JP4363133B2 - Organic electroluminescent device material and organic electroluminescent 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

An example in which an indole derivative is applied to an organic EL element is already known (see Patent Document 1). However, only an organic EL element utilizing fluorescence is described. In addition, there is a report of an example in which an azole ring is applied to an organic phosphorescent light emitting device (see Patent Documents 2 and 3).
Applied Physics Letters, 51, 913, 1987 Nature, 395, 151 pages, 1998 Applied Physics Letters, 75, 4 pages, 1999 Japanese Patent No. 3229654 JP 2002-1000047 A JP 2002-203683 A

  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 has been found from the fact that the compound (A) represented by the following general formula [1] has become an excellent organic electroluminescence device when used together with a phosphorescent material.

That is, the present invention provides a compound (A) comprising a condensed heteroaromatic ring in which a benzene ring and a nitrogen-containing five-membered ring represented by the following general formula [1] are condensed, and a linking group containing an arylene group, and phosphorescence about the luminescent material (B) and comprising a material for organic electroluminescence devices.
General formula [1]

また、本発明は、化合物（Ａ）が、下記一般式［２］で示される化合物である上記有機エレクトロルミネッセンス素子用材料に関する。
一般式［２］ [In formula, n is an integer of 2-6.
A represents a ring assembly formed by a direct bond of two or more arylene rings, or an aggregate composed of an arylene ring, a carbon-carbon double bond, and an arylene ring.
X is N or C—R ¹ ;
Y, when X is N when N or C-R ^2, X is C-R ¹ is C-R ^2.
R ^{1 to} R ⁶ are each independently a hydrogen atom, halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted Or 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, wherein R ¹ and R ² are both If either is present, R ² is a substituent other than a hydrogen atom when only R ² is present.
Moreover, R < ² > -R < ⁶ > may form the ring integrally by the adjacent substituents, respectively. The n condensed heteroaromatic rings bonded to A may be the same or different in the structure of X, Y and R ^{3 to} R ⁶ .
However, the case where the general formula [1] has the following structure is excluded. ]

Moreover, this invention relates to the said material for organic electroluminescent elements whose compound (A) is a compound shown by following General formula [2].
General formula [2]

[In formula, n is an integer of 2-6.
A represents a ring assembly formed by a direct bond of two or more arylene rings, or an aggregate composed of an arylene ring, a carbon-carbon double bond, and an arylene ring .
R ^{1 to} R ⁶ are each independently a hydrogen atom, halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted Or 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 either R ¹ or R ² Is a substituent other than a hydrogen atom.
Moreover, R < ² > -R < ⁶ > may form the ring integrally by the adjacent substituents, respectively. In the n condensed heteroaromatic rings bonded to A, the structures of R ^{1 to} R ⁶ may be the same or different from each other. ]

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

  Moreover, the present invention provides 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.

  Further, the present invention provides 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 the light emitting layer contains the material for an organic electroluminescence device. It relates to an element.

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

  The material for an organic electroluminescent element of the present invention has a very high stability of a thin film, and an organic electroluminescent element using the thin film is an organic electroluminescent element having a long emission lifetime.

  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. By containing the compound (A) shown in the present invention, the chemical stability is improved and crystallization in a thin film state is suppressed.

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

  The nitrogen-containing five-membered ring in the present invention includes a pyrrole ring, a pyrazole ring, and a triazole ring.

Fused heteroaromatic ring and a benzene ring and nitrogen-containing five-membered ring in the present invention are condensed is a following general formula [3].
General formula [3]

Wherein, X is N or C-R ^1, Y, when X is N when N or C-R ^2, X is C-R ¹ is C-R ^2. R ¹ and R ² represent substituents described later, and when both R ¹ and R ² are present, one of them is a substituent other than a hydrogen atom. Substituents may be bonded to the benzene ring part, and the substituents or R ² may form a ring together. ]

Specific examples of the skeleton ring represented by the above following general formula, indole, isoindole, indazole, a benzotriazole. Regardless of whether or not X and Y are N, when R ¹ or R ² is present, a substituent other than a hydrogen atom is more preferable in terms of structural stability. In addition, the structures including a plurality of substituents of the ring forming the compound may be all the same or different.

The divalent or higher valent linking group containing an arylene group in the present invention is composed of a ring assembly formed by a direct bond of two or more arylene rings, or an aggregate composed of an arylene ring, a carbon-carbon double bond, and an arylene ring. It is.

  Specific examples of the arylene group in the present invention include monocyclic phenylene groups and condensed polycyclic naphthalene, anthracene, phenanthrene, fluorene, acenaphthene, azulene, pyrene, perylene, triphenylene, naphthacene, pentacene, azulene, coronene, Some groups have a rubicene skeleton.

  In addition, examples in which two or more arylene rings are directly bonded include monocyclic arylene groups or condensed polycyclic arylene groups, or those composed of the monocyclic arylene group and condensed polycyclic arylene groups, specifically, Biphenyl, terphenyl, binaphthyl, bifluorenyl, phenylene naphthylene and the like.

Furthermore, two or more arylene groups, examples bonded through conjugated double bonds, there is a group having a stilbene skeleton.

  The condensed heteroaromatic ring and the linking group A in the present invention may have a substituent. Specific examples of the types of substituents include a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, substituted or Examples thereof include an unsubstituted 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, heptalenyl 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.

  Examples of 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.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ in the present invention are each a hydrogen atom, 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 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 aryl group or heterocyclic group. Among these, a hydrogen atom or a substituted or unsubstituted alkyl group, aryl group or heterocyclic group is particularly preferable.

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

The compound (A) of the present invention has a structure represented by the general formula [1], and more preferably X and Y are not N, that is, an indole ring. The number of nitrogen-containing fused aromatic rings is preferably n = 2 to 6. When the number is 7 or more, it is difficult to synthesize a high-purity material having the same structure, because vapor deposition is difficult when the element is formed by vapor deposition.

  The compound (A) in the present invention has at least one substituent on the nitrogen-containing five-membered ring, or has two or more nitrogen atoms and a divalent or higher linking group. It is possible to produce an organic thin film having high stability by suppressing stacking and aggregation between each other. In addition, since the glass transition point and melting point are high, the resistance to Joule heat (heat resistance) generated in the organic layer, between the organic layers, or between the organic layer and the metal electrode during electroluminescence is improved. When used as, it exhibits high emission luminance and is advantageous when emitting light for a long time.

  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 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.

  In the case of the 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 compound of the present invention, a known light emitting material, doping material, hole injecting material, and electron injecting material containing 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. A typical example of the phosphorescent material (B) is specifically illustrated below, but the present 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 (A) of the present invention in the light-emitting layer may be the main component. Preferably, the phosphorescent light-emitting material (B) or doping is used. It is to be used as a host material having an abundance ratio of the compound of the present invention of 50% or more with respect to the material.

  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, acylhydrazone, 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) A1Pc, (HO) GaPc, OP , Phthalocyanine derivatives such as TiOPc, MoOPc, GaPc-O-GaPc, and naphthalocyanine derivatives, but are not limited thereto.

  Specific examples of triphenylene derivatives 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.

  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, etc., 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.

Synthesis method of exemplary compound (1) Am. Chem. Soc. 123, page 7727, 2001.

  Under a nitrogen atmosphere, 2-phenylindole (5.7 g), 4,4′-diiodobiphenyl (5.0 g), copper iodide (47 mg), cyclohexanediamine (280 mg), potassium phosphate (11 g), dioxane ( 50 mL) was weighed into a Schlenk tube and stirred at 110 ° C. for 8 hours. Extraction with chloroform (100 mL × 3) -ion exchange water (100 mL) and reprecipitation from methanol gave the target compound (2.0 g) in a yield of 30%.

Synthetic method of exemplary compound (19) In the synthetic method of exemplary compound (1), except that 3-phenyl-1H-indazole was used instead of 2-phenylindole, it was the same as the synthetic method of exemplary compound (1). The exemplary compound (19) was obtained with a yield of 40%.

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 1
Compound (5), compound (D2), N, N ′-(3-methylphenyl) -N, N′-diphenyl-1,1′-biphenyl-4,4 ′ is placed on the cleaned glass plate with an ITO electrode. -Diamine (TPD), 2,5-bis (1-naphthyl) -1,3,4-oxadiazole, polycarbonate resin (Teijin Chemicals: Panlite K-1300) at 20: 5: 15: 10: 50 A light emitting layer having a thickness of 100 nm was obtained by dissolving in tetrahydrofuran by weight and spin coating. The film obtained at this time was very stable, and the phenomenon of aggregation and crystallization was not observed. On top of this, an electrode having a thickness of 150 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. As for the light emission characteristics of this device, green light emission with a light emission luminance of 150 (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 8.7 (cd / A) was obtained. .

Example 2
TPD was vacuum-deposited on the cleaned glass plate with an ITO electrode to obtain a hole injection layer having a thickness of 20 nm. Next, the compound (1) 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 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 obtained green light emission with a light emission luminance of 4300 (cd / m ² ), a maximum light emission luminance of 85000 (cd / m ² ), and a light emission efficiency of 32 (cd / A) at a DC voltage of 10V.

Example 4
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 30 nm was obtained. Next, the compound (28) and the compound (D5) were co-evaporated at a ratio of 95: 5 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 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 520 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 24800 (cd / m ² ), and a light emission efficiency of 8.5 (cd / A).

Example 5
On the washed glass plate with an ITO electrode, the compound (22) and the compound (D6) were dissolved in methylene chloride at a ratio of 98: 2, and a hole injection type light emitting layer having a thickness of 50 nm 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 produced red light emission with a light emission luminance of 310 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 9800 (cd / m ² ), and a light emission efficiency of 4.4 (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 (24) 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 produced blue light emission with a light emission luminance of 3800 (cd / m ² ), a maximum light emission luminance of 31600 (cd / m ² ), and a light emission efficiency of 9.7 (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, NPD was vacuum-deposited to obtain a hole transport layer having a thickness of 30 nm. Further, the compound (2) and the compound (D1) are co-evaporated at a ratio of 93: 7 to form a light emitting layer with a thickness of 40 nm, and then bathocuproine is evaporated to form a hole blocking layer with 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 emitted green light with a luminance of 3810 (cd / m ² ) at a DC voltage of 10 V, a maximum luminance of 95600 (cd / m ² ), and a luminous efficiency of 45 (cd / A). Further, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5200 hours.

Example 8
Copper phthalocyanine was vacuum-deposited on the washed glass plate with the ITO electrode to obtain a 10 nm-thick hole injection layer. Subsequently, 4,4′-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl was vacuum-deposited to obtain a 40 nm-thick hole transport layer. Next, the compound (19) and the compound (D4) were co-evaporated at a ratio of 92: 8 to form a light-emitting layer having a thickness of 50 nm, and 3- (4-biphenylyl) -4-phenyl-5- (4- tert-butylphenyl) -1,2,4-triazole was deposited to form a 5 nm thick hole blocking layer, and then bis (2-methyl-8-hydroxyquinolinate) (p-cyanopheno) Lat) gallium complex was deposited to obtain an electron injection layer having a thickness of 30 nm. Further, 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 light emitting device. This device emitted light with a DC voltage of 10 V and an emission luminance of 2390 (cd / m ² ), a maximum emission luminance of 38900 (cd / m ² ), and an emission efficiency of 12 (cd / A). Further, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 3700 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 (3) and the compound (D7) were co-evaporated at a ratio of 97: 3 to prepare a light-emitting layer having a thickness of 40 nm, and then bis (2-methyl-5-phenyl-8-hydroxyquinolinate). A (phenolate) aluminum complex was vapor-deposited to form a 30 nm-thick hole blocking layer, and Alq3 was vacuum-deposited to produce a 20-nm-thick electron injection layer. 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 1800 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 16200 (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 4400 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 (14) 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 having a light emission luminance of 2750 (cd / m ² ) at a DC voltage of 10 V, a maximum light emission luminance of 46500 (cd / m ² ), and a light emission efficiency of 6.4 (cd / A). Further, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 2800 hours.

Comparative Example 1
A device was prepared in the same manner as in Example 1 except that the following compound (C1) in which the 2- ^t Bu-indole ring was replaced with a carbazole ring was used instead of the compound (5). The spin coat film has the disadvantage that it easily aggregates and crystallizes. Regarding the light emission characteristics of this device, light emission of 60 (cd / m ² ) at a DC voltage of 10 V, 1200 (cd / m ² ) of maximum light emission, and 1.8 (cd / A) of light emission efficiency was obtained. The light and dark areas were mixed, not uniform light emission. Further, when the device was driven at a constant current with an emission luminance of 500 (cd / m ² ), it was short-circuited in about 3 hours.
Compound (C1)

Comparative Example 2
A device was prepared in the same manner as in Example 2 except that CBP was used instead of the compound (1). 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 1800 (cd / m ² ), maximum light emission luminance of 52000 (cd / m ² ), and light emission efficiency of 24 (cd / A) was obtained. However, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 700 hours.

Comparative Example 3
Implementation was carried out except that the following compound (C2) in which the 1,2,3-benzotriazole ring was replaced with a 2,5-bis (1-naphthyl) -1,3,4-triazole ring instead of the compound (14) was used. A device was prepared in the same manner as in Example 10. 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 1560 (cd / m ² ), maximum light emission luminance of 32400 (cd / m ² ), and light emission efficiency of 4.2 (cd / A) was obtained. However, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 150 hours.
Compound (C2)

Example 12
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 (10) was vacuum-deposited alone to obtain a 30 nm-thick hole transport layer. Further, the compound (10) and the compound (D2) were co-evaporated at a ratio of 90:10 to prepare a light emitting layer having a thickness of 40 nm, and then bis (2-methyl-8-hydroxyquinolinate) (p- A 10-nm-thick hole blocking layer was formed by vapor-depositing a cyanophenolate) aluminum complex, and Alq3 was further vacuum-deposited to form an electron-injecting layer having a thickness of 30 nm. An electrode was formed thereon by vacuum-depositing lithium fluoride at 0.7 nm and then aluminum at 200 nm to obtain an organic phosphorescent device. This device emitted light having a light emission luminance of 8510 (cd / m ² ), a maximum light emission luminance of 74300 (cd / m ² ), and a light emission efficiency of 34 (cd / A) at a DC voltage of 10V. The half life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 4800 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, the compound (34) is vacuum-deposited to deposit a 10 nm-thick hole blocking layer, and further bis (2-methyl-5-phenyl-8-hydroxyquinolinato) phenolate gallium complex is deposited to a thickness of 30 nm. An electron injection 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 7800 (cd / m ² ), a maximum light emission luminance of 51600 (cd / m ² ), and a light emission efficiency of 8.2 (cd / A) at a DC voltage of 10V.

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 compound (38) and compound (D6) were co-deposited at a ratio of 97: 3 to give 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 vapor deposition of 0.7 nm and then 200 nm of aluminum to obtain an organic phosphorescent light emitting device having an emission luminance of 7530 (cd / m ² ) at a DC voltage of 10 V and a maximum emission luminance of 12400. (Cd / m ² ), a light emission efficiency of 5.9 (cd / A) was obtained, and the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 6800 hours. .

Comparative 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 following compound (C3) and 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-8-hydroxyquinolinato) phenolate aluminum complex Were 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. 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 has an emission luminance of 250 (cd / m ² ) at a DC voltage of 10 V, a maximum emission luminance of 24600 (cd / m ² ), an emission efficiency of 18 (cd / A), and an emission luminance of 500 (cd / m ^2). ), The half-life when driven at a constant current was 900 hours.
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.

  Finally, the results of observing the difference in film formability between the compound of the present invention and the comparative compound are shown.

Comparative Example 5
A CBP film was formed to a thickness of 50 nm on the cleaned quartz substrate. Immediately after the film formation, a uniform film was obtained, but when it was allowed to stand at room temperature in the atmosphere for about a week, the film became cloudy.

  The surface shape of the CBP vapor deposited film left for one week was measured using an atomic force microscope (AFM). The measurement results are shown in FIG. As can be seen from FIG. 1, undulations of about 200 nm were observed. This suggests that the molecules aggregate easily. Further, the root mean square roughness (RMS) at this time was 49 nm, and the surface area ratio was 1.30797.

Example 19
Exemplified compound (1) was formed to a thickness of 50 nm on the washed quartz substrate. It was impossible to visually observe the difference between the film immediately after the film formation and the film left for about a week at room temperature in the atmosphere.

  The surface shape of the deposited film of the exemplary compound (1) left for one week was measured using an atomic force microscope (AFM). The measurement results are shown in FIG. As can be seen from the scale in the Z-axis direction, it can be seen that the film is as flat as about 10 nm. The root mean square roughness (RMS) at this time was 0.85 nm, and the surface area ratio was 1.00067.

As is clear by comparing Comparative Example 5 and Example 19 , a more stable organic thin film can be formed by using the compound shown in the present invention.

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.

Surface shape of CBP vapor deposition film when left for one week Surface shape of the deposited film of Example Compound (1) when left for one week

Claims (8)

A compound (A) containing a condensed heteroaromatic ring in which a benzene ring and a nitrogen-containing five-membered ring represented by the following general formula [1] are condensed, and a linking group containing an arylene group, and a phosphorescent material (B) A material for an organic electroluminescence device comprising:
General formula [1]

[In formula, n is an integer of 2-6.
A represents a ring assembly formed by a direct bond of two or more arylene rings, or an aggregate composed of an arylene ring, a carbon-carbon double bond, and an arylene ring.
X is N or C—R ¹ ;
Y, when X is N when N or C-R ^2, X is C-R ¹ is C-R ^2.
R ^{1 to} R ⁶ are each independently a hydrogen atom, halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted Or 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, wherein R ¹ and R ² are both If either is present, R ² is a substituent other than a hydrogen atom when only R ² is present.
Moreover, R < ² > -R < ⁶ > may form the ring integrally by the adjacent substituents, respectively. The n condensed heteroaromatic rings bonded to A may be the same or different in the structure of X, Y and R ^{3 to} R ⁶ .
However, the case where the general formula [1] has the following structure is excluded. ]

Compound (A), an organic electroluminescence device material according to claim 1, wherein the compound represented by the following general formula [2].
General formula [2]

[In formula, n is an integer of 2-6.
A represents a ring assembly formed by a direct bond of two or more arylene rings, or an aggregate composed of an arylene ring, a carbon-carbon double bond, and an arylene ring .
R ^{1 to} R ⁶ are each independently a hydrogen atom, halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted Or 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 either R ¹ or R ² Is a substituent other than a hydrogen atom.
Moreover, R < ² > -R < ⁶ > may form the ring integrally by the adjacent substituents, respectively. In the n condensed heteroaromatic rings bonded to A, the structures of R ^{1 to} R ⁶ may be the same or different from each other. ] The organic electroluminescent element material according to claim 1 or 2 , wherein the phosphorescent material (B) comprises an iridium or platinum complex comprising an organic compound or a ligand of an organic residue. In the organic electroluminescent element formed by forming the organic compound thin film of the multiple layers containing a light emitting layer or a light emitting layer between a pair of electrodes, either of the said layers is for organic electroluminescent elements in any one of Claims 1-3 . An organic electroluminescence device containing a material. In the organic electroluminescent element formed by forming the light emitting layer or a plurality of layers of organic compound thin films including the light emitting layer between the pair of electrodes, the light emitting layer contains the material for an organic electroluminescent element according to any one of claims 1 to 3. Organic electroluminescence device. 6. The organic electroluminescence device according to claim 4, further comprising an electron injection layer formed between the cathode and the light emitting layer. Furthermore, a hole blocking layer is formed between an electron injection layer and a light emitting layer, The organic electroluminescent element in any one of Claims 4-6 characterized by the above-mentioned. Furthermore, a positive hole injection layer is formed between an anode and a light emitting layer, The organic electroluminescent element in any one of Claims 4-7 characterized by the above-mentioned.

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