JP3826948B2 - Material for organic electroluminescence device and organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescence element used for a planar light source and display. More specifically, the present invention relates to an organic electroluminescent element for red light emission and a material for an organic electroluminescent element that exhibit high color purity and luminance at a low driving voltage.

  An organic electroluminescence (EL) element that emits light when an electron injected from a cathode and a hole injected from an anode are recombined in an organic phosphor sandwiched between these two electrodes is a solid light emitting display element. In recent years, research and development has been actively conducted.

This study was conducted by Eastman Kodak's C.I. W. Tang et al., Appl. Phys. Lett. 51, 913, published in 1987, which originated from an EL element with an organic thin film laminated. In this report, a metal chelate complex is used for the light emitting layer and an amine compound is used for the hole injection layer. Thus, green light emission having a luminance of several thousand (cd / m ² ) at a DC voltage of 6 to 10 V and a maximum luminous efficiency of 1.5 (lm / W) is obtained. It can be said that the organic EL elements currently being developed by various research institutes basically follow the configuration of Eastman Kodak Company.

  Among organic EL elements, organic EL elements that emit red light have been researched for various elements because of their usefulness, but a method such as co-evaporation of a small amount of dopant in the host material. A method of forming a light-emitting layer by mixing them to obtain light emission from a dopant has been studied as an effective method. As such an example, C.I. H. Chen et al., Macromol. Symp. 125, 34-36 and 49-58, published in 1997, tris (8-hydroxyquinolinate) aluminum as a host material and 4H such as DCM, DCJ, DCJT, DCJTB -An organic EL device capable of emitting orange to red light using a pyran derivative as a dopant has been reported.

Further, regarding organic EL devices using a compound having a 1,4-diketopyrrolo (3,4-c) pyrrole structure known as a red pigment, for example, JP-A-2-29691 and JP-A-5-320633 are disclosed. JP 2001-139940 A, WO 03/048268 pamphlet, and JP 2003-155286 A are known.
Appl. Phys. Lett. 51, 913, 1987 Macromol. Symp. 125, 34-36 and 49-58, 1997 Japanese Patent Laid-Open No. 2-29691 JP-A-5-320633 JP 2001-139940 A WO03 / 048268 pamphlet JP 2003-155286 A

  In the organic EL device for obtaining red high-intensity light emission described in the prior art, the organic EL device using a 4H-pyran derivative as a dopant has insufficient light emission color, high driving voltage and low light emission luminance. There was a problem. In addition, an organic EL device using a compound having a 1,4-diketopyrrolo (3,4-c) pyrrole structure as a dopant can produce a device with high color purity, but the concentration of molecules is high due to high molecular cohesion. Quenching is likely to occur and control of the doping concentration is an important issue. Therefore, there has been a demand for a material for an organic EL element that can obtain red light emission exhibiting high light emission luminance and long life without causing problems such as concentration quenching.

  As a result of intensive studies to solve the above problems, the present inventors have arrived at the present invention. That is, this invention relates to the material for organic electroluminescent elements containing the diketopyrrolopyrrole compound represented by following General formula [1].

General formula [1]

[Wherein R ¹ and R ² each independently represents a substituted or unsubstituted alkylene group, and R ³ and R ⁴ each independently represent a substituted or unsubstituted aliphatic heterocyclic group or a general formula [ 2] is represented. R ^{5 to} R ¹⁴ each independently represents a hydrogen atom or a substituent, and at least one of R ^{5 to} R ¹⁴ is an amino group represented by the general formula [3]. ]

General formula [2]

[Wherein, X represents an oxygen atom or a sulfur atom, and R ¹⁵ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted group. Represents a monovalent aromatic heterocyclic group. ]

General formula [3]
[Wherein R ¹⁶ and R ¹⁷ are each independently a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted Represents a monovalent aromatic heterocyclic group. ]

Moreover, this invention relates to the said organic electroluminescent element material whose diketopyrrolopyrrole compound represented by General formula [1] is a diketopyrrolopyrrole compound represented by following General formula [4].

General formula [4]

[Wherein R ¹ and R ² each independently represents a substituted or unsubstituted alkylene group, and R ³ and R ⁴ each independently represent a substituted or unsubstituted aliphatic heterocyclic group or a general formula [ 2] is represented. R ^{5 to} R ¹² each independently represents a hydrogen atom or a substituent. R ^{18 to} R ²¹ are each independently a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent Represents an aromatic heterocyclic group. ]

General formula [2]

[Wherein, X represents an oxygen atom or a sulfur atom, and R ¹⁵ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted group. Represents a monovalent aromatic heterocyclic group. ]

Moreover, this invention relates to the said organic electroluminescent element material whose diketopyrrolopyrrole compound represented by General formula [2] is a diketopyrrolopyrrole compound represented by following General formula [5].

General formula [5]

[Wherein R ¹ and R ² each independently represents a substituted or unsubstituted alkylene group, and R ³ and R ⁴ each independently represent a substituted or unsubstituted aliphatic heterocyclic group or a general formula [ 2] is represented. R ^{5 to} R ¹² and R ^{22 to} R ⁴¹ each independently represent a hydrogen atom or a substituent. ]

General formula [2]

[Wherein, X represents an oxygen atom or a sulfur atom, and R ¹⁵ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted group. Represents a monovalent aromatic heterocyclic group. ]

Moreover, this invention relates to the said organic electroluminescent element material which comprises the said organic electroluminescent element material and the amine compound represented by General formula [6].

General formula [6]

[Wherein Ar ¹ represents a substituted or unsubstituted perylenyl group, R ⁴² and R ⁴³ each independently represents a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent group. An aromatic heterocyclic group. Ar ¹ and R ⁴² , Ar ¹ and R ⁴³ , and R ⁴² and R ⁴³ may be bonded to each other to form a ring. ]

In addition, the present invention provides an organic electroluminescence device in which a light emitting layer or a plurality of organic compound thin films including a light emitting layer is formed between a pair of electrodes composed of an anode and a cathode. The present invention relates to an organic electroluminescence element including an element material.

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

  The organic EL device material containing the diketopyrrolopyrrole compound of the present invention is particularly excellent in red light emission due to the specific structure of the diketopyrrolopyrrole compound, and is difficult to cause concentration quenching, achieving both high emission luminance and long life. It is characterized by being able to do it. Organic EL devices created using this material can be used suitably as flat panel displays and flat light emitters, such as light sources for copiers and printers, light sources for liquid crystal displays and instruments, display boards, indicator lights, etc. Application to is possible.

Hereinafter, the present invention will be described in detail. In the diketopyrrolopyrrole compound represented by the general formula [1], R ¹ and R ² represent a substituted or unsubstituted alkylene group. R ³ and R ⁴ represent a substituted or unsubstituted aliphatic heterocyclic group or a substituent represented by the general formula [2]. R ^{5 to} R ¹⁴ represent a hydrogen atom or a substituent, and at least one of R ^{5 to} R ¹⁴ is an amino group represented by the general formula [2].

  Here, examples of the substituent in the present invention include a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, a monovalent aliphatic heterocyclic group, a monovalent aromatic heterocyclic group, a halogen atom, Examples include an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, a trialkylsilyl group, a cyano group, and an amino group.

  In addition, the alkylene group referred to in the present invention includes a methylene group, an ethylene group, a propylene group, a butylene group, a sec-butylene group, a tert-butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, etc. 10 alkylene groups are mentioned.

  Examples of the aliphatic heterocyclic group in the present invention include 1,3-dioxolanyl group, 1,3-dioxanyl group, 1,4-dioxanyl group, 2-tetrahydrofuryl group, 2-morpholino group, and 4-morpholino group. And monovalent aliphatic heterocyclic groups having 3 to 18 carbon atoms such as piperidino group.

  In addition, the monovalent aliphatic hydrocarbon group referred to in the present invention refers to a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms, such as an alkyl group, an alkenyl group, an alkynyl group, a cyclohexane. And an alkyl group.

  In addition, as the alkyl group in the present invention, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, hexyl group, heptyl group , An octyl group, a decyl group, a dodecyl group, a pentadecyl group, an octadecyl group, and an alkyl group having 1 to 18 carbon atoms.

  Examples of the alkenyl group in the present invention include a vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-octenyl group, 1-octenyl group, Examples thereof include alkenyl groups having 2 to 18 carbon atoms such as decenyl group and 1-octadecenyl group.

  The alkynyl group referred to in the present invention includes ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, 1-octynyl group, 1-decynyl group, 1 -C2-C18 alkynyl groups, such as an octadecynyl group.

  In addition, the cycloalkyl group referred to in the present invention includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclooctadecyl group, a 2-bornyl group, a 2-isobornyl group, and a 1-adamantyl group. Examples thereof include cycloalkyl groups having 3 to 18 carbon atoms such as groups.

  Furthermore, examples of the monovalent aromatic hydrocarbon group in the present invention include monovalent monocyclic, condensed ring, and ring-aggregated aromatic hydrocarbon groups having 6 to 30 carbon atoms. Here, as a monovalent monocyclic aromatic hydrocarbon group having 6 to 30 carbon atoms, phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,4-xylyl group, p-cumenyl And monovalent monocyclic aromatic hydrocarbon groups having 6 to 30 carbon atoms such as a group and a mesityl group.

  The monovalent condensed ring aromatic hydrocarbon group referred to in the present invention includes 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 5-anthryl group, 1-phenanthryl group, 9 -Phenanthryl group, 1-acenaphthyl group, 2-azurenyl group, 1-pyrenyl group, 2-triphenylyl group, 1-pyrenyl group, 2-pyrenyl group, 1-perylenyl group, 2-perylenyl group, 3-perylenyl group, 2 -A monovalent condensed ring hydrocarbon group having 10 to 30 carbon atoms such as a trephenylenyl group, a 2-indenyl group, a 1-acenaphthylenyl group, a 2-naphthacenyl group, and a 2-pentacenyl group.

  Examples of the monovalent ring-aggregated aromatic hydrocarbon group in the present invention include an o-biphenylyl group, m-biphenylyl group, p-biphenylyl group, terphenylyl group, 7- (2-naphthyl) -2-naphthyl group, and the like. And a monovalent ring-assembled hydrocarbon group having 12 to 30 carbon atoms.

  The monovalent aromatic heterocyclic group referred to in the present invention includes 2-furyl group, 3-furyl group, 2-thienyl group, 3-thienyl group, N-pyrrolyl group, 2-benzofuryl group, 2-benzoyl group. Examples thereof include monovalent aromatic heterocyclic groups having 3 to 30 carbon atoms such as thienyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-quinolyl, and 5-isoquinolyl group.

  In addition, examples of the halogen atom in the present invention include a fluorine atom, a chlorine atom, and a bromine atom.

  In addition, as the alkoxyl group in the present invention, methoxy group, ethoxy group, propoxy group, butoxy group, tert-butoxy group, octyloxy group, tert-octyloxy group, 2-bornyloxy group, 2-isobornyloxy group And an alkoxyl group having 1 to 18 carbon atoms such as a 1-adamantyloxy group.

  The aryloxy group referred to in the present invention is an aryloxy group having 6 to 30 carbon atoms such as a phenoxy group, 4-tert-butylphenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, 9-anthryloxy group. Group.

  Examples of the alkylthio group in the present invention include C1-C18 alkylthio groups such as methylthio group, ethylthio group, tert-butylthio group, hexylthio group, and octylthio group.

  Examples of the arylthio group in the present invention include arylthio groups having 6 to 30 carbon atoms such as a phenylthio group, a 2-methylphenylthio group, and a 4-tert-butylphenylthio group.

  Examples of the acyl group in the present invention include C2-C18 acyl groups such as acetyl group, propionyl group, pivaloyl group, cyclohexylcarbonyl group, benzoyl group, toluoyl group, anisoyl group, and cinnamoyl group.

  Examples of the alkoxycarbonyl group in the present invention include C2-C18 alkoxycarbonyl groups such as methoxycarbonyl group, ethoxycarbonyl group, and benzyloxycarbonyl group.

  In addition, examples of the aryloxycarbonyl group referred to in the present invention include aryloxycarbonyl groups having 7 to 30 carbon atoms such as a phenoxycarbonyl group and a naphthyloxycarbonyl group.

  Moreover, as an alkylsulfonyl group as used in the field of this invention, C1-C18 alkylsulfonyl groups, such as a mesyl group, an ethylsulfonyl group, a propylsulfonyl group, are mention | raise | lifted.

  Examples of the arylsulfonyl group include arylsulfonyl groups having 6 to 30 carbon atoms such as a benzenesulfonyl group and a p-toluenesulfonyl group.

  Examples of the trialkylsilyl group in the present invention include trialkylsilyl groups having 6 to 18 carbon atoms such as a trimethylsilyl group, a triethylsilyl group, a dimethylethylsilyl group, a triisopropylsilyl group, and a tributylsilyl group.

  Examples of the amino group in the present invention include amino groups having 6 to 30 carbon atoms such as diethylamino group, dibutylamino group, diphenylamino group, ditolylamino group, and ethylphenylamino group.

  These substituents may be further substituted with other substituents, and these substituents may be bonded to each other to form a ring.

Next, in the general formula [2], R ¹⁵ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic group. Represents a heterocyclic group. Here, the monovalent aliphatic hydrocarbon group, monovalent aromatic hydrocarbon group, and monovalent aromatic heterocyclic group include the monovalent aliphatic hydrocarbon group and the monovalent group in the general formula [1] described above. These are the same as the aromatic hydrocarbon group and monovalent aromatic heterocyclic group.

In the general formula [3], R ¹⁶ and R ¹⁷ represent a hydrogen atom, a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent aromatic heterocyclic group. Here, as the monovalent aliphatic hydrocarbon group, monovalent aromatic hydrocarbon group, and monovalent aromatic heterocyclic group, the monovalent aliphatic hydrocarbon group in the above general formula [1], 1 It is synonymous with a monovalent aromatic hydrocarbon group and a monovalent aromatic heterocyclic group.

In the general formula [4], R ^{18 to} R ²¹ represent a hydrogen atom, a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent aromatic heterocyclic group. Here, as the monovalent aliphatic hydrocarbon group, monovalent aromatic hydrocarbon group, and monovalent aromatic heterocyclic group, the monovalent aliphatic hydrocarbon group in the above general formula [1], 1 It is synonymous with a monovalent aromatic hydrocarbon group and a monovalent aromatic heterocyclic group.

In the general formula [5], R ²² ~R ⁴¹ represents a hydrogen atom or a substituent. Here, the substituent is synonymous with the substituent in the aforementioned general formula [1], and is a monovalent aliphatic hydrocarbon group, monovalent aromatic hydrocarbon group, monovalent aliphatic heterocyclic group, monovalent. Aromatic heterocyclic group, halogen atom, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, trialkylsilyl group, cyano group And amino groups.

Further, preferably 1 to 18 as the number of carbon atoms in the substituents of R ¹ to R ⁴¹ mentioned above, 1 to 12 is more preferred. The reason for this is that if the carbon number of these substituents increases, there is a concern that the vapor deposition property when an element is formed by vapor deposition is deteriorated.

  The diketopyrrolopyrrole compound used in the present invention has been described above, but the molecular weight of these diketopyrrolopyrrole compounds is preferably 2000 or less, more preferably 1500 or less, and particularly preferably 1000 or less. This is because, when the molecular weight is large, there is a concern that the vapor deposition property in the case of producing an element by vapor deposition is deteriorated.

  Hereinafter, typical examples of the amine compound represented by the general formula [1] that can be used as the material for the organic EL element of the present invention are shown in Table 1, but the present invention is not limited thereto.

  Next, the amine compound represented by the general formula [6] used in the present invention will be described.

Ar ¹ in the general formula [6] represents a substituted or unsubstituted perylenyl group, and examples of the unsubstituted perylenyl group include a 1-perylenyl group, a 2-perylenyl group, and a 3-perylenyl group. These perylenyl groups may be further substituted with other substituents. As the substituent for Ar ^1, a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, a monovalent aliphatic heterocyclic group, a monovalent aromatic heterocyclic group, a halogen atom, an alkoxyl group, Aryloxy group, alkylthio group, arylthio group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, trialkylsilyl group, cyano group and the like can be mentioned.

R ⁴² and R ⁴³ are a monovalent organic residue selected from a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. The substituent for R ⁴² and R ⁴³ has the same meaning as the substituent described for the substituent for Ar ¹ .

  Here, the monovalent aliphatic hydrocarbon group refers to a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms, such as an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group. Can be given.

  Examples of the alkyl group, alkenyl group, alkynyl group, and cycloalkyl group mentioned here are the same as those in the general formula [1].

Furthermore, examples of the monovalent aromatic hydrocarbon group include monovalent monocyclic, condensed ring, and ring-aggregated aromatic hydrocarbon groups having 6 to 30 carbon atoms.
Here, the monovalent monocyclic aromatic hydrocarbon group having 6 to 30 carbon atoms, the monovalent condensed ring aromatic hydrocarbon group, and the monovalent ring assembly aromatic hydrocarbon group are represented by the general formula [1]. These are the same.

  In addition, as the monovalent aliphatic heterocyclic group, a monovalent fatty acid having 3 to 18 carbon atoms such as a 3-isochromanyl group, a 7-chromanyl group, a 3-coumarinyl group, a piperidino group, a morpholino group, and a 2-morpholino group. Group heterocyclic group.

  Monovalent aromatic heterocyclic group, halogen atom, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, trialkylsilyl Examples of the group include the same groups as those in the general formula [1].

  These substituents may be further substituted with other substituents, and these substituents may be bonded to each other to form a ring.

Ar ¹ in the general formula [6] described above includes a substituted or unsubstituted 1-perylenyl group, a substituted or unsubstituted 2-perylenyl group, and a substituted or unsubstituted 3-perylenyl group. Of these, a substituted or unsubstituted 3-perylenyl group is preferable, and an unsubstituted 3-perylenyl group is particularly preferable.

Moreover, as carbon number in the substituent of Ar < ¹ >, R ^<42> , R ^<43 > mentioned above, 1-18 are preferable and 1-12 are more preferable. The reason for this is that if the carbon number of these substituents increases, there is a concern that the vapor deposition property when an element is formed by vapor deposition is deteriorated.

  The amine compound represented by the general formula [6] used in the present invention has been described above. The molecular weight of these amine compounds is preferably 2000 or less, more preferably 1500 or less, and particularly preferably 1000 or less. This is because, when the molecular weight is large, there is a concern that the vapor deposition property in the case of producing an element by vapor deposition is deteriorated.

  Table 2 below shows typical examples of amine compounds represented by the general formula [6] that can be used as the material for the organic EL device of the present invention, but the present invention is not limited to these ( In the table, t-Bu represents a tert-butyl group, Ph represents a phenyl group, and Tol represents a p-tolyl group).

  By the way, the organic EL element is composed of an element in which a single layer or a multilayer organic layer is formed between an anode and a cathode. Here, the single layer type organic EL element is composed only of a light emitting layer between an anode and a cathode. The element which becomes. On the other hand, the multilayer organic EL element facilitates injection of holes and electrons into the light emitting layer in addition to the light emitting layer, and facilitates recombination of holes and electrons in the light emitting layer. For the purpose of this, it refers to a layer in which a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and the like are laminated. Therefore, typical element configurations of the multilayer organic EL element include (1) anode / hole injection layer / light emitting layer / cathode, and (2) anode / hole injection layer / hole transport layer / light emitting layer / cathode. (3) Anode / hole injection layer / light emitting layer / electron injection layer / cathode, (4) Anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode, (5) Anode / positive Hole injection layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (6) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (7) An element structure in which a multilayer structure of anode / light emitting layer / hole blocking layer / electron injection layer / cathode, (8) anode / light emitting layer / electron injection layer / cathode, etc., is considered.

  Here, the hole injection layer has a hole injection material that exhibits an excellent hole injection effect for the light emitting layer and can form a hole injection layer having excellent adhesion to the anode interface and thin film formation. Used. In addition, when such materials are laminated in multiple layers and a material having a high hole injection effect and a material having a high hole transport effect are laminated, the materials used for each are called a hole injection material and a hole transport material. Sometimes. Examples of such hole injection materials or hole transport materials include phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolethione derivatives, pyrazoline derivatives, pyrazolone derivatives. , Tetrahydroimidazole derivatives, oxazole derivatives, oxadiazole derivatives, hydrazone derivatives, acyl hydrazone derivatives, stilbene derivatives, aromatic tertiary amine derivatives, polyvinyl carbazole derivatives, polysilane derivatives, etc. However, the material is not particularly limited as long as the material can inject holes from the anode and transport holes.

  Among the above materials, examples of the hole injection material or the hole transport material that can be particularly preferably used include aromatic tertiary amine derivatives and phthalocyanine derivatives. Examples of the aromatic tertiary amine derivative include 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-methylphenyl) -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, and oligomers having these aromatic tertiary amine skeletons Or polymers, these are holes Input materials, can be suitably used for any hole transport material. Examples of the phthalocyanine (Pc) derivative include H2Pc, CuPc, CoPc, NiPc, ZnPc, PdPc, FePc, MnPc, ClAlPc, ClGaPc, ClInPc, ClSnPc, Cl2SiPc, (HO) AlPc, (HO) GaPc, VOPc, Examples thereof include phthalocyanine derivatives such as TiOPc, MoOPc, and GaPc—O—GaPc, and these can be suitably used particularly for hole injection materials.

  On the other hand, for the electron injection layer, an electron injection material that exhibits an excellent electron injection effect with respect to the light emitting layer and that can form an electron injection layer excellent in adhesion to the cathode interface and thin film formability is used. Examples of such electron injection materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, fluorenone derivatives, anthraquinodimethane derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, perylenetetracarboxylic acid derivatives, fluorenylidenemethane. Derivatives, anthrone derivatives, silole derivatives, calcium acetylacetonate, sodium acetate and the like. In addition, inorganic / organic composite materials doped with metal such as cesium in bathophenanthroline (Proceedings of the Society of Polymer Science, Vol. 50, No. 4, 660, published in 2001) and the 50th Applied Physics Related Lecture Conference Proceedings, No. Examples of electron injection materials include BCP, TPP, T5MPyTZ, etc. published on page 3, 1402, 2003. Electrons can be transported by forming a thin film necessary for device fabrication and injecting electrons from the cathode. If it is material, it will not specifically limit to these.

  Among the electron injection materials, particularly effective electron injection materials include metal complex compounds and nitrogen-containing five-membered ring derivatives. Among the electron injection materials that can be used in the present invention, preferable metal complex compounds include tris (8-hydroxyquinolinato) aluminum (Alq3), tris (2-methyl-8-hydroxyquinolinato) aluminum, tris ( 5-phenyl-8-hydroxyquinolinato) aluminum, bis (8-hydroxyquinolinato) (1-naphtholato) aluminum, bis (8-hydroxyquinolinato) (2-naphtholato) aluminum, bis (8-hydroxy) Quinolinate) (phenolate) aluminum, bis (8-hydroxyquinolinate) (4-cyano-1-naphtholate) aluminum, bis (4-methyl-8-hydroxyquinolinato) (1-naphtholato) aluminum, bis (5-Methyl-8-hydroxyquinolinate) (2 Naphthalate) aluminum, bis (5-phenyl-8-hydroxyquinolinato) (phenolate) aluminum, bis (5-cyano-8-hydroxyquinolinato) (4-cyano-1-naphtholato) aluminum, bis (8- Hydroxyquinolinato) chloroaluminum, aluminum complex compounds such as bis (8-hydroxyquinolinato) (o-cresolate) aluminum, tris (8-hydroxyquinolinato) gallium, tris (2-methyl-8-hydroxychi) Norinato) gallium, tris (2-methyl-5-phenyl-8-hydroxyquinolinato) gallium, bis (2-methyl-8-hydroxyquinolinato) (1-naphtholato) gallium, bis (2-methyl-) 8-hydroxyquinolinate) (2-naphtholate) Bis (2-methyl-8-hydroxyquinolinate) (phenolate) gallium, bis (2-methyl-8-hydroxyquinolinate) (4-cyano-1-naphtholato) gallium, bis (2,4- Dimethyl-8-hydroxyquinolinate) (1-naphtholato) gallium, bis (2,5-dimethyl-8-hydroxyquinolinato) (2-naphtholato) gallium, bis (2-methyl-5-phenyl-8- Hydroxyquinolinate) (phenolate) gallium, bis (2-methyl-5-cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholato) gallium, bis (2-methyl-8-hydroxyquinolinate) ) Gallium such as chlorogallium, bis (2-methyl-8-hydroxyquinolinate) (o-cresolate) gallium In addition to complex compounds, 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinate) manganese, bis (10-hydroxybenzo [h] quinolinato) beryllium, bis (8 -Hydroxyquinolinato) zinc, metal complex compounds such as bis (10-hydroxybenzo [h] quinolinato) zinc.

  Among the electron injection materials that can be used in the present invention, preferable nitrogen-containing five-membered ring derivatives include oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, and triazole derivatives. , 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- (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-phenyloxadiazolyl) -4-tert-butyl benzene], 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- Examples thereof include bis (1-naphthyl) -1,3,4-triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

  Furthermore, a hole blocking material that can prevent holes from passing through the light emitting layer from reaching the electron injection layer and form a layer having excellent thin film formability is used for the hole blocking layer. Examples of such hole blocking materials include aluminum complex compounds such as bis (8-hydroxyquinolinate) (4-phenylphenolate) aluminum, and bis (2-methyl-8-hydroxyquinolinate) ( 4-phenylphenolate) gallium complex compounds such as gallium, and nitrogen-containing condensed aromatic compounds such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

  Moreover, when using the organic EL element material of this invention for a light emitting layer, you may contain another host material and a dopant. In this case, the dopant concentration is preferably contained in the range of 0.001 to 30% by weight with respect to the host material, more preferably in the range of 0.01 to 10% by weight, More preferably, it is contained in the range of ˜5% by weight.

  In the light emitting layer of the present organic EL device, in addition to the organic EL device material of the present invention, not only other light emitting materials and doping materials, but also the above-described hole injection materials and electron injection materials are used. Two or more kinds of materials can be used in combination. Further, the hole injection layer, the light emitting layer, and the electron injection layer may each be formed with a layer configuration of two or more layers.

  Furthermore, the materials used for the anode of the organic EL device of the present invention are metals such as carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum, palladium, and alloys thereof, zinc oxide, oxidation Examples thereof include conductive metal oxides such as tin, indium oxide and indium tin oxide (ITO), and conductive polymers such as polythiophene, polypyrrole and polyaniline. In particular, as a conductive material used for the anode of the organic EL device of the present invention, a material having a resistance value as low as possible is preferable, and ITO glass and NESA glass are preferably used.

  The material used for the cathode of the organic EL device of the present invention is not particularly limited as long as it can efficiently inject electrons into the organic EL device, but in general, platinum, gold, silver, copper, iron, tin, Examples thereof include zinc, aluminum, indium, chromium, lithium, sodium, potassium, calcium, magnesium, and alloys thereof. Here, examples of the alloy include magnesium / silver, magnesium / indium, lithium / aluminum, and the like, but alloys containing a low work function metal such as lithium, sodium, potassium, calcium, and magnesium are preferable. In addition, an inorganic salt such as lithium fluoride can be used in place of the low work function metal. Moreover, as a preparation method of these cathodes, they can be prepared by methods known in the industry such as resistance heating, electron beam beam irradiation, sputtering, ion plating, and coating. The anode and cathode described above may be formed with a layer structure of two or more layers as necessary.

  In order to efficiently extract light emitted from the organic EL device of the present invention, it is desirable that the substrate material on the surface from which light is extracted is sufficiently transparent. Specifically, the transmittance of light emitted from the device in the light emission wavelength region is high. It is desirable that it is 50% or more, preferably 90% or more. These substrates have mechanical and thermal strength and are not particularly limited as long as they are transparent. For example, in addition to glass, transparent polymers such as polyethylene, polyethersulfone, and polypropylene are recommended.

  In addition, as a method for forming each layer of the organic EL element of the present invention, a dry film forming method such as vacuum deposition, electron beam beam irradiation, sputtering, plasma, ion plating, or a wet process such as spin coating, dipping, or flow coating is used. Any of the membrane methods can be applied. The film thickness of each layer is not particularly limited, but if the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. Conversely, if the film thickness is too thin, pinholes, etc. And it becomes difficult to obtain sufficient light emission luminance even when an electric field is applied. Accordingly, the thickness of each layer is suitably in the range of 1 nm to 1 μm, but more preferably in the range of 10 nm to 0.2 μm.

  Further, in order to improve the stability of the organic EL element with respect to temperature, humidity, atmosphere and the like, a protective layer may be provided on the surface of the element, or the entire element may be covered or sealed with a resin or the like. In particular, when the entire element is covered or sealed, a photocurable resin that is cured by light is preferably used.

  As described above, this organic EL element can obtain red light emission exhibiting high color purity and luminance at a low driving voltage. Therefore, this organic EL device can be applied to flat panel displays such as wall-mounted televisions and flat light emitters, as well as light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, and indicator lights. Can be considered.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example at all. In this example, all mixing ratios indicate weight ratios unless otherwise specified. Moreover, the characteristic of the organic EL element with an electrode area of 2 mm × 2 mm was measured.

Example 1
On the washed glass plate with an ITO electrode, the following NPD was vacuum-deposited to obtain a 20 nm-thick hole transport layer. Subsequently, the compound 2 of Table 1 was vacuum-deposited as a diketopyrrolopyrrole compound, and the light emitting layer with a film thickness of 40 nm was obtained. Next, tris (8-hydroxyquinolinate) aluminum (Alq3) was deposited to obtain an electron injection layer having a thickness of 30 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. When an energization test was performed on this device, red light emission with a maximum light emission luminance of 15000 cd / m ² was obtained. Further, the half life when driven at a constant current at 500 cd / m ² was 1300 hours.

Example 2 to Example 10
An organic EL device was produced in the same manner as in Example 1 except that the diketopyrrolopyrrole compound shown in Table 3 was used instead of Compound 2. Table 3 shows the maximum light emission luminance of these devices and the half life when driven at a constant current of 500 cd / m ² .

Comparative Example 1 and Comparative Example 2
An organic EL device was produced in the same manner as in Example 1 except that the following Comparative Compound A and Comparative Compound B were used in place of Compound 2. Table 3 shows the maximum light emission luminance of this device and the half life when driven at a constant current of 500 cd / m ² .

As is clear by comparing Examples 1 to 10 and Comparative Examples 1 and 2, by using the compound represented by the general formula [1], it was possible to achieve both high maximum emission luminance and long half-life. .

Example 11
NPD was vacuum-deposited on the washed glass plate with the ITO electrode to obtain a 20 nm-thick hole transport layer. Subsequently, the compound 2 of Table 1 as a diketopyrrolopyrrole compound and the compound 43 of Table 2 as an amine compound were co-evaporated with the composition ratio of 5:95 (weight ratio), and the light emitting layer with a film thickness of 40 nm was obtained. Next, tris (8-hydroxyquinolinate) aluminum (Alq3) was deposited to obtain an electron injection layer having a thickness of 30 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. When an energization test was performed on this device, red light emission with a maximum light emission luminance of 37200 cd / m ² was obtained. Further, the half life when driven at a constant current at 500 cd / m ² was 3100 hours.

Examples 12 to 16
An organic EL device was produced in the same manner as in Example 1 except that the diketopyrrolopyrrole compound shown in Table 4 was used instead of compound 2. Table 4 shows the maximum light emission luminance of these elements and the half life when driven at a constant current of 500 cd / m ² .

Comparative Example 3
An organic EL device was produced in the same manner as in Example 1 except that tris (8-hydroxyquinolinato) aluminum (Alq3) was used instead of compound 43. Table 4 shows the maximum light emission luminance of this device and the half life when driven at a constant current of 500 cd / m ² .

As is apparent from comparison between Examples 11 to 16 and Comparative Example 3, particularly excellent performance was obtained by using the compound represented by the general formula [1] and the amine compound represented by the general formula [6]. Indicates.

Claims (6)

The material for organic electroluminescent elements containing the diketopyrrolopyrrole compound represented by following General formula [1].
General formula [1]
[Wherein R ¹ and R ² each independently represents a substituted or unsubstituted alkylene group, and R ³ and R ⁴ each independently represent a substituted or unsubstituted aliphatic heterocyclic group or a general formula [ 2] is represented. R ^{5 to} R ¹⁴ each independently represents a hydrogen atom or a substituent, and at least one of R ^{5 to} R ¹⁴ is an amino group represented by the general formula [3]. ]
General formula [2]
[Wherein, X represents an oxygen atom or a sulfur atom, and R ¹⁵ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted group. Represents a monovalent aromatic heterocyclic group. ]
General formula [3]
[Wherein R ¹⁶ and R ¹⁷ are each independently a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted Represents a monovalent aromatic heterocyclic group. ] The material for organic electroluminescent elements according to claim 1, wherein the diketopyrrolopyrrole compound represented by the general formula [1] is a diketopyrrolopyrrole compound represented by the following general formula [4].
General formula [4]
[Wherein R ¹ and R ² each independently represents a substituted or unsubstituted alkylene group, and R ³ and R ⁴ each independently represent a substituted or unsubstituted aliphatic heterocyclic group or a general formula [ 2] is represented. R ^{5 to} R ¹² each independently represents a hydrogen atom or a substituent. R ^{18 to} R ²¹ are each independently a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent Represents an aromatic heterocyclic group. ]
General formula [2]
[Wherein, X represents an oxygen atom or a sulfur atom, and R ¹⁵ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted group. Represents a monovalent aromatic heterocyclic group. ] The diketopyrrolopyrrole compound represented by the general formula [2] is a diketopyrrolopyrrole compound represented by the following general formula [5].
General formula [5]
[Wherein R ¹ and R ² each independently represents a substituted or unsubstituted alkylene group, and R ³ and R ⁴ each independently represent a substituted or unsubstituted aliphatic heterocyclic group or a general formula [ 2] is represented. R ^{5 to} R ¹² and R ^{22 to} R ⁴¹ each independently represent a hydrogen atom or a substituent. ]
General formula [2]
[Wherein, X represents an oxygen atom or a sulfur atom, and R ¹⁵ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted group. Represents a monovalent aromatic heterocyclic group. ] The organic electroluminescent element material which contains the organic electroluminescent element material in any one of Claim 1 thru | or 3, and the amine compound represented by General formula [6].
General formula [6]
[Wherein Ar ¹ represents a substituted or unsubstituted perylenyl group, R ⁴² and R ⁴³ each independently represents a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent group. An aromatic heterocyclic group. Ar ¹ and R ⁴² , Ar ¹ and R ⁴³ , and R ⁴² and R ⁴³ may be bonded to each other to form a ring. ] 5. The organic electroluminescence device according to claim 1, wherein at least one layer is formed in a light emitting layer or a plurality of layers of an organic compound thin film including a light emitting layer between a pair of electrodes composed of an anode and a cathode. An organic electroluminescence device comprising a material for an organic electroluminescence device. 5. The organic electroluminescent device in which a light emitting layer or a plurality of organic compound thin films including a light emitting layer is formed between a pair of electrodes composed of an anode and a cathode, wherein the light emitting layer is any one of claims 1 to 4. An organic electroluminescence device comprising a material for an organic electroluminescence device.