JP2010254642A - Dibenzochalcogenylpyrazole iridium complex, luminescent material consisting of the same and organic el element containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new dibenzochalcogenylpyrazole iridium complex, a luminescent material consisting of the same and an organic EL element containing the same. <P>SOLUTION: This dibenzochalcogenylpyrazole iridium complex is expressed by general formula (1) [wherein R<SP>1</SP>, R<SP>2</SP>are each independently selected from the group consisting of 1C-4C linear or branched alkyl groups; R<SP>8</SP>to R<SP>13</SP>are each independently selected from the group consisting of H and 1C-4C linear or branched alkyl groups; and E is a chalcogen element selected from the group consisting of O, S, Se and Te elements], and the luminescent material consisting of the same and the organic EL element containing the same are provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a novel dibenzochalcogenylpyrazole iridium complex, a light emitting material comprising the same, and an organic EL device containing the same.

The organic EL element emits light when excitation energy generated by recombination of holes and electrons injected from the electrode relaxes to a ground state through a light emission process. However, there are two types of excited states generated by recombination of holes and electrons, a singlet excited state and a triplet excited state, in a ratio of 1: 3. In many cases, a fluorescent material that utilizes light emission from a singlet excited state has been used as a light emitting material. Therefore, the internal quantum efficiency is 25% at the maximum. The external quantum yield was theoretically limited to 5% (Non-patent Document 1).
In recent years, improvement in luminous efficiency has been reported by using light emission from a triplet excited state, that is, phosphorescence emission, using complex compounds utilizing heavy atom effects such as iridium and platinum. The maximum internal quantum efficiency can theoretically reach 100% by utilizing light emission from the triplet excited state in addition to the singlet excited state, and phosphorescent materials are attracting attention as light emitting materials. (Non-patent document 2).

For example, as a green light emitting material, the following formula
Tris (2-phenylpyridinato) iridium (III) [Ir (ppy) ₃ ] shown in FIG.

In addition, Adachi et al.
Bis [2- (4,6-difluorophenyl) pyridinato] picorinatoiridium (III) (FIrpic), which has been attracting attention, has since been studied, and studies on improving the efficiency of organic EL devices using FIrpic and New blue phosphorescent complex search research has been actively conducted (Non-patent Document 3).
The FIrpic ligand used as a blue phosphorescent material has a fluorine group at the 4,6-position of the aromatic ring of phenylpyridine. As a result of introduction of a fluorine group, the emission spectrum is shorter than that of the phenylpyridine Ir complex. There are various reasons for this, but since the fluorine group is an electron withdrawing group, the same effect can be expected for other electron withdrawing groups if the wavelength is shortened by the electron withdrawing effect.

Toshio Higuchi: Electroluminescent display, p. 114, Industrial Books (1991) C. Adachi, R.A. C. Kwon, M .; A. Baldo, M .; E. Thompson, S.M. R. Forrest, Proc. 8th IDW 01, P.I. 1420 (2001) Appl. Phys. Lett. 79, 2082 (2001)

  The object of the present invention is to pay attention to a phenyl compound having a cyano group which is an electron withdrawing group or a phenyl compound having a heterocyclic phenylchalcogenyl which shows an electron withdrawing tendency, and dialkylpyrazoles having these compounds as ligands. The object is to provide a dibenzochalcogenylpyrazole iridium complex used, a light emitting material comprising the same, and an organic EL device containing the same.

The first of the present invention is the following general formula (1)
[Wherein, R ¹ and R ² are a group consisting of a linear or branched alkyl group having 1 to 4 carbon atoms, and R ^{8 to} R ¹³ are a group consisting of hydrogen and a linear or branched alkyl group having 1 to 4 carbon atoms. E represents a chalcogen element selected from the group consisting of oxygen element, sulfur element, selenium element and tellurium element. ]
The dibenzo chalcogenyl pyrazole iridium complex shown by these.
The second of the present invention is the following general formula (2)
[Wherein, R ¹ and R ² are a group consisting of a linear or branched alkyl group having 1 to 4 carbon atoms, and R ^{8 to} R ¹³ are a group consisting of hydrogen and a linear or branched alkyl group having 1 to 4 carbon atoms. E represents a chalcogen element selected from the group consisting of oxygen element, sulfur element, selenium element and tellurium element. ]
The dibenzo chalcogenyl pyrazole iridium complex shown by these. The polonium element, which is one of the chalcogen elements, is not used because it is very toxic.
A third aspect of the present invention relates to a light-emitting material comprising the dibenzochalcogenylpyrazole iridium complex according to claim 1 or 2.
4th of this invention is related with the organic EL element characterized by containing the dibenzo chalcogenyl pyrazole iridium complex of any one of Claim 1 or 2.

(1) The dibenzochalcogenylpyrazole iridium complex of the present compound is used as a blue organic EL dopant because the UV spectrum and PL spectrum shift to the short wavelength side due to the electron-withdrawing effect of the dibenzochalcogenyl compound. it can.
(2) Even if the dibenzochalcogenylpyrazole iridium complex of the present invention is used alone, it is useful as a material constituting a high-performance multicolor or area color display.
Examples of R ¹ and R ² in the present invention include linear or branched alkyl groups having 1 to 4 carbon atoms. The positions of R ¹ and R ² may be any of positions 3 to 5 of the pyrazole ring, but it is particularly preferable to add them at the 3 and 5 positions. R ^{8 to} R ¹³ are preferably hydrogen or a linear or branched alkyl group having 1 to 4 carbon atoms.

¹ H-NMR of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran synthesized in Example 1 is shown. The result of the mass spectrometry of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran synthesized in Example 1 is shown. ¹ H-NMR of the tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran] iridium (III) complex synthesized in Example 1 is shown. The result of the mass spectrometry of the tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran] iridium (III) complex synthesized in Example 1 is shown. The vacuum TGA measurement result of the tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran] iridium (III) complex synthesized in Example 1 is shown. The horizontal axis represents temperature (° C.), and the vertical axis represents weight reduction rate (%). The PL spectrum measured in the atmosphere of the tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran] iridium (III) complex synthesized in Example 1 is shown. The PL spectrum measured in the vacuum of the tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran] iridium (III) complex synthesize | combined in Example 1 is shown. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention.

As the most typical compound relating to the dibenzochalcogenylpyrazole iridium complex of the present invention, a compound of the following formula wherein E is an oxygen element
Can be mentioned.

As another typical compound relating to the dibenzochalcogenylpyrazole iridium complex of the present invention, a compound of the following formula wherein E is a sulfur element
Can be mentioned.

Examples of the compounds of the present invention are shown in the following formula group. E in the formula represents oxygen, sulfur, selenium, or tellurium.
In addition, although the alkyl group of R < ⁸ > -R < ¹³ > shows the example which the methyl group substituted, suppose that it does not have any trouble in reading this with another alkyl group, ie, an ethyl group, a propyl group, or a butyl group.

An example of the synthesis method of the compound of the present invention is shown below. In the following formulae, R ¹ and R ² are the same as described in the claims.
The cyanophenylpyrazole iridium complex consists of the following three reactions.
That is, in the first reaction, the ligand cyanobenzochalcogenylpyrazole is synthesized. In the second reaction, this ligand is reacted with iridium trichloride to synthesize an intermediate chlorobrich. In the final third reaction, this intermediate is reacted with 1 equivalent of a ligand (in this case, cyanobenzochalcogenylpyrazole) to synthesize the desired cyanobenzochalcogenylpyrazoleiridium complex.
For the synthesis of this iridium complex, the synthesis of FIrpic [Appl. Phys. Lett. , 79, 2082 (2001)] and the like.

An example of the synthesis method when R ¹ and R ² are methyl groups is shown. This reaction is not limited to the case where E is O, but proceeds in the same manner when E is S, Se, or Te.
The synthesis of the iridium complex in this reaction consists of a three-step reaction. For synthesis, a ligand is synthesized in the first reaction. In the second reaction, the ligand and iridium trichloride are reacted to synthesize an intermediate chlorobrich. Then, the target iridium complex is synthesized by reacting with another equivalent of ligand in the third reaction.

  The dibenzochalcogenylpyrazole iridium complex of the present invention can be used as an organic compound for an organic EL device. In the organic EL device of the present invention, in which an organic thin film layer composed of a plurality of layers is sandwiched between a cathode and an anode, the light emitting layer preferably contains the dibenzochalcogenylpyrazole iridium complex of the present invention.

In the organic EL device of the present invention, as described above, a plurality of organic thin film layers are formed between the anode and the cathode, and among these layers, the dibenzochalcogenylpyrazole iridium complex of the present invention is used as an appropriate layer. It is an element. In the element configuration, a hole injecting material, a hole transporting material or an electron injecting material, and an electron transporting material are included in order to transport holes injected from the anode or electrons injected from the cathode to the light emitting material. You may contain. Further, the light emitting material of the present invention exhibits extremely high fluorescence quantum efficiency, and can form a uniform thin film by vapor deposition or sputtering.
Examples of the configuration of the multilayer organic EL device include, for example, ITO / hole transport layer / light emitting layer / electron transport layer / cathode, ITO / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode, ITO / hole. Transport layer / light emitting layer / hole block layer / electron transport layer / cathode, ITO / hole transport layer / light emitting layer / hole block layer / electron transport layer / electron injection layer / cathode, ITO / hole injection layer / hole transport layer / light emission A layer / hole block layer / electron transport layer / electron injection layer / layer having a multilayer structure such as a cathode may be used. Moreover, you may have a sealing layer on a cathode as needed.

  In addition to the compound of the present invention, further known host materials, light emitting materials, doping materials, hole injecting materials, and electron injecting materials can be used in combination in the light emitting layer as necessary. By making the organic EL element have a multilayer structure, it is possible to prevent a decrease in luminance and lifetime due to quenching, and by using other doping materials, it is possible to improve light emission luminance and light emission efficiency and to obtain red and white light emission. Moreover, the hole (hole) injection layer, the hole transport layer, the light-emitting layer, the electron transport layer, and the electron injection layer in the organic EL device of the present invention may be formed of two or more layers. In that case, in the case of a hole injection layer, a layer for injecting holes from the anode is called a hole injection layer, and a layer for receiving holes from the hole injection layer and transporting holes to the light emitting layer is called a hole transport layer. Similarly, in the case of an electron injection layer, a layer that plays the role of injecting electrons from the cathode is called an electron injection layer, and a layer that receives electrons from the electron injection layer and transports electrons to the light emitting layer is called an electron transport layer. Each of these layers is selected and used depending on factors such as the energy level of the material, heat resistance, adhesion with the organic thin film layer or the metal electrode.

  The hole injection material or hole transport material has the ability to transport holes, has a hole injection effect from the anode, an excellent hole injection effect or hole transport effect for the light emitting layer or light emitting material, and occurs in the light emitting layer. A compound that prevents the exciton from moving to the electron injection layer or the electron injection material and has an excellent thin film forming ability is preferable. Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, hydrazone, acylhydrazone, polyarylalkane, stilbene, benzidine type Examples include triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine, and derivatives thereof, and polymer materials such as polyvinyl carbazole, polysilane, and conductive polymer, but are not limited thereto. Absent.

Among these hole injection materials or hole transport materials, more effective materials are aromatic tertiary amine derivatives or phthalocyanine derivatives. Specific examples of the aromatic tertiary amine derivative include triphenylamine, tolylamine, tridiphenylamine, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4, 4'-diamine, N, N, N ', N'-(4-methylphenyl) -1,1'-phenyl-4,4'-diamine, N, N, N ', N'-(4-methyl Phenyl) -1,1'-biphenyl-4,4'-diamine, N, N'-diphenyl-N, N'-dinaphthyl-1,1'-biphenyl-4,4'-diamine, N, N'- (Methylphenyl) -N, N ′-(4-n-butylphenyl) -phenanthrene-9,10-diamine, N, N-bis (4-di-4-tolylaminophenyl) -4-phenyl-cyclohexane, etc. Or these aromatic tertiary amino acids An oligomer or polymer having a backbone, but not limited thereto. Specific examples of the phthalocyanine (Pc) derivative are PCH ₂ , PcCu, PcCo, PcNi, PcZn, PcPd, PcFe, PcMn, PcClAl, PcClGa, PcClIn, PcClSn, PcCl ₂ Si, Pc (HO) Al, Pc (HO) Ga Phthalocyanine derivatives such as PcVO, PcTiO, and PcMoO (see Sankyo Publishing Co., Ltd., Daigaku Dictionary, phthalocyanine complex salt) and naphthalocyanine derivatives. Examples of the conductive polymer include, but are not limited to, polyaniline derivatives (PAni) and polythiophene derivatives (PEDOT).

  The compound used as an electron injecting material or an electron transporting material has the ability to transport electrons, has an electron injecting effect from the cathode, and has an excellent electron transporting effect with respect to the light emitting layer or the light emitting material. A compound that prevents exciton migration to the hole transport layer and is excellent in thin film formation is preferable. Examples include, but are not limited to, fluorenone, anthraquinodimethane, diphenoquinone, thiopyrandioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthrone, and their derivatives. Is not to be done.

  In the organic EL device of the present invention, a more effective electron transport material is a metal complex compound, a nitrogen-containing five-membered ring derivative, or a nitrogen-containing aromatic compound. Specific examples of the metal complex compound include tris (8-quinolinato) lithium, tris (8-quinolinato) zinc, tris (8-quinolinato) copper, tris (8-quinolinato) manganese, tris (8-quinolinato) aluminum, tris. (2-Methyl-8-quinolinato) aluminum, tris (4-methyl-8-quinolinato) aluminum, tris (4-propyl-8-quinolinato) aluminum, tris (4-benzyl-8-quinolinato) aluminum, bis (2 -Methyl-8-quinolinato) (phenolate) aluminum, bis (2-methyl-8-quinolinato) (o-cresolate) aluminum, bis (2-methyl-8-quinolinato) (m-cresolate) aluminum, bis (2- Methyl-8-quinolinate) (p- Resoleate) aluminum, bis (2-methyl-8-quinolinato) (m-phenylphenolate) aluminum, bis (2-methyl-8-quinolinato) (p-phenylphenolate) aluminum, bis (2-methyl-8- Quinolinate) (3,5-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinato) (1-naphtholato) aluminum, bis (2-methyl-8-quinolinato) (2-naphtholato) gallium, bis (2 -Methyl-8-quinolinato) (p-cresolate) gallium, bis (8-quinolinato) zinc, bis (8-quinolinato) copper, bis (8-quinolinato) manganese, and the like. Absent.

  Further, specific examples of the nitrogen-containing five-membered ring derivative are preferably an oxazole derivative, a thiazole derivative, an oxadiazole derivative, a thiadiazole derivative, or a triazole derivative. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1 -Phenyl) -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-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl)- 1,3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-thiazole, 2,5-bis (1-naphthyl)- 1,3,4-thiazole, 1,4-bis [2- (5-phenylthiadi Zolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1,3,4 -Triazole, 4-bis [2- (5-phenyltriazolyl)] benzene and the like are exemplified, but not limited thereto.

  Furthermore, a specific example of the nitrogen-containing aromatic compound is preferably a phenanthroline derivative. Specifically, 4,7-diphenyl-1,10-phenanthroline, 4,7-di-m-tolyl-1,10-phenanthroline, 4,7-di-p-tolyl-1,10-phenanthroline, , 9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-di-p-tolyl-1,10-phenanthroline, 2,9-dimethyl-4,7-di -M-tolyl-1,10-phenanthroline, 2,9-diethyl-4,7-diphenyl-1,10-phenanthroline, 2,9-diethyl-4,7-di-p-tolyl-1,10-phenanthroline 2,9-diethyl-4,7-di-m-tolyl-1,10-phenanthroline, 2,9-dimethyl-4,7-bis (naphthalen-1-yl) -1,10-phenanthroline, 2, 9 Dimethyl-4,7-bis (naphthalen-2-yl) -1,10-phenanthroline, 2,9-diphenyl-4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-bis (Biphenylene-4-yl) -1,10-phenanthroline, 3,8-di (α-naphthyl) -1,10-phenanthroline, 3,8-di (β-naphthyl) -1,10-phenanthroline, 1, 4-di (1,10-phenanthrolin-2-yl) benzene, 4,4'-di (1,10-phenanthroline-2-yl) biphenyl, 1,5-di (1,10-phenanthrolin-2-yl) ) Anthracene, 1,3,5-tri (1,10-phenanthrolin-2-yl) benzene and the like, but are not limited thereto.

  As a conductive material used for an anode of an organic electroluminescence element, 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 alloys thereof, ITO substrates, tin oxides used for tin oxide (NESA) substrates, metal oxides such as indium oxide, and organic conductive resins such as polythiophene and polypyrrole are used. As the conductive material used for the cathode, a material having a work function smaller than 4 eV is suitable, and magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, and alloys thereof are used. 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 can be appropriately controlled by the temperature of the vapor deposition source, the atmosphere, the degree of vacuum, and the like. The anode and the cathode may be composed of two or more layers as necessary.

  The transparent electrode support substrate used in the organic EL device of the present invention is desirably sufficiently transparent in order to efficiently emit light. The transparent electrode is set using the above-described conductive material so that predetermined translucency can be ensured by a method such as vapor deposition or sputtering. It is desirable that the light transmittance of the light emitting surface electrode (the electrode on the side from which the emitted light is extracted, for example, an electrode in which ITO is deposited on a glass substrate by sputtering) is 10% or more. The substrate is not limited as long as it has mechanical and thermal strength and is transparent, and examples thereof include a glass substrate and a transparent resin film and sheet. Transparent resins used for films and sheets include polyethylene, polyethylene copolymer, polypropylene, polypropylene copolymer, polystyrene, polystyrene copolymer, syndiotactic polystyrene, polymethyl methacrylate, nylon, polyethersulfone, and polysulfone. , Polycarbonate, polycarbonate copolymer, polyarylate, polyetherimide, tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and the like.

  Formation of each layer of the organic electroluminescence element in the present invention can be performed by a dry film forming method such as vacuum deposition, sputtering, plasma, ion plating or the like. The thickness of each layer of the organic thin film layer sandwiched between the anode and the cathode is not particularly limited, but must be set to an appropriate thickness. The normal film thickness is preferably selected as appropriate in the range of 0.5 nm to 500 nm.

  The organic electroluminescent device obtained by the present invention can be provided with a protective layer on the surface of the device or can be protected by a resin or the like in order to improve stability against temperature, humidity, atmosphere, etc. .

  In FIGS. 8-21, the preferable example of the organic electroluminescent element of this invention is shown.

  FIG. 8 is a cross-sectional view showing an example of the organic electroluminescence element of the present invention. FIG. 8 shows a structure in which an anode 2, a light emitting layer 3 and a cathode 4 are sequentially provided on a substrate 1. The light-emitting material used here is useful when it has a single hole-transporting property, electron-transporting property, and light-emitting function, or a mixture of compounds having the respective functions. It is.

  FIG. 9 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 9 shows a configuration in which an anode 2, a hole transport layer 5, a light emitting layer 3, and a cathode 4 are sequentially provided on a substrate 1. In this case, the light emitting layer is useful when it has an electron transporting function.

  FIG. 10 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 10 shows a configuration in which an anode 2, a light emitting layer 3, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. In this case, the light emitting layer is useful when it has a hole transporting function.

  FIG. 11 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 11 shows a configuration in which an anode 2, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. This separates the functions of carrier transport (which means both hole transport and electron transport) and light emission, and increases the degree of freedom in material selection, thus increasing the efficiency of light emission and the degree of freedom in light emission color. It will be.

  FIG. 12 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 12 shows a structure in which an anode 2, a hole injection layer 7, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. In this case, the provision of the hole injection layer 7 improves the adhesion between the anode 2 and the hole transport layer 5, improves the injection of holes from the anode, and is effective in lowering the voltage of the light emitting element.

  FIG. 13 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 13 shows a structure in which an anode 2, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6, an electron injection layer 8 and a cathode 4 are sequentially provided on a substrate 1. In this case, injection of electrons from the cathode 4 is improved, which is effective for lowering the voltage of the light emitting element.

  FIG. 14 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 14 shows a structure in which an anode 2, a hole injection layer 7, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6, an electron injection layer 8 and a cathode 4 are sequentially provided on a substrate 1. In this case, hole injection from the anode 2 is improved and electron injection from the cathode 4 is improved, which is the most effective for driving at a low voltage.

  15 to 21 are sectional views of the device in which the hole block layer 9 is inserted. The hole blocking layer 9 has an effect of preventing holes injected from the anode or excitons generated by recombination in the light emitting layer 3 from escaping to the cathode 4, and is effective in improving the light emission efficiency of the organic electroluminescence element. There is. The hole blocking layer 9 can be inserted between the light emitting layer 3 and the cathode 4, between the light emitting layer 3 and the electron transport layer 6, or between the light emitting layer 3 and the electron injection layer 8. More preferred is between the light emitting layer 3 and the electron transport layer 6.

  8 to 21, each of the hole transport layer 5, the hole injection layer 7, the electron transport layer 6, the electron injection layer 8, the light emitting layer 3, and the hole block layer 9 may have a single layer structure. A multilayer structure may be used.

  FIGS. 8-21 is a fundamental element structure to the last, and the structure of the organic electroluminescent element using the compound of this invention is not limited to this.

  Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited thereby.

Example 1: Synthesis of tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzofuran] iridium (III) complex (abbreviation fac-Ir [dmpzdbf] ₃ ) 1) 1- (3,5 -Dimethyl-1H-pyrazol-1-yl) (abbreviation dmpzdbf)
In a four-necked flask under a nitrogen stream, 1-iododibenzofuran (IDBF), 3,5-dimethylpyrazole (dmPz), cesium carbonate, cuprous iodide, L-(-)-proline, dimethylformamide (dehydration) Was added and stirred at 150 ° C. for 48 hours. After completion of the reaction, water was added, extracted with ethyl acetate, dried over anhydrous magnesium sulfate, filtered and concentrated. Purification is performed by a silica gel column chromatography method (developing solvent: n-hexane: ethyl acetate = 3: 1, n-hexane: ethyl acetate = 5: 1), and after concentration, recrystallization is performed to obtain a yellow solid. It was. Identification was performed by ¹ H-NMR spectrum and Mass spectrum.
Table 33 shows the amount of raw material used and the yield of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzofuran (dmpzdbf) obtained.
The ¹ H-NMR in dmpzdbf Figure 1 shows the results of mass spectrometry in FIG.
2) Synthesis of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzofuran-chlorobridge dimer (abbreviation [(dmpzdbf) ₂ IrCl] ₂ )
In a four-necked flask under a nitrogen stream, 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran (dmpzdbf), iridium trichloride trihydrate, 2-ethoxyethanol, and water were added. Stirring was carried out at 24 ° C. for 24 hours. After completion of the reaction, the precipitate was filtered, washed with ion exchange water and ethanol, and then dried under reduced pressure to obtain a yellow solid. The crude product was used in the next reaction.
Table 34 shows the amounts of raw materials used and the yield of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran-chlorobridge dimer [(dmpzdbf) ₂ IrCl] ₂ obtained.
3) Synthesis of tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran] iridium (III) complex (abbreviation fac-Ir [dmpzdbf] ₃ )
In an eggplant flask, the product of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran-chlorobridge dimer [(dmpzdbf) ₂ IrCl] ₂ [ _{2 of} Example 1] Abbreviation], 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran (dmpzdbf) [product of Example 1)], cesium carbonate, and glycerin were added, and the mixture was heated to 200 ° C. under a nitrogen stream. For 120 hours. Extraction was not performed after completion of the reaction, and purification was performed by a silica gel column chromatography method (developing solvent: n-hexane: dichloromethane = 1: 1), concentrated and dried under reduced pressure to obtain a yellow solid. Identification was performed by ¹ H-NMR spectrum and Mass spectrum.
Table 35 shows the amounts of raw materials used and the yield of the obtained tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) benzofuran] iridium (III) {fac-Ir [dmpzdbf] ₃ } complex. .
FIG. 3 shows ¹ H-NMR of fac-Ir [dmpzdbf] ₃ , and FIG. 4 shows the results of mass spectrometry.
The obtained fac-Ir [dmpzdbf] ₃ was checked for sublimation under high vacuum using a vacuum TGA measuring device manufactured by ULVAC. The sample weight was 5.4 mg, the degree of vacuum was 1.3 × 10 ⁻⁴ torr, the heating rate was 1 ° C./min, and the maximum heating temperature was 500 ° C.
The measurement results are shown in FIG.

A film (1 wt%) in which fac-Ir [dmpzdbf] ₃ synthesized in Example 1 was dispersed in polymethyl methacrylate (PMMA) was prepared, and photoluminescence (PL) was measured in a nitrogen atmosphere. The result is shown in FIG.
Moreover, PL spectrum in vacuum was measured with a streak camera using the same dispersion film. The result is shown in FIG.

Example 2: Synthesis of tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene] iridium (III) complex (abbreviation fac-Ir [dmpzdbt] ₃ ) 1) 1- (3 Synthesis of 5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene (abbreviation dmpzdbt)
In a four-necked flask under a nitrogen stream, 1-iododibenzothiophene (IDBT), 3,5-dimethylpyrazole (dmPz), cesium carbonate, cuprous iodide, L-(-)-proline, dimethylformamide (dehydration) ) Was added and stirred with heating at 150 ° C. for 48 hours. After completion of the reaction, water was added, extracted with ethyl acetate, dried over anhydrous magnesium sulfate, filtered and concentrated. Purification is performed by a silica gel column chromatography method (developing solvent: n-hexane: ethyl acetate = 3: 1, n-hexane: ethyl acetate = 5: 1), and after concentration, recrystallization is performed to obtain a yellow solid. It was.
Table 36 shows the amounts of raw materials used and the yield of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene (dmpzdbt) obtained.
2) Synthesis of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene-chlorobridge dimer (abbreviation [(dmpzdbt) ₂ IrCl] ₂ )
In a 4-necked flask under nitrogen flow, put 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene (dmpzdbt), iridium trichloride trihydrate, 2-ethoxyethanol, and water. The mixture was heated and stirred at 100 ° C. for 24 hours. After completion of the reaction, the precipitate was filtered, washed with ion exchange water and ethanol, and then dried under reduced pressure to obtain a yellow solid. The crude product was used in the next reaction.
Table 37 shows the amounts of raw materials used and the yield of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene-chlorobridge dimer [(dmpzdbt) ₂ IrCl] ₂ obtained.
3) Synthesis of tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene] iridium (III) complex (abbreviation fac-Ir [dmpzdbt] ₃ )
In a recovery flask, 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene-chlorobridge dimer [abbreviated as CBD in Table 38] [(dmpzdbt) ₂ IrCl] ₂ , 1- (3,5- Dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene (dmpzdbt), cesium carbonate, and glycerin were added, and the mixture was heated and stirred at 200 ° C. for 120 hours under a nitrogen stream. Extraction after completion of the reaction was not performed, and purification was performed by a silica gel column chromatography method (developing solvent: n-hexane: dichloromethane = 1: 1), concentrated and dried under reduced pressure to obtain a yellow solid.
Table 38 shows the amounts of raw materials used and the yield of tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzothiophene] iridium (III) complex {fac-Ir [dmpzdbt] ₃ }. Show.

Example 3: Synthesis of tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene] iridium (III) complex (abbreviation fac-Ir [dmpzdbs] ₃ ) 1) 1- (3 , 5-Dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene (abbreviation dmpzdbs)
In a four-necked flask under a nitrogen stream, 1-iododibenzoselenophene (IDBS), 3,5-dimethylpyrazole (dmPz), cesium carbonate, cuprous iodide, L-(-)-proline, dimethylformamide ( (Dehydration) was added and the mixture was stirred at 150 ° C. for 48 hours. After completion of the reaction, water was added, extracted with ethyl acetate, dried over anhydrous magnesium sulfate, filtered and concentrated. Purification is performed by a silica gel column chromatography method (developing solvent: n-hexane: ethyl acetate = 3: 1, n-hexane: ethyl acetate = 5: 1), and after concentration, recrystallization is performed to obtain a yellow solid. It was.
Table 39 shows the amounts of raw materials used and the yield of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene (dmpzdbs) obtained.
2) Synthesis of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene-chlorobridge dimer (abbreviation [(dmpzdbs) ₂ IrCl] ₂ )
Place 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene (dmpzdbs), iridium trichloride trihydrate, 2-ethoxyethanol, and water in a four-necked flask under a nitrogen stream. The mixture was heated and stirred at 100 ° C. for 24 hours. After completion of the reaction, the precipitate was filtered, washed with ion exchange water and ethanol, and then dried under reduced pressure to obtain a yellow solid. The crude product was used in the next reaction.
Table 40 shows the amounts of raw materials used and the yield of 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene-chlorobridge dimer [(dmpzdbs) ₂ IrCl] ₂ obtained.
3) Synthesis of tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene] iridium (III) complex (abbreviation fac-Ir [dmpzdbs] ₃ )
In a recovery flask, 1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene-chlorobridge dimer (abbreviated as CBD in Table 41) [(dmpzdbs) ₂ IrCl] ₂ , 1- (3 5-Dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene (dmpzdbs), cesium carbonate, and glycerin were added, and the mixture was heated and stirred at 200 ° C. for 120 hours in a nitrogen stream. Extraction after completion of the reaction was not performed, and purification was performed by a silica gel column chromatography method (developing solvent: n-hexane: dichloromethane = 1: 1), concentrated and dried under reduced pressure to obtain a yellow solid.
Table 41 shows the amount of raw materials used and the yield of the obtained tris [1- (3,5-dimethyl-1H-pyrazolyl-1-yl) dibenzoselenophene] iridium (III) complex.

1 Substrate 2 Anode (ITO)
3 Light emitting layer 4 Cathode 5 Hole transport layer (hole transport layer)
6 Electron transport layer 7 Hole injection layer (hole injection layer)
8 Electron injection layer 9 Hole blocking layer (hole blocking layer)

Claims (4)

The following general formula (1)
[Wherein, R ¹ and R ² are a group consisting of a linear or branched alkyl group having 1 to 4 carbon atoms, and R ^{8 to} R ¹³ are a group consisting of hydrogen and a linear or branched alkyl group having 1 to 4 carbon atoms. E represents a chalcogen element selected from the group consisting of oxygen element, sulfur element, selenium element and tellurium element. ]
A dibenzochalcogenylpyrazole iridium complex represented by: The following general formula (2)
[Wherein, R ¹ and R ² are a group consisting of a linear or branched alkyl group having 1 to 4 carbon atoms, and R ^{8 to} R ¹³ are a group consisting of hydrogen and a linear or branched alkyl group having 1 to 4 carbon atoms. E represents a chalcogen element selected from the group consisting of oxygen element, sulfur element, selenium element and tellurium element. ]
A dibenzochalcogenylpyrazole iridium complex represented by:   A luminescent material comprising the dibenzochalcogenylpyrazole iridium complex according to claim 1.   An organic EL device comprising the dibenzochalcogenylpyrazole iridium complex according to claim 1.