JP4682503B2 - Material for organic electroluminescence device and organic electroluminescence device using the same - Google Patents

Description

  The present invention relates to a light-emitting material for organic phosphorescent light-emitting elements and a light-emitting element with high luminance and high efficiency used for flat light sources and displays.

  An organic electroluminescence (EL) element using an organic substance is expected to be used as an inexpensive large-area full-color display element of a solid light emitting type and has been developed in many ways. In general, an organic EL element is composed of a light emitting layer and a pair of counter electrodes sandwiching the layer. In light emission, when an electric field is applied between both electrodes, electrons are injected from the cathode side, holes are injected from the anode side, the electrons recombine with holes in the light emitting layer, and the energy level starts from the conduction band. It is a phenomenon in which energy is released as light when returning to the valence band.

Conventional organic EL elements have a higher driving voltage and lower light emission luminance and light emission efficiency than inorganic EL elements. Further, the characteristic deterioration has been remarkably not put into practical use.
In recent years, organic EL elements in which thin films containing organic compounds having high fluorescence quantum efficiency that emit light at a low voltage of 10 V or less have been reported and attracted interest (see Non-Patent Document 1). This method uses a metal chelate complex as a light emitting layer and an amine compound as a hole injection layer to obtain a high luminance green light emission. The luminance is several thousand cd / m ² at a direct current voltage of 6 to 7 V, maximum. The luminous efficiency is 1.5 lm / W, and the performance is close to the practical range (see Non-Patent Document 1).

  Furthermore, an organic EL element using light emission from a triplet excited state (hereinafter, abbreviated as an organic phosphorescent light emitting element), which has greatly improved efficiency, compared to a conventional organic EL element using a singlet excited state, has been reported. It has attracted attention (see Non-Patent Documents 2 and 3).

  Many of the organic phosphorescent light emitting devices so far contain a compound having a carbazole skeleton as shown in the following compound (hereinafter abbreviated as CBP). In addition, these compounds have very high crystallinity and it is difficult to obtain a stable film. Therefore, organic phosphorescent light emitting devices using these materials have a problem that their lifetime is short.

CBP

In order to improve the above-mentioned drawbacks and at the same time improve the properties, several improved techniques have been proposed for materials having a carbazole skeleton (Patent Documents 1 to 7), but they are still not satisfactory. In addition, it is presumed that the purpose of these techniques is to improve the film quality and stability at the time of film formation by substituting the hydrogen atom of the 6-membered carbon ring outside carbazole with other substituents. Examples are also disclosed, but specific examples are limited to general groups such as alkyl groups and phenyl groups.
Applied Physics Letters, 51, 913, 1987 Nature, 395, 151 pages, 1998 Applied Physics Letters, 75, 4 pages, 1999 JP 2001-313178 A JP 2001-313179 A Japanese Patent Laid-Open No. 2002-8860 JP 2002-1000047 A Japanese Patent Laid-Open No. 2003-77664 JP 2003-133075 A Republication No. 01/072927

  An object of the present invention is to provide a material for an organic electroluminescence element having high emission luminance and luminous efficiency and excellent stability during repeated use, and an organic electroluminescence element using the same.

The present invention relates to a material for an organic electroluminescence device comprising a compound (A) represented by the following general formula [1] and a phosphorescent material (B) .

One general formula [1]

[In the formula, E is an electron-withdrawing group having a double bond which is any of an electron-withdrawing group including a carbonyl group, a cyanoimino group, and a dicyanomethylene group, and the electron-withdrawing group is a direct bond. Or a benzene ring outside the carbazole ring through a double bond of a vinylene group or a butadienylene group . The other bond of the carbonyl group is any of a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. is there. The electron withdrawing group may have two or more of the same or different.
The portion on the ring where E is not substituted is independently a halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or The substituent may be substituted with an unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. And may form a ring integrally.
A is a substituent bonded to N and a carbon atom, or a linking group that connects a plurality of the same or different carbazole rings. ]

  The present invention also relates to the material for an organic electroluminescence device, wherein the phosphorescent material (B) is an iridium or platinum complex composed of an organic compound or a ligand of an organic residue.

  Furthermore, the present invention relates to an organic electroluminescence device comprising a light emitting layer or a plurality of organic compound thin films including a light emitting layer between a pair of electrodes, wherein any one of the layers comprises the material for an organic electroluminescent device. It is related with the organic electroluminescent element to contain.

  In addition, the present invention provides an organic electroluminescence device in which a light emitting layer or a plurality of organic compound thin films including a light emitting layer is formed between a pair of electrodes, wherein the light emitting layer contains an organic electroluminescent device material as described above. The present invention relates to an electroluminescence element.

  The present invention further relates to the organic electroluminescence element, wherein an electron injection layer is formed between the cathode and the light emitting layer.

  The present invention further relates to the organic electroluminescence device, wherein a hole blocking layer is formed between the electron injection layer and the light emitting layer.

  The present invention further relates to the organic electroluminescence element, wherein a hole injection layer is formed between the anode and the light emitting layer.

  The organic electroluminescent element material of the present invention is particularly excellent in stability, and the organic electroluminescent element using the material has excellent initial characteristics such as luminance and luminous efficiency, and has a long emission life and good environmental characteristics. It is an organic electroluminescence element.

  That is, the present invention provides an organic phosphorescent light-emitting device in which an organic layer having a light-emitting region is provided between an anode and a cathode, and includes an organic substance that emits light from a triplet excited state by current injection as a constituent element. When the compound shown in the present invention is contained, the device is characterized in that it has excellent device performance and durability due to its electrical properties and chemical stability.

Hereinafter, the compound (A) of the present invention will be specifically described .

The compound (A) of the present invention is a compound containing a carbazole ring represented by the general formula [1]. In this case, the hydrogen atom on the nitrogen atom is preferably substituted with the substituent or linking group A via the carbon atom of A, and more preferably with an aryl group.

In the compound (A) of the present invention, there may be two or more carbazole rings , which may be connected via a linking group. In this case, the type and position of the linking group may be basically any as long as the structure and bond are chemically stable, but are preferably linked via the nitrogen atom of the carbazole ring . Another preferable condition is that the carbon atom of the linking group is bonded to the carbazole ring . In particular, in the general formula [1], A serving as a linking group is a group bonded to a nitrogen atom of two or more carbazole rings by a carbon atom. More preferably, the bonding terminal of the linking group is an aryl group, and the linking group is π-conjugated. In addition, when the number of carbazole rings is 4 or more, it is difficult to stably synthesize a high-purity product having the same structure, or it becomes difficult to deposit due to the high molecular weight. More preferably it is.

In the compound (A) of the present invention, an important structure along with the carbazole ring is that an electron-withdrawing group having a double bond is substituted on the ring. In addition, an electron withdrawing group may be expressed as an electron withdrawing group depending on literature. Usually it seems to refer to the same concept, but lexically it is correct to write an electron withdrawing group. The electron withdrawing group having a double bond in the present invention is an electron withdrawing group containing a carbonyl group, a cyanoimino group, or a dicyanomethylene group. A group other than an electron withdrawing group containing a carbonyl group is a derivative in which an electron withdrawing group containing a carbonyl group is used as a basic structure, and an atom constituting this double bond is substituted with another atom or atomic group. Since it can be considered, hereinafter, the description with respect to the electron withdrawing group containing a carbonyl group also applies to other groups unless otherwise specified.

In the electron withdrawing group having a double bond of the present invention, the double bond is conjugated to and bonded to the carbazole ring . That is, the carbon atom of the electron withdrawing group including a carbonyl group is bonded to the carbazole ring through a direct bond or a double bond of a vinylene group or a butadienylene group . Of course, since these double bonds are also part of the electron withdrawing group, they are not part of the components of the carbazole ring in the same manner as the double bond of the electron withdrawing group including the carbonyl group.

Therefore, an electron withdrawing group containing a carbonyl group has one more bond, but here, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group Or either a substituted or unsubstituted heterocyclic group will be attached. Furthermore, any of a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, Another carbazole ring may be bonded, and the electron withdrawing group itself having a double bond may link two carbazole rings .

Although monovalent group carbonyl carbon is bonded position, usually called an acyl group, specific examples, toluoyl group, or an aryl substituent of acyl group such as naphthoyl group, other, alkoxycarbonyl group, (N-substituted) carbamoyl Among them, an acyl group composed of a hydrocarbon-based substituent is preferable from the viewpoint of chemical stability and physical properties.

However, the carbazole ring portion component and the electron-withdrawing moiety, it is preferred that are connected by π conjugated through direct, or an aromatic ring such. In addition, the number of electron withdrawing groups to be substituted is not particularly limited, but preferably, when each of the ring-closing portions of the bond in the condensed ring is counted as a ring, the number of substituted groups is 1 or less per ring. It is preferable.

  In the present invention, when the compound (A) is a carbazole ring represented by the general formula [1], the bonding position of the electron withdrawing group E is necessarily limited to one of the hydrogen atoms of the outer benzene ring. The number of E is not particularly limited, but is preferably 1 or 2, and in the case of 2, it is preferable that one be bonded to each benzene ring. Moreover, about the part which E has not substituted, the following general substituent may couple | bond.

  Specific examples of the general substituent type that is not particularly limited in the present invention include a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted group. Examples thereof include an aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted amino group, or a substituted or unsubstituted carbocyclic group or heterocyclic group. In the following, more detailed representative examples of each substituent will be shown, but the present invention is not limited thereto, and these substituents may further have a substituent bonded thereto.

  Examples of the halogen atom serving as a substituent in the present invention include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the substituted or unsubstituted alkyl group in the present invention include methyl group, ethyl group, propyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, stearyl group, 2-phenylisopropyl group, trichloromethyl group, trifluoromethyl group, benzyl group, α-phenoxybenzyl group, α, α-dimethylbenzyl group, α, α-methylphenylbenzyl group, α, α-ditrifluoromethylbenzyl group , Triphenylmethyl group, α-benzyloxybenzyl group and the like.

  Examples of the substituted or unsubstituted alkoxy group in the present invention include an unsubstituted alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a tert-butoxy group, an octyloxy group, and a tert-octyloxy group; , 3-trifluoroethoxy group, and substituted alkoxy group such as benzyloxy group.

  Examples of the substituted or unsubstituted aryloxy group in the present invention include unsubstituted aryloxy groups such as phenoxy group, 4-tert-butylphenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, and 9-anthryloxy group. And substituted aryloxy groups such as 4-nitrophenoxy group, 3-fluorophenoxy group, pentafluorophenoxy group and 3-trifluoromethylphenoxy group.

  Examples of the substituted or unsubstituted alkylthio group in the present invention include an unsubstituted alkylthio group such as methylthio group, ethylthio group, tert-butylthio group, hexylthio group, and octylthio group, 1,1,1-tetrafluoroethylthio group, And substituted alkylthio groups such as benzylthio group and trifluoromethylthio group.

  Examples of the substituted or unsubstituted arylthio group in the present invention include an unsubstituted arylthio group such as a phenylthio group, a 2-methylphenylthio group, and a 4-tert-butylphenylthio group, a 3-fluorophenylthio group, and a pentafluorophenylthio group. And substituted arylthio groups such as a 3-trifluoromethylphenylthio group.

  Examples of the substituted or unsubstituted amino group in the present invention include an amino group, a mono- or dialkylamino group, a mono- or diarylamino group, and an alkylarylamino group. Specific examples of the alkylamino group include an ethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, a benzylamino group, and a dibenzylamino group. Specific examples of the arylamino group include a phenylamino group, ( 3-methylphenyl) amino group, (4-methylphenyl) amino group, etc. Specific examples of the arylamino group include phenylamino group, phenylmethylamino group, diphenylamino group, ditolylamino group, dibiphenylylamino group Di (4-methylbiphenyl) amino group, di (3-methylphenyl) amino group, di (4-methylphenyl) amino group, naphthylphenylamino group, bis [4- (α, α'-dimethylbenzyl) phenyl There are amino groups and the like. Specific examples of the alkylarylamino group include an N-ethyl-N-phenylamino group and an N-methyl-N-naphthylamino group. Also included are structures in which substituents to amino groups such as bis (methoxyphenyl) amino group and bis (acetoxyethyl) amino group are further substituted.

The substituted or unsubstituted carbocyclic group in the present invention includes a monocyclic group or a condensed polycyclic group.
Specific examples of the monocyclic group include a monocyclic cycloalkyl group and a monocyclic aryl group.
Examples of the monocyclic cycloalkyl group include cycloalkyl groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.
A monocyclic aryl group includes a phenyl group.
Examples of the substituted or unsubstituted condensed polycyclic group include a condensed polycyclic aryl group and a condensed polycyclic cycloalkyl group.

  Examples of the condensed polycyclic aryl group include a naphthyl group, anthryl group, phenanthryl group, fluorenyl group, acenaphthyl group, azulenyl group, heptaenyl group, pyrenyl group, perylenyl group, and triphenylenyl group.

Examples of the substituted or unsubstituted heterocyclic group in the present invention include a monocyclic heterocyclic group and a condensed polycyclic heterocyclic group.
Monocyclic heterocyclic groups include thienyl, furyl, pyrrolyl, imidazolyl, pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, There are thiadiazolyl and imidadiazolyl groups.
As the condensed polycyclic heterocyclic group, indolyl group, quinolyl group, isoquinolyl group, phthalazinyl group, quinoxalinyl group, quinazolinyl group, carbazolyl group, acridinyl group, phenazinyl group, benzofuryl group, isothiazolyl group, isoxazolyl group, furazanyl group, phenoxazinyl group Benzothiazolyl group, benzoxazolyl group, benzimidazolyl group, benzotriazolyl group, pyranyl group and the like. Examples of other condensed polycyclic groups include 1-tetralyl group, 2-tetralyl group, tetrahydroquinolyl group and the like.

  In the present invention, the compound (A) represented by the general formula [1] is obtained by directly acylating a carbazole ring in a Friedel-Crafts reaction or brominating a carbazole ring and reacting it with a carboxylic acid amide. It can be made by generating a carbonyl group using an active methylene sulfur compound. A method of synthesizing from a substituted alkenyl group having an alkyl group or a double bond is also conceivable. A cyanoimino group or dicyanomethylene group can be synthesized by converting a carbonyl group. Depending on the compound, the final product may be synthesized through further steps after synthesizing an intermediate with an electron-withdrawing group introduced.

  Specific examples of the compound (A) of the present invention are specifically shown below, but the present invention is not limited to these representative examples.

In the compound (A) of the present invention , since an electron-withdrawing group is substituted on the carbazole ring, the rigidity of the molecule is increased and the structure is highly stable compared to a compound composed of an unsubstituted ring. However, the glass transition point and melting point are high. On the other hand, the crystallinity is lowered due to the attachment of the substituent. This improves the film quality and stability during film formation, and improves the resistance (heat resistance) against Joule heat generated in the organic layer, between the organic layers, or between the organic layer and the metal electrode during electroluminescence. When used as a phosphorescent light-emitting element material, it exhibits high emission luminance and is advantageous when emitting light for a long time. In addition, since an electron-withdrawing group having a double bond such as a carbonyl group can be expected to stabilize the triplet excited state, there is a concern that the conventional fluorescent organic EL element may weaken light emission. However, when it is used simultaneously with the phosphorescent material (B) in the organic phosphorescent light emitting device, an effect of enhancing light emission can be expected.

  An organic phosphorescent light-emitting device is a device in which a single-layer or multilayer organic thin film is formed between an anode and a cathode. The basic configuration is the same as that of a conventional organic EL element, but is characterized in that material selection and layer configuration are devised so that triplet excited state energy can be used for light emission. In the present invention, the “phosphorescent light-emitting element” means not only a case where a light-emitting material or a doping material directly emits light from a triplet state, but also a triplet generated by recombination of charges injected from both electrodes. It includes all elements having a structure designed to have a mechanism and a process that can be effectively used for light emission in the element without turning the excited state into energy emission other than light. In this sense, the compound (A) of the present invention is suitable as a material constituting each layer because it easily generates and maintains a triplet excited state structurally and physically. In particular, when it is used as a component of a light emitting layer in which the triplet excited state is most present during device driving, the maximum effect is exhibited.

  When the organic EL element or the organic phosphorescent light emitting element is a single layer type, a light emitting layer is provided between the anode and the cathode. The light emitting layer contains a light emitting material, and may further contain a hole injecting material or an electron injecting material in order to transport holes injected from the anode or electrons injected from the cathode to the light emitting material. The electron injection material is a material having the ability to inject electrons from the cathode, and the electron transport material is a material having the ability to transport the injected electrons to the light emitting layer. The hole injection material is a material having the ability to inject holes from the anode, and the hole transport material is a material having the ability to transport the injected holes to the light emitting layer. The multilayer type includes (anode / hole injection layer / light emitting layer / cathode), (anode / hole injection layer / hole transport layer / light emitting layer / cathode), (anode / light emitting layer / electron injection layer / cathode), (Anode / light emitting layer / electron transport layer / electron injection layer / cathode), (anode / hole injection layer / light emitting layer / electron injection layer / cathode), (anode / hole injection layer / hole transport layer / light emitting layer) There is an organic phosphorescent light emitting device laminated in a multilayer structure of / electron transport layer / electron injection layer / cathode). The multilayer hole transport layer and the electron transport layer may be composed of a plurality of layers. Here, a hole injection layer and a hole transport layer, in some cases up to a light emitting layer having a strong hole transport property, up to a hole injection band, an electron injection layer and an electron transport layer, and in some cases to a light emitting layer having a strong electron transport property May be referred to as an electron injection band, and materials used in each band may be collectively referred to as a hole injection material (or hole transport material) or an electron injection material (or electron transport material). In the case of an organic phosphorescent light emitting device, the electron transporting layer is required to prevent holes from escaping from the light emitting layer to the cathode side due to the electron transportability in terms of device characteristics and materials used. In order to give more importance to the blocking property, it is often called a hole blocking layer or a hole blocking layer, and the material used for this layer is sometimes called a hole blocking material. Since these designations are given to emphasize one aspect of the necessary characteristics of the material for the target element, the essence of the material does not differ depending on the designation. The material of each of these layers and the structure thereof are selected and determined according to various factors such as the energy level of the material, heat resistance, and adhesion to the organic layer or metal electrode.

  If necessary, in addition to the material of the present invention, a known light emitting material, doping material, hole injecting material, and electron injecting material containing a further existing organic fluorescent dye can be used for the light emitting layer. The organic phosphorescent light emitting element can prevent a decrease in luminance and lifetime due to quenching by adopting a multilayer structure. If necessary, a light emitting material, a doping material, a hole injection material, and an electron injection material can be used in combination. Further, by using a doping material, emission luminance and luminous efficiency can be improved, and light emission ranging from blue to red can be obtained.

  Examples of the phosphorescent light emitting material (B) or doping material that can be used in the light emitting layer together with the compound (A) of the present invention include an organic compound or a metal complex composed of an organic residue ligand. The metal atom is usually a transition metal, and is preferably an element of the 5th or 6th period in the period, and from the 6th group to the 11th group in the group, and more preferably in the 8th to 10th group. Specific examples include iridium and platinum. Examples of the ligand include 2-phenylpyridine and 2- (2'-benzothienyl) pyridine, and the carbon atom on these ligands is directly bonded to the metal. Another example is a porphyrin or tetraazaporphyrin ring complex. Examples of the central metal include platinum. Although the typical example of a phosphorescent luminescent material is specifically illustrated below, this invention is not limited to this representative example. Note that this example is an example of a material for which it is known that light is emitted directly from a triplet excited state, and there is another mechanism that can be used for light emission effectively without losing triplet excitation energy in the device. In addition, more materials can be used as the light emitting material or the doping material, and the possibility that the existing organic fluorescent dye, the organic EL light emitting material, and the doping material can be used for the organic phosphorescent light emitting element is not denied.

  Any of the above-mentioned materials that can be used in the light-emitting layer and the abundance ratio of the compound of the present invention in the light-emitting layer may be the main component, but preferably the above-mentioned phosphorescent light-emitting material (B) or doping material In other words, it is used as a host material having an abundance ratio of the compound (A) of the present invention of 50% or more.

  As a hole injection material, it has the ability to transport holes, has a hole injection effect from the anode, an excellent hole injection effect for the light emitting layer or the light emitting material, and excitons generated in the light emitting layer. Examples thereof include compounds that prevent movement to an electron injection zone or an electron injection material and have an excellent thin film forming ability. Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acyl hydrazone, polyaryl Alkane, stilbene, butadiene, benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine, etc., and their derivatives, and polymer materials such as polyvinyl carbazole, polysilane, conductive polymer, etc. However, it is not limited to these.

  Among the hole injection materials that can be used in the organic phosphorescent light emitting device of the present invention, more effective hole injection materials are arylamine derivatives, phthalocyanine compounds, or triphenylene derivatives. Specific examples of the arylamine derivative include triphenylamine, tolylamine, tolyldiphenylamine, N, N′-diphenyl-N, N′-di-m-tolyl-4,4′-biphenyldiamine, N, N, N ', N'-tetra (p-tolyl) -p-phenylenediamine, N, N, N', N'-tetra-p-tolyl-4,4'-biphenyldiamine, N, N'-diphenyl-N, N′-di (1-naphthyl) -4,4′-biphenyldiamine, N, N′-di (4-n-butylphenyl) -N, N′-di-p-tolyl-9,10-phenanthrenediamine 4,4 ′, 4 ″ -tris (N-phenyl-Nm-tolylamino) triphenylamine, 1,1-bis [4- (di-p-tolylamino) phenyl] cyclohexane, or the like There are oligomers or polymers having tertiary amine skeletons, though not particularly limited thereto.

  Specific examples of the phthalocyanine (Pc) compound include H2Pc, CuPc, CoPc, NiPc, ZnPc, PdPc, FePc, MnPc, ClAlPc, ClGaPc, ClInPc, ClSnPc, Cl2SiPc, (HO) AlPc, OP , Phthalocyanine derivatives such as TiOPc, MoOPc, GaPc-O-GaPc, and naphthalocyanine derivatives, but are not limited thereto.

  Specific examples of the triphenylene derivative include hexaalkoxytriphenylenes such as hexamethoxytriphenylene, hexaethoxytriphenylene, hexahexyloxytriphenylene, hexabenzyloxytriphenylene, trimethylenedioxytriphenylene, triethylenedioxytriphenylene, hexaphenoxytriphenylene, hexanaphthyl. Examples include, but are not limited to, hexaaryloxytriphenylenes such as oxytriphenylene, hexabiphenylyloxytriphenylene, and triphenylenedioxytriphenylene, and hexaacyloxytriphenylenes such as hexaacetoxytriphenylene and hexabenzoyloxytriphenylene.

  As an electron injection material, it has the ability to transport electrons, has a hole injection effect from the cathode, and an excellent electron injection effect for the light-emitting layer or light-emitting material, and hole injection of excitons generated in the light-emitting layer Examples thereof include compounds that prevent migration to the zone and have an excellent thin film forming ability. For example, there are fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, anthrone and their derivatives. However, it is not limited to these. Further, it can be sensitized by adding an electron accepting substance to the hole injecting material and an electron donating substance to the electron injecting material.

  In the organic phosphorescent light emitting device of the present invention, a more effective electron injection material is a metal complex compound or a nitrogen-containing five-membered ring derivative. Specifically, as the metal complex compound, 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinate) zinc, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinate) manganese , Tris (8-hydroxyquinolinato) aluminum, tris (2-methyl-8-hydroxyquinolinato) aluminum, tris (8-hydroxyquinolinato) gallium, bis (10-hydroxybenzo [h] quinolinato) beryllium Bis (10-hydroxybenzo [h] quinolinato) zinc, bis (2-methyl-8-hydroxyquinolinato) chlorogallium, bis (2-methyl-8-hydroxyquinolinato) (o-cresolate) gallium, Bis (2-methyl-8-hydroxyquinolinate) (1-naphthlar ) Aluminum, bis (2-methyl-8-hydroxyquinolinato) (2-naphtholato) gallium, bis (2-methyl-8-hydroxyquinolinato) phenolate gallium, bis (o- (2-benzoxazolyl) (L) phenolate) zinc, bis (o- (2-benzothiazolyl) phenolate) zinc, bis (o- (2-benzotriazolyl) phenolate) zinc, and the like, but are not limited thereto.

  Further, as the nitrogen-containing five-membered ring derivative, an oxazole, thiazole, oxadiazole, thiadiazole or triazole derivative is preferable. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, dimethyl POPOP, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5- Bis (1-phenyl) -1,3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-oxadiazole, 2, 5-bis (1-naphthyl) -1,3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyl) Oxadiazolyl) -4-tert-butylbenzene], 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-thiadiazole, 2,5-bis (1- Naphthyl) -1,3,4-thiadiazole, 1,4-bis [2- (5 Phenylthiadiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1, Examples include, but are not limited to, 3,4-triazole and 1,4-bis [2- (5-phenyltriazolyl)] benzene.

  As a hole blocking material, it has the ability to prevent holes from being transported to the cathode, has the effect of preventing the exciton generated in the light emitting layer from moving to the electron injection zone, and has excellent thin film forming ability Compounds. Many of the electron injection materials can be used as hole blocking materials. For example, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-triazole and 2,5- Azoles (nitrogen-containing five-membered rings) represented by bis (1-phenyl) -1,3,4-oxadiazole, phenanthroline derivatives represented by bathocuproine, bis (2-methyl-8-hydroxyquinolinate) ) (4-biphenyloxolate) aluminum (III), nitrogen-containing six-membered rings such as metal complexes represented by bis (2-methyl-8-hydroxyquinolinato) phenolate gallium and the ligands Metal complexes, silacyclobutene (silole) derivatives, and the like, but are not limited thereto.

  Since the compound (A) of the present invention has an electron withdrawing group, the electron transporting property is higher than the hole transporting property and can be used as one of the hole blocking material or the electron injecting material. is there. Therefore, it can be suitably used as a hole blocking layer of an organic phosphorescent material. The compound (A) can also be applied to an electron transport layer, an electron injection layer, and a hole blocking layer in a conventional fluorescent organic EL device using a singlet excited state. However, when used in a fluorescent element, the compound (A) is particularly useful since the electron-withdrawing group having a double bond such as a carbonyl group contributes to the generation and stabilization of the triplet state. When there is a high probability that recombination of holes and electrons occurs in the layer containing A) or in the immediate vicinity of the layer, the brightness and efficiency may be deteriorated as a whole. Thus, it may be necessary to carefully select materials and usage configurations.

  In order to improve the stability of the organic phosphorescent light-emitting device obtained by the present invention with respect to temperature, humidity, atmosphere, etc., a protective layer may be provided on the surface of the device, or the entire device may be protected with silicon oil, resin, etc. Is possible.

  As the conductive material used for the anode of the organic phosphorescent light emitting device, a material having a work function larger than 4 eV is suitable, and carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum, palladium And their alloys, metal oxides such as tin oxide and indium oxide used for ITO substrates and NESA substrates, and organic conductive resins such as polythiophene and polypyrrole.

  As the conductive material used for the cathode, those having a work function smaller than 4 eV are suitable, and magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, aluminum, and alloys thereof are used. However, it is not limited to these. Examples of alloys include magnesium / silver, magnesium / indium, lithium / aluminum, and the like, but are not limited thereto. The ratio of the alloy is controlled by the temperature of the vapor deposition source, the atmosphere, the degree of vacuum, etc., and is selected to an appropriate ratio. Further, as a cathode, an alkali metal such as lithium fluoride, magnesium fluoride, or lithium oxide, a fluoride of an alkaline earth metal, or an oxide is formed on the organic layer with a film thickness of 1 nm or less, and aluminum or silver is formed thereon. A metal having a relatively high conductivity such as, for example, may be formed. Moreover, the anode and the cathode may be formed with a layer structure of two or more layers if necessary.

  In the organic phosphorescent light emitting device, in order to emit light efficiently, it is desirable that at least one of them is sufficiently transparent in the light emitting wavelength region of the device. The substrate is also preferably transparent. The transparent electrode is set using the above-described conductive material so as to ensure a predetermined translucency by a method such as vapor deposition or sputtering. The electrode on the light emitting surface preferably has a light transmittance of 10% or more. The substrate is not limited as long as it has mechanical and thermal strength and has transparency. For example, a glass substrate, a polyethylene plate, a polyethylene terephthalate plate, a polyethersulfone plate, Examples thereof include a transparent resin such as a polypropylene plate.

  The formation of each layer of the organic phosphorescent light emitting device according to the present invention applies any of dry deposition methods such as vacuum deposition, sputtering, plasma, and ion plating, and wet deposition methods such as spin coating, dipping, and flow coating. can do. The film thickness is not particularly limited, but must be set to an appropriate film thickness. If the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. If the film thickness is too thin, pinholes and the like are generated, and sufficient light emission luminance cannot be obtained even when an electric field is applied. The normal film thickness is suitably in the range of 5 nm to 10 μm, but more preferably in the range of 10 nm to 0.2 μm.

  In the case of the wet film forming method, the material for forming each layer is dissolved or dispersed in an appropriate solvent such as ethanol, chloroform, tetrahydrofuran, dioxane or the like to form a thin film, and any solvent may be used. In any organic thin film layer, an appropriate resin or additive may be used for improving film formability and preventing pinholes in the film. Usable resins include insulating resins such as polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethyl methacrylate, polymethyl acrylate, and cellulose, and copolymers thereof, poly-N-vinyl. Examples thereof include photoconductive resins such as carbazole and polysilane, and conductive resins such as polythiophene and polypyrrole. Examples of the additive include an antioxidant, an ultraviolet absorber, and a plasticizer.

  As described above, by using the compound of the present invention in the light emitting layer of the organic phosphorescent light emitting device, the characteristics of the organic phosphorescent light emitting device such as the light emission efficiency and the maximum light emission luminance can be improved. In addition, this element is extremely stable against heat and current, and can be used for light emission brightness that can be used practically at a low driving voltage, so that the degradation that has been a major problem until now is greatly reduced. I was able to.

Hereinafter, the present invention will be described in more detail based on examples.
Method of synthesizing compound (10) 9.4 g of N-ethylcarbazole, 13.9 g of AlCl ₃ and 120 mL of benzene were placed in a flask, and 14.6 g of benzoyl chloride was added to 20 mL of benzene while cooling to 5 ° C. or lower in an ice-water bath. The solution dissolved in was added dropwise over 40 minutes. After completion of the dropwise addition, the mixture was returned to room temperature with stirring, and then the reaction solution was poured into 1500 mL of ice water to precipitate the product. After adding 1000 mL of benzene and stirring, the oil layer portion was taken out and 2 mL was added with 500 mL of deionized water. Washed twice. Recrystallization was performed with a chloroform-hexane mixed solvent to obtain 12.9 g of a product. Further sublimation purification was performed.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example. In the examples, all mixing ratios are weight ratios unless otherwise specified. Vapor deposition (vacuum deposition) was performed in a vacuum of 10 ⁻⁶ Torr and under conditions without temperature control such as substrate heating and cooling. In the evaluation of the light emission characteristics of the element, the characteristics of an organic EL element having an electrode area of 2 mm × 2 mm were measured. The measurement recorded current, luminance, and chromaticity at each voltage while increasing by 1V. The maximum light emission luminance and efficiency are the maximum values measured for each voltage, and the voltage at that time varies depending on the element.

Example 2
N, N '-(1-naphthyl) -N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPD) is vacuum-deposited on a cleaned glass plate with an ITO electrode. A hole injection layer having a thickness of 20 nm was obtained. Next, the compound (15) and the compound (D1) were co-evaporated at a ratio of 93: 7 to form a light-emitting layer having a thickness of 40 nm, and then bis (2-methyl-5-phenyl-8-hydroxyquinolinato) pheno An electron injection layer having a thickness of 30 nm was obtained by depositing a gallium complex. On top of this, an electrode having a thickness of 100 nm was formed from an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic phosphorescent light emitting device. This device emitted green light with a light emission luminance of 3700 (cd / m ² ), a maximum light emission luminance of 66000 (cd / m ² ), and a light emission efficiency of 48 (cd / A) at a DC voltage of 10V.

Example 3
A device was fabricated in the same manner as in Example 2 except that the compound (10) was used instead of the compound (15). This device emitted green light with a light emission luminance of 7300 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 62400 (cd / m ² ), and a light emission efficiency of 38 (cd / A).

Example 4
NPD was vacuum-deposited on the cleaned glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 30 nm. Next, the compound (19) and the compound (D5) were co-evaporated at a ratio of 95: 5 to prepare a light-emitting layer having a film thickness of 40 nm, and then bis (2-methyl-8-hydroxyquinolinate) (p-phenylphenol) Lat) An aluminum complex was vapor-deposited to form a hole blocking layer having a thickness of 10 nm, and further tris (8-hydroxyquinolinato) aluminum complex (Alq3) was vapor-deposited to obtain an electron injection layer having a thickness of 30 nm. On top of this, first, 1 nm of lithium fluoride and then 200 nm of aluminum were vapor-deposited to form an electrode to obtain an organic phosphorescent light emitting device. This device produced red light emission with a light emission luminance of 540 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 28300 (cd / m ² ), and a light emission efficiency of 9.8 (cd / A).

Example 5
The compound (35) and the compound (D6) were dissolved in methylene chloride at a ratio of 98: 2 on the washed glass plate with the ITO electrode, and a 50 nm-thick hole injection type light emitting layer was obtained by a spin coating method. Next, bathocuproine was evaporated to form a hole blocking layer having a thickness of 5 nm, and further Alq3 was evaporated to obtain an electron injection layer having a thickness of 30 nm. On top of that, first, 0.5 nm of lithium fluoride and then 200 nm of aluminum were vapor-deposited to form an electrode to obtain an organic phosphorescent device. This device obtained red light emission with a light emission luminance of 920 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 8400 (cd / m ² ), and a light emission efficiency of 4.9 (cd / A).

Example 6
NPD was vacuum-deposited on the cleaned glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 30 nm. Next, the compound (28) and the compound (D3) were co-evaporated at a ratio of 94: 6 to obtain a light-emitting layer having a thickness of 50 nm. Next, a bis (2-methyl-8-hydroxyquinolinate) (p-cyanophenolate) gallium complex is vacuum-deposited to form a 20-nm-thick hole blocking layer, and Alq3 is further deposited to deposit 20-nm-thick electrons. A layer was obtained. On top of this, an electrode having a thickness of 250 nm was formed from an alloy in which magnesium and silver were mixed at a ratio of 10: 1 (weight ratio) to obtain an organic phosphorescent device. This device obtained blue light emission with a light emission luminance of 2300 (cd / m ² ), a maximum light emission luminance of 21200 (cd / m ² ), and a light emission efficiency of 10.1 (cd / A) at a DC voltage of 10V.

Example 7
Copper phthalocyanine was vacuum-deposited on the washed glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 20 nm. Subsequently, only the compound (37) was vacuum-deposited alone to obtain a 30 nm-thick hole transport layer. Further, the compound (37) and the compound (D1) were co-evaporated at a ratio of 93: 7 to prepare a light-emitting layer having a thickness of 40 nm, and then bathocuproine was evaporated to form a hole-blocking layer having a thickness of 10 nm. Was vacuum-deposited to prepare an electron injection layer having a thickness of 30 nm. An electrode was formed thereon by vacuum deposition of 0.7 nm of lithium fluoride (LiF) and then 150 nm of aluminum (Al) to obtain an organic phosphorescent device. This device produced green light emission with a light emission luminance of 3810 (cd / m ² ), a maximum light emission luminance of 74700 (cd / m ² ), and a light emission efficiency of 39 (cd / A) at a DC voltage of 10V. Further, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5200 hours.

Example 9
NPD was vacuum-deposited on the cleaned glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 30 nm. Next, the compound (14) and the compound (D7) were co-evaporated at a ratio of 97: 3 to form a light-emitting layer having a thickness of 40 nm, and then only the compound (3) was vapor-deposited alone to form a positive film with a thickness of 30 nm. A hole blocking layer and further Alq3 were vacuum deposited to form an electron injection layer having a thickness of 20 nm. First, an electrode was formed by vacuum deposition of lithium fluoride at 0.5 nm and aluminum at 200 nm to obtain an organic phosphorescent device. This device produced red light emission with a light emission luminance of 4600 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 19900 (cd / m ² ), and a light emission efficiency of 9.5 (cd / A). Further, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5800 hours.

Example 10
NPD was vacuum-deposited on the cleaned glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 50 nm. Next, the compound (18) and the compound (D3) were co-evaporated at a weight ratio of 85:15 to prepare a light-emitting layer having a thickness of 40 nm, and then bis (2-methyl-8-hydroxyquinolinate) (p -Phenylphenolate) An aluminum complex was vapor-deposited to form a hole blocking layer having a thickness of 10 nm, and further Alq3 was vapor-deposited to obtain an electron injection layer having a thickness of 30 nm. Furthermore, an electrode was first formed thereon by vacuum deposition of 0.5 nm of magnesium fluoride and 200 nm of aluminum, to obtain an organic phosphorescent light emitting device. This device emitted light with an emission luminance of 3250 (cd / m ² ) at a DC voltage of 10 V, a maximum emission luminance of 52600 (cd / m ² ), and an emission efficiency of 5.4 (cd / A). Further, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 3100 hours.

Comparative Example 1
A device was prepared in the same manner as in Example 1 except that the following compound (C1) was used instead of the compound (2). The spin coat film has the disadvantage that it easily aggregates and crystallizes. The light emission characteristics of this device were that light emission with a direct current voltage of 10 V was 70 (cd / m ² ), the maximum light emission luminance was 1600 (cd / m ² ), and the light emission efficiency was 1.5 (cd / A). The light and dark areas were mixed, not uniform light emission. Further, when the device was driven at a constant current with a light emission luminance of 500 (cd / m ² ), the short circuit occurred in about 2 hours.
Compound (C1)

Comparative Example 2
A device was produced in the same manner as in Example 2 except that CBP was used instead of the compound (15). With respect to the light emission characteristics of this device, light emission with a direct current voltage of 10 V of light emission luminance of 1700 (cd / m ² ), maximum light emission luminance of 48000 (cd / m ² ), and light emission efficiency of 25 (cd / A) was obtained. However, the half-life when driven at a constant current with an emission luminance of 500 (cd / m ² ) was 820 hours.

Comparative Example 3
A device was prepared in the same manner as in Example 10 except that the following compound (C2) was used instead of the compound (18). With respect to the light emission characteristics of the device, light emission with a direct current voltage of 10 V of light emission luminance of 2560 (cd / m ² ), maximum light emission luminance of 30100 (cd / m ² ), and light emission efficiency of 4.5 (cd / A) was obtained. However, the half life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 180 hours.
Compound (C2)

Example 11
A device was prepared in the same manner as in Example 4 except that the compound (24) was used instead of the compound (19). This device produced red light emission with a light emission luminance of 730 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 19800 (cd / m ² ), and a light emission efficiency of 9.6 (cd / A). The half life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 8700 hours.

Example 13
On the washed glass plate with an ITO electrode, 4,4′-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl was vacuum-deposited to obtain a hole injection layer having a thickness of 30 nm. Next, the compound (16) and the compound (D3) were co-evaporated at a ratio of 95: 5 to obtain a light emitting layer having a thickness of 50 nm. Next, a bis (2-methyl-8-hydroxyquinolinate) (p-phenylphenolate) aluminum complex was vacuum-deposited to form a 10 nm-thick hole blocking layer, and bis (2-methyl-5-phenyl-8). -Hydroxyquinolinato) phenolate gallium complex was evaporated to obtain an electron injection layer having a thickness of 30 nm. On top of this, an electrode having a thickness of 250 nm was formed from an alloy in which magnesium and silver were mixed at a ratio of 10: 1 (weight ratio) to obtain an organic phosphorescent device. This device produced blue light emission with a light emission luminance of 8300 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 55500 (cd / m ² ), and a light emission efficiency of 7.5 (cd / A).

Example 14
A device was prepared in the same manner as in Example 7 except that the compound (38) was used instead of the compound (37) in the light emitting layer. This device emitted green light with a luminance of 8530 (cd / m ² ), a maximum luminance of 61200 (cd / m ² ), and a luminous efficiency of 45 (cd / A) at a DC voltage of 10V. In addition, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 7800 hours.

Example 15
4,4 ′, 4 ″ -tris [N- (1-naphthyl) -N-phenylamino] triphenylamine is vacuum-deposited on a cleaned glass plate with an ITO electrode to form a 20 nm-thick hole injection layer. Next, NPD was vacuum-deposited to obtain a 30 nm-thick hole transport layer, and the compound (12) and the compound (D6) were co-deposited at a ratio of 97: 3 to obtain a thickness of 40 nm. Then, a 5 nm-thick hole blocking layer was deposited by vapor deposition of bathophenanthroline, and an electron injection layer having a thickness of 30 nm was created by vacuum-depositing Alq3. An electrode was formed by vacuum deposition of 0.7 nm and then 200 nm of aluminum to obtain an organic phosphorescent light-emitting device having an emission luminance of 6250 (cd / m ² ) at a DC voltage of 10 V and a maximum emission luminance of 13400. (Cd / m ² ), light emission efficiency of 5.0 (cd / A) was obtained, and the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 8400 hours. .

Example 16
NPD was vacuum-deposited on the cleaned glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 30 nm. Next, the compound (30) and the compound (D5) were co-evaporated at a ratio of 98: 2 to prepare a light-emitting layer having a thickness of 40 nm, and then bis (2-methyl-8-hydroxyquinolinate) (p-phenylphenol) Lat) An aluminum complex was evaporated to form a hole blocking layer having a thickness of 10 nm, and further Alq3 was evaporated to obtain an electron injection layer having a thickness of 30 nm. On top of this, first, 1 nm of lithium fluoride and then 200 nm of aluminum were vapor-deposited to form an electrode to obtain an organic phosphorescent light emitting device. This device produced red light emission with a light emission luminance of 1880 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 15000 (cd / m ² ), and a light emission efficiency of 7.2 (cd / A).

Example 17
NPD was vacuum-deposited on the cleaned glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 30 nm. Next, the compound (27) and the compound (D1) were co-evaporated at a ratio of 95: 5 to prepare a light-emitting layer having a thickness of 40 nm, and then a bis (2-methyl-8-hydroxyquinolinato) phenolate aluminum complex was formed. A hole blocking layer having a thickness of 10 nm was deposited, and Alq3 was further deposited to obtain an electron injection layer having a thickness of 30 nm. On top of this, first, 1 nm of lithium fluoride and then 200 nm of aluminum were vapor-deposited to form an electrode to obtain an organic phosphorescent light emitting device. This device emitted green light with a luminance of 4570 (cd / m ² ) at a DC voltage of 10 V, a maximum luminance of 98200 (cd / m ² ), and a luminous efficiency of 47 (cd / A).

Example 18
On the washed glass plate with an ITO electrode, 4,4′-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl was vacuum-deposited to obtain a hole injection layer having a thickness of 30 nm. Next, the compound (14) and the compound (D1) were co-evaporated at a ratio of 93: 7 to form a light-emitting layer having a thickness of 40 nm, and then bis (2-methyl-5-phenyl-8-hydroxyquinolinato) pheno Lat aluminum complex was evaporated to form a hole blocking layer having a thickness of 10 nm, and Alq3 was further evaporated to obtain an electron injection layer having a thickness of 30 nm. On top of this, first, 1 nm of lithium fluoride and then 200 nm of aluminum were vapor-deposited to form an electrode to obtain an organic phosphorescent light emitting device. This device emitted green light with a luminance of 2990 (cd / m ² ), a maximum luminance of 91200 (cd / m ² ), and a luminous efficiency of 49 (cd / A) at a DC voltage of 10V. Further, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 9300 hours.

Comparative Example 4
A device was prepared in the same manner as in Example 18 except that the following compound (C3) was used instead of the compound (14). This device has a light emission luminance of 260 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 15600 (cd / m ² ), a light emission efficiency of 13 (cd / A), and a light emission luminance of 500 (cd / m ^2). ) Had a half life of 980 hours when driven at a constant current.
Compound (C3)

In the devices other than the examples in which the half life was specified in this example, when the device was driven at a constant current with a light emission luminance of 500 (cd / m ² ), all of the devices of the examples were reduced from 80% of the initial luminance at 1000 hours. There was nothing I did.

The organic phosphorescent light emitting device of the present invention can be applied to flat panel displays such as wall-mounted televisions, flat light emitters, light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, and indicator lights. And its industrial value is very large. The material of the present invention can also be used in the fields of conventional organic EL devices, electrophotographic photoreceptors, photoelectric conversion devices, solar cells, image sensors and the like.

Claims (7)

An organic electroluminescent element material comprising a compound (A) represented by the following general formula [1] and a phosphorescent material (B).
General formula [1]

[In the formula, E is an electron-withdrawing group having a double bond which is any of an electron-withdrawing group including a carbonyl group, a cyanoimino group, and a dicyanomethylene group, and the electron-withdrawing group is a direct bond. Or a benzene ring outside the carbazole ring through a double bond of a vinylene group or a butadienylene group . The other bond of the carbonyl group is any of a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. is there. The electron withdrawing group may have two or more of the same or different.
The portion on the ring where E is not substituted is independently a halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or The substituent may be substituted with an unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. And may form a ring integrally.
A is a substituent bonded to N and a carbon atom, or a linking group that connects a plurality of the same or different carbazole rings. ] Phosphorescent material (B) The organic electroluminescent device material of claim 1, wherein an iridium or platinum complex consisting of ligands of the organic compound or an organic residue. In the organic electroluminescent element formed by forming a light emitting layer or a plurality of layers of organic compound thin films including a light emitting layer between a pair of electrodes, any one of the layers comprises the material for an organic electroluminescent element according to claim 1 or 2. An organic electroluminescence element to be contained. 3. An organic electroluminescence device comprising a light emitting layer or a plurality of organic compound thin films including a light emitting layer formed between a pair of electrodes, wherein the light emitting layer is an organic material containing the organic electroluminescent device material according to claim 1 or 2. Electroluminescence element. Further, the organic electroluminescent device according to claim 3 or 4, wherein the forming the electron injecting layer between the cathode and the light-emitting layer. The organic electroluminescence device according to any one of claims 3-5, characterized in that to form a hole blocking layer between the electron injection layer and the light emitting layer. Further, an anode an organic electroluminescent device according to any one of claims 3-6, characterized in that to form the hole injection layer between the light emitting layer.