on intermediate layer 1 so that the ratio of platinum complex 2 to mCP was 15% by mass. The thickness was 5 nm.
Intermediate layer 2: Compound AD1 was formed to a thickness of 0.5 nm on the second light emitting layer.
Third light emitting layer: BAlq and Ir (piq) ₃ were co-deposited on the intermediate layer 2 so that the ratio of Ir (piq) _{3 to} BAlq was 5% by mass. The thickness was 5 nm.

(Production of Comparative Element B)
In the production of the element 10 of the present invention, a comparative element B was produced in the same manner as in the production of the element 10 of the present invention except for the intermediate layer 1 and the intermediate layer 2.

2. Performance Evaluation About the obtained element of the present invention and the comparative element, the performance was evaluated in the same manner as in Example 1.
The results are shown in Table 2.

  From the results shown in Table 2, the device 10 of the present invention having an intermediate layer between the light emitting layers had a lower driving voltage, higher external quantum efficiency, and better driving durability than the comparative device B.

Example 3
In the production of the elements of the present invention of Examples 1-2, the same organic EL element was produced using the compound AD2 (the following structure) instead of the compound AD1 as an intermediate layer binder, and the performance was evaluated. Similarly, the driving voltage was low, the external quantum efficiency was high, and the driving durability was excellent.

Example 4
1. Production of organic EL element (production of element 11 of the present invention)
In the production of the element 1 of the present invention of Example 1, the element 11 of the present invention was produced in the same manner as the element 1 of the present invention, except that the following materials were used as the light emitting layer and the intermediate layer.

First light emitting layer: On the hole transport layer, the host material 1 and 15% by mass of the platinum complex 3 with respect to the host material 1 were co-evaporated. The thickness was 20 nm.
Intermediate layer: Compound AD2 was deposited to a thickness of 0.5 nm on the first light-emitting layer.
Second light emitting layer: ternary vapor deposition of host material 1, 15% by mass of platinum complex 2 and 0.5% by mass of Ir (piq) ₃ with respect to host material 1 was performed on the intermediate layer. The thickness was 10 nm.

(Preparation of elements 12 and 13 of the present invention)
In the production of the element 1 of the present invention, the thickness of the intermediate layer was changed to 1 nm and 2 nm, respectively, and the other elements 12 and 13 of the present invention were produced in the same manner as the production of the element 1 of the present invention.

(Production of Comparative Element C)
In the production of the element 11 of the present invention, a comparative element C was produced in the same manner as the production of the element 11 of the present invention except for the intermediate layer.

2. Performance Evaluation About the obtained element of the present invention and the comparative element, the performance was evaluated in the same manner as in Example 1.
The results are shown in Table 3.

  From the results shown in Table 3, the devices 11 to 13 of the present invention having an intermediate layer between the light emitting layers had lower driving voltage, higher external quantum efficiency, and better driving durability than the comparative device C. The thickness of the intermediate layer is most preferably a thin layer of 0.5 nm, and as the thickness increases to 2 nm, the driving voltage slightly increases and the external quantum efficiency and driving durability tend to decrease slightly. Indicated.

Example 5
1. Production of organic EL element (production of element 14 of the present invention)
In the production of the element 11 of the present invention in Example 3, the light emitting layer and the intermediate layer were the same as the element 11 of the present invention except that the first light emitting layer to the third light emitting layer and the intermediate layer having the following constitution were used. The element 14 of the present invention was produced.
A first light-emitting layer, an intermediate layer 1, a second light-emitting layer, an intermediate layer 2, and a third light-emitting layer were provided in this order from the hole transport layer side.
First light emitting layer: On the hole transport layer, the host material 1 and 15% by mass of the platinum complex 3 with respect to the host material 1 were co-evaporated. The thickness was 20 nm.
Intermediate layer 1: Compound AD2 was formed to a thickness of 0.5 nm on the first light emitting layer.
Second light emitting layer: On the intermediate layer 1, the host material 2 and the platinum complex 2 were co-deposited so that the ratio of the platinum complex 2 to the host material 2 was 15% by mass. The thickness was 5 nm.
Intermediate layer 2: Compound AD2 was formed to a thickness of 0.5 nm on the second light emitting layer.
Third light emitting layer: BAlq and Ir (piq) ₃ were co-deposited on the intermediate layer 2 so that the ratio of Ir (piq) _{3 to} BAlq was 5% by mass. The thickness was 5 nm.

(Production of Comparative Element D)
In the production of the element 14 of the present invention, a comparative element D was produced in the same manner as in the production of the element 14 of the present invention except for the intermediate layer 1 and the intermediate layer 2.

2. Performance Evaluation About the obtained element of the present invention and the comparative element, the performance was evaluated in the same manner as in Example 1.
The results are shown in Table 4.

  From the results shown in Table 4, the device 14 of the present invention having an intermediate layer between the light emitting layers had a lower driving voltage, higher external quantum efficiency, and better driving durability than the comparative device D.

Example 6
1. Production of organic EL element (production of element 15 of the present invention)
In the production of the element 11 of the present invention in Example 4, the following host material 2 was used as the host material of the light emitting layer, and the first light emitting layer, the second light emitting layer and the intermediate layer having the following constitution were used. The element 15 of the present invention was produced in the same manner as the element 11 of the present invention.

First light emitting layer: On the hole transport layer, the host material 2 and 15% by mass of platinum complex 3 (emission peak wavelength: 468 nm blue light emission) with respect to the host material 2 were co-evaporated. The thickness was 20 nm.
Intermediate layer: Compound AD2 was deposited to a thickness of 0.5 nm on the first light-emitting layer.
Second light emitting layer: ternary vapor deposition of host material 2, 15% by mass of platinum complex 2 and 0.5% by mass of Ir (piq) ₃ with respect to host material 2 was performed on the intermediate layer. The thickness was 10 nm.

(Preparation of elements 16 and 17 of the present invention)
In the production of the element 15 of the present invention, the thickness of the intermediate layer was changed to 1 nm and 2 nm, respectively, and the other elements 12 and 13 of the present invention were produced in the same manner as the production of the element 1 of the present invention.

(Production of Comparative Element E)
In the production of the element 15 of the present invention, a comparative element E was produced in the same manner as the production of the element 15 of the present invention except for the intermediate layer.

2. Performance Evaluation About the obtained element of the present invention and the comparative element, the performance was evaluated in the same manner as in Example 1.
The results are shown in Table 5.

  From the results shown in Table 5, the devices 15 to 17 of the present invention having an intermediate layer between the light emitting layers had lower driving voltage, higher external quantum efficiency, and better driving durability than the comparative device E. The thickness of the intermediate layer is most preferably a thin layer of 0.5 nm, and as the thickness increases to 2 nm, the driving voltage slightly increases and the external quantum efficiency and driving durability tend to decrease slightly. Indicated.

Example 7
1. Fabrication of organic EL elements

(Preparation of element 18 of the present invention)
In the production of the element 15 of the present invention in Example 6, the same procedure as for the element 15 of the present invention was performed except that the first to third light emitting layers to the third light emitting layer and the intermediate layer having the following constitution were used as the light emitting layer and the intermediate layer. The element 18 of the present invention was produced.
A first light-emitting layer, an intermediate layer 1, a second light-emitting layer, an intermediate layer 2, and a third light-emitting layer were provided in this order from the hole transport layer side.
First light emitting layer :: Host material 2 and 15% by mass of platinum complex 3 with respect to host material 2 were co-deposited on the hole transport layer. The thickness was 20 nm.
Intermediate layer 1: Compound AD2 was formed to a thickness of 0.5 nm on the first light emitting layer.
Second light emitting layer: On the intermediate layer 1, the host material 2 and the platinum complex 2 were co-deposited so that the ratio of the platinum complex 2 to the host material 2 was 15% by mass. The thickness was 5 nm.
Intermediate layer 2: Compound AD2 was formed to a thickness of 0.5 nm on the second light emitting layer.
Third light emitting layer: BAlq and Ir (piq) ₃ were co-deposited on the intermediate layer 2 so that the ratio of Ir (piq) _{3 to} BAlq was 5% by mass. The thickness was 5 nm.

(Production of Comparative Element F)
In the production of the element 18 of the present invention, a comparative element F was produced in the same manner as in the production of the element 18 of the present invention except for the intermediate layer 1 and the intermediate layer 2.

2. Performance Evaluation About the obtained element of the present invention and the comparative element, the performance was evaluated in the same manner as in Example 1.
The results are shown in Table 6.

  From the results shown in Table 6, the device 18 of the present invention having an intermediate layer between the light emitting layers had a lower driving voltage, higher external quantum efficiency, and better driving durability than the comparative device F.

Example 8
1. Production of organic EL element (production of element 19 of the present invention)
In the production of the element 1 of the present invention of Example 1, the present invention except that the first to third light emitting layers to the third light emitting layer, the intermediate layer 1 and the intermediate layer 2 having the following constitution were used as the light emitting layer and the intermediate layer. The element 19 of the present invention was produced in the same manner as the element 1 in FIG.
First light-emitting layer: BAlq and iridium complex 1 (emission peak wavelength: 604 nm, red light emission) were co-deposited on the hole transport layer so that iridium complex 1 was 2% by mass with respect to BAlq. The thickness was 5 nm.
Intermediate layer 1: Compound Alk-1 was formed to a thickness of 0.5 nm on the first light emitting layer.
Second light-emitting layer: Host material 1 and platinum complex 2 were co-deposited on intermediate layer 1 so that the ratio of platinum complex 2 to host material 1 was 15% by mass. The thickness was 5 nm.
Intermediate layer 2: A compound Alk-1 was formed to a thickness of 0.5 nm on the second light emitting layer.
Third light emitting layer: Host material 1 and platinum complex 4 (light emission peak wavelength: 469 nm, blue light emission) are formed on intermediate layer 1 so that the ratio of platinum complex 4 to host material 1 is 15% by mass. Were co-evaporated. The thickness was 20 nm.

(Production of Comparative Element G)
In the production of the element 19 of the present invention, a comparative element G was produced in the same manner as the production of the element 19 of the present invention except for the intermediate layer 1 and the intermediate layer 2.

2. Performance Evaluation About the obtained element of the present invention and the comparative element, the performance was evaluated in the same manner as in Example 1. The results are shown in Table 7.

  From the results shown in Table 7, the device 19 of the present invention having an intermediate layer between the light emitting layers had a driving voltage lower than that of the comparative device G, high external quantum efficiency, and excellent driving durability.

Example 9
1. Production of organic EL device (production of device 20 of the present invention)
In the production of the element 1 of the present invention of Example 1, the present invention except that the first to third light emitting layers to the third light emitting layer, the intermediate layer 1 and the intermediate layer 2 having the following constitution were used as the light emitting layer and the intermediate layer. The device 20 of the present invention was fabricated in the same manner as the device 1 of FIG.
First light-emitting layer: BAlq and iridium complex 2 (emission peak wavelength: 620 nm, red light emission) were co-deposited on the hole transport layer so that the iridium complex 2 was 2% by mass with respect to BAlq. The thickness was 5 nm.
Intermediate layer 1: Compound TR-1 was formed to a thickness of 0.5 nm on the first light-emitting layer.
Second light-emitting layer: host material 3 and iridium complex 3 (emission peak wavelength: 517 nm green light emission) on intermediate layer 1 so that the ratio of iridium complex 3 to host material 3 is 8% by mass. Were co-evaporated. The thickness was 5 nm.
Intermediate layer 2: Compound TR-1 was formed to a thickness of 0.5 nm on the second light emitting layer.
Third light emitting layer: Host material 1 and iridium complex 4 (light emission peak wavelength: 463 nm blue light emission) are formed on intermediate layer 1 such that the ratio of iridium complex 4 to host material 1 is 8% by mass. Were co-evaporated. The thickness was 20 nm.

(Production of comparative element H)
In the production of the element 20 of the present invention, a comparative element H was produced in the same manner as in the production of the element 20 of the present invention except for the intermediate layer 1 and the intermediate layer 2.

2. Performance Evaluation About the obtained element 20 of the present invention and the comparative element H, the performance was evaluated in the same manner as in Example 1. The results are shown in Table 8.

  From the results of Table 8, the device 20 of the present invention having an intermediate layer between the light emitting layers had a driving voltage lower than that of the comparative device H, high external quantum efficiency, and excellent driving durability.

Example 10
1. Production of organic EL element (production of element 21 of the present invention)
In the production of the element 1 of the present invention of Example 1, the present invention except that the first to third light emitting layers to the third light emitting layer, the intermediate layer 1 and the intermediate layer 2 having the following constitution were used as the light emitting layer and the intermediate layer. The element 21 of the present invention was produced in the same manner as the element 1 of the above. First light emitting layer: BAlq and iridium complex 5 (emission peak wavelength: 635 nm red light emission) were formed on the hole transporting layer with respect to BAlq. Co-deposition was performed so that the complex 5 was 2% by mass. The thickness was 5 nm.
Intermediate layer 1: Compound TPM-1 was formed to a thickness of 0.5 nm on the first light emitting layer.
Second light-emitting layer: host material 3 and iridium complex 6 (emission peak wavelength: 522 nm green light emission) on intermediate layer 1 so that the ratio of iridium complex 6 to host material 3 is 8% by mass. Were co-evaporated. The thickness was 5 nm.
Intermediate layer 2: Compound TPM-1 was formed to a thickness of 0.5 nm on the second light emitting layer.
Third light emitting layer: Host material 1 and iridium complex 7 (emission peak wavelength: 465 nm, blue light emission) are formed on intermediate layer 1 such that the ratio of iridium complex 7 to host material 1 is 8% by mass. Were co-evaporated. The thickness was 20 nm.

(Production of Comparative Element I)
In the production of the element 21 of the present invention, a comparative element I was produced in the same manner as in the production of the element 21 of the present invention except for the intermediate layer 1 and the intermediate layer 2.

2. Performance Evaluation The performance of the obtained device 21 of the present invention and comparative device I was evaluated in the same manner as in Example 1. The results are shown in Table 9.

  From the results shown in Table 9, the device 21 of the present invention having an intermediate layer between the light emitting layers had a lower driving voltage, higher external quantum efficiency, and better driving durability than the comparative device I.

1: Substrate 2: Anode 3: Hole injection layer 4: Hole transport layer 5-1: First light emitting layer 5-2: Second light emitting layer 6: Electron transport layer 7: Electron injection layer 8: Cathode 9 : Intermediate layer 15-1: First light emitting layer 15-2: Second light emitting layer 15-3: Third light emitting layer 19-1: First intermediate layer 19-2: Second intermediate layer 25- 1: First light emitting layer 25-2: Second light emitting layer 29: Intermediate layer 35-1: First light emitting layer 35-2: Second light emitting layer 35-3: Third light emitting layer 39-1 : First intermediate layer 39-2: Second intermediate layer

Claims (7)

An organic electroluminescent element having a pair of electrodes and at least one organic layer between the electrodes on a substrate, wherein the organic layer is provided between at least two light emitting layers and at least two light emitting layers. Each of the at least two light emitting layers contains a phosphorescent light emitting material, and the phosphorescent light emitting material has a blue phosphorescent light emitting material having an emission peak at 420 nm or more and less than 500 nm, and 500 nm or more and less than 570 nm. And at least one selected from the group consisting of a green phosphorescent material having an emission peak and a red phosphorescent material having an emission peak at 570 nm to 650 nm, and the phosphorescent material contained in each layer of the light emitting layer is The organic electroluminescent element which has a mutually different light emission peak and the said intermediate | middle layer contains the binder material represented by following General formula (1) .


(In General Formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or aryl. Group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano group, ester group, amide group, halogen atom, perfluoroalkyl group having 1 to 6 carbon atoms, Represents a silyl group, and at least one of R _{1 to} R ₄ is a group having a double bond or a triple bond, X _{1 to} X ₁₂ each independently represents a hydrogen atom, an alkyl having 1 to 6 carbon atoms; Group, alkenyl group having 2 to 6 carbon atoms, alkynyl group having 2 to 6 carbon atoms, aryl group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano group ,ester , An amide group, a halogen atom, a perfluoroalkyl group having 1 to 6 carbon atoms, a silyl group and the table,
The aryl group represented by R _{1 to} R ₄ and the aryl group represented by X _{1 to} X ₁₂ are phenyl, o-tolyl, m-tolyl, p-tolyl, 1- (2,3- Dimethylphenyl), 1- (3,4-dimethylphenyl), 2- (1,3-dimethylphenyl), 1- (3,5-dimethylphenyl), 1- (2,5-dimethylphenyl), p- From cumenyl, mesityl, 1-naphthyl, 2-naphthyl, 1-anthranyl, 2-anthranyl, 9-anthranyl, 4-biphenylyl, 3-biphenylyl, 2-biphenylyl, 4-p-terphenylyl, and 4-m-terphenylyl Selected from the group consisting of ) An organic electroluminescent element having a pair of electrodes and at least one organic layer between the electrodes on a substrate, wherein the organic layer is provided between at least two light emitting layers and at least two light emitting layers. Each of the at least two light emitting layers contains a phosphorescent light emitting material, and the phosphorescent light emitting material has a blue phosphorescent light emitting material having an emission peak at 420 nm or more and less than 500 nm, and 500 nm or more and less than 570 nm. And at least one selected from the group consisting of a green phosphorescent material having an emission peak and a red phosphorescent material having an emission peak at 570 nm to 650 nm, and the phosphorescent material contained in each layer of the light emitting layer is Organic having different emission peaks, wherein the intermediate layer contains a binder material selected from the group consisting of the following linear saturated hydrocarbon compounds Field light-emitting element.

The organic electric field according to claim 1 or 2 , wherein the at least two light emitting layers include a layer containing the blue phosphorescent material and a layer containing the green phosphorescent material and the red phosphorescent material. Light emitting element. The at least two light emitting layers are a layer containing the blue phosphorescent material, a layer containing the green phosphorescent material, and a layer containing the red phosphorescent material in order from the substrate side, and the blue phosphorescent material. A first intermediate layer between the layer containing the light emitting material and the layer containing the green phosphorescent light emitting material, and between the layer containing the green phosphorescent light emitting material and the layer containing the red phosphorescent light emitting material The organic electroluminescent element according to claim 1, which has a second intermediate layer. The at least two light emitting layers are a layer containing the green phosphorescent material, a layer containing the blue phosphorescent material, and a layer containing the red phosphorescent material in order from the substrate side, and the green phosphorescent material. A first intermediate layer between the layer containing the light emitting material and the blue phosphorescent material, and a second intermediate between the layer containing the blue phosphorescent material and the layer containing the red phosphorescent material. The organic electroluminescent element according to claim 1 or 2 which has a layer. The organic electroluminescent element according to claim 2 , wherein the linear saturated hydrocarbon compound is solid at room temperature. The film thickness of the intermediate layer, the organic electroluminescent device according to any one of claims 1 to 6 or more and less than 0.1 nm 5 nm.