Composition for organic electroluminescent element, organic electroluminescent element, display device, and lighting device

Abstract

The present application provides an organic electroluminescent element composition, comprising a compound represented by the following formula (1), a high molecular compound having a repeating unit comprising a structure represented by the following formula (2), a compound represented by the following formula (3), and a solvent. The present application also provides an organic electroluminescent element having a light-emitting layer formed using the organic electroluminescent element composition.

Description

Technical Field

[0001] This invention relates to an organic electroluminescent element composition useful for forming a light-emitting layer of an organic electroluminescent element (hereinafter, sometimes referred to as an "organic EL element"). The invention also relates to an organic electroluminescent element having a light-emitting layer formed using the composition for organic electroluminescent elements, a method for manufacturing the same, and display and lighting devices having the organic electroluminescent element. Background Technology

[0002] Organic EL (OLED) components, such as OLED lighting and OLED displays, have been put into practical use. Because OLEDs consume little power due to their low applied voltage and ability to emit all three primary colors of light, they are not only used in large monitors but are also beginning to be applied to small and medium-sized displays, such as those in mobile phones and smartphones.

[0003] Organic light-emitting diodes (OLEDs) are manufactured by stacking multiple layers, including a light-emitting layer, a charge injection layer, and a charge transport layer. Currently, most OLEDs are manufactured by vapor-depositing organic materials under vacuum.

[0004] Vacuum evaporation deposition is a complex process with poor yield.

[0005] Organic electroluminescent elements manufactured by vacuum evaporation are extremely difficult to scale up for use in lighting and display panels.

[0006] In recent years, wet deposition (coating) has been studied as a highly efficient process for manufacturing organic electroluminescent elements for use in large displays and lighting. Compared with vacuum evaporation, wet deposition has the advantage of easily forming stable layers, and therefore holds promise for mass production of displays and lighting devices, as well as applications in large-scale equipment.

[0007] To manufacture organic electroluminescent devices using wet film deposition, the materials used must be completely soluble in organic solvents for use as inks. If the materials have poor solubility, prolonged heating or other processes are required, potentially leading to material degradation before use. Furthermore, if the material cannot maintain a homogeneous state in solution for an extended period, precipitation will occur, making film deposition using inkjet printing devices impossible. Therefore, materials used in wet film deposition require both rapid dissolution in organic solvents and the ability to maintain a homogeneous state without precipitation after dissolution.

[0008] In recent years, attempts have been made to improve the luminous efficiency of organic electroluminescent elements or to improve the performance of organic electroluminescent elements by reducing the driving voltage. The ink contains: compounds whose solubility in organic solvents is improved by introducing specific substituents into the structure of organometallic coordination compounds with iridium as the central metal, which are widely used as luminescent dopants; and polymeric compounds containing fluorene structures (e.g., Patent Document 1 and Patent Document 2).

[0009] Another advantage of wet film deposition over vacuum evaporation is the ability to use a wider variety of materials in a single layer. In vacuum evaporation, it becomes difficult to control the deposition rate consistently if the number of materials increases. On the other hand, in wet film deposition, even with an increased variety of materials, as long as each material is dissolved in an organic solvent, an ink with a specific composition ratio can be prepared and a layer formed.

[0010] In recent years, attempts have been made to use specific compounds containing triazine or pyrimidine rings as one of the many components contained in inks used to form the luminescent layer for the purpose of facilitating electron transport (e.g., Patent Documents 3 and 4).

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: International Publication No. 2017 / 154884

[0014] Patent Document 2: Japanese Patent Application Publication No. 2018-83941

[0015] Patent Document 3: International Publication No. 2014 / 024889

[0016] Patent Document 4: International Publication No. 2017 / 178311 Summary of the Invention

[0017] However, in the aforementioned prior art, although the solubility of the luminescent dopant and the stability of the ink are improved due to the introduction of specific substituents, the electron transport properties of the luminescent material are reduced due to the introduction of these specific substituents. Therefore, the performance of organic electroluminescent elements is not sufficient for display and lighting applications, and there is a need to further reduce the driving voltage, improve luminous efficiency, and extend driving life.

[0018] The objective of this invention is to provide a composition for organic electroluminescent elements that can be fabricated by a wet film deposition method, resulting in organic electroluminescent elements with lower driving voltage, higher luminous efficiency, and longer driving life compared to conventional methods.

[0019] In order to flexibly utilize the advantages of wet film deposition methods that allow for the use of a wider variety of materials in a single layer, the inventors conducted in-depth research on the aforementioned issues. The results showed that by using iridium coordination compounds with specific substituents that are highly soluble in organic solvents as luminescent dopants, and by using, in addition to polymers containing fluorene structures, specific compounds containing triazine or pyrimidine rings that undertake electron transport as host materials, compositions for organic electroluminescent elements that dissolve in solvents were prepared. Organic electroluminescent elements were fabricated using these compositions, thereby improving the performance of the organic electroluminescent elements.

[0020] The organic electroluminescent element composition of the present invention uses an iridium coordination compound with specific substituents that is highly soluble in organic solvents as a luminescent dopant, thus preventing the precipitation of luminescent material and exhibiting excellent storage stability. Furthermore, because it includes specific compounds containing triazine or pyrimidine rings that undertake electron transport, it is possible to fabricate organic electroluminescent elements with improved electron transport capability in the luminescent layer, lower driving voltage, higher luminous efficiency, and longer driving lifetime compared to conventional methods.

[0021] The main points of this invention are as follows.

[0022] [1] A composition for an organic electroluminescent element, comprising:

[0023] The compound shown in formula (1) below,

[0024] A polymeric compound having repeating units comprising the structure shown in formula (2) below, a compound shown in formula (3) below, and

[0025] Solvent.

[0026]

[0027] In equation (1), R 1 R 2 Each group is independently any one of the following: alkyl (1-20 carbon atoms), (hetero)arylalkyl (7-40 carbon atoms), alkoxy (1-20 carbon atoms), (hetero)aryloxy (3-20 carbon atoms), alkylsilyl (1-20 carbon atoms), arylsilyl (6-20 carbon atoms), alkylcarbonyl (2-20 carbon atoms), arylcarbonyl (7-20 carbon atoms), alkylamino (1-20 carbon atoms), arylamino (6-20 carbon atoms), and (hetero)aryl (3-30 carbon atoms), or a combination thereof. These groups may further have substituents. R 1 R 2 When multiple R exist, multiple R 1 R 2 They can be the same or different. The adjacent R bonds to the benzene ring...1 or R 2 They can bond with each other to form a ring fused with the benzene ring.

[0028] a is an integer from 0 to 4. b is an integer from 0 to 3.

[0029] m is an integer from 1 to 20.

[0030] n is an integer between 0 and 2.

[0031] Ring A can be a pyridine ring, pyrazine ring, pyrimidine ring, or imidazole ring. Any one of the following: azole ring, thiazole ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azirbenzanthroline ring, or carboline ring.

[0032] Ring A may have substituents. These substituents are any one of the following: fluorine atom, chlorine atom, bromine atom, alkyl group with 1-20 carbon atoms, (hetero)arylalkyl group with 7-40 carbon atoms, alkoxy group with 1-20 carbon atoms, (hetero)aryloxy group with 3-20 carbon atoms, alkylsilyl group with 1-20 carbon atoms, arylsilyl group with 6-20 carbon atoms, alkylcarbonyl group with 2-20 carbon atoms, arylcarbonyl group with 7-20 carbon atoms, alkylamino group with 2-20 carbon atoms, arylamino group with 6-20 carbon atoms, and (hetero)aryl group with 3-20 carbon atoms, or combinations thereof. Adjacent substituents bonded to ring A can bond to each other to form a ring fused with ring A.

[0033] Z 1 This indicates an aromatic linking group that is directly bonded or has an m+1 valence.

[0034] L 1 This represents the auxiliary ligand. l is an integer from 1 to 3. When multiple auxiliary ligands exist, they can be different or the same.

[0035]

[0036] In equation (2), R 3 R 4 Each group is independently any one of the following: alkyl with 1 to 20 carbon atoms, (hetero)arylalkyl with 7 to 40 carbon atoms, alkoxy with 1 to 20 carbon atoms, (hetero)aryloxy with 3 to 20 carbon atoms, alkylsilyl with 1 to 20 carbon atoms, arylsilyl with 6 to 20 carbon atoms, alkylcarbonyl with 2 to 20 carbon atoms, arylcarbonyl with 7 to 20 carbon atoms, alkylamino with 1 to 20 carbon atoms, arylamino with 6 to 20 carbon atoms, and (hetero)aryl with 3 to 30 carbon atoms, or a combination thereof. These groups may further have substituents.

[0037]

[0038] In formula (3), X 1 Indicates C or N,

[0039] R 5 ~R 7 Each group is independently any one of the following: alkyl (1-20 carbon atoms), (hetero)arylalkyl (7-40 carbon atoms), alkoxy (1-20 carbon atoms), (hetero)aryloxy (3-20 carbon atoms), alkylsilyl (1-20 carbon atoms), arylsilyl (6-20 carbon atoms), alkylcarbonyl (2-20 carbon atoms), arylcarbonyl (7-20 carbon atoms), alkylamino (1-20 carbon atoms), arylamino (6-20 carbon atoms), and (hetero)aryl (3-30 carbon atoms), or a combination thereof. These groups may further have substituents. R 5 When multiple R exist, multiple R 5 They can be the same or different. The adjacent R bonds to the benzene ring... 5 They can bond with each other to form a ring fused with the benzene ring.

[0040] c is an integer from 0 to 5.

[0041] Where c is 0, R 6 and R 7 [Not simultaneously unsubstituted phenyl]

[0042] [2] The composition for organic electroluminescent elements according to [1], wherein Z in the above formula (1) 1 It is a direct bond.

[0043] [3] The composition for organic electroluminescent elements according to [1], wherein the compound represented by formula (1) above is the compound represented by formula (1-1) below.

[0044]

[0045] In equation (1-1),

[0046] 3 X 2 It can represent either C or N.

[0047] Z 2 This indicates an aromatic linker group that is directly bonded or has a p+1 valence.

[0048] Z 3 This indicates an aromatic linker group that is directly bonded or has a q+1 valence.

[0049] p and q are integers from 1 to 10.

[0050] R 1 R 2 , a, b, n, ring A, L 1, l and R in equation (1) 1 R 2 , a, b, n, ring A, L 1 [The meanings of 'l' and 'l' are the same]

[0051] [4] The composition for organic electroluminescent elements according to [1] or [2], wherein the compound shown in formula (1) above is the compound shown in formula (1-2).

[0052]

[0053] In equation (1-2), R 1 a, m, n, ring A, Z 1 L 1 , l and R in equation (1) 1 a, m, n, ring A, Z 1 L 1 The characters 、 and l have the same meaning.

[0054] R 15 ~R 17 [For substituents]

[0055] [5] The composition for an organic electroluminescent element according to any one of [1] to [4], wherein l in the above formula (1) is 3.

[0056] [6] The composition for an organic electroluminescent element according to any one of [1] to [5], wherein the polymeric compound having a repeating unit comprising the structure shown in formula (2) above comprises a repeating unit shown in formula (2-1) below.

[0057]

[0058] In equation (2-1), Ar 21 ~Ar 23 Each can independently represent a divalent (hetero)aryl group with 3 to 30 carbon atoms that may have substituents.

[0059] Ar 24 Ar 25 Each can independently represent a (hetero)aryl group with 3 to 30 carbon atoms that may have substituents.

[0060] r represents an integer from 0 to 2.

[0061] [7] The composition for an organic electroluminescent element according to any one of [1] to [6], wherein, in the compound shown in formula (3) above, [phenylene-(R 5 )c]、R 6 and R 7These three parts are not the same structure. When a part has substituents, it also includes those substituents.

[0062] [8] The composition for an organic electroluminescent element according to any one of [1] to [7], wherein R in the compound shown in formula (3) above 5 ~R 7 Each of the termini independently contains phenyl, naphthyl, fluorenyl, carbazolyl, indolocarbazolyl, indocarbazolyl, or indofluorenyl.

[0063] [9] A method for manufacturing an organic electroluminescent element, comprising a step of forming a light-emitting layer by using the organic electroluminescent element composition described in any one of [1] to [8] and by a wet film deposition method.

[0064]

[10] An organic electroluminescent element having a light-emitting layer formed using any one of the organic electroluminescent element compositions described in any one of [1] to [8].

[0065]

[11] A display device having the organic electroluminescent element described in

[10] .

[0066]

[12] A lighting device having the organic electroluminescent element described in

[10] .

[0067] According to the present invention, an organic electroluminescent element with lower driving voltage, higher luminous efficiency and longer driving lifetime compared with the past can be provided by wet film deposition method. Attached Figure Description

[0068] Figure 1 This is a cross-sectional view schematically illustrating an example of the structure of the organic electroluminescent element of the present invention. Detailed Implementation

[0069] The embodiments of the present invention will now be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within its scope.

[0070] In this specification, (hetero)aryl, (hetero)aryloxy, and (hetero)aryl refer to aralkyl, aryloxy, and aryl groups that may contain heteroatoms, respectively. "May contain heteroatoms" means that one or more carbon atoms in the main skeleton forming the aryl, aralkyl, or aryloxy group are replaced with heteroatoms. Examples of heteroatoms include nitrogen, oxygen, sulfur, phosphorus, and silicon atoms. From a durability point of view, nitrogen atoms are preferred. The same applies to (hetero)arylene groups.

[0071] In this specification, "aromatic linking group" refers not only to aromatic hydrocarbon linking groups, i.e., linking groups with aromatic hydrocarbon rings, but also to aromatic linking groups in a broader sense, including heteroaromatic linking groups, i.e., linking groups with heteroaromatic rings.

[0072] [Luminescent dopant]

[0073] The composition for organic electroluminescent devices of the present invention comprises a compound represented by the following formula (1) as a light-emitting dopant.

[0074]

[0075] In equation (1), R 1 R 2 Each group is independently any one of the following: alkyl (1-20 carbon atoms), (hetero)arylalkyl (7-40 carbon atoms), alkoxy (1-20 carbon atoms), (hetero)aryloxy (3-20 carbon atoms), alkylsilyl (1-20 carbon atoms), arylsilyl (6-20 carbon atoms), alkylcarbonyl (2-20 carbon atoms), arylcarbonyl (7-20 carbon atoms), alkylamino (1-20 carbon atoms), arylamino (6-20 carbon atoms), and (hetero)aryl (3-30 carbon atoms), or a combination thereof. These groups may further have substituents. R 1 R 2 When multiple R exist, multiple R 1 R 2 They can be the same or different. The adjacent R bonds to the benzene ring... 1 or R 2 They can bond with each other to form a ring fused with the benzene ring.

[0076] a is an integer from 0 to 4. is an integer from 0 to 3.

[0077] m is an integer from 1 to 20.

[0078] n is an integer between 0 and 2.

[0079] Ring A can be a pyridine ring, pyrazine ring, pyrimidine ring, or imidazole ring. Any one of the following: azole ring, thiazole ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azirbenzanthroline ring, or carboline ring.

[0080] Ring A may have substituents. These substituents are any one of the following: fluorine atom, chlorine atom, bromine atom, alkyl group with 1 to 20 carbon atoms, (hetero)arylalkyl group with 7 to 40 carbon atoms, alkoxy group with 1 to 20 carbon atoms, (hetero)aryloxy group with 3 to 20 carbon atoms, alkylsilyl group with 1 to 20 carbon atoms, arylsilyl group with 6 to 20 carbon atoms, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 2 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, and (hetero)aryl group with 3 to 20 carbon atoms, or combinations thereof. Adjacent substituents bonded to ring A may bond to each other to form a ring fused with ring A.

[0081] Z 1 This indicates an aromatic linking group that is directly bonded or has an m+1 valence.

[0082] L 1 [This represents the auxiliary ligand, where l is an integer from 1 to 3. When multiple auxiliary ligands exist, they can be different or the same.]

[0083] In equation (1), from the perspective of durability, R 1 R 2 Each of the following is preferably an alkyl group having 1 to 20 carbon atoms, a heteroaryl group having 7 to 40 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a heteroaryl group having 3 to 30 carbon atoms; more preferably an alkyl group having 1 to 20 carbon atoms, a heteroaryl group having 7 to 40 carbon atoms, or a heteroaryl group having 3 to 20 carbon atoms.

[0084] Two adjacent R 2 They can be connected to form a ring.

[0085] From the perspective of ease of manufacture, a is preferably 0; from the perspective of improving solubility, a is preferably 1 or 2; and more preferably 1.

[0086] From the perspective of ease of manufacture, b is preferably 0; from the perspective of improving durability and solubility, b is preferably 1 or 2; and more preferably 1.

[0087] Two adjacent R 2 When the elements are interconnected to form a ring, b is preferably 2 or 3.

[0088] To improve the solubility of the phenyl group with a tert-butyl terminal in organic solvents, m is preferably 2 or more. The phenyl group with a tert-butyl terminal has minimal involvement in charge transport or luminescence; therefore, if there is too much of it, there are concerns about increased driving voltage or decreased luminescence efficiency. Therefore, m is preferably 8 or less, and more preferably 4 or less.

[0089] From the perspective of having both solubility and low driving voltage and high luminous efficiency, the compound shown in formula (1) preferably has 4 or more, particularly 6 or more and 48 or less, particularly 24 or less, terminal tert-butyl groups as a whole.

[0090] From the perspective of ease of manufacture, n is preferably 0 or 1. From the perspective of minimizing concerns about increased driving voltage, n is preferably 0. From the perspective of improving solubility, n is preferably 1 or 2.

[0091] From a durability perspective, ring A is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring.

[0092] From the perspectives of durability and improved solubility, the hydrogen atom on ring A is preferably replaced by an alkyl group with 1 to 20 carbon atoms, a heteroaryl group with 7 to 40 carbon atoms, or a heteroaryl group with 3 to 20 carbon atoms.

[0093] From the perspective of ease of manufacture, the hydrogen atoms on ring A are preferably not substituted.

[0094] From the perspective that excitons are easily generated when used in organic electroluminescent elements, thus improving luminous efficiency, the hydrogen atom on ring A is preferably replaced by a phenyl or naphthyl group that can have substituents.

[0095] Ring A forms a fused ring by bonding with substituents on ring A, thereby forming quinoline, isoquinoline, quinazoline, quinoxaline, azirmonanene, or carbline rings. When these rings are formed, the emission wavelength increases, making them useful for applications involving red emission. From the perspectives of durability and exhibiting red emission, ring A preferably forms a quinoline, isoquinoline, or quinazoline ring.

[0096] From the perspective of ease of manufacturing, Z 1 Direct bonding is preferred.

[0097] From the perspective of minimizing concerns about increased drive voltage, Z 1 Preferably, it is an aromatic linking group with an m+1 valence.

[0098] When m is 1, from a durability perspective, Z 1 Preferably, it is phenylene, biphenylene, terphenylene, or fluorenediyl, with p-phenylene being particularly preferred.

[0099] When m is 2 or higher, from a durability perspective, Z 1 Preferably, it contains a benzene ring with bonding positions at the 1, 3, and 5 positions or a triazine ring with bonding positions at the 2, 4, and 6 positions.

[0100] Z 1Preferably, it contains a trivalent group as shown in formula (1-2A) or (1-2B) below.

[0101]

[0102] The group represented by formula (1-2A) or formula (1-2B) is further preferably bonded to a benzene ring or ring A bonded to iridium.

[0103] At this time, the compound represented by formula (1) is preferably the compound represented by formula (1-1) below.

[0104]

[0105] In equation (1-1),

[0106] 3 X 2 It can represent either C or N.

[0107] Z 2 This indicates an aromatic linker group that is directly bonded or has a p+1 valence.

[0108] Z 3 This indicates an aromatic linker group that is directly bonded or has a q+1 valence.

[0109] p and q are integers from 1 to 10.

[0110] R 1 R 2 , a, b, n, ring A, L 1 , l and R in equation (1) 1 R 2 , a, b, n, ring A, L 1 [The meanings of 'l' and 'l' are the same]

[0111] In the above formula (1-1), from the perspective of ease of manufacture, Z 2 Z 3 Direct bonding is preferred.

[0112] From the perspective of minimizing concerns about increased drive voltage, Z 2 and Z 3 Preferably, the aromatic linking groups have p+1 and q+1 valences. In this case, for example, when p and q are 1, from a durability perspective, Z... 2 and Z 3 Preferably, it is phenylene, biphenylene, terphenylene, or fluorenediyl, with p-phenylene being particularly preferred.

[0113] From a durability perspective, Z is the value of p when it is 2 or higher. 2 Z when q is 2 or higher 3 Preferably, it contains a benzene ring with bonding positions at the 1, 3, and 5 positions, or a triazine ring with bonding positions at the 2, 4, and 6 positions. That is, Z2 and Z 3 Preferably, it contains a trivalent group as shown in formula (1-2A) or (1-2B) below.

[0114]

[0115] L 1 For auxiliary ligands. No particular restrictions, L 1 Preferably, it is a monovalent bidentate ligand, more preferably selected from the ligands shown in the following formulas (1A), (1B), and (1C).

[0116] The dashed lines in equations (1A) to (1C) below represent coordinate bonds.

[0117] l is 1 and there are 2 auxiliary ligands L 1 At that time, the auxiliary ligand L 1 They can be identical or have different structures.

[0118] When l is 3, L does not exist. 1 .

[0119]

[0120] In equations (1A) and (1B) above, R 9 R 10 From the above R 1 R 2 The same applies to selecting the best examples from the same group.

[0121] g is an integer from 0 to 4. h is an integer from 0 to 4. From the perspective of ease of manufacture, g and h are preferably 0, and from the perspective of improving solubility, they are preferably 1 or 2, and more preferably 1.

[0122] Ring B can be a pyridine ring, pyrimidine ring, imidazole ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azirconium-phenanthroline ring, carbline ring, benzothiazole ring, or benzo[a][b][c]. Any of the elements in the azole ring may have substituents.

[0123] From a durability perspective, ring B is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring.

[0124] From the perspectives of durability and improved solubility, the hydrogen atom on ring B is preferably replaced by an alkyl group with 1 to 20 carbon atoms, a heteroaryl group with 7 to 40 carbon atoms, or a heteroaryl group with 3 to 20 carbon atoms.

[0125] From the perspective of ease of manufacture, the hydrogen atoms on ring B are preferably not substituted.

[0126] From the perspective that it is easy to generate excitons when used in organic electroluminescent elements, thus improving luminous efficiency, the hydrogen atom on ring B is preferably replaced by a phenyl or naphthyl group that can have substituents.

[0127] Ring B forms a fused ring by bonding with substituents on ring B, thereby forming quinoline, isoquinoline, quinazoline, quinoxaline, azirbenzenephenanthrene, or carbline rings. When this occurs, excitons are readily generated on the auxiliary dopant, making it preferable from the perspective of improving luminescence efficiency. Specifically, from the perspectives of durability and exhibiting red luminescence, ring B preferably forms a quinoline, isoquinoline, or quinazoline ring.

[0128] In equation (1C), R 11 ~R 13 Each of these can independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms that can be substituted with a fluorine atom, a phenyl group having 1 to 20 carbon atoms that can be substituted with an alkyl group, or a halogen atom. More preferably, R 11 and R 13 It is methyl or tert-butyl, R 12 It consists of hydrogen atoms and alkyl or phenyl groups with 1 to 20 carbon atoms.

[0129] The compound shown in formula (1) is also preferably adjacent to R. 2 Compounds with the following formula (1-2) that bond together to form fluorene rings.

[0130]

[0131] In equation (1-2), R 1 a, m, n, ring A, Z 1 L 1 , l and R in equation (1) 1 a, m, n, ring A, Z 1 L 1 The characters 、 and l have the same meaning.

[0132] R 15 ~R 17 [For substituents]

[0133] As R 15 The above R can be cited as an example. 2 Possible substituents. More preferably R 15 It is an alkyl group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 30 carbon atoms that can be replaced by one or two alkyl groups having 1 to 20 carbon atoms. Here, an aromatic hydrocarbon group having 6 to 30 carbon atoms refers to a group consisting of a monocyclic, bicyclic, or tricyclic fused ring, or multiple monocyclic, bicyclic, or tricyclic fused rings connected together. R 15 Further preferred are alkyl groups having 1 to 20 carbon atoms, and particularly preferred are alkyl groups having 1 to 8 carbon atoms.

[0134] R 16 R 17 For the above R 2 Part of or the above R 2 The substituents that may be present are preferably alkyl groups having 1 to 12 carbon atoms, aromatic hydrocarbon groups having 6 to 20 carbon atoms that can be replaced by one or two alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, or aromatic hydrocarbon groups having 6 to 20 carbon atoms that can be replaced by one or two alkoxy groups having 1 to 12 carbon atoms. Here, aromatic hydrocarbon groups having 6 to 20 carbon atoms refer to groups formed by connecting multiple monocyclic, bicyclic, or tricyclic fused rings. R 16 R 17 Further preferred are alkyl groups, each independently comprising 1 to 8 carbon atoms, or aromatic hydrocarbon groups comprising 6 or 12 carbon atoms that can be substituted by one or two alkyl groups comprising 1 to 8 carbon atoms. Particularly preferred are alkyl groups comprising 1 to 8 carbon atoms, or aromatic hydrocarbon groups comprising 6 carbon atoms that can be substituted by one or two alkyl groups comprising 1 to 8 carbon atoms. Here, the aromatic hydrocarbon structure comprising 6 carbon atoms is a benzene structure, and the aromatic hydrocarbon structure comprising 12 carbon atoms is a biphenyl structure.

[0135] The following are preferred examples of the light-emitting dopant, i.e., the compound represented by formula (1), contained in the composition for the organic electroluminescent element of the present invention. The present invention is not limited to these examples.

[0136]

[0137]

[0138]

[0139] [Polymer compounds]

[0140] The composition for organic electroluminescent elements of the present invention comprises a polymer compound having repeating units (hereinafter sometimes referred to as “repeating unit (2)”) having a structure represented by the following formula (2).

[0141]

[0142] In equation (2), R 3 R 4Each group is independently any one of the following: alkyl with 1 to 20 carbon atoms, (hetero)arylalkyl with 7 to 40 carbon atoms, alkoxy with 1 to 20 carbon atoms, (hetero)aryloxy with 3 to 20 carbon atoms, alkylsilyl with 1 to 20 carbon atoms, arylsilyl with 6 to 20 carbon atoms, alkylcarbonyl with 2 to 20 carbon atoms, arylcarbonyl with 7 to 20 carbon atoms, alkylamino with 1 to 20 carbon atoms, arylamino with 6 to 20 carbon atoms, and (hetero)aryl with 3 to 30 carbon atoms, or a combination thereof. These groups may further have substituents.

[0143] In equation (2), from the perspective of solubility, R 3 R 4 Each is independently preferred to be an alkyl group having 1 to 20 carbon atoms or a (hetero)aryl group having 7 to 40 carbon atoms. From the perspective of heat resistance, R... 3 R 4 Each is preferably a (hetero)aryl group with 3 to 30 carbon atoms.

[0144] From the perspective of improving charge transport, the polymer compound contained in the organic electroluminescent element composition of the present invention preferably includes, in addition to the repeating unit (2), a repeating unit having the structure shown in the following formula (2-1) (hereinafter sometimes referred to as "repeating unit (2-1)"). In this case, the repeating unit (2) may also be included in the repeating unit (2-1).

[0145]

[0146] In equation (2-1), Ar 21 ~Ar 23 Each can independently represent a divalent (hetero)aryl group with 3 to 30 carbon atoms that may have substituents.

[0147] Ar 24 Ar 25 Each can independently represent a (hetero)aryl group with 3 to 30 carbon atoms that may have substituents.

[0148] r represents an integer from 0 to 2.

[0149] From a durability perspective, Ar 21 ~Ar 23 Each group is preferably a divalent group with 30 or fewer carbon atoms, formed independently of phenylene, biphenylene, terphenylene, fluorenediyl, or any combination of these groups, and is particularly preferred to be p-phenylene or biphenylene. These groups may have substituents.

[0150] When equation (2-1) includes the structure shown in equation (2), Ar 21 Ar22 Or when r is 1 or more, it is selected from at least one Ar 23 At least one of them is a fluorene group, as shown in formula (2), which may have a substituent at the 9,9' position.

[0151] From a durability perspective, Ar 24 Ar 25 Each group is preferably phenyl, biphenyl, terphenyl, or fluorenyl, with phenyl or fluorenyl being particularly preferred. These groups may have substituents.

[0152] The polymer compound contained in the organic electroluminescent element composition of the present invention may contain only one repeating unit (2) or two or more. Alternatively, it may contain only one repeating unit (2-1) or two or more.

[0153] The weight-average molecular weight (Mw) of the polymer compound contained in the organic electroluminescent element composition of the present invention is generally 2,000,000 or less, preferably 500,000 or less, more preferably 100,000 or less, even more preferably 50,000 or less, generally 2,500 or more, preferably 5,000 or more, more preferably 10,000 or more, even more preferably 20,000 or more.

[0154] If the weight-average molecular weight is below the upper limit mentioned above, the polymer exhibits excellent solubility in solvents and excellent film-forming properties. If the weight-average molecular weight is above the lower limit mentioned above, the polymer compound has high glass transition temperature, melting point, and vaporization temperature, and excellent heat resistance.

[0155] The number average molecular weight (Mn) of the polymer compound contained in the organic electroluminescent element composition of the present invention is generally 1,000,000 or less, preferably 250,000 or less, more preferably 50,000 or less, even more preferably 25,000 or less, generally 2,000 or more, preferably 4,000 or more, more preferably 8,000 or more, and even more preferably 15,000 or more.

[0156] The dispersion (Mw / Mn) of the polymer compound contained in the composition for the organic electroluminescent element of the present invention is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. A smaller dispersion value is better; therefore, the lower limit is ideally 1. If the dispersion of the polymer compound is below the above-mentioned upper limit, it is easy to purify and exhibits good solubility in solvents and good charge transport ability.

[0157] Typically, the weight-average molecular weight of polymers is determined by size exclusion chromatography (SEC). In SEC, higher molecular weight components require shorter elution times, while lower molecular weight components require longer elution times. A calibration curve is calculated using the elution time of polystyrene (a standard sample) with a known molecular weight. The elution time of the sample is then converted to molecular weight, thus calculating the weight-average molecular weight. The number-average molecular weight is calculated similarly.

[0158] The method for manufacturing the polymer compound contained in the composition for the organic electroluminescent element of the present invention is not particularly limited, and any polymer compound having repeating units (2) can be obtained. For example, it can be manufactured by polymerization methods based on the Suzuki reaction, polymerization methods based on the Grignard reaction, polymerization methods based on the Yamamoto reaction, polymerization methods based on the Ullmann reaction, polymerization methods based on the Buchwald-Hartwig reaction, etc.

[0159] The following examples show preferred embodiments of repeating units and combinations thereof in the organic electroluminescent element compositions of the present invention, which contain repeating units (2) of polymeric compounds. The present invention is not limited to these examples.

[0160]

[0161] [charge transport materials]

[0162] The composition for organic electroluminescent elements of the present invention comprises a compound represented by the following formula (3) as a charge transport material.

[0163]

[0164] In formula (3), X 1 It represents C or N.

[0165] R 5 ~R 7 Each group is independently any one of the following: alkyl (1-20 carbon atoms), (hetero)arylalkyl (7-40 carbon atoms), alkoxy (1-20 carbon atoms), (hetero)aryloxy (3-20 carbon atoms), alkylsilyl (1-20 carbon atoms), arylsilyl (6-20 carbon atoms), alkylcarbonyl (2-20 carbon atoms), arylcarbonyl (7-20 carbon atoms), alkylamino (1-20 carbon atoms), arylamino (6-20 carbon atoms), and (hetero)aryl (3-30 carbon atoms), or a combination thereof. These groups may further have substituents. R 5 When multiple R exist, multiple R 5They can be the same or different. The adjacent R bonds to the benzene ring... 5 They can bond with each other to form a ring fused with the benzene ring.

[0166] c is an integer from 0 to 5.

[0167] Where c is 0, R 6 and R 7 [Not simultaneously unsubstituted phenyl]

[0168] In equation (3), from the perspective of durability, R 5 ~R 7 Each of the following is preferably an alkyl group having 1 to 20 carbon atoms, a heteroaryl group having 7 to 40 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a heteroaryl group having 3 to 30 carbon atoms; more preferably an alkyl group having 1 to 20 carbon atoms, a heteroaryl group having 7 to 40 carbon atoms, or a heteroaryl group having 3 to 20 carbon atoms; and even more preferably an aryl group having 6 to 20 carbon atoms.

[0169] From the perspective of charge transport, R 5 ~R 7 Each of the components is preferably a (hetero)aryl group having 3 to 20 carbon atoms. The (hetero)aryl group having 3 to 20 carbon atoms includes monocyclic or fused-ring aryl groups, monocyclic or fused-ring heteroaryl groups, structures formed by connecting multiple monocyclic or fused-ring aryl groups, structures formed by connecting multiple monocyclic or fused-ring heteroaryl groups, and structures formed by arbitrarily connecting multiple monocyclic or fused-ring aryl groups or monocyclic or fused-ring heteroaryl groups. Further preferred is R. 5 ~R 7 Each group is independently selected from phenyl, naphthyl, fluorenyl, carbazole, indolocarbazole, indobenzocarbazole, indobenzofluorenyl, or a group consisting of 3 to 20 carbon atoms formed by arbitrarily connecting multiple groups selected from phenyl, naphthyl, fluorenyl, and carbazole. Indobenzocarbazole, indobenzocarbazole, indobenzofluorenyl, phenyl, or groups formed by connecting two or three phenyl groups are particularly preferred. These groups may further have substituents.

[0170] From the perspectives of charge transport, luminous efficiency, and driving lifetime, R 5 ~R 7 Each of the terminals preferably contains phenyl, naphthyl, fluorenyl, carbazole, indolocarbazole, indoxocarbazole, or indoxofluorenyl. When these groups are present, the following scheme (i) is preferred, the following scheme (ii) is more preferred, and the following scheme (iii) is even more preferred.

[0171] (i) One or more R when c is 1 or more 5 R 6 and R 7In the presence of at least one compound, at least one compound having a carbazoyl group, an indolocarbazoyl group, an indocarbazoyl group, or an indofluorenyl group at the terminal.

[0172] (ii) One or more R when c is 1 or more 5 R 6 and R 7 In this group, only one or two of them contain naphthyl, fluorenyl, carbazolyl, indolocarbazolyl, indocarbazolyl, or indofluorenyl at the terminal.

[0173] (iii) One or more R when c is 1 or more 5 R 6 and R 7 In this group, only one or two of them contain a naphthyl, fluorenyl, or carbazolyl group at the end, or only one of them contains an indolocarbazolyl, indocarbazolyl, or indofluorenyl group.

[0174] The R mentioned here 5 ~R 7 The end can be R 5 ~R 7 The substituents it contains.

[0175] These structures can further have substituents.

[0176] As an example of these end structures, the structure shown in the figure below can be cited.

[0177]

[0178] In the above structure, * represents the bonding position, Ar 20 R represents an aromatic hydrocarbon group with 6 to 20 carbon atoms. 14 [This indicates substituents; these structures can further have substituents.]

[0179] These structures can have substituents and R 5 ~R 7 The same applies to the substituents that can be present.

[0180] Ar 20 Preferably, it is an aromatic hydrocarbon group with 6 to 20 carbon atoms, more preferably phenyl or biphenyl, and even more preferably phenyl.

[0181] With 2 R 14 In the structure, there are 2 R 14 They can be the same or different. R 14Preferably, it is an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aroxy group having 6 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms that can be substituted by an alkyl group having 1 to 8 carbon atoms, or a heteroaryl group having 3 to 30 carbon atoms that can be substituted by an alkyl group having 1 to 8 carbon atoms, more preferably, it is an alkyl group having 1 to 2 carbon atoms. The alkyl group having 0 carbon atoms, the aralkyl group having 7 to 40 carbon atoms, the alkoxy group having 1 to 20 carbon atoms, the aroxy group having 6 to 20 carbon atoms, or the aryl group having 6 to 30 carbon atoms that can be substituted by the alkyl group having 1 to 8 carbon atoms, more preferably the alkyl group having 1 to 8 carbon atoms, the aralkyl group having 7 to 20 carbon atoms, the alkoxy group having 1 to 8 carbon atoms, the aroxy group having 6 to 14 carbon atoms, or the aryl group having 6 to 14 carbon atoms that can be substituted by the alkyl group having 1 to 8 carbon atoms.

[0182] From the viewpoint of improving solubility and amorphity in solvents, one or more R values ​​with c being 1 or higher are preferred. 5 R 6 and R 7 At least one of them has 1,2-phenylene or 1,3-phenylene, and moreover, from the perspective of ease of synthesis, at least one of them preferably contains 1,3-phenylene.

[0183] From a durability perspective, c is preferably an integer between 0 and 2.

[0184] In the compound shown in formula (3), R will be present. 5 When the benzene ring is represented by "Bz", Bz-(R) 5 c, R 6 and R 7 These three partial structures can be three identical structures, one different structure, or three completely different structures. When a partial structure has substituents, those substituents are also included. Preferably, there is only one different structure or three completely different structures; more preferably, there are three completely different structures. The reasons for this are explained later.

[0185] The compound represented by formula (3) included as a charge transport material is a low molecular weight compound, preferably with a molecular weight of 400 or more, more preferably 450 or more, even more preferably 500 or more, particularly preferably 600 or more, preferably 3000 or less, more preferably 2000 or less, even more preferably 1500 or less, and even more preferably 1200 or less.

[0186] Hereinafter, preferred examples of compounds of formula (3) included as charge transport materials in the organic electroluminescent element compositions of the present invention, other than those shown in the embodiments, are presented. The present invention is not limited to these.

[0187]

[0188] [Specific examples of each structure]

[0189] The following examples illustrate R as a component in equations (1), (1-1), (1-2), (1A) to (1C), (2), (2-1), and (3). 1 ~R 7 R 9 ~R 13 Ar 21 ~Ar 25 Specific examples and preferred structures of various structures of ring A and ring B.

[0190] The alkyl group having 1 to 20 carbon atoms can be any of straight-chain, branched, or cyclic alkyl groups. Examples include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, isopropyl, isobutyl, isopentyl, tert-butyl, and cyclohexyl. Preferably, straight-chain alkyl groups having 1 to 8 carbon atoms, such as methyl, ethyl, n-butyl, n-hexyl, and n-octyl, are preferred.

[0191] The aforementioned heteroaryl groups with 7 to 40 carbon atoms refer to groups in which a portion of the hydrogen atoms constituting a straight-chain, branched, or cyclic alkyl group is replaced by a heteroaryl group. Specifically, examples include 2-phenyl-1-ethyl, cumyl, 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, 7-phenyl-1-heptyl, and tetrahydronaphthyl. Among these, 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, and 7-phenyl-1-heptyl are preferred.

[0192] Specific examples of alkoxy groups with 1 to 20 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, hexoxy, cyclohexoxy, and octadecoxy. Among these, hexoxy is preferred.

[0193] Specific examples of (hetero)aryloxy groups with 3 to 20 carbon atoms include phenoxy and 4-methylphenyloxy. Among them, phenoxy is preferred.

[0194] Specific examples of alkylsilyl groups having 1 to 20 carbon atoms include trimethylsilyl, triethylsilyl, triisopropylsilyl, dimethylphenyl, tert-butyldimethylsilyl, and tert-butyldiphenylsilyl. Among these, triisopropylsilyl, tert-butyldimethylsilyl, and tert-butyldiphenylsilyl are preferred.

[0195] Specific examples of arylsilyl compounds with 6 to 20 carbon atoms include diphenylpyridinylsilyl and triphenylsilyl. Among them, triphenylsilyl is preferred.

[0196] Specific examples of alkyl carbonyl groups with 2 to 20 carbon atoms include acetyl, propionyl, neopentyl, hexanoyl, decyl, and cyclohexyl carbonyl. Among these, acetyl and neopentyl are preferred.

[0197] Specific examples of aryl carbonyl groups with 7 to 20 carbon atoms include benzoyl, naphthoyl, and anthraceneyl. Among these, benzoyl is preferred.

[0198] Specific examples of alkylamino groups having 1 to 20 carbon atoms include methylamino, dimethylamino, diethylamino, ethylmethylamino, dihexylamino, dioctylamino, and dicyclohexylamino. Among these, dimethylamino and dicyclohexylamino are preferred.

[0199] Specific examples of arylamino groups with 6 to 20 carbon atoms include phenylamino, diphenylamino, di(4-tolyl)amino, and di(2,6-dimethylphenyl)amino. Among these, diphenylamino and di(4-tolyl)amino are preferred.

[0200] The aforementioned (hetero)aryl groups with 3 to 30 carbon atoms refer to aromatic hydrocarbon groups and aromatic heterocyclic groups with one free valence, or linked aromatic hydrocarbon groups formed by connecting multiple aromatic hydrocarbon groups, linked aromatic heterocyclic groups formed by connecting multiple aromatic heterocyclic groups, or groups formed by arbitrarily connecting one or more aromatic hydrocarbon groups with one or more aromatic heterocyclic groups.

[0201] Specific examples of (hetero)aryl groups with 3 to 30 carbon atoms include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetraphenylene rings, pyrene rings, and benzo[a]pyrene rings, all having one free valence atom. Rings, triphenylene rings, fluoranthene rings, furan rings, benzofuran rings, dibenzofuran rings, thiophene rings, benzothiophene rings, dibenzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, Diazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrazole ring, thienopyrazole ring, thienopyrazole ring, furanopyrazole ring, furanofuran ring, thienofuran ring, benzyl isocyanate The groups include azole rings, benzisothiazolium rings, benzimazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, borazolinium rings, quinoxaline rings, piridine rings, quinazoline rings, quinazolinone rings, and azurite rings. Examples of linked aromatic hydrocarbon groups, such as biphenyl and terphenyl, are also included.

[0202] From a durability point of view, among the aforementioned heteroaryl groups, aryl groups having one free valence ring are preferred, including benzene ring, naphthyl ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, pyridine ring, pyrimidine ring, and triazine ring. More preferably, aryl groups having one free valence ring and being substituted by an alkyl group having 1 to 8 carbon atoms, such as benzene ring, naphthyl ring, or phenanthrene ring, or having 6 to 18 carbon atoms; or pyridine rings having one free valence ring and being substituted by an alkyl group having 1 to 4 carbon atoms. Even more preferably, aryl groups having one free valence ring and being substituted by an alkyl group having 1 to 8 carbon atoms, such as benzene ring, naphthyl ring, or phenanthrene ring, or having 6 to 18 carbon atoms.

[0203] The divalent (hetero)aryl groups with 3 to 30 carbon atoms described above, except that they have two free valence atoms, are the same as the examples of (hetero)aryl groups with 3 to 30 carbon atoms described above, and the preferred examples are also the same.

[0204] As combinations of these substituents, for example, combinations of aryl and alkyl, aryl and aralkyl, or aryl and alkyl, aralkyl combinations can be used. As combinations of aryl and aralkyl, for example, combinations of phenyl, biphenyl, or terphenyl with 5-phenyl-1-pentyl or 6-phenyl-1-hexyl can be used.

[0205] [Specific examples of substituents]

[0206] In the following equations (1), (1-1), (1-2), (1A) to (1C), (2), (2-1), and (3), R... 1 ~R 7 R 9 ~R 13 Ar 21 ~Ar 25 The substituents that ring A and ring B may have are alkyl groups with 1 to 20 carbon atoms, (hetero)arylalkyl groups with 7 to 40 carbon atoms, alkoxy groups with 1 to 20 carbon atoms, (hetero)aryloxy groups with 3 to 20 carbon atoms, alkylsilyl groups with 1 to 20 carbon atoms, arylsilyl groups with 6 to 20 carbon atoms, alkylcarbonyl groups with 2 to 20 carbon atoms, arylcarbonyl groups with 7 to 20 carbon atoms, alkylamino groups with 1 to 20 carbon atoms, arylamino groups with 6 to 20 carbon atoms, (hetero)aryl groups with 3 to 30 carbon atoms, or crosslinking groups. Specific examples of various substituents are listed.

[0207] The alkyl group having 1 to 20 carbon atoms can be any of straight-chain, branched, or cyclic alkyl groups. Examples include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, isopropyl, isobutyl, isopentyl, tert-butyl, and cyclohexyl. Preferably, straight-chain alkyl groups having 1 to 8 carbon atoms, such as methyl, ethyl, n-butyl, n-hexyl, and n-octyl, are preferred.

[0208] The aforementioned heteroaryl groups with 7 to 40 carbon atoms refer to groups in which a portion of the hydrogen atoms constituting a straight-chain, branched, or cyclic alkyl group is replaced by a heteroaryl group. Specifically, examples include 2-phenyl-1-ethyl, cumyl, 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, 7-phenyl-1-heptyl, and tetrahydronaphthyl. Among these, 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, and 7-phenyl-1-heptyl are preferred.

[0209] Specific examples of alkoxy groups with 1 to 20 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, hexoxy, cyclohexoxy, and octadecoxy. Among these, hexoxy is preferred.

[0210] Specific examples of (hetero)aryloxy groups with 3 to 20 carbon atoms include phenoxy and 4-methylphenyloxy. Among them, phenoxy is preferred.

[0211] Specific examples of alkylsilyl groups having 1 to 20 carbon atoms include trimethylsilyl, triethylsilyl, triisopropylsilyl, dimethylphenyl, tert-butyldimethylsilyl, and tert-butyldiphenylsilyl. Among these, triisopropylsilyl, tert-butyldimethylsilyl, and tert-butyldiphenylsilyl are preferred.

[0212] Specific examples of arylsilyl compounds with 6 to 20 carbon atoms include diphenylpyridinylsilyl and triphenylsilyl. Among them, triphenylsilyl is preferred.

[0213] Specific examples of alkyl carbonyl groups with 2 to 20 carbon atoms include acetyl, propionyl, neopentyl, hexanoyl, decyl, and cyclohexyl carbonyl. Among these, acetyl and neopentyl are preferred.

[0214] Specific examples of aryl carbonyl groups with 7 to 20 carbon atoms include benzoyl, naphthoyl, and anthraceneyl. Among these, benzoyl is preferred.

[0215] Specific examples of alkylamino groups having 1 to 20 carbon atoms include methylamino, dimethylamino, diethylamino, ethylmethylamino, dihexylamino, dioctylamino, and dicyclohexylamino. Among these, dimethylamino and dicyclohexylamino are preferred.

[0216] Specific examples of arylamino groups with 6 to 20 carbon atoms include phenylamino, diphenylamino, di(4-tolyl)amino, and di(2,6-dimethylphenyl)amino. Among these, diphenylamino and di(4-tolyl)amino are preferred.

[0217] The aforementioned (hetero)aryl groups with 3 to 30 carbon atoms refer to aromatic hydrocarbon groups and aromatic heterocyclic groups with one free valence, or linked aromatic hydrocarbon groups formed by connecting multiple aromatic hydrocarbon groups, linked aromatic heterocyclic groups formed by connecting multiple aromatic heterocyclic groups, or groups formed by arbitrarily connecting one or more aromatic hydrocarbon groups with one or more aromatic heterocyclic groups.

[0218] Specific examples of (hetero)aryl groups with 3 to 30 carbon atoms include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetraphenylene rings, pyrene rings, and benzo[a]pyrene rings, all having one free valence atom. Rings, triphenylene rings, fluoranthene rings, furan rings, benzofuran rings, dibenzofuran rings, thiophene rings, benzothiophene rings, dibenzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, Diazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrazole ring, thienopyrazole ring, thienopyrazole ring, furanopyrazole ring, furanofuran ring, thienofuran ring, benzyl isocyanate The aromatic hydrocarbon group can be composed of azole rings, benzisothiazolium rings, benzimazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, borazolinium rings, quinoxaline rings, piridine rings, quinazoline rings, quinazolineone rings, azulene rings, and other similar groups. Examples of linked aromatic hydrocarbon groups, such as biphenyl and terphenyl, are also included.

[0219] From a durability point of view, among the aforementioned heteroaryl groups, aryl groups having one free valence ring are preferred, including benzene ring, naphthyl ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, pyridine ring, pyrimidine ring, and triazine ring. More preferably, aryl groups having one free valence ring and being substituted by an alkyl group having 1 to 8 carbon atoms, such as benzene ring, naphthyl ring, or phenanthrene ring, or having 6 to 18 carbon atoms; or pyridine rings having one free valence ring and being substituted by an alkyl group having 1 to 4 carbon atoms. Even more preferably, aryl groups having one free valence ring and being substituted by an alkyl group having 1 to 8 carbon atoms, such as benzene ring, naphthyl ring, or phenanthrene ring, or having 6 to 18 carbon atoms.

[0220] As combinations of these substituents, for example, combinations of aryl and alkyl, aryl and aralkyl, or aryl and alkyl, aralkyl combinations can be used. As combinations of aryl and aralkyl, for example, combinations of phenyl, biphenyl, or terphenyl with 5-phenyl-1-pentyl or 6-phenyl-1-hexyl can be used.

[0221] Among these substituents, alkyl groups with 1 to 20 carbon atoms, aralkyl groups with 7 to 40 carbon atoms, alkoxy groups with 1 to 20 carbon atoms, aroxy groups with 3 to 20 carbon atoms, alkylsilyl groups with 1 to 20 carbon atoms, arylsilyl groups with 6 to 20 carbon atoms, arylamino groups with 6 to 20 carbon atoms, and (hetero)aryl groups with 3 to 30 carbon atoms are preferred.

[0222] Further preferred are alkyl groups with 1 to 20 carbon atoms, alkoxy groups with 1 to 20 carbon atoms, alkylsilyl groups with 1 to 20 carbon atoms, arylsilyl groups with 6 to 20 carbon atoms, arylamino groups with 6 to 20 carbon atoms, and (hetero)aryl groups with 3 to 30 carbon atoms.

[0223] Particularly preferred are alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, and (hetero)aryl groups having 3 to 30 carbon atoms.

[0224] The specific structures and preferred carbon numbers of these preferred substituents are described in the specific examples of the substituents above.

[0225] When these substituents further have substituents, the above-described exemplified substituents can be cited as examples of such substituents.

[0226] [The mechanism by which the composition for organic electroluminescent elements of the present invention achieves the effects of the present invention]

[0227] The light-emitting layer of the organic electroluminescent element made using the composition of the present invention comprises a light-emitting dopant of formula (1), a polymer compound having a repeating unit having a structure of formula (2) (a polymer compound having a repeating unit (2)), and a compound of formula (3).

[0228] In the light-emitting layer of the organic electroluminescent element of the present invention, the polymer compound having repeating unit (2) mainly undertakes hole transport. In the case where the repeating unit (2) is included in the repeating unit (2-1), the hole transport is greatly improved due to the presence of the arylamine structure. The compound shown in formula (3) has high electron transport. Therefore, the charge transport in the light-emitting layer is improved, and the voltage is reduced. In addition, it is believed that the charge balance between holes and electrons becomes better, and the luminous efficiency is improved. Here, the light-emitting dopant shown in formula (1) has an alkyl group containing tert-butyl. The tert-butyl group is bulky and therefore becomes a steric hindrance. Therefore, the charge-transporting compound is usually located at a certain distance from the charge-receiving site of the light-emitting dopant, and the charge does not easily move from the charge-transporting compound to the light-emitting dopant. Here, in the present invention, the material undertaking hole transport is mainly a polymer compound, and holes can easily move along the polymer chain, so holes exist in a wider range of locations on the polymer chain. It is believed that in polymer chains containing holes over a wide range, holes can relatively easily migrate to the sites of the luminescent dopant shown in Formula (1), and then migrate from those sites to the luminescent dopant shown in Formula (1). Thus, in the luminescent layer of the organic electroluminescent element of the present invention, it is believed that holes first migrate to the neutral luminescent dopant. It is believed that electrons then migrate from the compound shown in Formula (3) to the luminescent dopant, recombine, and emit light. It is believed that the luminescent dopant shown in Formula (1) has low durability for electrons but high durability for holes, thus extending the lifespan of the element.

[0229] Furthermore, in the compound shown in formula (3) above, [phenylene-(R 5 )c]、R 6 and R 7 Preferably, these three partial structures are not identical, and when a partial structure has substituents, those substituents are also included. More preferably, the three partial structures are distinct from each other. In this invention, such a structure is referred to as an asymmetric structure.

[0230] The compound shown in formula (3) above is further preferably R. 5 ~R 7 Only one or two of the atoms in the membrane contain an asymmetric structure with a naphthyl, fluorenyl, carbazole, indole-carbazole, indene-carbazole, or indene-fluorenyl groups at their ends. By employing such an asymmetric structure, amorphousness is improved, resulting in a uniform and stable film. Furthermore, it facilitates the formation of films that mix uniformly with other materials. Additionally, it is preferred from the viewpoint of improved solubility in solvents and enhanced stability in solution. In particular, the ease of uniform mixing with other materials is especially beneficial when further incorporating polymeric materials as charge transport materials.

[0231] The reason is believed to be that when the organic electroluminescent element composition, which is a mixture of the compound shown in formula (3) and the polymer compound having the repeating unit (2) dissolved in a solvent, is used as a composition for forming a light-emitting layer for wet film formation, the solvent evaporates during drying and the composition for forming the light-emitting layer is being concentrated. Because the compound shown in formula (3) is asymmetric, it is easy to form a film directly in a state where it is uniformly mixed with the polymer chain ring of the polymer compound having the repeating unit (2).

[0232] In particular, where it exists, one or more R 5 R 6 and R 7 When at least one of the components contains a carbazole group, indolocarbazole group, indocarbazole group, or indofluorene group at its terminal, it is considered that since the carbazole group, indolocarbazole group, indocarbazole group, or indofluorene group, although to varying degrees, all possess hole transport capability, they have high affinity for hole-transporting polymers and are easily and uniformly mixed with hole-transporting polymers to form a stable membrane. Among these, the carbazole group is considered to have a moderately small structure, making it easier to mix with polymers, and is therefore preferred.

[0233] Furthermore, it is believed that by using the compound shown in formula (3) above as a charge transport material, which is asymmetric, the luminescence efficiency of the compound shown in formula (1) as a luminescent dopant can be improved. The reasons for this are explained below.

[0234] The luminescent dopant shown in formula (1) has an alkyl group containing a tert-butyl group. Typically, because the tert-butyl group acts as a steric hindrance, the charge transport material exists at a certain distance from the luminescent dopant shown in formula (1). In this invention, since the material responsible for hole transport is primarily a polymer compound, holes exist in a wider range of locations on the polymer chain, making it easier for holes to move to the luminescent dopant shown in formula (1). On the other hand, because the tert-butyl group of the luminescent dopant shown in formula (1) acts as a steric hindrance, low-molecular-weight compounds typically exist at a certain distance from the luminescent dopant, making it difficult for charges to move from the low-molecular-weight compounds to the luminescent dopant. However, when the electron transport material shown in formula (3) of this invention has an asymmetric structure, the distribution of LUMO is skewed, and it is believed that there are locations where electrons can easily move. Therefore, it is believed that electrons can easily move to the luminescent dopant with steric hindrance such as the tert-butyl group, resulting in lower voltage, higher luminescence efficiency, and longer device lifetime.

[0235] In addition, R in the compound shown in formula (3) above 5 ~R 7When at least one of the terminal groups contains a carbazole group, an indolocarbazole group, an indocarbazole group, or an indofluorene group, the compound shown in formula (3) above is considered to readily accept both electrons and holes, thus readily accepting both electrons and holes to form an excited state. In this case, it is believed that the excitation energy moves directly to the luminescent dopant, and even for luminescent dopants with a tert-butyl group as in formula (1), the excitation energy moves efficiently. As a result, the luminescent efficiency is considered to be higher, and the driving lifetime of the device is considered to be longer.

[0236] Furthermore, it is believed that even if the compound shown in formula (3) above is symmetrical, in R 5 ~R 7 When all terminals are carbazole groups, the luminous efficiency is higher and the driving lifetime of the device is longer for the same reason, making it preferred. The carbazole group has a smaller molecular structure, therefore even with R... 5 ~R 7 All the ends have carbazole groups, which have little effect on the stereostructure of the compound shown in formula (3) above, and are therefore preferred.

[0237] The compound represented by formula (3) is symmetrical in that c = 1 and [phenylene-R 5 ]、R 6 and R 7 When all three parts of the structure are identical, and the part of the structure has substituents, those substituents are also included.

[0238] [Synthetic method of the compound shown in formula (1)]

[0239] The compound of formula (1) included as a light-emitting dopant in the organic electroluminescent element composition of the present invention is an iridium coordination compound. The synthesis method of this iridium coordination compound is shown below.

[0240] Ligands of iridium coordination compounds can be synthesized by combinations of known methods. Ligands can be synthesized by known reactions such as the Suzuki-Miyaura coupling reaction of arylboronic acids with haloaryl groups, and the Friedlaender cyclization reaction of 2-formyl or acylaniline groups or ortho-acyl-aminopyridine groups (Chem. Rev. 2009, 109, 2652 or Organic Reactions, 28(2), 37-201).

[0241] <Synthetic methods of iridium coordination compounds>

[0242] Iridium coordination compounds can be synthesized from ligands and iridium chloride hydrate, etc., using a combination of known methods. This will be explained below.

[0243] For ease of understanding, examples of methods for synthesizing iridium coordination compounds include, but are not limited to, the following method using phenylpyridine ligands as an example, crosslinking an iridium dinuclear coordination compound with chlorine as shown in formula [A] (MG Colombo, TCBrunold, T. Riedener, HU Gudel, Inorg. Chem. 1994, 33, 545-550), and the following method using formula [B] to further crosslink a dinuclear coordination compound with chlorine and exchange it with acetylacetone to obtain a mononuclear coordination compound (S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, R. Kwong, I. Tsyba, M. Borz, B. Mui, R. Bau, M. Thompson, Inorg. Chem. 2001, 40, 1704-1711).

[0244] For example, the conditions for a typical reaction as shown in the following formula [A] are as follows.

[0245] As the first stage, chlorinated crosslinked iridium dinuclear coordination compounds are synthesized by reacting a 2-equivalent amount of the first ligand with a 1-equivalent amount of iridium chloride n-hydrate. The solvent is typically a mixture of 2-ethoxyethanol and water, but solvent-free solutions or other solvents may also be used. An excess of the ligand or additives such as bases can be used to promote the reaction. Other crosslinked anionic ligands, such as bromine, can also be used instead of chlorine.

[0246] There are no particular limitations on the reaction temperature, but it is generally preferred to be above 0°C, more preferably above 50°C, more preferably below 250°C, and even more preferably below 150°C. By using a reaction temperature within this range, there is a tendency to achieve high selectivity by allowing the target reaction to proceed without the presence of byproducts and decomposition reactions.

[0247] [A]

[0248]

[0249] In the second stage, a halide ion scavenger, such as silver trifluoromethanesulfonate, is added to contact the second ligand, yielding the target coordination compound. The solvent is typically ethoxyethanol or diethylene glycol dimethyl ether; depending on the type of ligand, solvent-free methods or combinations of solvents may be used. The reaction sometimes proceeds even without a halide ion scavenger, so it may not be necessary. However, adding the scavenger is advantageous for improving reaction yield and selectively synthesizing planar isomers with higher quantum yields. There are no particular restrictions on the reaction temperature, which is typically carried out in the range of 0°C to 250°C.

[0250] The typical reaction conditions shown in the following formula [B] are explained.

[0251] The first-stage binuclear coordination compound can be synthesized in the same manner as formula [A].

[0252] The second stage involves reacting the binuclear coordination compound with at least one equivalent of a 1,3-diketone compound such as acetylacetone and at least one equivalent of sodium carbonate, a basic compound from which the active hydrogen of the 1,3-diketone compound can be extracted, to convert it into a mononuclear coordination compound that coordinates with a 1,3-diketone ligand. Solvents such as ethoxyethanol and dichloromethane, which dissolve the binuclear coordination compound as a starting material, are typically used. When the ligand is in a liquid state, the reaction can also be carried out in a solvent-free environment. There are no particular restrictions on the reaction temperature, which is usually carried out in the range of 0°C to 200°C.

[0253] [B]

[0254]

[0255] The third stage involves the reaction of at least one equivalent of the second ligand. There are no particular restrictions on the type or amount of solvent; the second ligand can be in a solvent-free state if it is liquid at the reaction temperature. The reaction temperature is also not particularly limited, but due to slightly insufficient reactivity, the reaction is mostly carried out at higher temperatures between 100°C and 300°C. Therefore, high-boiling-point solvents such as glycerol are preferred.

[0256] After the final reaction, purification is performed to remove unreacted starting materials, reaction byproducts, and solvent. While conventional purification procedures in organic synthesis chemistry can be applied, normal silica gel column chromatography is primarily used for purification, as described in the aforementioned non-patent literature. The developing solvent can be a single or mixed solution of hexane, heptane, dichloromethane, chloroform, ethyl acetate, toluene, methyl ethyl ketone, or methanol. Purification can be performed multiple times under varying conditions. Other chromatographic techniques (reversed-phase silica gel column chromatography, size exclusion chromatography, paper chromatography), liquid-liquid separation and washing, reprecipitation, recrystallization, powder suspension washing, and vacuum drying can be performed as needed.

[0257] [solvent]

[0258] The composition for organic electroluminescent devices of the present invention contains a solvent.

[0259] The solvent contained in the organic electroluminescent element composition of the present invention is a volatile liquid component used to form a layer containing a light-emitting dopant by wet film deposition.

[0260] The solvent is not particularly limited as long as it is a compound of formula (1) that serves as a solute or a luminescent dopant, a polymeric compound having a repeating unit (2), a compound of formula (3), other luminescent materials that may be contained as required, or a solvent that can readily dissolve a charge-transporting material.

[0261] Preferred solvents include, for example: alkanes such as n-decane, cyclohexane, ethylcyclohexane, decahydronaphthalene, and dicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene (phenylcyclohexane), and tetrahydronaphthalene; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene; and 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethyl anisole, and 2, Aromatic ethers such as 4-dimethyl anisole and diphenyl ether; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; alicyclic ketones such as cyclohexanone, cyclooctanone, and fentanyl; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; aliphatic alcohols such as butanol and hexanol; and aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA). Alkanes and aromatic hydrocarbons are preferred. Cyclohexylbenzene, in particular, exhibits preferred viscosity and boiling point in wet film-forming processes.

[0262] These solvents can be used alone, or in any combination and ratio of two or more.

[0263] The boiling point of the solvent is typically above 80°C, preferably above 100°C, more preferably above 150°C, particularly preferably above 200°C, typically below 270°C, preferably below 250°C, and more preferably below 240°C. If the boiling point is below this range, the film stability may decrease during wet film formation due to solvent evaporation from the composition.

[0264] [composition]

[0265] The organic electroluminescent element composition of the present invention is generally used to form a layer or film by a wet film deposition method, and is particularly preferred for forming a light-emitting layer of an organic electroluminescent element.

[0266] The content of the compound represented by formula (1) as a light-emitting dopant in the composition for organic electroluminescent devices is typically 0.01% by mass or more, preferably 0.1% by mass or more, typically 20% by mass or less, and preferably 10% by mass or less. By keeping the content of the compound represented by formula (1) within this range, when the composition is used for organic electroluminescent devices, there is less movement of excitation energy to adjacent layers (e.g., hole transport layer, hole blocking layer), and in addition, there is less extinction due to the interaction of excitons with each other, thus improving the luminous efficiency.

[0267] The composition for organic electroluminescent elements of the present invention may contain only one compound represented by formula (1), or may contain two or more compounds in combination.

[0268] The content of the polymer compound having repeating unit (2) in the organic electroluminescent element composition of the present invention is generally 0.01% by mass or more, preferably 0.1% by mass or more, generally 20% by mass or less, and preferably 10% by mass or less. By setting the content of the polymer compound within this range, when the composition is used for organic electroluminescent element applications, there is less movement of excitation energy to adjacent layers (e.g., hole transport layer, hole blocking layer), and in addition, there is less extinction due to the interaction of excitons with each other, thus improving luminous efficiency.

[0269] The composition for organic electroluminescent elements of the present invention may contain only one type of polymer compound having repeating unit (2), or may contain two or more types in combination.

[0270] The content of the compound represented by formula (3) in the organic electroluminescent element composition of the present invention is generally 0.005% by mass or more, preferably 0.05% by mass or more, generally 10% by mass or less, and preferably 5% by mass or less. By making the content of the compound represented by formula (3) within this range, when the composition is used for organic electroluminescent element applications, electrons can be efficiently injected from the adjacent cathode-side layer (e.g., hole blocking layer) to the light-emitting layer, thereby reducing the driving voltage.

[0271] The composition for organic electroluminescent elements of the present invention may contain only one compound represented by formula (3), or may contain two or more compounds in combination.

[0272] From the viewpoint of luminous efficiency, the composition for the organic electroluminescent element of the present invention preferably contains 5 to 100 parts by mass, particularly 15 to 60 parts by mass, of the compound shown in formula (1) relative to a total of 100 parts by mass of the polymer compound having repeating unit (2) and the compound shown in formula (3). If too little of the compound shown in formula (1) is used to carry out luminescence, the efficiency decreases; if too much is used, it becomes easy to extinct, and the efficiency decreases.

[0273] From the viewpoint of proper charge balance and improved efficiency, the composition for organic electroluminescent elements of the present invention preferably contains 20 to 98 parts by mass, particularly 50 to 90 parts by mass, of the polymer compound having repeating unit (2) in a total of 100 parts by mass of the polymer compound having repeating unit (2) and the compound shown in formula (3).

[0274] The solvent content of the organic electroluminescent element composition of the present invention is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, particularly preferably 80 parts by mass or more, preferably 99.95 parts by mass or less, more preferably 99.9 parts by mass or less, and particularly preferably 99.8 parts by mass or less.

[0275] As will be described later, the thickness of the light-emitting layer is typically around 3 nm to 200 nm. If the solvent content is above the lower limit mentioned above, the viscosity of the composition will not become too high, and the film-forming workability will be good. On the other hand, if the solvent content is below the upper limit mentioned above, the thickness of the film obtained after removing the solvent can be obtained after film formation, thus there is a tendency for film formation to become easier.

[0276] As described above, the composition for organic electroluminescent elements of the present invention may contain only one solvent or may contain two or more solvents in combination.

[0277] Organic electroluminescent devices

[0278] The organic electroluminescent element of the present invention comprises a light-emitting layer formed by using the organic electroluminescent element composition of the present invention and by a wet film deposition method.

[0279] The organic electroluminescent element of the present invention preferably has at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, and includes a light-emitting layer formed by using the organic electroluminescent element composition of the present invention and by a wet film deposition method as at least one of the organic layers.

[0280] In this invention, wet film formation refers to a method that uses wet film formation methods, such as spin coating, dip coating, mold coating, bar coating, doctor blade coating, roller coating, spray coating, capillary coating, inkjet coating, nozzle printing, screen printing, gravure printing, and flexographic printing, as the film formation method, i.e., the coating method, and then dries the film formed by these methods to form a film.

[0281] Figure 1 This is a schematic diagram showing a cross-section of a preferred structural example for the organic electroluminescent element 10 of the present invention. Figure 1 In the diagram, symbol 1 represents the substrate, symbol 2 represents the anode, symbol 3 represents the hole injection layer, symbol 4 represents the hole transport layer, symbol 5 represents the light-emitting layer, symbol 6 represents the hole blocking layer, symbol 7 represents the electron transport layer, symbol 8 represents the electron injection layer, and symbol 9 represents the cathode.

[0282] The materials used in these structures can be of well-known quality and are not particularly restricted. The following description of representative materials and manufacturing methods for each layer is provided as an example. In the following references to publications or papers, the content may be appropriately adopted and applied to the extent that it is within the common knowledge of those skilled in the art.

[0283] <Substrate 1>

[0284] The substrate 1 serves as the support for the organic electroluminescent element and is typically made of materials such as quartz, glass, metal plates or foils, or plastic films or sheets. Among these, plates made of transparent synthetic resins such as glass, polyester, polymethyl methacrylate, polycarbonate, or polysulfone are preferred. To minimize degradation of the organic electroluminescent element caused by external gases, the substrate 1 is preferably made of a material with high gas barrier properties. In particular, when using a material with low gas barrier properties, such as a substrate made of synthetic resin, it is preferable to provide a dense silicon oxide film or similar material on at least one side of the substrate 1 to improve gas barrier properties.

[0285] <Anode 2>

[0286] Anode 2 is responsible for injecting holes into the light-emitting layer. Anode 2 is typically composed of metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium and / or tin oxides; metal halides such as copper iodide; or conductive polymers such as carbon black, poly(3-methylthiophene), polypyrrole, and polyaniline.

[0287] Anode 2 is typically formed using dry methods such as sputtering or vacuum evaporation. When forming anode 2 using metal particles such as silver, copper iodide, carbon black, conductive metal oxide microparticles, or conductive polymer powders, it can also be formed by dispersing these particles in a suitable binder resin solution and coating them onto a substrate. In the case of conductive polymers, anode 2 can also be formed directly on the substrate through electrolytic polymerization to form a thin film, or by coating the substrate with a conductive polymer (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0288] Anode 2 is typically a single-layer structure, but it can also be made into a multilayer structure as appropriate. When anode 2 is a multilayer structure, different conductive materials can be stacked on the first anode layer.

[0289] The thickness of anode 2 can be determined based on the required transparency and material properties. Especially when high transparency is required, a thickness with a visible light transmittance of 60% or more is preferred, and a thickness with a visible light transmittance of 80% or more is even more preferred. The thickness of anode 2 is typically 5 nm or more, preferably 10 nm or more, typically 1000 nm or less, and preferably 500 nm or less.

[0290] If transparency is not required, the thickness of anode 2 can be any thickness as needed for the required strength, etc. In this case, anode 2 can be the same thickness as substrate 1.

[0291] When forming a film on the surface of anode 2, it is preferable to remove impurities on the anode by performing treatments such as ultraviolet light + ozone, oxygen-oxygen plasma, or argon-oxygen plasma before film formation, and to improve hole injection by adjusting its ionization potential.

[0292] <Cavity Injection Layer 3>

[0293] The layer that performs the function of transporting holes from the anode 2 side to the light-emitting layer 5 side is usually called the hole injection transport layer or hole transport layer. When there are two or more layers performing the function of transporting holes from the anode 2 side to the light-emitting layer 5 side, the layer closer to the anode 2 side is sometimes called the hole injection layer 3. From the perspective of enhancing the function of transporting holes from the anode 2 side to the light-emitting layer 5 side, the hole injection layer 3 is preferred. When using the hole injection layer 3, the hole injection layer 3 is usually formed on the anode 2.

[0294] The thickness of the hole injection layer 3 is typically above 1 nm, preferably above 5 nm, typically below 1000 nm, and preferably below 500 nm.

[0295] The hole injection layer 3 can be formed by vacuum evaporation or wet film deposition. From the perspective of excellent film formation properties, wet film deposition is preferred.

[0296] The hole injection layer 3 preferably contains a hole-transporting compound, more preferably a hole-transporting compound and an electron-accepting compound. Furthermore, it is preferable that the hole injection layer 3 contains a cationic radical compound, and particularly preferably a cationic radical compound and a hole-transporting compound.

[0297] (hole-transporting compounds)

[0298] The composition for forming a hole injection layer typically contains a hole transport compound as the hole injection layer 3.

[0299] In the case of wet film formation, a solvent is usually further included. The composition for forming the hole injection layer preferably has high hole transport properties, enabling efficient transport of injected holes. Therefore, a high hole mobility is preferred, minimizing the generation of impurities that could become traps during manufacturing and use. Furthermore, excellent stability, low ionization potential, and high transparency to visible light are preferred. Particularly when the hole injection layer 3 is in contact with the light-emitting layer 5, a material that does not cause extinction of light emission from the light-emitting layer 5, and a material that does not form excimer complexes with the light-emitting layer 5, thereby reducing luminescence efficiency, is preferred.

[0300] From the viewpoint of the charge injection barrier from the anode 2 to the hole injection layer 3, compounds having an ionization potential of 4.5 eV to 6.0 eV are preferred as hole-transporting compounds. Examples of hole-transporting compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds formed by linking tertiary amines with fluorene groups, hydrazone compounds, silazane compounds, and quinacridone compounds.

[0301] Of the exemplified compounds described above, aromatic amine compounds are preferred from the perspectives of amorphousness and visible light transmittance, and aromatic tertiary amine compounds are particularly preferred. An aromatic tertiary amine compound refers to a compound having an aromatic tertiary amine structure and further comprising a group derived from an aromatic tertiary amine.

[0302] There are no particular limitations on the types of aromatic tertiary amine compounds. From the perspective of easily obtaining uniform luminescence through surface smoothing effect, polymeric compounds (polymeric compounds with linked repeating units) with a weight average molecular weight of 1,000 to 1,000,000 are preferred. As a preferred example of an aromatic tertiary amine polymeric compound, a polymeric compound having repeating units as shown in the following formula (I) can be cited.

[0303]

[0304] In formula (I), Ar 1 and Ar 2 Each independently represents an aromatic group that may have substituents or a heteroaromatic group that may have substituents, Ar 3 ~Ar 5 Each of these groups independently represents an aromatic group that may have substituents or a heteroaromatic group that may have substituents. Q represents a linking group selected from the following group of linking groups. Additionally, Ar... 1 ~Ar 5 In this context, two groups bonded to the same nitrogen atom can bond together to form a ring.

[0305] The linking groups are shown below.

[0306]

[0307] [In the above formulas, Ar] 6 ~Ar 16 Each can independently represent an aromatic group that may have substituents or a heteroaromatic group that may have substituents, R a ~R b Each can independently represent a hydrogen atom or any substituent.

[0308] As Ar 1 ~Ar 16 The aromatic and heteroaromatic groups are preferably derived from benzene rings, naphthalene rings, phenanthrene rings, thiophene rings, and pyridine rings, taking into account the solubility, heat resistance, and hole injection transport properties of the polymer compound. Groups derived from benzene rings and naphthalene rings are even more preferred.

[0309] Specific examples of aromatic tertiary amine polymers having repeating units as shown in formula (I) include compounds described in International Publication No. 2005 / 089024.

[0310] (Electron-accepting compounds)

[0311] In order to improve the conductivity of the hole injection layer 3 by oxidizing the hole transport compound, the hole injection layer 3 preferably contains an electron accepting compound.

[0312] As an electron-accepting compound, a compound having oxidizing ability and the ability to accept an electron from the aforementioned hole-transporting compound is preferred. Specifically, compounds with an electron affinity of 4 eV or higher are preferred, and compounds with an electron affinity of 5 eV or higher are even more preferred.

[0313] Examples of such electron-accepting compounds include, for example, triarylboron compounds, metal halides, Lewis acids, organic acids, and... Compounds comprising one or more of the following groups: salts, salts of aryl amines and metal halides, and salts of aryl amines and Lewis acids. Specifically, 4-isopropyl-4'-methyldiphenyliodide is an example. Organic groups such as tetra(pentafluorophenyl)borate and triphenylsulfonium tetrafluoroborate have been substituted. Salts (International Publication No. 2005 / 089024); ferric chloride (III) (Japanese Patent Application Publication No. 11-251067), ammonium persulfate and other high-valence inorganic compounds; cyano compounds such as tetracyanoethylene; aromatic boron compounds such as tris(pentafluorophenyl)borane (Japanese Patent Application Publication No. 2003-31365); fullerene derivatives and iodine, etc.

[0314] (Cat radical compounds)

[0315] As a cationic radical compound, it is preferable to be an ionic compound consisting of a cationic radical, which is a chemical species that removes an electron from a hole-transporting compound, and a counter anion. When the cationic radical originates from a hole-transporting polymer, the cationic radical has a structure obtained by removing an electron from a repeating unit of the polymer.

[0316] As a cationic free radical, it is preferably a chemical species obtained by removing one electron from the compounds described above as hole-transporting compounds. From the perspectives of amorphousness, visible light transmittance, heat resistance, and solubility, it is preferable to obtain a chemical species obtained by removing one electron from compounds preferred as hole-transporting compounds.

[0317] Cationic radical compounds can be generated by mixing the aforementioned hole-transporting and electron-accepting compounds. By mixing these compounds, electrons move from the hole-transporting compound to the electron-accepting compound, generating a cationic compound composed of a cationic radical from the hole-transporting compound and a counter anion.

[0318] Cationic radical compounds derived from polymers, such as PEDOT / PSS (Adv. Mater., 2000, Vol. 12, p. 481) and emerald green imine hydrochloride (J. Phys. Chem., 1990, Vol. 94, p. 7716), can also be generated through oxidative polymerization (dehydrogenation polymerization).

[0319] The oxidative polymerization described here refers to the chemical or electrochemical oxidation of monomers in an acidic solution using persulfate or similar substances. In this case of oxidative polymerization (dehydrogenation polymerization), the monomers are polymerized through oxidation, generating cationic free radicals that remove an electron from the repeating unit of the polymer, using an anion from the acidic solution as a counter-anion.

[0320] (Formation of hole injection layer 3 based on wet film formation method)

[0321] When forming the hole injection layer 3 by a wet film deposition method, the material that will become the hole injection layer 3 is usually mixed with a solvent that can dissolve the material (a solvent for the hole injection layer) to prepare a film-forming composition (a composition for forming the hole injection layer). This composition for forming the hole injection layer is then deposited on a layer (usually the anode 2) corresponding to the lower layer of the hole injection layer 3 by a wet film deposition method and dried, thereby forming the hole injection layer 3. The drying of the film can be performed in the same way as the drying method used in the formation of the light-emitting layer 5 based on the wet film deposition method.

[0322] The concentration of the hole-transporting compound in the hole injection layer formation composition is arbitrary, provided it does not significantly impair the effects of the present invention. Regarding this concentration, a lower concentration is preferred from the perspective of film thickness uniformity, while a higher concentration is preferred from the perspective of minimizing defects in the hole injection layer 3. The concentration of the hole-transporting compound in the hole injection layer formation composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[0323] Examples of solvents include ether solvents, ester solvents, aromatic hydrocarbon solvents, and amide solvents.

[0324] Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA), and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

[0325] Examples of ester solvents include phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, and other aromatic esters.

[0326] Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene.

[0327] Examples of amide solvents include N,N-dimethylformamide and N,N-dimethylacetamide.

[0328] In addition to these, dimethyl sulfoxide and other similar substances can also be used.

[0329] The formation of the hole injection layer 3 using a wet film-forming method is typically performed as follows: After preparing a composition for forming the hole injection layer, it is coated onto a layer (typically the anode 2) corresponding to the lower layer of the hole injection layer 3 and then dried. The hole injection layer 3 is typically dried after film formation by heating, depressurization drying, or similar methods.

[0330] (Formation of hole injection layer 3 based on vacuum evaporation)

[0331] When forming the hole injection layer 3 by vacuum evaporation, one or more of the constituent materials of the hole injection layer 3 (such as the aforementioned hole transport compounds and electron acceptor compounds) are typically placed in a crucible placed inside a vacuum container (when using two or more materials, they are usually placed in different crucibles). The vacuum container is then evacuated to 1000 liters using a vacuum pump. -4 After heating to approximately 100 Pa, the crucible is heated (when using two or more materials, each crucible is typically heated individually), and the evaporation rate of the material inside the crucible is controlled while evaporating (when using two or more materials, each material is typically evaporated independently while evaporating), forming a hole injection layer 3 on the anode 2 of the substrate placed facing the crucible. When using two or more materials, a mixture of them can also be placed in the crucible and heated to evaporate and form the hole injection layer 3.

[0332] The vacuum level during vapor deposition is not particularly limited, provided it does not significantly impair the effectiveness of the invention; it is typically 0.1 × 10⁻⁶. -6 Torr(0.13×10-4 Pa)~9.0×10 -6 Torr(12.0×10 -4 Pa). The evaporation rate is not limited as long as it does not significantly impair the effectiveness of the invention; it is typically [amount missing]. The film-forming temperature during vapor deposition is not limited as long as it does not significantly impair the effect of the present invention, but is preferably carried out at 10°C to 50°C.

[0333] <Hole transport layer 4>

[0334] The hole transport layer 4 is a layer that performs the function of transporting holes from the anode 2 side to the light-emitting layer 5 side. The hole transport layer 4 is not a necessary layer in the organic electroluminescent element of the present invention, but it is preferred to provide this layer from the perspective of enhancing the function of transporting holes from the anode 2 to the light-emitting layer 5. When the hole transport layer 4 is provided, it is usually formed between the anode 2 and the light-emitting layer 5. When a hole injection layer 3 is present, the hole transport layer 4 is formed between the hole injection layer 3 and the light-emitting layer 5.

[0335] The thickness of the hole transport layer 4 is typically 5 nm or more, preferably 10 nm or more, typically less than 300 nm, and preferably less than 100 nm.

[0336] The hole transport layer 4 can be formed by vacuum evaporation or wet deposition. From the perspective of excellent film formation properties, wet deposition is preferred.

[0337] Hole transport layer 4 typically contains hole-transporting compounds that constitute hole transport layer 4. Examples of hole-transporting compounds contained in hole transport layer 4 include, in particular, aromatic diamines containing two or more tertiary amines and with two or more fused aromatic rings substituted on the nitrogen atom, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (Japanese Patent Application Publication No. 5-234681); aromatic amine compounds with a starburst structure, such as 4,4',4”-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., Vol. 72-74, p. 985, 1997); and aromatic amine compounds composed of tetramers of triphenylamine (C...). Spirocyclic compounds such as 2,2',7,7'-tetra-(diphenylamino)-9,9'-spirodifluorene (Synth. Metals, Vol. 91, p. 209, 1997), and carbazole derivatives such as 4,4'-N,N'-dicarbazole biphenyl, are also preferred. Polyvinylcarbazole, polyvinyltriphenylamine (Japanese Patent Application Publication No. 7-53953), and polyarylene ether sulfones containing tetraphenylbenzidine (Polym. Adv. Tech., Vol. 7, p. 33, 1996) are also preferred.

[0338] (Formation of hole transport layer 4 based on wet film formation method)

[0339] When forming the hole transport layer 4 by a wet film deposition method, the hole transport layer forming composition is usually used instead of the hole injection layer forming composition, just as in the case of forming the hole injection layer 3 by a wet film deposition method.

[0340] When forming the hole transport layer 4 by a wet film deposition method, the composition for forming the hole transport layer typically further contains a solvent. The solvent used in the composition for forming the hole transport layer can be the same solvent used in the composition for forming the hole injection layer described above.

[0341] The concentration of the hole-transporting compound in the composition for forming the hole transport layer can be within the same range as the concentration of the hole-transporting compound in the composition for forming the hole injection layer.

[0342] The formation of the hole transport layer 4 based on the wet film formation method can be carried out in the same way as the film formation method of the hole injection layer 3 described above.

[0343] (Formation of hole transport layer 4 based on vacuum evaporation)

[0344] When forming the hole transport layer 4 by vacuum evaporation, the same material used to form the hole injection layer 3 as that used to form the hole injection layer 3 by wet deposition can be used instead of the material used to form the hole transport layer 4. The film formation conditions, such as vacuum level, deposition rate, and temperature, can be the same as those used for the vacuum evaporation of the hole injection layer 3.

[0345] <Emitting Layer 5>

[0346] The light-emitting layer 5 is the layer that is excited to emit light when an electric field is applied between a pair of electrodes by recombination of holes injected from the anode 2 and electrons injected from the cathode 9.

[0347] The light-emitting layer 5 is formed between the anode 2 and the cathode 9. When the anode 2 has a hole injection layer 3, the light-emitting layer 5 is formed between the hole injection layer 3 and the cathode 9. When the anode 2 has a hole transport layer 4, the light-emitting layer 5 is formed between the hole transport layer 4 and the cathode 9.

[0348] The thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effect of the present invention. A thicker layer is preferred from the perspective of minimizing defects in the film, while a thinner layer is preferred from the perspective of easily achieving a low driving voltage. The thickness of the light-emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, generally preferably 200 nm or less, and more preferably 100 nm or less.

[0349] In the organic electroluminescent element of the present invention, the light-emitting layer 5 is formed using the organic electroluminescent element composition of the present invention and preferably by a wet film deposition method.

[0350] When the organic electroluminescent element composition of the present invention is used to form a light-emitting layer by a wet film-forming method, the organic electroluminescent element composition of the present invention may contain other light-emitting materials and charge-transporting materials in addition to the compound shown in formula (1), the polymer compound having repeating unit (2) and the compound shown in formula (3).

[0351] Other luminescent materials and charge transport materials are described in detail below.

[0352] (Luminescent materials)

[0353] Luminescent materials other than the compound shown in formula (1) emit light at the desired emission wavelength. There are no particular limitations as long as the effect of the present invention is not impaired, and known luminescent materials can be used. The luminescent material can be a fluorescent luminescent material or a phosphorescent luminescent material, and materials with good luminescent efficiency are preferred. From the viewpoint of internal quantum efficiency, phosphorescent luminescent materials are preferred.

[0354] Examples of fluorescent materials include the following.

[0355] Examples of fluorescent materials that provide blue light emission include naphthalene, perylene, pyrene, anthracene, and coumarin. p-Bis(2-phenylvinyl)benzene and their derivatives, etc.

[0356] Examples of fluorescent materials that provide green light emission include quinacridone derivatives, coumarin derivatives, and aluminum coordination compounds such as Al(C9H6NO)3.

[0357] Examples of fluorescent materials that provide yellow light emission include rubrene and naphthalene-intercalated diazoxide derivatives.

[0358] Examples of fluorescent materials that provide red emission (red fluorescent materials) include DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxan derivatives, and azabenzothioxan.

[0359] Examples of phosphorescent materials include organometallic coordination compounds containing metals selected from Groups 7 to 11 of the long-period periodic table (unless otherwise specified, "periodic table" refers to the long-period periodic table). Preferred metals selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.

[0360] As ligands for organometallic coordination compounds, ligands formed by linking a (hetero)arylpyridine ligand, a (hetero)arylpyrazole ligand, or other (hetero)aryl group to pyridine, pyrazole, phenanthroline, etc., are preferred, with phenylpyridine ligands and phenylpyrazole ligands being particularly preferred. Here, (hetero)aryl means aryl or heteroaryl.

[0361] Preferred phosphorescent materials include, specifically, phenylpyridine coordination compounds such as tris(2-phenylpyridine)iridium, tris(2-phenylpyridine)ruthenium, tris(2-phenylpyridine)palladium, bis(2-phenylpyridine)platinum, tris(2-phenylpyridine)osmium, and tris(2-phenylpyridine)rhenium, as well as porphyrin coordination compounds such as octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethylpalladium porphyrin, and octaphenylpalladium porphyrin.

[0362] Examples of polymer-based luminescent materials include poly(9,9-dioctylfluorene-2,7-diyl), poly[(9,9-dioctylfluorene-2,7-diyl)-copolymer-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)], poly[(9,9-dioctylfluorene-2,7-diyl)-copolymer-(1,4-benzo-2{2,1'-3}-triazole)], and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], etc.

[0363] (charge transport materials)

[0364] The charge transport material is a material that has positive charge (hole) or negative charge (electron) transport properties. There are no particular restrictions on the use of charge transport materials other than the compound shown in formula (3), as long as it does not impair the effect of the present invention. Known materials can be used.

[0365] The charge transport material can be compounds that have been used in the light-emitting layer of organic electroluminescent devices. Compounds used as the host material of the light-emitting layer are particularly preferred.

[0366] Specifically, examples of charge transport materials include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds formed by linking tertiary amines with fluorene groups, hydrazone compounds, silazane compounds, silaneamine compounds, phosphoramide compounds, and quinacridone compounds, which are examples of hole transport compounds used as hole injection layer 3. In addition, anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, and phenanthroline compounds are also examples. Diazole compounds, thiophene compounds, and other electron-transporting compounds, etc.

[0367] As charge transport materials, aromatic diamines containing two or more tertiary amines and with two or more fused aromatic rings substituted on the nitrogen atom, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (Japanese Patent Application Publication No. 5-234681), and aromatic amine compounds with starburst structures, such as 4,4',4”-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., Vol. 72-74, p. 985, 1997), and tetramers of triphenylamine, are also preferred. Examples of hole-transporting compounds for hole transport layer 4 include aromatic amine compounds (Chem. Commun., p. 2175, 1996), fluorene compounds such as 2,2',7,7'-tetra-(diphenylamino)-9,9'-spirodifluorene (Synth. Metals, Vol. 91, p. 209, 1997), and carbazole compounds such as 4,4'-N,N'-dicarbazole biphenyl. Additionally, 2-(4-biphenyl)-5-(p-tert-butylphenyl)-1,3,4- diazole (tBu-PBD), 2,5-bis(1-naphthyl)-1,3,4- diazole (BND), etc. Diazole compounds, thiophene compounds such as 2,5-bis(6'-(2',2”-bipyridyl))-1,1-dimethyl-3,4-diphenylthiophene (PyPySPyPy), phenanthroline compounds such as BPhen and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bath copper spirit), etc.

[0368] (Formation of the light-emitting layer 5 based on the wet film deposition method)

[0369] The organic electroluminescent element of the present invention has a light-emitting layer formed by using the organic electroluminescent element composition of the present invention and by a wet film deposition method. The organic electroluminescent element of the present invention may have a light-emitting layer 5 other than the light-emitting layer formed by using the organic electroluminescent element composition of the present invention and by a wet film deposition method. The method for forming this light-emitting layer can be vacuum evaporation or a wet film deposition method; from the perspective of excellent film formation properties, a wet film deposition method is preferred.

[0370] When the light-emitting layer 5 is formed by wet film deposition, similar to the case of forming the hole injection layer 3 by wet film deposition, the light-emitting layer is formed by using the organic electroluminescent element composition of the present invention, or a light-emitting layer forming composition prepared by mixing the material that will become the light-emitting layer 5 with a solvent that can dissolve the material (a solvent for the light-emitting layer) instead of the hole injection layer forming composition.

[0371] As solvents, examples include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents for the formation of the hole injection layer 3, as well as alkane-based solvents, halogenated aromatic hydrocarbon-based solvents, aliphatic alcohol-based solvents, alicyclic alcohol-based solvents, aliphatic ketone-based solvents, and alicyclic ketone-based solvents. The solvents used are also exemplified as solvents in the compositions for organic electroluminescent elements of the present invention. Specific examples of solvents are given below, but are not limited to these examples without impairing the effects of the present invention.

[0372] Examples include aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); aromatic ether solvents such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethyl anisole, 2,4-dimethyl anisole, and diphenyl ether; aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; and solvents such as toluene, xylene, mesitylene, and cyclohexylbenzene. Aromatic hydrocarbon solvents such as tetrahydronaphthalene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decahydronaphthalene, and dicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohol solvents such as cyclohexanol and cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and fentanyl ketone. Among these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

[0373] To obtain a more uniform film, it is preferable that the solvent evaporates from the liquid film immediately after film formation at an appropriate rate. Therefore, the boiling point of the solvent used is as described above, typically above 80°C, preferably above 100°C, more preferably above 120°C, typically below 270°C, preferably below 250°C, and more preferably below 230°C.

[0374] The amount of solvent used is arbitrary as long as it does not significantly impair the effects of the present invention. However, as described above, from the perspective of facilitating film formation due to its low viscosity, the total content in the composition for forming the light-emitting layer, i.e., the composition for organic electroluminescent elements, is preferably higher, while from the perspective of facilitating film formation in a thick film, it is preferably lower. As described above, the solvent content in the composition for organic electroluminescent elements is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, preferably 99.99% by mass or less, more preferably 99.9% by mass or less, and particularly preferably 99% by mass or less.

[0375] As a method for removing solvent after wet film formation, heating or reduced pressure can be used. When using a heating method, a cleaning oven or a heating plate is preferred from the perspective of providing heat evenly to the entire film.

[0376] The heating temperature in the heating process is arbitrary as long as it does not significantly impair the effects of the present invention. However, a higher temperature is preferred from the perspective of shortening the drying time, while a lower temperature is preferred from the perspective of minimizing damage to the material. The upper limit of the heating temperature is generally 250°C or less, preferably 200°C or less, and more preferably 150°C or less. The lower limit of the heating temperature is generally 30°C or more, preferably 50°C or more, and more preferably 80°C or more. Temperatures exceeding the above upper limit are less desirable because they may decompose or crystallize due to higher heat resistance than commonly used charge transport materials or phosphorescent materials. Temperatures below the above lower limit require a longer solvent removal time, which is also undesirable. The heating time in the heating process can be appropriately determined based on the boiling point and vapor pressure of the solvent in the composition for forming the light-emitting layer, the heat resistance of the material, and the heating conditions.

[0377] (Formation of light-emitting layer 5 based on vacuum evaporation)

[0378] When forming the light-emitting layer 5 by vacuum evaporation, one or more of the constituent materials of the light-emitting layer 5 (such as the aforementioned light-emitting materials and charge-transporting compounds) are typically placed in a crucible placed inside a vacuum container (when using two or more materials, they are usually placed in different crucibles). The vacuum container is then evacuated to 100 kJ / m³ using a vacuum pump. -4After heating to approximately 100 Pa, the crucible is heated (when using two or more materials, each crucible is usually heated individually), and the evaporation rate of the material in the crucible is controlled while the material evaporates (when using two or more materials, the evaporation rate is usually controlled independently for each material), forming a light-emitting layer 5 on the hole injection layer 3 or hole transport layer 4 placed facing the crucible. When using two or more materials, a mixture of them can also be placed in the crucible and heated to evaporate and form the light-emitting layer 5.

[0379] The vacuum level during vapor deposition is not limited as long as it does not significantly impair the effectiveness of the invention; it is typically 0.1 × 10⁻⁶. - 6 Torr(0.13×10 -4 Pa)~9.0×10 -6 Torr(12.0×10 -4 Pa). The evaporation rate is not limited as long as it does not significantly impair the effectiveness of the invention; it is typically [amount missing]. The film-forming temperature during vapor deposition is not limited as long as it does not significantly impair the effect of the present invention, but is preferably carried out at 10°C to 50°C.

[0380] <Cavity Blocking Layer 6>

[0381] A hole blocking layer 6 can be provided between the light-emitting layer 5 and the electron injection layer 8 (described later). The hole blocking layer 6 is a layer stacked on the light-emitting layer 5 in such a way that it is in contact with the interface on the cathode 9 side of the light-emitting layer 5.

[0382] The hole blocking layer 6 serves to block holes migrating from the anode 2 from reaching the cathode 9 and to efficiently transport electrons injected from the cathode 9 towards the light-emitting layer 5. Required physical properties for the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, a large bandgap (difference between HOMO and LUMO), and a high excited triplet energy level (T1).

[0383] Examples of materials that satisfy such conditions for the hole-blocking layer 6 include, for instance, mixed ligand coordination compounds such as bis(2-methyl-8-hydroxyquinoline)(phenol)aluminum and bis(2-methyl-8-hydroxyquinoline)(triphenylsilanol)aluminum, metal coordination compounds such as bis(2-methyl-8-hydroxyquinoline)aluminum-μ-oxo-bis(2-methyl-8-hydroxyquinoline)aluminum dinuclear metal coordination compounds, styryl compounds such as stilbene biphenyl derivatives (Japanese Patent Application Publication No. 11-242996), triazole derivatives such as 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Application Publication No. 7-41759), and phenanthrene-rholine derivatives such as copper sulfate (Japanese Patent Application Publication No. 10-79297). Compounds having at least one pyridine ring substituted at positions 2, 4, and 6, as described in International Publication No. 2005 / 022962, are also preferred as materials for hole blocking layer 6.

[0384] There are no restrictions on the method of forming the hole blocking layer 6; it can be formed in the same way as the method of forming the light-emitting layer 5 described above.

[0385] The thickness of the hole blocking layer 6 is arbitrary as long as it does not significantly impair the effect of the present invention. It is usually 0.3 nm or more, preferably 0.5 nm or more, usually 100 nm or less, and preferably 50 nm or less.

[0386] <Electron Transport Layer 7>

[0387] To further improve the current efficiency of the component, the electron transport layer 7 is disposed between the light-emitting layer 5 or the hole blocking layer 6 and the electron injection layer 8.

[0388] The electron transport layer 7 is formed of a compound that can efficiently transport electrons injected from the cathode 9 to the light-emitting layer 5 between the electrodes providing the electric field. As the electron transport compound used in the electron transport layer 7, it is necessary to have a high electron injection efficiency from the cathode 9 or the electron injection layer 8 and a high electron mobility, and to efficiently transport the injected electrons.

[0389] Examples of electron-transporting compounds that meet these conditions include, for example, aluminum coordination compounds of 8-hydroxyquinoline and other metal coordination compounds (Japanese Patent Application Publication No. 59-194393), metal coordination compounds of 10-hydroxybenzo[h]quinoline, etc. Diazole derivatives, stilbene biphenyl derivatives, thiophene derivatives, 3-hydroxyflavone metal coordination compounds, 5-hydroxyflavone metal coordination compounds, benzo[a] Azole metal coordination compounds, benzothiazole metal coordination compounds, tribenzimidazolylbenzene (US Patent No. 5,645,948), quinoxaline compounds (Japanese Patent Application Publication No. 6-207,169), phenanthroline derivatives (Japanese Patent Application Publication No. 5-331,459), 2-tert-butyl-9,10-N,N'-dicyanoanthraquinone diimide, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, etc.

[0390] The thickness of the electron transport layer 7 is typically 1 nm or more, preferably 5 nm or more, typically less than 300 nm, and preferably less than 100 nm.

[0391] The electron transport layer 7 is formed on the light-emitting layer 5 or the hole blocking layer 6 by means of wet film deposition or vacuum evaporation, just like the light-emitting layer 5. Vacuum evaporation is usually used.

[0392] <Electron Injection Layer 8>

[0393] The electron injection layer 8 plays a role in efficiently injecting electrons injected from the cathode 9 into the electron transport layer 7 or the light-emitting layer 5.

[0394] To ensure efficient electron injection, the material forming the electron injection layer 8 is preferably a metal with a low work function. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium.

[0395] The thickness of the electron injection layer 8 is preferably 0.1 nm to 5 nm.

[0396] Inserting extremely thin insulating films (with a thickness of about 0.1 nm to 5 nm) such as LiF, MgF2, Li2O, and Cs2CO3 at the interface between the cathode 9 and the electron transport layer 7 as the electron injection layer 8 is also an effective method to improve the efficiency of the device (Appl. Phys. Lett., Vol. 70, p. 152, 1997; Japanese Patent Application Publication No. 10-74586; IEEE Trans. Electron. Devices, Vol. 44, p. 1245, 1997; SID 04 Digest, p. 154).

[0397] Furthermore, by doping organic electron transport materials with alkali metals such as sodium, potassium, cesium, lithium, and rubidium (as described in Japanese Patent Application Publication Nos. 10-270171, 2002-100478, and 2002-100482, etc.), electron injection and transport properties can be improved, and the film quality is also excellent, which is therefore preferred. The film thickness is typically 5 nm or more, preferably 10 nm or more, typically 200 nm or less, and preferably 100 nm or less.

[0398] The electron injection layer 8 is formed, in the same way as the light-emitting layer 5, by laminating it onto the hole blocking layer 6 or the electron transport layer 7 on the light-emitting layer 5 or by using a wet film deposition method or a vacuum evaporation method.

[0399] The details of the wet film formation method are the same as those for the light-emitting layer 5 described above.

[0400] <Cathode 9>

[0401] The cathode 9 functions as a layer that injects electrons into the light-emitting layer 5 (electron injection layer 8 or light-emitting layer 5, etc.). The cathode 9 can be made of the same material used in the anode 2 described above. From the perspective of efficient electron injection, a metal with a low work function is preferred. For example, metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys thereof, can be used as materials for the cathode 9. Examples of low work function alloy electrodes for the cathode 9 include magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys.

[0402] From the perspective of component stability, it is preferable to stack a metal layer with a high work function and atmospheric stability on the cathode 9 to protect the cathode 9, which is composed of a metal with a low work function. Examples of metals that can be used for stacking include aluminum, silver, copper, nickel, chromium, gold, and platinum.

[0403] The film thickness of the cathode is usually the same as that of the anode.

[0404] <Other Constituent Layers>

[0405] The above, with Figure 1 The description focuses on the layered components shown. However, without compromising performance, any additional layers may be present between the anode 2 and cathode 9 of the organic electroluminescent element and the light-emitting layer 5, besides those described above. Furthermore, any layer other than the light-emitting layer 5 may be omitted.

[0406] For example, for the same purpose as hole blocking layer 6, it is also effective to place an electron blocking layer between hole transport layer 4 and light-emitting layer 5. The electron blocking layer has the following functions: increasing the recombination probability of holes in light-emitting layer 5 by blocking electrons migrating from light-emitting layer 5 from reaching hole transport layer 4 and confining the generated excitons in light-emitting layer 5; and efficiently transporting holes injected from hole transport layer 4 to light-emitting layer 5.

[0407] The required characteristics of an electron blocking layer include high hole transport, a large bandgap (the difference between HOMO and LUMO), and a high excited triplet energy level (T1).

[0408] When the light-emitting layer 5 is formed by wet film deposition, the electron blocking layer is also formed by wet film deposition, which makes the device manufacturing easier and is therefore preferred.

[0409] Therefore, the electron blocking layer is preferably suitable for wet film formation. Examples of materials used in such electron blocking layers include copolymers of dioctylfluorene and triphenylamine, such as F8-TFB (International Publication No. 2004 / 084260).

[0410] It can also be with Figure 1 The opposite structure involves sequentially stacking a cathode 9, an electron injection layer 8, an electron transport layer 7, a hole blocking layer 6, a light-emitting layer 5, a hole transport layer 4, a hole injection layer 3, and an anode 2 on a substrate 1. Alternatively, the organic electroluminescent element of the present invention can be disposed between two substrates, at least one of which has high transparency.

[0411] It can also be multiple overlapping segments Figure 1 The structure shown is composed of layers (a structure with multiple light-emitting units stacked). In this case, if V2O5 or similar material is used as a charge-generating layer to replace the interface layer between segments (between light-emitting units) (these two layers refer to when the anode is ITO and the cathode is Al), the potential barrier between segments is reduced, which is more preferable from the viewpoint of luminous efficiency and driving voltage.

[0412] This invention can be applied to any of the following: organic electroluminescent elements are single elements, elements composed of structures arranged in an array, and structures in which the anode and cathode are arranged in an XY matrix.

[0413] [Display devices and lighting devices]

[0414] The display device and lighting device of the present invention use the organic electroluminescent element of the present invention as described above. There are no particular limitations on the form or structure of the display device and lighting device of the present invention; they can be assembled using the organic electroluminescent element of the present invention according to conventional methods.

[0415] For example, the display device of the present invention can be formed using the method described in "Organic EL Display" (Ohm Corporation, published on August 20, 2004, written by Shizushi Tokito, Chinatsuya Adachi, and Hideyuki Murata).

[0416] Example

[0417] The present invention will be described in more detail below with reference to embodiments.

[0418] This invention is not limited to the following embodiments. As long as it does not depart from the spirit of the invention, it can be arbitrarily modified and implemented.

[0419] [Example 1]

[0420] Organic electroluminescent elements are fabricated using the following method.

[0421] An anode was formed by depositing a 50 nm thick transparent conductive film of indium tin oxide (ITO) on a glass substrate using conventional photolithography and hydrochloric acid etching to pattern it into 2 mm wide stripes. The ITO-patterned substrate was then sequentially cleaned using ultrasonic cleaning based on a surfactant-based aqueous solution, followed by rinsing with ultrapure water, ultrasonic cleaning again with ultrapure water, and rinsing with ultrapure water. After drying with compressed air, it was finally subjected to ultraviolet ozone cleaning.

[0422] As a composition for forming a hole injection layer, a composition is prepared in which a hole-transporting polymer compound of formula (P-1) is dissolved in ethyl benzoate at a concentration of 3.0% by mass and a compound of formula (HI-1) is dissolved in ethyl benzoate at a concentration of 0.3% by mass.

[0423]

[0424] The hole injection layer forming composition was spin-coated onto the substrate in the atmosphere and dried in the atmosphere at 240°C for 30 minutes using a heating plate to form a uniform thin film with a thickness of 40 nm, which served as the hole injection layer.

[0425] Next, a hole transport layer forming composition prepared by dissolving 3% by mass of the charge transport polymer compound of the following structural formula (HT-1) in cyclohexylbenzene is spin-coated onto a substrate on which the hole injection layer is formed in a nitrogen glove box, and dried at 230°C for 30 minutes using a heating plate in the nitrogen glove box to form a uniform thin film with a thickness of 43 nm as the hole transport layer.

[0426]

[0427] Next, as materials for the light-emitting layer, 75 parts by mass of the polymer compound (Mw = 39000, Mw / Mn = 1.41) shown in the following structural formula (H-1), 25 parts by mass of the compound shown in the following structural formula (H-2), and 20 parts by mass of the compound shown in the following structural formula (D-1) were weighed and dissolved in cyclohexylbenzene in such a total amount as 6.0% by mass to prepare a composition for forming the light-emitting layer.

[0428]

[0429] The composition for forming the light-emitting layer was spin-coated onto a substrate having the hole transport layer formed thereon in a nitrogen glove box. The substrate was then dried at 120°C for 20 minutes using a heating plate in the nitrogen glove box to form a uniform thin film with a thickness of 70 nm, which served as the light-emitting layer.

[0430] The substrate to which the light-emitting layer is formed is placed in a vacuum evaporation apparatus, and the air inside the apparatus is evaporated to a pressure of 2×10⁻⁶. -4 Below Pa.

[0431] Next, the compound shown in the following structural formula (HB-1) and lithium 8-hydroxyquinoline were deposited by vacuum evaporation at a film thickness ratio of 2:3. The hole blocking layer is co-deposited onto the light-emitting layer at a high speed to form a hole blocking layer with a thickness of 30 nm.

[0432]

[0433] Next, a 2mm wide striped shadow mask was used as the cathode evaporation mask, orthogonal to the ITO stripes of the anode, and tightly fitted to the substrate. It was placed in another vacuum evaporation apparatus as the cathode, and the aluminum was heated using a molybdenum boat at a evaporation rate... An aluminum layer with a thickness of 80 nm is formed to form the cathode.

[0434] Next, in the nitrogen glove box, the vapor deposition section is covered by a glass cap with absorbent pads, and the vapor deposition section is bonded and sealed to the glass cap using UV-cured resin.

[0435] The above describes an organic electroluminescent element with a light-emitting area of ​​2mm × 2mm.

[0436] [Example 2]

[0437] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(H-2):(D-1) = 50:50:20. Otherwise, the element is made in the same manner as in Example 1.

[0438] [Example 3]

[0439] The composition for forming the light-emitting layer contains materials with a material composition (parts by mass) of (H-1):(H-3):(D-1) = 75:25:20. The element is fabricated in the same manner as in Example 1, except that the composition is otherwise identical. The structural formula of (H-3) is shown below.

[0440]

[0441] [Comparative Example 1]

[0442] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(D-1) = 100:20. Otherwise, the element is made in the same manner as in Example 1.

[0443] [Component Evaluation]

[0444] The organic electroluminescent elements prepared in Examples 1-3 and Comparative Example 1 were measured to have a brightness of 1000 cd / m². 2The voltage (V) during emission was calculated, and the difference between the voltage of Comparative Example 1 and the voltage of Comparative Example 1 (voltage of Examples 1-3 and Comparative Example 1 - voltage of Comparative Example 1) was obtained as the voltage difference (V).

[0445] The organic electroluminescent elements prepared in Examples 1-3 and Comparative Example 1 were measured to have a brightness of 1000 cd / m². 2 The luminous efficiency (cd / A) of the current during emission is calculated, and the relative value is obtained when the luminous efficiency of Comparative Example 1 is set to 100, which is taken as the relative luminous efficiency.

[0446] Determine how to make the organic electroluminescent elements fabricated in Examples 1-3 and Comparative Example 1 achieve a brightness of 1000 cd / m². 2 The external quantum efficiency during emission (denoted as EQE) is defined as the relative value when the EQE of Comparative Example 1 is set to 100.

[0447] These evaluation results are shown in Table 1.

[0448] As shown in Table 1, it can be seen that the organic electroluminescent element of the present invention has higher luminous efficiency and lower voltage compared with the organic electroluminescent element of the comparative example.

[0449] [Table 1]

[0450]

[0451] [Example 4]

[0452] The compound shown in structural formula (H-2) is used instead of the compound shown in structural formula (H-4) to make the material composition (parts by mass) contained in the composition for forming the light-emitting layer (H-1):(H-4):(D-1) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0453]

[0454] [Example 5]

[0455] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(H-4):(D-1) = 50:50:20. Otherwise, the element is made in the same manner as in Example 1.

[0456] [Example 6]

[0457] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(H-4):(D-1) = 25:75:20. Otherwise, the element is made in the same manner as in Example 1.

[0458] [Example 7]

[0459] The compound shown in structural formula (H-5) is used instead of the structure shown in structural formula (H-2) to make the material composition (parts by mass) contained in the composition for forming the light-emitting layer (H-1):(H-5):(D-1) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0460]

[0461] [Example 8]

[0462] The compound shown in structural formula (H-2) is used instead of the compound shown in structural formula (H-6) to make the material composition (parts by mass) contained in the composition for forming the light-emitting layer (H-1):(H-6):(D-1) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0463]

[0464] [Comparative Example 2]

[0465] The components were made in the same manner as in Comparative Example 1.

[0466] [Comparative Example 3]

[0467] The compound shown in structural formula (H-7) is used instead of the compound shown in structural formula (H-2) to make the material composition (parts by mass) contained in the composition for forming the light-emitting layer (H-1):(H-7):(D-1) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0468]

[0469] [Comparative Example 4]

[0470] The compound shown in structural formula (D-1) is used instead of the compound shown in structural formula (D-2) to make the material composition (parts by mass) contained in the composition for forming the light-emitting layer (H-1):(H-4):(D-2) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0471]

[0472] [Comparative Example 5]

[0473] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(H-5):(D-2) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0474] [Comparative Example 6]

[0475] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(H-6):(D-2) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0476] [Comparative Example 7]

[0477] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(H-7):(D-2) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0478] [Component Evaluation]

[0479] The organic electroluminescent elements prepared in Examples 4-8 and Comparative Examples 2-7 were measured to have a brightness of 1000 cd / m². 2 The voltage (V) during light emission is used to calculate the difference between the voltage of the element in Comparative Example 2 and the voltage of each element (voltage of Examples 4-8 and Comparative Examples 2-7 - voltage of Comparative Example 2), which is taken as the voltage difference (V).

[0480] Determine how to make the organic electroluminescent elements prepared in Examples 4-8 and Comparative Examples 2-7 achieve a brightness of 1000 cd / m². 2 The external quantum efficiency (EQE) during light emission is calculated, and the relative values ​​of the EQE of each element are obtained when the EQE of Comparative Example 2 is set to 100, which are used as the relative EQE.

[0481] The organic electroluminescent elements prepared in Examples 4-8 and Comparative Examples 2-7 were driven with a constant current to achieve an initial luminance Lo = 3000 cd / m². 2 The conversion was performed to calculate the time it takes for the brightness to decrease to 95% of the initial brightness, which was taken as LT95 (hr). The relative values ​​of LT95 for each element when the LT95 of Comparative Example 2 was set to 100 were calculated as the relative drive life.

[0482] These results are shown in Table 2.

[0483] As shown in Table 2, the organic electroluminescent element of the present invention has low voltage, high luminous efficiency (EQE), and long driving life.

[0484] [Table 2]

[0485]

[0486] [Example 9]

[0487] The components are fabricated in the same manner as in Example 1.

[0488] [Comparative Example 8]

[0489] The composition of materials contained in the light-emitting layer forming composition has a material composition (parts by mass) of (H-1):(H-2):(D-2) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0490] [Comparative Example 9]

[0491] The polymer compound represented by the following structural formula (H-8) is used instead of the polymer compound represented by the structural formula (H-1) to make the material composition (parts by mass) contained in the composition for forming the light-emitting layer (H-8):(H-2):(D-1) = 75:25:20. Otherwise, the element is made in the same manner as in Example 1.

[0492]

[0493] [Component Evaluation]

[0494] The organic electroluminescent elements prepared in Example 9, Comparative Example 8, and Comparative Example 9 were measured to have a brightness of 1000 cd / m². 2 The voltage (V) when the light is emitted is calculated, and the difference between the voltage of Comparative Example 2 and the voltage of Comparative Example 2 (voltage of Example 9, Comparative Example 2, 8, 9 - voltage of Comparative Example 2) is obtained as the voltage difference (V).

[0495] Determine how to make the organic electroluminescent elements fabricated in Example 9, Comparative Example 8, and Comparative Example 9 achieve a brightness of 1000 cd / m². 2 The external quantum efficiency during emission (denoted as EQE) is defined as the relative value when the EQE of Comparative Example 2 is set to 100.

[0496] The organic electroluminescent elements fabricated in Example 9, Comparative Example 8, and Comparative Example 9 were driven with a constant current to an initial luminance Lo = 3000 cd / m². 2 The time it takes for the brightness to decrease to 95% of the initial brightness was calculated and taken as LT95 (hr). The relative values ​​of LT95 for each element when the LT95 of Comparative Example 2 was set to 100 were calculated and taken as the relative drive lifetime. These results are shown in Table 3.

[0497] As shown in Table 3, the element of the present invention has low voltage, high luminous efficiency (EQE), and high driving durability. On the other hand, the element of Comparative Example 9, whose polymer compound in the light-emitting layer does not contain the structure shown in formula (2) of the present invention, has high voltage and low luminous efficiency.

[0498] [Table 3]

[0499]

[0500] Although the invention has been described in detail using specific methods, it will be apparent to those skilled in the art that various modifications may be made without departing from the spirit and scope of the invention.

[0501] This application is based on, and is incorporated herein by reference in its entirety, Japanese Patent Application No. 2019-110408, filed on June 13, 2019.

[0502] Symbol Explanation

[0503] 1 substrate

[0504] 2 Anode

[0505] 3. Hole injection layer

[0506] 4. Hole transport layer

[0507] 5. Light-emitting layer

[0508] 6. Cavity barrier layer

[0509] 7. Electron Transport Layer

[0510] 8 Electron Injection Layer

[0511] 9 Cathode

[0512] 10 Organic electroluminescent elements

Claims

1. A composition for an organic electroluminescent element, comprising: The compound represented by the following formula (1), Polymer compounds having repeating units comprising the structure shown in formula (2) below, The compound shown in formula (3) below, and Solvent; ， In equation (1), a and b are both 0. m is an integer from 1 to 20. n is an integer between 0 and 2. Ring A can be a pyridine ring, pyrazine ring, pyrimidine ring, or imidazole ring. Any one of the following: azole ring, thiazole ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azirbenzanthroline ring, or carbline ring. Z 1 This indicates an aromatic linker group that is directly bonded or has an m+1 valence. L 1 The symbol represents the auxiliary ligand, where l is an integer from 1 to 3. When multiple auxiliary ligands exist, they can be different or the same. ， In equation (2), R 3 R 4 Each is an alkyl group having 1 to 20 carbon atoms. ， In equation (3), X 1 N represents R 5 Each group is an independent group consisting of 3 to 20 carbon atoms formed by arbitrarily connecting multiple groups selected from phenyl and carbazole groups. These groups may further have substituents. R 6 R 7 Each group is independently a group consisting of 3 to 20 carbon atoms formed by linking multiple groups selected from phenyl and carbazole groups. These groups may further have substituents. R 5 ~R 7 Each of the termini independently contains either a phenyl or a carbazole group. R 5 When multiple R exist, multiple R 5 They can be the same or different. The adjacent R bonded to the benzene ring 5 They can bond with each other to form a ring fused with the benzene ring. c is an integer between 0 and 5. R 5 ~R 7 It can have substituents that are (hetero)aryl groups with 3 to 30 carbon atoms. For Z 1 Aromatic linking groups, When m is 1, it is phenylene, biphenylene, terphenylene, or fluorenediyl. When m is 2 or more, it is a benzene ring with bonding positions at the 1, 3, and 5 positions, or a triazine ring with bonding positions at the 2, 4, and 6 positions. in, When c is 0, R 6 and R 7 They are not both unsubstituted phenyl groups.

2. The composition for organic electroluminescent elements according to claim 1, wherein, Z in equation (1) 1 It is a direct bond.

3. The composition for organic electroluminescent elements according to claim 1, wherein, The compound represented by formula (1) is the compound represented by formula (1-1) below. ， In equation (1-1), 3 X 2 It can represent either C or N. Z 2 This indicates an aromatic linker group that is directly bonded or has a p+1 valence. Z 3 This indicates an aromatic linker group that is directly bonded or has a q+1 valence. p and q are integers from 1 to 10. R 1 R 2 , a, b, n, ring A, L 1 , l and R in equation (1) 1 R 2 , a, b, n, ring A, L 1 The characters 、 and l have the same meaning.

4. The composition for organic electroluminescent elements according to claim 3, wherein, Z in equation (1-1) 2 Z 3 It is a direct bond.

5. The composition for an organic electroluminescent element according to claim 3, wherein, In equation (1-1), p=1, q=1, Z 2 and Z 3 It is phenylene, biphenylene, terphenylene, or fluorenediyl.

6. The composition for an organic electroluminescent element according to claim 3, wherein, In equation (1-1), Z is defined as the value of p being 2 or higher. 2 Z when q is 2 or higher 3 A trivalent group consisting of a benzene ring with bonding positions at the 1, 3, and 5-positions, as shown in formula (1-2A) or a triazine ring with bonding positions at the 2, 4, and 6-positions, as shown in formula (1-2B). 。 7. The composition for an organic electroluminescent element according to claim 1, wherein, In the above formula (1), l is 3.

8. The composition for an organic electroluminescent element according to any one of claims 1 to 7, wherein, Polymer compounds having repeating units comprising the structure shown in formula (2) comprise repeating units as shown in formula (2-1) below. ， In equation (2-1), Ar 21 ~Ar 23 Each can independently represent a divalent (hetero)arylene group with 3 to 30 carbon atoms that may have substituents. Ar 24 Ar 25 Each can independently represent a (hetero)aryl group with 3 to 30 carbon atoms that may have substituents. r represents an integer from 0 to 2. Ar 21 ~Ar 23 Ar 24 Ar 25 The substituents that may be present are alkyl groups with 1 to 20 carbon atoms, (hetero)aryl groups with 7 to 40 carbon atoms, alkoxy groups with 1 to 20 carbon atoms, (hetero)aryl groups with 3 to 20 carbon atoms, alkylsilyl groups with 1 to 20 carbon atoms, arylsilyl groups with 6 to 20 carbon atoms, alkylcarbonyl groups with 2 to 20 carbon atoms, arylcarbonyl groups with 7 to 20 carbon atoms, alkylamino groups with 1 to 20 carbon atoms, arylamino groups with 6 to 20 carbon atoms, (hetero)aryl groups with 3 to 30 carbon atoms, or crosslinking groups.

9. The composition for an organic electroluminescent element according to any one of claims 1 to 7, wherein, In the compound represented by formula (3), [phenylene-(R 5 )c]、R 6 and R 7 These three parts are not the same structure. When a part has substituents, it also includes those substituents.

10. The composition for an organic electroluminescent element according to any one of claims 1 to 7, wherein, R in the compound represented by formula (3) 5 ~R 7 Each of the ends has the following independent structure: ， In the above structure, * indicates a bonding position. Ar 20 This refers to aromatic hydrocarbon groups with 6 to 20 carbon atoms. These structures may further have substituents, and these structures may have substituents that are related to R in equation (3). 5 ~R 7 The same applies to the substituents that can be present.

11. A method for manufacturing an organic electroluminescent element, comprising a step of forming a light-emitting layer using the organic electroluminescent element composition according to any one of claims 1 to 10 by a wet film deposition method.

12. An organic electroluminescent element having a light-emitting layer formed using the composition for an organic electroluminescent element according to any one of claims 1 to 10.

13. A display device having the organic electroluminescent element of claim 12.

14. A lighting device having the organic electroluminescent element as described in claim 12.

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