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

Abstract

To provide a composition for organic electroluminescent elements capable of producing an organic electroluminescent element having a lower driving voltage, higher luminous efficiency, and longer driving lifetime compared with a conventional technique by a wet deposition method.SOLUTION: A composition for organic electroluminescent elements contains a compound represented by formula (1), a polymer compound having a repeating unit that contains a specific structure, a specific compound, and a solvent. An organic electroluminescent element comprises a light emitting layer that is formed using this composition for organic electroluminescent elements.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for organic electroluminescent elements (hereinafter, sometimes referred to as "organic EL elements") that is useful for forming a light-emitting layer of an organic electroluminescent element. The present invention also relates to an organic electroluminescent element having a light-emitting layer formed using the composition for organic electroluminescent elements, a method for producing the same, and a display device and a lighting device that include the organic electroluminescent element. [Background technology]

[0002] Various electronic devices using organic EL elements, such as organic EL lighting and organic EL displays, have been put to practical use. Organic electroluminescent elements consume little power due to the low applied voltage and are capable of emitting light in all three primary colors, so they are beginning to be applied not only to large display monitors but also to small and medium-sized displays such as those used in mobile phones and smartphones.

[0003] Organic electroluminescent devices are manufactured by stacking multiple layers, such as a light-emitting layer, a charge injection layer, a charge transport layer, etc. Currently, most organic electroluminescent devices are manufactured by evaporating organic materials under vacuum. In the vacuum deposition method, the deposition process is complicated and the productivity is poor. It is extremely difficult to increase the size of lighting or display panels using organic electroluminescent devices manufactured by vacuum deposition.

[0004] In recent years, wet film formation (coating) has been researched as an efficient process for manufacturing organic electroluminescent elements that can be used in large displays and lighting. The wet film formation method has the advantage of being able to easily form stable layers compared to vacuum deposition methods, and is therefore expected to be applied to the mass production of displays and lighting devices and to large devices.

[0005] To manufacture organic electroluminescent devices using the wet film-forming method, all materials used must be soluble in organic solvents and usable as ink. If the materials used have poor solubility, they may deteriorate before use due to the need for prolonged heating and other processes. Furthermore, if the materials cannot be maintained in a homogeneous state for a long time in solution, they will precipitate from the solution, making film formation using inkjet equipment impossible. Materials used in the wet film-forming method must be soluble in two ways: they must dissolve quickly in organic solvents, and they must remain homogeneous after dissolution without precipitating.

[0006] In recent years, attempts have been made to improve the performance of organic electroluminescent devices by using inks containing compounds that have improved solubility in organic solvents by introducing specific substituents into organometallic complex structures with iridium as the central metal, which is widely used as a light-emitting dopant, and polymer compounds that have a fluorene structure, thereby increasing the luminous efficiency of organic electroluminescent devices and lowering their driving voltage (e.g., Patent Documents 1 and 2).

[0007] Another advantage of wet deposition over vacuum deposition is that it allows for the use of more materials in a single layer. With vacuum deposition, it becomes difficult to maintain a constant deposition rate as the number of materials increases. On the other hand, with wet deposition, even if the number of materials increases, it is possible to prepare an ink with a constant component ratio and form a layer, as long as each material dissolves in an organic solvent.

[0008] In recent years, attempts have been made to use a specific compound containing a triazine ring or a pyrimidine ring for the purpose of transporting electrons as one of the components contained in the ink for forming the light-emitting layer (e.g., Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2017 / 154884 [Patent Document 2] Japanese Patent Application Publication No. 2018-83941 [Patent Document 3] International Publication No. 2014 / 024889 [Patent Document 4] International Publication No. 2017 / 178311

[0010] However, in the above-mentioned prior art, although the introduction of a specific substituent improves the solubility of the luminescent dopant and improves the stability of the ink, the introduction of the specific substituent reduces the electron transport property of the luminescent material. Therefore, the performance of the organic electroluminescent device is not sufficient for display or lighting applications, and further reduction in driving voltage and improvement in luminous efficiency and driving life have been required. Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a composition for organic electroluminescent elements that can be used to fabricate organic electroluminescent elements using a wet film-forming method, which have a lower driving voltage, higher luminous efficiency, and longer driving life than conventional elements. [Means for solving the problem]

[0012] The present inventors have conducted extensive research in light of the above-mentioned problems, in order to take advantage of the wet film-forming method, which allows the use of multiple material types in one layer. As a result, they have found that the performance of an organic electroluminescent element can be improved by using an iridium complex having a specific substituent introduced therein as an emitting dopant, and a specific compound having a triazine ring or a pyrimidine ring responsible for electron transport in addition to a polymer having a fluorene structure as a host material, dissolving these in a solvent to form a composition for an organic electroluminescent element, and using this to fabricate an organic electroluminescent element.

[0013] The composition for organic electroluminescent elements of the present invention uses an iridium complex having a specific substituent introduced therein as a light-emitting dopant, which is highly soluble in organic solvents, and therefore is less susceptible to precipitation of the light-emitting material and has excellent storage stability. Furthermore, the composition contains a specific compound having a triazine ring or a pyrimidine ring that is responsible for electron transport, which improves the electron transport ability in the light-emitting layer compared to conventional compositions, enabling the production of organic electroluminescent elements with low driving voltage, high luminous efficiency, and long operating life.

[0014] The gist of the present invention is as follows.

[0015] [1] A compound represented by the following formula (1): a polymer compound having a repeating unit including a structure represented by the following formula (2); A composition for organic electroluminescent devices comprising a compound represented by the following formula (3) and a solvent:

[0016] [ka] [In formula (1), R 1 , R 2 are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent. R 1 , R 2 If there are multiple R 1 , R 2 may be the same or different. Adjacent R bonded to the benzene ring 1 or R 2 may be bonded to each other to form a ring fused to the benzene ring. a is an integer of 0 to 4. b is an integer of 0 to 3. m is an integer from 1 to 20. n is an integer of 0 to 2. Ring A is any one of a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring, a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring. Ring A may have a substituent. The substituent is any one of a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 2 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 20 carbon atoms, or a combination thereof. Adjacent substituents bonded to ring A may be bonded to each other to form a ring fused to ring A. Z 1 represents a direct bond or an m+1 valent aromatic linking group. L 1 represents an auxiliary ligand, and l is an integer of 1 to 3. When there are multiple auxiliary ligands, they may be different from each other or the same.]

[0017] [ka]

[0018] [In formula (2), R 3 , R 4are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent.]

[0019] [ka]

[0020] [In formula (3), X 1 represents C or N. R 5 ~R 7 are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent. R 5 If there are multiple R 5 may be the same or different. Adjacent R bonded to the benzene ring 5 may be bonded to each other to form a ring fused to the benzene ring. c is an integer of 0 to 5. However, if c is 0, R 6 and R 7 is not also an unsubstituted phenyl group.

[0021] [2] Z in the formula (1) 1The composition for organic electroluminescent devices according to [1], wherein

[0022] [3] The composition for organic electroluminescent elements according to [1], wherein the compound represented by formula (1) is a compound represented by the following formula (1-1):

[0023] [ka]

[0024] [In formula (1-1), Three Xs 2 represents C or N at the same time. Z 2 represents a direct bond or a p+1 valent aromatic linking group. Z 3 represents a direct bond or a q+1-valent aromatic linking group. p and q are integers of 1 to 10. R 1 , R 2 , a, b, n, m, Ring A, L 1 , l is R in Equation (1) 1 , R 2 , a, b, m, n, Ring A, L 1 , which is synonymous with l.]

[0025] [4] The composition for organic electroluminescent devices according to [1] or [2], wherein the compound represented by formula (1) is a compound represented by formula (1-2):

[0026] [ka]

[0027] [In formula (1-2), R 1 , a, m, n, ring A, Z 1 , L 1 , l is R in Equation (1) 1 , a, m, n, ring A, Z 1 , L 1 , which is synonymous with l. R 15 ~R 17is a substituent.

[0028] [5] The composition for organic electroluminescent devices according to any one of [1] to [4], wherein l in the formula (1) is 3.

[0029] [6] The composition for organic electroluminescent elements according to any one of [1] to [5], wherein the polymer compound having a repeating unit including a structure represented by formula (2) contains a repeating unit represented by the following formula (2-1):

[0030] [ka]

[0031] [In formula (2-1), Ar 21 ~Ar 23 each independently represents a divalent (hetero)arylene group having 3 to 30 carbon atoms which may have a substituent. Ar 24 , Ar 25 each independently represents a (hetero)aryl group having 3 to 30 carbon atoms which may have a substituent. and r represents an integer of 0 to 2.

[0032] [7] In the compound represented by the formula (3), [phenylene-(R 5 )c], R 6 and R 7 The composition for organic electroluminescent elements according to any one of [1] to [6], wherein the three partial structures, including the substituents if any, are not identical to each other.

[0033] [8] R in the compound represented by formula (3) 5 ~R 7 The composition for organic electroluminescent elements according to any one of [1] to [7], wherein the terminals of each independently contain a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group.

[0034] [9] A method for producing an organic electroluminescent device, comprising the step of forming a light-emitting layer by a wet film-forming method using the organic electroluminescent device composition according to any one of [1] to [8].

[0035]

[10] An organic electroluminescent device having a light-emitting layer formed using the organic electroluminescent device composition according to any one of [1] to [8].

[0036]

[11] A display device having the organic electroluminescent device according to

[10] .

[0037]

[12] A lighting device having the organic electroluminescent device according to

[10] . [Effects of the Invention]

[0038] According to the present invention, it is possible to provide an organic electroluminescent device using a wet film-forming method, which has a lower driving voltage, higher luminous efficiency, and longer driving life than conventional devices. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of the structure of an organic electroluminescent device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the preferred embodiments. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0041] In this specification, the terms (hetero)aralkyl group, (hetero)aryloxy group, and (hetero)aryl group refer to an aralkyl group which may contain a heteroatom, an aryloxy group which may contain a heteroatom, and an aryl group which may contain a heteroatom, respectively. The term "may contain a heteroatom" means that one or more of the carbon atoms forming the main skeleton of the aryl group, aralkyl group, or aryloxy group are substituted with a heteroatom. Examples of heteroatoms include a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, and a silicon atom. Among these, a nitrogen atom is preferred from the viewpoint of durability. The same applies to a (hetero)arylene group.

[0042] In this specification, the term "aromatic linking group" refers to an aromatic linking group in a broad sense, including not only aromatic hydrocarbon linking groups, i.e., linking groups having an aromatic hydrocarbon ring, but also heteroaromatic linking groups, i.e., linking groups having a heteroaromatic ring.

[0043] [Light-emitting dopant] The composition for organic electroluminescent devices of the present invention contains a compound represented by the following formula (1) as a light-emitting dopant.

[0044] [ka]

[0045] [In formula (1), R 1 , R 2 are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent. R 1 , R 2 If there are multiple R1 , R 2 may be the same or different. Adjacent R bonded to the benzene ring 1 or R 2 may be bonded to each other to form a ring fused to the benzene ring. a is an integer of 0 to 4. b is an integer of 0 to 3. m is an integer from 1 to 20. n is an integer of 0 to 2. Ring A is any one of a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring, a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring. Ring A may have a substituent. The substituent is any one of a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 2 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 20 carbon atoms, or a combination thereof. Adjacent substituents bonded to ring A may be bonded to each other to form a ring fused to ring A. Z 1 represents a direct bond or an m+1 valent aromatic linking group. L 1 represents an auxiliary ligand, and l is an integer of 1 to 3. When there are multiple auxiliary ligands, they may be different from each other or the same.]

[0046] In formula (1), R 1 , R 2and are preferably each independently an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a (hetero)aryl group having 3 to 30 carbon atoms, from the viewpoint of durability, and more preferably an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, or a (hetero)aryl group having 3 to 20 carbon atoms. Two adjacent R 2 may be linked to each other to form a ring.

[0047] a is preferably 0 in terms of ease of production, and is preferably 1 or 2, more preferably 1, in terms of increased solubility. b is preferably 0 in terms of ease of production, and is preferably 1 or 2, more preferably 1, in terms of enhanced durability and solubility. Two adjacent R 2 When they are linked to each other to form a ring, b is preferably 2 or 3.

[0048] Since the phenyl group having a terminal t-butyl group increases the solubility in organic solvents, m is preferably 2 or more. Since the phenyl group having a terminal t-butyl group has little contribution to charge transport and light emission, if there are too many, there is a concern that the driving voltage will be high and the light-emitting efficiency will be low. For this reason, m is preferably 8 or less, and more preferably 4 or less.

[0049] The compound represented by formula (1) preferably has 4 or more, particularly 6 or more, and 48 or less, particularly 24 or less, of such terminal t-butyl groups in the entire compound, in terms of achieving both solubility, low driving voltage, and high luminous efficiency.

[0050] In terms of ease of production, n is preferably 0 or 1. In terms of reducing the risk of an increase in driving voltage, n is preferably 0. In terms of increasing solubility, n is preferably 1 or 2.

[0051] From the viewpoint of durability, ring A is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring.

[0052] From the viewpoint of improving durability and solubility, the hydrogen atom on ring A is preferably substituted with an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, or a (hetero)aryl group having 3 to 20 carbon atoms. It is preferred that the hydrogen atom on ring A is not substituted in terms of ease of production. It is preferable that the hydrogen atom on ring A is substituted with a phenyl group or naphthyl group which may have a substituent, since this facilitates the generation of excitons when used in an organic electroluminescent device, thereby improving the luminous efficiency.

[0053] When the substituents on ring A are bonded to each other to form a fused ring fused to ring A, such as a quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azatriphenylene ring, or carboline ring, the emission wavelength becomes longer, and therefore ring A is useful for red light emission applications. Among these, ring A forming a quinoline ring, isoquinoline ring, or quinazoline ring is preferred from the viewpoints of durability and red light emission.

[0054] Z 1 is preferably a direct bond in terms of ease of production. Z 1 is preferably an aromatic linking group with a valence of m+1, since there is little concern that the driving voltage will increase.

[0055] If m is 1, then Z 1 In terms of durability, a phenylene group, a biphenylene group, a terphenylene group, or a fluorenediyl group is preferred, and a p-phenylene group is particularly preferred.

[0056] If m is 2 or more, Z 1 In terms of durability, it is preferable that the compound contains a benzene ring bonded at the 1,3,5-positions or a triazine ring bonded at the 2,4,6-positions.

[0057] Z 1 preferably contains a trivalent group represented by the following formula (1-2A) or (1-2B).

[0058] [ka]

[0059] It is more preferable that the group represented by formula (1-2A) or (1-2B) is bonded to the benzene ring or ring A bonded to iridium. In this case, the compound represented by formula (1) is preferably a compound represented by the following formula (1-1).

[0060] [ka]

[0061] [In formula (1-1), Three Xs 2 represents C or N at the same time. Z 2 represents a direct bond or a p+1 valent aromatic linking group. Z 3 represents a direct bond or a q+1-valent aromatic linking group. p and q are integers of 1 to 10. R 1 , R 2 , a, b, n, m, Ring A, L 1 , l is R in Equation (1) 1 , R 2 , a, b, m, n, Ring A, L 1 , which is synonymous with l.]

[0062] In the above formula (1-1), Z 2 , Z 3 is preferably a direct bond in terms of ease of production.

[0063] Z 2 and Z 3is preferably an aromatic linking group having a valence of p+1 and q+1, since there is little concern that the driving voltage will increase. In this case, for example, when p and q are 1, Z 2 and Z 3 In terms of durability, a phenylene group, a biphenylene group, a terphenylene group, or a fluorenediyl group is preferred, and a p-phenylene group is particularly preferred.

[0064] Z when p is 2 or greater 2 and Z when q is 2 or greater 3 In terms of durability, it is preferable that Z contains a benzene ring bonded at the 1,3,5-positions or a triazine ring bonded at the 2,4,6-positions. 2 and Z 3 preferably contains a trivalent group represented by the following formula (1-2A) or (1-2B).

[0065] [ka]

[0066] L 1 is an auxiliary ligand. There is no particular limitation, but L 1 is preferably a monovalent bidentate ligand, and more preferably selected from the ligands represented by the following formulae (1A), (1B) and (1C). The dashed lines in the following formulas (1A) to (1C) represent coordinate bonds. l is 1 and two ancillary ligands L 1 If present, the ancillary ligand L 1 may be identical to each other or may have different structures. When l is 3, L 1 does not exist.

[0067] [ka]

[0068] In the above formulas (1A) and (1B), R 9 , R 10 is the R 1 , R2 The preferred examples are also selected from the same group as above. g is an integer of 0 to 4. h is an integer of 0 to 4. g and h are preferably 0 in terms of ease of production, and are preferably 1 or 2, and more preferably 1, in terms of enhanced solubility.

[0069] Ring B is any one of a pyridine ring, a pyrimidine ring, an imidazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, a carboline ring, a benzothiazole ring, and a benzoxazole ring, which may have a substituent. From the viewpoint of durability, ring B is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring.

[0070] From the viewpoint of improving durability and solubility, the hydrogen atom on ring B is preferably substituted with an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, or a (hetero)aryl group having 3 to 20 carbon atoms. It is preferred that the hydrogen atoms on ring B are not substituted in terms of ease of production. It is preferable that the hydrogen atom on ring B is substituted with a phenyl group or naphthyl group which may have a substituent, since this facilitates the generation of excitons when used in an organic electroluminescent device, thereby improving the luminous efficiency.

[0071] It is preferable that the ring B forms a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, or a carboline ring by forming a fused ring in which substituents on the ring B are bonded to each other and fused to the ring B, since this facilitates the generation of excitons on the assist dopant and improves the luminous efficiency. Among these, in terms of durability and red luminescence, the ring B is preferably a quinoline ring, an isoquinoline ring, or a quinazoline ring.

[0072] In formula (1C), R 11 ~R 13each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a phenyl group which may be substituted with an alkyl group having 1 to 20 carbon atoms, or a halogen atom. More preferably, R 11 and R 13 is a methyl group or a t-butyl group, and R 12 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a phenyl group.

[0073] The compound represented by formula (1) is 2 It is also preferable that the compounds are compounds represented by the following formula (1-2) in which the groups are bonded to each other to form a fluorene ring.

[0074] [ka]

[0075] [In formula (1-2), R 1 , a, m, n, ring A, Z 1 , L 1 , l is R in Equation (1) 1 , a, m, n, ring A, Z 1 , L 1 , which is synonymous with l. R 15 ~R 17 is a substituent.

[0076] R 15 As the above R 2 More preferably, R 15 R is an alkyl group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 30 carbon atoms which may be substituted with one or two alkyl groups having 1 to 20 carbon atoms. Here, the aromatic hydrocarbon group having 6 to 30 carbon atoms is a monocyclic ring, a condensed two-ring ring, or a condensed three-ring ring, or a group in which multiple monocyclic rings, condensed two-ring rings, or condensed three-ring rings are linked together. 15 is more preferably an alkyl group having 1 to 20 carbon atoms, and particularly preferably an alkyl group having 1 to 8 carbon atoms.

[0077] R 16 , R17 is the above R 2 Part of or the R 2 are substituents that R may have, and preferably each independently represents an alkyl group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms which may be substituted with one or two alkyl groups having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms which may be substituted with one or two alkoxy groups having 1 to 12 carbon atoms. Here, the aromatic hydrocarbon group having 6 to 20 carbon atoms is a monocyclic ring, a fused two-ring ring, or a fused three-ring ring, or a group in which multiple monocyclic rings, fused two-ring rings, or fused three-ring rings are linked together. 16 , R 17 and are more preferably each independently an alkyl group having 1 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 or 12 carbon atoms which may be substituted with one or two alkyl groups having 1 to 8 carbon atoms, and particularly preferably an alkyl group having 1 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 carbon atoms which may be substituted with one or two alkyl groups having 1 to 8 carbon atoms. Here, the aromatic hydrocarbon structure having 6 carbon atoms is a benzene structure, and the aromatic hydrocarbon structure having 12 carbon atoms is a biphenyl structure.

[0078] Preferred specific examples of the compound represented by formula (1) that is the light-emitting dopant contained in the composition for organic electroluminescent elements of the present invention are shown below, but the present invention is not limited to these.

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [High molecular compound] The composition for organic electroluminescent elements of the present invention contains a polymer compound having a repeating unit containing a structure represented by the following formula (2) (hereinafter, sometimes referred to as "repeating unit (2)").

[0083] [ka]

[0084] [In formula (2), R 3 , R 4 are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent.]

[0085] In formula (2), R 3 , R 4 From the viewpoint of solubility, R are each independently preferably an alkyl group having 1 to 20 carbon atoms or a (hetero)aralkyl group having 7 to 40 carbon atoms. 3 , R 4 are each independently preferably a (hetero)aryl group having 3 to 30 carbon atoms in terms of heat resistance.

[0086] In order to enhance charge transport properties, the polymer compound contained in the composition for organic electroluminescent elements of the present invention preferably contains, in addition to the repeating unit (2), a repeating unit containing a structure represented by the following formula (2-1) (hereinafter, sometimes referred to as "repeating unit (2-1)"). In this case, the repeating unit (2) may be contained in the following repeating unit (2-1).

[0087] [ka]

[0088] [In formula (2-1), Ar 21 ~Ar 23 each independently represents a divalent (hetero)arylene group having 3 to 30 carbon atoms which may have a substituent. Ar 24 , Ar 25 each independently represents a (hetero)aryl group having 3 to 30 carbon atoms which may have a substituent. and r represents an integer of 0 to 2.

[0089] Ar 21 ~Ar 23 are each independently preferably a phenylene group, a biphenylene group, a terphenylene group, a fluorenediyl group, or a divalent group having 30 or less carbon atoms formed by linking arbitrarily selected groups thereof, and particularly preferably a p-phenylene group or a biphenylene group, from the viewpoint of durability. These groups may have a substituent. When formula (2-1) contains a structure represented by formula (2), Ar 21 , Ar 22 , or if r is 1 or more, at least one Ar 23 At least one selected from the above is a fluorenyl group represented by formula (2) which may have substituents at the 9- and 9'-positions.

[0090] Ar 24 , Ar 25 In terms of durability, each of the groups is preferably a phenyl group, a biphenyl group, a terphenyl group, or a fluorenyl group, and more preferably a phenyl group or a fluorenyl group. These groups may have a substituent.

[0091] The polymer compound contained in the composition for organic electroluminescent elements of the present invention may contain only one type of repeating unit (2), or may contain two or more types of repeating unit (2-1).

[0092] The weight-average molecular weight (Mw) of the polymer compound contained in the composition for organic electroluminescent elements of the present invention is usually 2,000,000 or less, preferably 500,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less, and is usually 2,500 or more, preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 20,000 or more.

[0093] When the weight-average molecular weight is equal to or less than the upper limit, the polymer compound has excellent solubility in solvents and excellent film-forming properties, and when the weight-average molecular weight is equal to or more than the lower limit, the polymer compound has high glass transition temperature, melting point, and vaporization temperature, and excellent heat resistance.

[0094] The number average molecular weight (Mn) of the polymer compound contained in the composition for organic electroluminescent elements of the present invention is usually 1,000,000 or less, preferably 250,000 or less, more preferably 50,000 or less, and even more preferably 25,000 or less, and is usually 2,000 or more, preferably 4,000 or more, more preferably 8,000 or more, and even more preferably 15,000 or more.

[0095] The dispersity (Mw / Mn) of the polymer compound contained in the composition for organic electroluminescent elements of the present invention is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. The smaller the dispersity value, the better, so the lower limit is ideally 1. When the dispersity of the polymer compound is the above upper limit or less, purification is easy and the solubility in solvents and charge transport ability are good.

[0096] The weight-average molecular weight of polymer compounds is usually determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the higher the molecular weight component, the shorter the elution time, and the lower the molecular weight component, the longer the elution time. The weight-average molecular weight is calculated by converting the elution time of the sample into molecular weight using a calibration curve calculated from the elution time of polystyrene (standard sample) of known molecular weight. The number-average molecular weight can also be calculated in the same way.

[0097] The method for producing the polymer compound contained in the composition for organic electroluminescent elements of the present invention is not particularly limited, and any method can be used as long as it can produce a polymer compound having the repeating unit (2). For example, the polymer compound can be produced by a polymerization method using the Suzuki reaction, a polymerization method using the Grignard reaction, a polymerization method using the Yamamoto reaction, a polymerization method using the Ullmann reaction, a polymerization method using the Buchwald-Hartwig reaction, etc.

[0098] Preferred specific examples of repeating units and combinations thereof of the polymer compound having the repeating unit (2) contained in the composition for organic electroluminescent elements of the present invention other than those shown in the examples are shown below, but the present invention is not limited to these.

[0099] [ka]

[0100] [Charge transport material] The composition for organic electroluminescent elements of the present invention contains a compound represented by the following formula (3) as a charge transporting material.

[0101] [ka]

[0102] [In formula (3), X 1 represents C or N. R 5 ~R 7 are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent. R 5If there are multiple R 5 may be the same or different. Adjacent R bonded to the benzene ring 5 may be bonded to each other to form a ring fused to the benzene ring. c is an integer of 0 to 5. However, if c is 0, R 6 and R 7 is not also an unsubstituted phenyl group.

[0103] In formula (3), R 5 ~R 7 and are each independently preferably an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a (hetero)aryl group having 3 to 30 carbon atoms, more preferably an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, or a (hetero)aryl group having 3 to 20 carbon atoms, and even more preferably an aryl group having 6 to 20 carbon atoms.

[0104] In terms of charge transport properties, R 5 ~R 7 are each preferably independently a (hetero)aryl group having 3 to 20 carbon atoms. The (hetero)aryl group having 3 to 20 carbon atoms includes a monocyclic or fused ring aryl group, a monocyclic or fused ring heteroaryl group, a structure in which multiple monocyclic or fused ring aryl groups are linked together, a structure in which multiple monocyclic or fused ring heteroaryl groups are linked together, and a structure in which any multiple monocyclic or fused ring aryl groups or monocyclic or fused ring heteroaryl groups are linked together. More preferably, R 5 ~R 7are each independently a group selected from a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, and an indenofluorenyl group, or a group having 3 to 20 carbon atoms in which a plurality of groups selected from a phenyl group, a naphthyl group, a fluorenyl group, and a carbazolyl group are linked together. Particularly preferred are an indolocarbazolyl group, an indenocarbazolyl group, an indenofluorenyl group, a phenyl group, or a group in which two or three phenyl groups are linked together. These groups may further have a substituent.

[0105] From the viewpoints of charge transport property, luminous efficiency of the device, and device operating life, R 5 ~R 7 It is more preferable that the ends of each independently contain a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group, and when these groups are present, the following embodiment (i) is preferable, more preferable than the following embodiment (ii), and the following embodiment (iii) is even more preferable. (i) one or more R where c is 1 or greater 5 , R 6 , and R 7 At least one of the groups contains a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group at its terminal. (ii) one or more R where c is 1 or greater 5 , R 6 , and R 7 Among these, only one or two contain a naphthyl group, a fluorenyl group, a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group at the terminal. (iii) one or more R where c is 1 or greater 5 , R 6 , and R 7 Among these, only one or two contain a naphthyl group, a fluorenyl group, or a carbazolyl group at the terminal, or only one contains an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group. The R here 5 ~R7 The end of R 5 ~R 7 may be a substituent possessed by

[0106] These structures may further have a substituent. Examples of these terminal structures include the structures shown below.

[0107] [ka]

[0108] [In the above structure, * indicates the bonding position. 20 represents an aromatic hydrocarbon group having 6 to 20 carbon atoms. 14 represents a substituent. These structures may further have a substituent.]

[0109] The substituents that these structures may have are R 5 ~R 7 The substituents are the same as those that may be possessed by the group.

[0110] Ar 20 is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms, more preferably a phenyl group or a biphenyl group, and even more preferably a phenyl group.

[0111] R 14 In a structure having two R 14 may be the same or different. 14is preferably 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 aryloxy group having 6 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, or a heteroaryl group having 3 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, more preferably 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 aryloxy group having 6 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, and even more preferably an alkyl group having 1 to 8 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms.

[0112] From the viewpoint of enhancing solubility in a solvent and amorphousness, one or more R 5 , R 6 , and R 7 At least one of these preferably has a 1,2-phenylene group or a 1,3-phenylene group, and from the viewpoint of ease of synthesis, it is more preferable that at least one contains a 1,3-phenylene group.

[0113] From the viewpoint of durability, c is preferably an integer of 0 to 2.

[0114] In the compound represented by formula (3), R 5 When the benzene ring having the formula "Bz" is represented as Bz-(R 5 )c, R 6 and R 7 The three partial structures may all be the same structure, or may be different in only one structure, or may be different in all three structures, including the substituent if the partial structure has one. Preferably, only one structure is different or all three structures are different, and more preferably, all three structures are different. The reason for this will be described later.

[0115] The compound represented by formula (3) contained as the charge transport material is a low molecular weight compound, and its molecular weight is preferably 400 or more, more preferably 450 or more, even more preferably 500 or more, and even more preferably 600 or more, and is preferably 3000 or less, more preferably 2000 or less, even more preferably 1500 or less, and even more preferably 1200 or less.

[0116] Preferred specific examples of the compound represented by formula (3) contained as a charge transport material in the composition for organic electroluminescent elements of the present invention other than those shown in the examples are shown below, but the present invention is not limited to these.

[0117] [ka]

[0118] [Specific examples of each structure] Below, R in formulas (1), (1-1), (1-2), (1A) to (1C), (2), (2-1), and (3) 1 ~R 7 ,R 9 ~R 13 , Ar 21 ~Ar 25 , as ring A and ring B Specific examples and preferred structures of various structures are listed below.

[0119] The alkyl group having 1 to 20 carbon atoms may be any of linear, branched, or cyclic alkyl groups, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an isopropyl group, an isobutyl group, an isopentyl group, a t-butyl group, a cyclohexyl group, etc. Among these, linear alkyl groups having 1 to 8 carbon atoms such as a methyl group, an ethyl group, an n-butyl group, an n-hexyl group, an n-octyl group, etc. are preferred.

[0120] The (hetero)aralkyl group having 7 to 40 carbon atoms refers to a group in which some of the hydrogen atoms constituting a linear, branched, or cyclic alkyl group are substituted with a (hetero)aryl group. Specific examples include a 2-phenyl-1-ethyl group, a cumyl group, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, a 7-phenyl-1-heptyl group, and a tetrahydronaphthyl group. Of these, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, and a 7-phenyl-1-heptyl group are preferred.

[0121] Specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a hexyloxy group, a cyclohexyloxy group, an octadecyloxy group, etc. Of these, a hexyloxy group is preferred.

[0122] Specific examples of the (hetero)aryloxy group having 3 to 20 carbon atoms include a phenoxy group, a 4-methylphenyloxy group, etc. Among these, the phenoxy group is preferred.

[0123] Specific examples of the alkylsilyl group having 1 to 20 carbon atoms include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a dimethylphenyl group, a t-butyldimethylsilyl group, a t-butyldiphenylsilyl group, etc. Among these, a triisopropylsilyl group, a t-butyldimethylsilyl group, and a t-butyldiphenylsilyl group are preferred.

[0124] Specific examples of the arylsilyl group having 6 to 20 carbon atoms include a diphenylpyridylsilyl group, a triphenylsilyl group, etc. Among these, a triphenylsilyl group is preferred.

[0125] Specific examples of the alkylcarbonyl group having 2 to 20 carbon atoms include an acetyl group, a propionyl group, a pivaloyl group, a caproyl group, a decanoyl group, a cyclohexylcarbonyl group, etc. Among these, an acetyl group and a pivaloyl group are preferred.

[0126] Specific examples of the arylcarbonyl group having 7 to 20 carbon atoms include a benzoyl group, a naphthoyl group, an anthrayl group, etc. Of these, a benzoyl group is preferred.

[0127] Specific examples of the alkylamino group having 1 to 20 carbon atoms include a methylamino group, a dimethylamino group, a diethylamino group, an ethylmethylamino group, a dihexylamino group, a dioctylamino group, a dicyclohexylamino group, etc. Of these, a dimethylamino group and a dicyclohexylamino group are preferred.

[0128] Specific examples of the arylamino group having 6 to 20 carbon atoms include a phenylamino group, a diphenylamino group, a di(4-tolyl)amino group, a di(2,6-dimethylphenyl)amino group, etc. Among these, a diphenylamino group and a di(4-tolyl)amino group are preferred.

[0129] The (hetero)aryl group having 3 to 30 carbon atoms means an aromatic hydrocarbon group and an aromatic heterocyclic group, each having one free valence, or a linked aromatic hydrocarbon group in which a plurality of aromatic hydrocarbon groups are linked together, a linked aromatic heterocyclic group in which a plurality of aromatic heterocyclic groups are linked together, or a group in which one or more aromatic hydrocarbon groups and one or more aromatic heterocyclic groups are arbitrarily linked together.

[0130] Specific examples of the (hetero)aryl group having 3 to 30 carbon atoms include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, a fluoranthene ring, a furan ring, a benzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carba ring, and a benzophenone ring, each of which has one free valence. Examples of the aromatic hydrocarbon group include an azole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, and an azulene ring. Examples of the linked aromatic hydrocarbon group in which multiple aromatic hydrocarbons are linked together include a biphenyl group and a terphenyl group.

[0131] Among the above (hetero)aryl groups, from the viewpoint of durability, preferred are benzene, naphthalene, dibenzofuran, dibenzothiophene, carbazole, pyridine, pyrimidine, and triazine rings, each having one free valence. Among these, more preferred are aryl groups having 6 to 18 carbon atoms, such as a benzene, naphthalene, or phenanthrene ring, which may be substituted with an alkyl group having 1 to 8 carbon atoms, or a pyridine ring, which may be substituted with an alkyl group having 1 to 4 carbon atoms, and even more preferred are aryl groups having 6 to 18 carbon atoms, such as a benzene, naphthalene, or phenanthrene ring, which may be substituted with an alkyl group having 1 to 8 carbon atoms, and which may be substituted with an alkyl group having 1 to 8 carbon atoms.

[0132] The divalent (hetero)arylene group having 3 to 30 carbon atoms is the same as the above-mentioned exemplified (hetero)aryl group having 3 to 30 carbon atoms, except that it has two free valences, and the preferred examples are also the same.

[0133] Examples of the combination of these substituents include a combination of an aryl group and an alkyl group, a combination of an aryl group and an aralkyl group, or a combination of an aryl group and an alkyl group or an aralkyl group. Examples of the combination of an aryl group and an aralkyl group include a combination of a phenyl group, a biphenyl group, or a terphenyl group with a 5-phenyl-1-pentyl group or a 6-phenyl-1-hexyl group.

[0134] [Specific examples of substituents] Below, R in formulas (1), (1-1), (1-2), (1A) to (1C), (2), (2-1), and (3) 1 ~R 7 ,R 9 ~R 13 , Ar 21 ~Ar 25 The substituents that ring A and ring B may have are alkyl groups having 1 to 20 carbon atoms, (hetero)aralkyl groups having 7 to 40 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, (hetero)aryloxy groups having 3 to 20 carbon atoms, alkylsilyl groups having 1 to 20 carbon atoms, arylsilyl groups having 6 to 20 carbon atoms, alkylcarbonyl groups having 2 to 20 carbon atoms, arylcarbonyl groups having 7 to 20 carbon atoms, alkylamino groups having 1 to 20 carbon atoms, arylamino groups having 6 to 20 carbon atoms, (hetero)aryl groups having 3 to 30 carbon atoms, or bridging groups. Specific examples of the various substituents are as follows:

[0135] The alkyl group having 1 to 20 carbon atoms may be any of linear, branched, or cyclic alkyl groups, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an isopropyl group, an isobutyl group, an isopentyl group, a t-butyl group, a cyclohexyl group, etc. Among these, linear alkyl groups having 1 to 8 carbon atoms such as a methyl group, an ethyl group, an n-butyl group, an n-hexyl group, an n-octyl group, etc. are preferred.

[0136] The (hetero)aralkyl group having 7 to 40 carbon atoms refers to a group in which some of the hydrogen atoms constituting a linear, branched, or cyclic alkyl group are substituted with a (hetero)aryl group, and specific examples include a 2-phenyl-1-ethyl group, a cumyl group, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, a 7-phenyl-1-heptyl group, and a tetrahydronaphthyl group. Of these, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, and a 7-phenyl-1-heptyl group are preferred.

[0137] Specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a hexyloxy group, a cyclohexyloxy group, an octadecyloxy group, etc. Of these, a hexyloxy group is preferred.

[0138] Specific examples of the (hetero)aryloxy group having 3 to 20 carbon atoms include a phenoxy group, a 4-methylphenyloxy group, etc. Among these, the phenoxy group is preferred.

[0139] Specific examples of the alkylsilyl group having 1 to 20 carbon atoms include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a dimethylphenyl group, a t-butyldimethylsilyl group, a t-butyldiphenylsilyl group, etc. Among these, a triisopropylsilyl group, a t-butyldimethylsilyl group, and a t-butyldiphenylsilyl group are preferred.

[0140] Specific examples of the arylsilyl group having 6 to 20 carbon atoms include a diphenylpyridylsilyl group, a triphenylsilyl group, etc. Among these, a triphenylsilyl group is preferred.

[0141] Specific examples of the alkylcarbonyl group having 2 to 20 carbon atoms include an acetyl group, a propionyl group, a pivaloyl group, a caproyl group, a decanoyl group, a cyclohexylcarbonyl group, etc. Among these, an acetyl group and a pivaloyl group are preferred.

[0142] Specific examples of the arylcarbonyl group having 7 to 20 carbon atoms include a benzoyl group, a naphthoyl group, an anthrayl group, etc. Of these, a benzoyl group is preferred.

[0143] Specific examples of the alkylamino group having 1 to 20 carbon atoms include a methylamino group, a dimethylamino group, a diethylamino group, an ethylmethylamino group, a dihexylamino group, a dioctylamino group, a dicyclohexylamino group, etc. Of these, a dimethylamino group and a dicyclohexylamino group are preferred.

[0144] Specific examples of the arylamino group having 6 to 20 carbon atoms include a phenylamino group, a diphenylamino group, a di(4-tolyl)amino group, a di(2,6-dimethylphenyl)amino group, etc. Among these, a diphenylamino group and a di(4-tolyl)amino group are preferred.

[0145] The (hetero)aryl group having 3 to 30 carbon atoms means an aromatic hydrocarbon group and an aromatic heterocyclic group, each having one free valence, or a linked aromatic hydrocarbon group in which a plurality of aromatic hydrocarbon groups are linked together, a linked aromatic heterocyclic group in which a plurality of aromatic heterocyclic groups are linked together, or a group in which one or more aromatic hydrocarbon groups and one or more aromatic heterocyclic groups are arbitrarily linked together.

[0146] Specific examples of the (hetero)aryl group having 3 to 30 carbon atoms include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, a fluoranthene ring, a furan ring, a benzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carba ring, and a benzophenone ring, each of which has one free valence. Examples of the aromatic hydrocarbon group include an azole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, and an azulene ring. Examples of the linked aromatic hydrocarbon group in which multiple aromatic hydrocarbons are linked together include a biphenyl group and a terphenyl group.

[0147] Among the above (hetero)aryl groups, from the viewpoint of durability, preferred are benzene, naphthalene, dibenzofuran, dibenzothiophene, carbazole, pyridine, pyrimidine, and triazine rings, each having one free valence. Among these, more preferred are aryl groups having 6 to 18 carbon atoms, such as a benzene, naphthalene, or phenanthrene ring, which may be substituted with an alkyl group having 1 to 8 carbon atoms, or a pyridine ring, which may be substituted with an alkyl group having 1 to 4 carbon atoms, and even more preferred are aryl groups having 6 to 18 carbon atoms, such as a benzene, naphthalene, or phenanthrene ring, which may be substituted with an alkyl group having 1 to 8 carbon atoms, and which may be substituted with an alkyl group having 1 to 8 carbon atoms.

[0148] Examples of the combination of these substituents include a combination of an aryl group and an alkyl group, a combination of an aryl group and an aralkyl group, or a combination of an aryl group and an alkyl group or an aralkyl group. Examples of the combination of an aryl group and an aralkyl group include a combination of a phenyl group, a biphenyl group, or a terphenyl group with a 5-phenyl-1-pentyl group or a 6-phenyl-1-hexyl group.

[0149] Among these substituents, preferred are alkyl groups having 1 to 20 carbon atoms, aralkyl groups having 7 to 40 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, aryloxy groups having 3 to 20 carbon atoms, alkylsilyl groups having 1 to 20 carbon atoms, arylsilyl groups having 6 to 20 carbon atoms, arylamino groups having 6 to 20 carbon atoms, and (hetero)aryl groups having 3 to 30 carbon atoms. More preferred are alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkylsilyl groups having 1 to 20 carbon atoms, arylsilyl groups having 6 to 20 carbon atoms, arylamino groups having 6 to 20 carbon atoms, and (hetero)aryl groups having 3 to 30 carbon atoms. 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. The specific structure and the preferred number of carbon atoms in each of these preferred substituents are as described in the specific examples of the substituents above.

[0150] When these substituents further have a substituent, examples of the substituent include the above-mentioned exemplary substituents.

[0151] [Mechanism by which the composition for organic electroluminescent elements of the present invention exhibits the effects of the present invention] The light-emitting layer of an organic electroluminescent element produced using the composition for organic electroluminescent elements of the present invention contains a light-emitting dopant represented by formula (1), a polymer compound having a repeating unit including a structure represented by formula (2) (a polymer compound having a repeating unit (2)), and a compound represented by formula (3).

[0152] In the light-emitting layer of the organic electroluminescent device of the present invention, the polymer compound having the repeating unit (2) is primarily responsible for hole transport. When the repeating unit (2) is contained in the repeating unit (2-1), the polymer compound has an arylamine structure, significantly improving hole transport properties. The compound represented by formula (3) has high electron transport properties. This improves charge transport properties in the light-emitting layer, resulting in lower voltages. It is also believed that the charge balance between holes and electrons improves, improving luminous efficiency. The light-emitting dopant represented by formula (1) has an alkyl group containing a t-butyl group. The t-butyl group is bulky and causes steric hindrance. Therefore, the charge-transporting compound is usually located at a certain distance from the charge-accepting portion of the light-emitting dopant, making it difficult for charges to transfer from the charge-transporting compound to the light-emitting dopant. In the present invention, the material responsible for hole transport is primarily a polymer compound, and holes move easily along the polymer chain, resulting in holes being present in a relatively wide area of ​​the polymer chain. In a polymer chain in which holes exist over a wide range, there are sites where holes can relatively easily move to the emitting dopant represented by formula (1), and it is believed that holes move from there to the emitting dopant represented by formula (1). Thus, in the light-emitting layer of the organic electroluminescent element of the present invention, it is believed that holes first move to the neutral emitting dopant. Next, electrons move from the compound represented by formula (3) to the emitting dopant, where they recombine to emit light. The emitting dopant represented by formula (1) has low durability against electrons but high durability against holes, which is believed to extend the life of the element.

[0153] Furthermore, the compound represented by the formula (3) can be a compound represented by the formula (3) 5 )c], R 6 and R 7 It is preferable that the three partial structures, including the substituents, if any, are not identical. More preferably, these three partial structures are different from each other. In the present invention, such a structure is referred to as an asymmetric structure.

[0154] The compound represented by the formula (3) is R 5 ~R 7It is more preferable that only one or two of the groups have an asymmetric structure containing a naphthyl group, a fluorenyl group, a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group at the terminal. This asymmetric structure is preferable in that it improves amorphousness, forming a uniform and stable film, and facilitating the formation of a film uniformly mixed with other materials, and also improves solubility in solvents and stability in solution. In particular, the fact that it is easy to mix uniformly with other materials is particularly effective when a polymer material is included as an additional charge transport material.

[0155] This is thought to be because, when a composition for organic electroluminescent elements, in which the compound represented by formula (3) and the polymer compound having the repeating unit (2) are dissolved in a solvent, is used as a composition for forming an emitting layer to form a film by a wet process, when the solvent evaporates during drying and the composition for forming an emitting layer is becoming concentrated, the compound represented by formula (3) is asymmetric, and therefore, it is easy to form a film while the compound remains uniformly mixed with the polymer chain rings of the polymer compound having the repeating unit (2).

[0156] In particular, if present, one or more R 5 , R 6 , and R 7

[0039] When at least one of the groups contains a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group at its terminal, the carbazolyl group, the indolocarbazolyl group, the indenocarbazolyl group, or the indenofluorenyl group has hole-transporting ability, although to varying degrees, and therefore is thought to have high affinity with a hole-transporting polymer compound, to be easily mixed uniformly with the hole-transporting polymer compound, and to easily form a stable film. Among these, the carbazolyl group is preferred because it has an appropriately small structure and is thought to be more easily mixed with a polymer compound.

[0157] Furthermore, it is believed that the asymmetric structure of the compound represented by formula (3), which is a charge transport material, can improve the luminous efficiency of the compound represented by formula (1), which is a light-emitting dopant. The reason for this is as follows.

[0158] The luminescent dopant represented by formula (1) has an alkyl group containing a t-butyl group. Typically, because the t-butyl group is a steric hindrance, the charge-transporting material is positioned at a certain distance from the luminescent dopant represented by formula (1). In the present invention, the material responsible for hole transport is primarily a polymer compound, and holes are present at a relatively wide range of sites on the polymer chain, making it easy for holes to move to the luminescent dopant represented by formula (1). Meanwhile, because the t-butyl group in the luminescent dopant represented by formula (1) is a steric hindrance, the low-molecular-weight compound is usually positioned at a certain distance from the luminescent dopant, making it difficult for charges to move from the low-molecular-weight compound to the luminescent dopant. However, when the electron-transporting material represented by formula (3) of the present invention has an asymmetric structure, it is believed that the LUMO distribution is biased, and that there are sites through which electrons can easily move. Therefore, it is believed that electrons can easily move to the luminescent dopant having a steric hindrance such as a t-butyl group, resulting in lower voltages, higher light emission efficiency, and a longer device life.

[0159] In addition, in the compound represented by the formula (3), R 5 ~R 7 When at least one of the terminals contains a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group, the compound represented by formula (3) is thought to be more likely to accept holes as well as electrons, and to accept both electrons and holes to form an excited state. In this case, it is thought that the excitation energy is transferred directly to the emitting dopant, and even in the case of an emitting dopant having a t-butyl group as in formula (1), the excitation energy is transferred efficiently. As a result, it is thought that the luminous efficiency is increased and the operating life of the device is extended.

[0160] Furthermore, even if the compound represented by the formula (3) is symmetric, R 5 ~R 7 For the same reason, if all the terminals are carbazolyl groups, the luminous efficiency is increased and the operating life of the device is prolonged, which is preferable. 5 ~R 7Even if all the terminals have such a structure, it is preferable since it has little effect on the three-dimensional structure of the compound represented by the formula (3). The compound represented by the formula (3) is symmetrical when c=1 and [phenylene-R 5 ], R 6 and R 7 In the case where the three partial structures have substituents, all three of them, including the substituents, have the same structure.

[0161] [Method for synthesizing the compound represented by formula (1)] The compound represented by formula (1) contained as a light-emitting dopant in the composition for organic electroluminescent elements of the present invention is an iridium complex. A method for synthesizing this iridium complex is shown below.

[0162] Ligands for iridium complexes can be synthesized by combining known methods, such as the Suzuki-Miyaura coupling reaction of arylboronic acids with heteroaryl halides, or the Friedlaender cyclization reaction of 2-formyl or acylanilines or acyl-aminopyridines in the ortho position (Chem. Rev. 2009, 109, 2652, or Organic Reactions, 28(2), 37-201).

[0163] <Method for synthesizing iridium complexes> Iridium complexes can be synthesized by combining known methods using ligands and iridium chloride n-hydrate as raw materials, as explained below.

[0164] Examples of methods for synthesizing iridium complexes include a method via a chlorine-bridged iridium dinuclear complex as shown in the following formula [A], which uses a phenylpyridine ligand as an example for ease of understanding (M.G. Colombo, T.C. Brunold, T.Riedener, H.U. Gudel, Inorg.Chem., 1994, 33, 545-550), and a method in which the chlorine bridge of a dinuclear complex of the following formula [B] is further exchanged with acetylacetonate to convert it into a mononuclear complex, and then the target compound is obtained (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). However, the methods are not limited to these.

[0165] For example, the conditions for a typical reaction represented by the following formula [A] are as follows:

[0166] In the first step, a chlorine-bridged iridium dinuclear complex is synthesized by reacting two equivalents of the first ligand with one equivalent of iridium chloride n-hydrate. A mixture of 2-ethoxyethanol and water is typically used as the solvent, but no solvent or other solvents can be used. The reaction can be accelerated by using an excess of the ligand or by using an additive such as a base. Other bridging anionic ligands, such as bromine, can also be used in place of chlorine.

[0167] There are no particular limitations on the reaction temperature, but it is usually preferably 0° C. or higher, more preferably 50° C. or higher, and preferably 250° C. or lower, more preferably 150° C. or lower. When the reaction temperature is in this range, only the target reaction proceeds without the occurrence of by-products or decomposition reactions, and high selectivity tends to be obtained.

[0168] [ka]

[0169] In the second step, a halide ion scavenger such as silver trifluoromethanesulfonate is added and the resulting complex is contacted with the second ligand to obtain the desired complex. Ethoxyethanol or diglyme is typically used as the solvent, but depending on the type of ligand, no solvent or other solvents can be used, or a mixture of multiple solvents can be used. The addition of a halide ion scavenger is not always necessary, as the reaction may proceed without it. However, the addition of such a scavenger is advantageous for increasing the reaction yield and selectively synthesizing a facial isomer with a higher quantum yield. The reaction temperature is not particularly limited, but is typically between 0°C and 250°C.

[0170] Typical reaction conditions represented by the following formula [B] are explained below.

[0171] The first step of the binuclear complex can be synthesized in the same manner as in formula [A].

[0172] In the second step, the dinuclear complex is converted into a mononuclear complex with a 1,3-dionato ligand by reacting it with at least one equivalent of a 1,3-dione compound such as acetylacetone and at least one equivalent of a basic compound capable of abstracting the active hydrogen of the 1,3-dione compound, such as sodium carbonate. A solvent such as ethoxyethanol or dichloromethane, which can dissolve the starting dinuclear complex, is usually used, but if the ligand is liquid, the reaction can be carried out without a solvent. The reaction temperature is not particularly limited, but is usually between 0°C and 200°C.

[0173] [ka]

[0174] In the third step, one or more equivalents of the second ligand are reacted. There are no particular restrictions on the type or amount of solvent, and if the second ligand is liquid at the reaction temperature, no solvent is necessary. There are also no particular restrictions on the reaction temperature, but because the reactivity is somewhat poor, the reaction is often carried out at relatively high temperatures of 100°C to 300°C. Therefore, a solvent with a high boiling point, such as glycerin, is preferably used.

[0175] After the final reaction, purification is carried out to remove unreacted raw materials, reaction by-products, and solvents. While purification procedures commonly used in organic synthetic chemistry can be applied, as described in the above-mentioned non-patent document, purification is primarily carried out by normal-phase silica gel column chromatography. The developing solution can be a single or mixed solution of hexane, heptane, dichloromethane, chloroform, ethyl acetate, toluene, methyl ethyl ketone, or methanol. Purification may be carried out multiple times under different conditions. Other chromatographic techniques (reverse-phase silica gel chromatography, size exclusion chromatography, paper chromatography), as well as purification procedures such as separation washing, reprecipitation, recrystallization, powder suspension washing, and vacuum drying, can also be used as needed.

[0176] [solvent] The composition for organic electroluminescent elements of the present invention contains a solvent.

[0177] The solvent contained in the composition for organic electroluminescent elements of the present invention is a volatile liquid component used for forming a layer containing a light-emitting dopant by wet film formation.

[0178] The solvent is not particularly limited as long as it is a solvent that can well dissolve the compound represented by formula (1) as the luminescent dopant, which is the solute, the polymer compound having the repeating unit (2), the compound represented by formula (3), and other luminescent materials and charge transport materials that may be contained as needed, which will be described later.

[0179] Preferred solvents include, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene (phenylcyclohexane), and tetralin; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene; and aromatic hydrocarbons such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether. Examples of suitable solvents include aromatic ethers; 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 fenchone; 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). Among these, alkanes and aromatic hydrocarbons are preferred. Cyclohexylbenzene, in particular, has a viscosity and boiling point suitable for wet film formation processes.

[0180] These solvents may be used singly or in any combination of two or more in any ratio.

[0181] The boiling point of the solvent is usually 80° C. or higher, preferably 100° C. or higher, more preferably 150° C. or higher, and particularly preferably 200° C. or higher, and is usually 270° C. or lower, preferably 250° C. or lower, and more preferably 240° C. or lower. If the boiling point is below this range, evaporation of the solvent from the composition during wet film formation may decrease film formation stability.

[0182] [composition] The composition for organic electroluminescent elements of the present invention is generally used to form a layer or film by a wet film-forming method, and is particularly preferably used to form a light-emitting layer of an organic electroluminescent element.

[0183] The content of the compound represented by formula (1), which is an emitting dopant, in the composition for organic electroluminescent elements is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 20% by mass or less, preferably 10% by mass or less. By setting the content of the compound represented by formula (1) within this range, when the composition is used for an organic electroluminescent element, there is little transfer of excitation energy to an adjacent layer (for example, a hole transport layer or a hole blocking layer), and quenching due to interactions between excitons is also little, so that the luminous efficiency can be increased.

[0184] The composition for organic electroluminescent elements of the present invention may contain only one type of compound represented by formula (1), or may contain a combination of two or more types.

[0185] The content of the polymer compound having the repeating unit (2) in the composition for organic electroluminescent elements of the present invention is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 20% by mass or less, 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 elements, there is little transfer of excitation energy to adjacent layers (e.g., hole transport layer or hole blocking layer) and there is little quenching due to interactions between excitons, thereby improving the luminous efficiency.

[0186] The composition for organic electroluminescent elements of the present invention may contain only one type of polymer compound having the repeating unit (2), or may contain a combination of two or more types.

[0187] The content of the compound represented by formula (3) in the composition for organic electroluminescent elements of the present invention is usually 0.005% by mass or more, preferably 0.05% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less. By setting the content of the compound represented by formula (3) within this range, when the composition is used for organic electroluminescent elements, electrons are efficiently injected from the adjacent layer on the cathode side (e.g., a hole-blocking layer) to the light-emitting layer, and the driving voltage can be reduced.

[0188] The composition for organic electroluminescent elements of the present invention may contain only one type of compound represented by formula (3), or may contain a combination of two or more types.

[0189] From the viewpoint of luminous efficiency, the composition for organic electroluminescent elements of the present invention preferably contains 5 to 100 parts by mass, particularly 15 to 60 parts by mass, of the compound represented by formula (1) relative to 100 parts by mass in total of the polymer compound having the repeating unit (2) and the compound represented by formula (3). If the amount of the compound represented by formula (1), which is responsible for luminescence, is too small, the efficiency decreases, whereas if it is too large, quenching occurs easily, resulting in a decrease in efficiency.

[0190] 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 the repeating unit (2) per 100 parts by mass of the polymer compound having the repeating unit (2) and the compound represented by formula (3), from the viewpoint of achieving an appropriate charge balance and improving efficiency.

[0191] The content of the solvent in the composition for organic electroluminescent elements of the present invention is, per 100 parts by mass of the composition, preferably 10 parts by mass or more, more preferably 50 parts by mass or more, particularly preferably 80 parts by mass or more, and is preferably 99.95 parts by mass or less, more preferably 99.9 parts by mass or less, particularly preferably 99.8 parts by mass or less.

[0192] As described later, the thickness of the light-emitting layer is usually about 3 to 200 nm, but if the content of the solvent is equal to or greater than the lower limit, the viscosity of the composition does not become too high, and the film-forming workability becomes good. On the other hand, if the content of the solvent is equal to or less than the upper limit, the thickness of the film obtained by removing the solvent after film formation can be increased, and film formation tends to be easier.

[0193] As described above, the composition for organic electroluminescent elements of the present invention may contain only one type of solvent, or may contain a combination of two or more types of solvents.

[0194] [Organic electroluminescent device] The organic electroluminescent device of the present invention comprises a light-emitting layer formed by a wet film-forming method using the composition for organic electroluminescent devices of the present invention.

[0195] The organic electroluminescent device 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, as at least one of the organic layers, a light-emitting layer formed by a wet film-forming method using the composition for organic electroluminescent devices of the present invention.

[0196] In the present invention, the wet film formation method refers to a film formation method, i.e., a coating method, which employs a wet film formation method such as spin coating, dip coating, die coating, bar coating, blade coating, roll coating, spray coating, capillary coating, inkjet printing, nozzle printing, screen printing, gravure printing, or flexographic printing, and then dries the film formed by such a method to form a film.

[0197] Fig. 1 is a schematic cross-sectional view showing an example of a structure suitable for an organic electroluminescent element 10 of the present invention. In Fig. 1, reference numeral 1 represents a substrate, reference numeral 2 represents an anode, reference numeral 3 represents a hole injection layer, reference numeral 4 represents a hole transport layer, reference numeral 5 represents a light-emitting layer, reference numeral 6 represents a hole blocking layer, reference numeral 7 represents an electron transport layer, reference numeral 8 represents an electron injection layer, and reference numeral 9 represents a cathode.

[0198] The materials used in these structures can be known materials and are not particularly limited, but representative materials and manufacturing methods for each layer are described below as examples. When publications, papers, etc. are cited below, the relevant content can be applied and adapted as appropriate within the scope of common sense of a person skilled in the art.

[0199] <Board 1> The substrate 1 serves as a support for the organic electroluminescent element, and is typically made of a quartz or glass plate, a metal plate or foil, a plastic film or sheet, or the like. Of these, a glass plate or a plate made of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferred. The substrate 1 is preferably made of a material with high gas barrier properties, as this makes it less likely for the organic electroluminescent element to deteriorate due to the outside air. In particular, when using a material with low gas barrier properties, such as a synthetic resin substrate, it is preferable to provide a dense silicon oxide film or the like on at least one surface of the substrate 1 to improve the gas barrier properties.

[0200] <Anode 2> The anode 2 functions to inject holes into the layer on the light-emitting layer side. The anode 2 is usually made of a metal such as aluminum, gold, silver, nickel, palladium, or platinum; a metal oxide such as indium and / or tin oxide; a metal halide such as copper iodide; or a conductive polymer such as carbon black, poly(3-methylthiophene), polypyrrole, or polyaniline.

[0201] The anode 2 is usually formed by a dry method such as sputtering or vacuum deposition. When the anode 2 is formed using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, or the like, the anode 2 can be formed by dispersing the material in an appropriate binder resin solution and applying it to the substrate. In the case of a conductive polymer, the anode 2 can be formed by forming a thin film directly on the substrate by electrolytic polymerization, or by applying the conductive polymer to the substrate (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0202] The anode 2 usually has a single layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, a different conductive material may be laminated on the first layer of the anode.

[0203] The thickness of the anode 2 may be determined depending on the required transparency, material, etc. When particularly high transparency is required, a thickness that provides a visible light transmittance of 60% or more is preferred, and a thickness that provides a visible light transmittance of 80% or more is more preferred. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. When transparency is not required, the thickness of the anode 2 may be arbitrarily determined depending on the required strength, etc. In this case, the anode 2 may have the same thickness as the substrate 1.

[0204] When forming a film on the surface of the anode 2, it is preferable to perform a treatment with ultraviolet light and ozone, oxygen plasma, argon plasma, or the like before the film formation to remove impurities on the anode and adjust its ionization potential to improve hole injection properties.

[0205] <Hole injection layer 3> A layer that transports holes from the anode 2 side to the light-emitting layer 5 side is usually called a hole injection transport layer or hole transport layer. When there are two or more layers that transport holes from the anode 2 side to the light-emitting layer 5 side, the layer closer to the anode 2 side may be called the hole injection layer 3. The hole injection layer 3 is preferably used in order to enhance the function of transporting holes from the anode 2 to the light-emitting layer 5 side. When the hole injection layer 3 is used, the hole injection layer 3 is usually formed on the anode 2.

[0206] The thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

[0207] The hole injection layer 3 may be formed by vacuum deposition or wet film formation, but is preferably formed by wet film formation in terms of excellent film formability.

[0208] The hole injection layer 3 preferably contains a hole transport compound, more preferably contains a hole transport compound and an electron acceptor compound, and further preferably contains a cation radical compound, particularly preferably contains a cation radical compound and a hole transport compound.

[0209] (Hole transporting compound) The composition for forming a hole injection layer usually contains a hole transporting compound that will become the hole injection layer 3 .

[0210] In the case of a wet film formation method, a solvent is usually further contained. The composition for forming a hole injection layer preferably has high hole transport properties and can efficiently transport injected holes. For this reason, it is preferable that the composition has high hole mobility and is less likely to generate impurities that become traps during production or use. It is also preferable that the composition has excellent stability, a small ionization potential, and high transparency to visible light. In particular, when the hole injection layer 3 is in contact with the light-emitting layer 5, it is preferable that the composition does not quench the light emission from the light-emitting layer 5 or that the composition does not form exciplexes with the light-emitting layer 5 to reduce the light-emitting efficiency.

[0211] The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of the charge injection barrier from the anode 2 to the hole injection layer 3. Examples of the hole transporting compound include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which a tertiary amine is linked via a fluorene group, hydrazone compounds, silazane compounds, and quinacridone compounds.

[0212] Among the above-mentioned exemplary compounds, aromatic amine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred, from the viewpoints of amorphousness and visible light transmittance. The aromatic tertiary amine compounds are compounds having an aromatic tertiary amine structure and also include compounds having a group derived from an aromatic tertiary amine.

[0213] The type of aromatic tertiary amine compound is not particularly limited, but it is preferable to use a polymer compound (polymerized compound having a series of repeating units) having a weight average molecular weight of 1,000 to 1,000,000, in terms of easily obtaining uniform light emission due to the surface smoothing effect. Preferred examples of aromatic tertiary amine polymer compounds include polymer compounds having a repeating unit represented by the following formula (I):

[0214] [ka]

[0215] [In formula (I), Ar 1 and Ar 2 each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. Ar 3 ~Ar 5 each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. Q represents a linking group selected from the group of linking groups shown below. In addition, Ar 1 ~Ar 5 Two groups bonded to the same N atom may be bonded to each other to form a ring.

[0216] The linking groups are shown below.

[0217] [ka]

[0218] [In each of the above formulas, Ar 6 ~Ar 16 R each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. a ~R b each independently represents a hydrogen atom or an arbitrary substituent.

[0219] Ar 1 ~Ar 16As the aromatic group and heteroaromatic group, from the viewpoints of the solubility, heat resistance, and hole injection and transport properties of the polymer compound, groups derived from a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, and a pyridine ring are preferred, and groups derived from a benzene ring and a naphthalene ring are more preferred.

[0220] Specific examples of aromatic tertiary amine polymer compounds having a repeating unit represented by formula (I) include those described in WO 2005 / 089024.

[0221] (Electron-accepting compounds) The hole injection layer 3 is provided with a layer having a hole transporting compound, which is oxidized to improve the conductivity of the hole injection layer 3. Since the electron-accepting compound can be contained, it is preferable that the electron-accepting compound is contained.

[0222] The electron-accepting compound is preferably a compound having oxidizing power and the ability to accept one electron from the hole-transporting compound. Specifically, a compound having an electron affinity of 4 eV or more is preferred, and a compound having an electron affinity of 5 eV or more is more preferred.

[0223] Examples of such electron-accepting compounds include one or more compounds selected from the group consisting of triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. Specific examples include organically substituted onium salts such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate and triphenylsulfonium tetrafluoroborate (WO 2005 / 089024), high-valent inorganic compounds such as iron(III) chloride (JP 11-251067 A) and ammonium peroxodisulfate, cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris(pentafluorophenyl)borane (JP 2003-31365 A), fullerene derivatives, and iodine.

[0224] (cation radical compound) The cation radical compound is preferably an ionic compound consisting of a cation radical, which is a chemical species obtained by removing one electron from a hole-transporting compound, and a counter anion. When the cation radical is derived from a hole-transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

[0225] The cation radical is preferably a chemical species obtained by removing one electron from the compound described above as a hole transport compound, which is preferable in terms of amorphousness, visible light transmittance, heat resistance, solubility, etc.

[0226] The cation radical compound can be generated by mixing the hole transport compound and the electron acceptor compound. By mixing the hole transport compound and the electron acceptor compound, electrons are transferred from the hole transport compound to the electron acceptor compound, and a cation ion compound consisting of the cation radical of the hole transport compound and a counter anion is generated.

[0227] Cation radical compounds derived from polymeric compounds such as PEDOT / PSS (Adv. Mater., 2000, Vol. 12, p. 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, Vol. 94, p. 7716) can also be produced by oxidative polymerization (dehydrogenative polymerization). The oxidative polymerization referred to here is a process in which a monomer is chemically or electrochemically oxidized in an acidic solution using peroxodisulfate or the like. In this oxidative polymerization (dehydrogenative polymerization), the monomer is oxidized to form a polymer, and a cation radical is generated by removing one electron from the repeating unit of the polymer, with the anion derived from the acidic solution as the counter anion.

[0228] (Formation of Hole Injection Layer 3 by Wet Film Formation Method) When the hole injection layer 3 is formed by a wet film formation method, a film formation composition (hole injection layer formation composition) is usually prepared by mixing the material for the hole injection layer 3 with a soluble solvent (hole injection layer solvent), and this hole injection layer formation composition is formed into a film on a layer corresponding to the layer below the hole injection layer 3 (usually the anode 2) by a wet film formation method, followed by drying. The formed film can be dried in the same manner as in the formation of the light emitting layer 5 by a wet film formation method.

[0229] The concentration of the hole transport compound in the composition for forming a hole injection layer is arbitrary as long as it does not significantly impair the effects of the present invention. A lower concentration is preferable in terms of film thickness uniformity, while a higher concentration is preferable in terms of reducing the likelihood of defects in the hole injection layer 3. The concentration of the hole transport compound in the composition for forming a hole injection layer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.5% by mass or more, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[0230] Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, and amide solvents.

[0231] 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, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

[0232] Examples of ester solvents include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

[0233] Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene.

[0234] Examples of amide solvents include N,N-dimethylformamide and N,N-dimethylacetamide.

[0235] In addition to these, dimethyl sulfoxide and the like can also be used.

[0236] The hole injection layer 3 is usually formed by a wet film formation method by preparing a composition for forming the hole injection layer, applying the composition to a layer (usually the anode 2) that corresponds to the layer below the hole injection layer 3, and then drying the applied film. After forming the hole injection layer 3, the applied film is usually dried by heating, drying under reduced pressure, or the like.

[0237] (Formation of Hole Injection Layer 3 by Vacuum Vapor Deposition) When forming the hole injection layer 3 by vacuum deposition, one or more of the constituent materials of the hole injection layer 3 (such as the hole transport compound and electron acceptor compound) are usually placed in a crucible installed in a vacuum chamber (when two or more materials are used, they are usually placed in separate crucibles), and the vacuum chamber is evacuated by a vacuum pump for 10 -4 After evacuating the chamber to about 100 Pa, the crucible is heated (when two or more materials are used, each crucible is usually heated), and the materials in the crucible are evaporated while controlling the evaporation rate (when two or more materials are used, each material is usually evaporated while controlling the evaporation rate independently), to form a hole injection layer 3 on the anode 2 on the substrate placed opposite the crucible. When two or more materials are used, a mixture of the materials can also be placed in the crucible, heated, and evaporated to form the hole injection layer 3.

[0238] The degree of vacuum during deposition is not limited as long as it does not significantly impair the effects of the present invention. -6 Torr (0.13 × 10 -4 Pa) or above, 9.0×10 -6Torr (12.0 × 10 -4 The deposition rate is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The deposition temperature during deposition is not limited as long as it does not significantly impair the effects of the present invention, but is preferably 10°C or more and 50°C or less.

[0239] <Hole transport layer 4> The hole transport layer 4 is a layer that transports holes from the anode 2 side to the light-emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, but it is preferable to provide this layer in order to enhance 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 the 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.

[0240] The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[0241] The hole transport layer 4 may be formed by vacuum deposition or wet film formation, but is preferably formed by wet film formation in terms of excellent film formability.

[0242] The hole transport layer 4 usually contains a hole transporting compound that becomes the hole transport layer 4. Examples of the hole transporting compound contained in the hole transport layer 4 include, in particular, aromatic diamines containing two or more tertiary amines and in which two or more fused aromatic rings are substituted with nitrogen atoms, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (JP-A-5-234681), and aromatic amine compounds having a starburst structure, such as 4,4',4''-tris(1-naphthylphenylamino)triphenylamine (J. Lumin. , vol. 72-74, p. 985, 1997), aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., p. 2175, 1996), spiro compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997), and carbazole derivatives such as 4,4'-N,N'-dicarbazolebiphenyl. Polyvinylcarbazole, polyvinyltriphenylamine (JP-A-7-53953), and polyarylene ether sulfones containing tetraphenylbenzidine (Polym. Adv. Tech., vol. 7, p. 33, 1996) are also preferably used.

[0243] (Formation of Hole Transport Layer 4 by Wet Film Formation Method) When the hole transport layer 4 is formed by a wet film formation method, it is usually formed using a composition for forming a hole transport layer instead of the composition for forming a hole injection layer, in the same manner as when the hole injection layer 3 described above is formed by a wet film formation method.

[0244] When the hole transport layer 4 is formed by a wet film formation method, the composition for forming a hole transport layer usually further contains a solvent. The solvent used in the composition for forming a hole transport layer can be the same as the solvent used in the composition for forming a hole injection layer described above. The concentration of the hole transporting compound in the composition for forming a hole transport layer can be set to the same range as the concentration of the hole transporting compound in the composition for forming a hole injection layer.

[0245] The hole transport layer 4 can be formed by a wet film formation method similar to the film formation method for the hole injection layer 3 described above.

[0246] (Formation of Hole Transport Layer 4 by Vacuum Vapor Deposition) When forming the hole transport layer 4 by vacuum deposition, it can usually be formed in the same manner as when forming the hole injection layer 3 by vacuum deposition, using the constituent material of the hole transport layer 4 instead of the constituent material of the hole injection layer 3. The film formation conditions during deposition, such as the degree of vacuum, deposition rate, and temperature, can be the same as those during vacuum deposition of the hole injection layer 3.

[0247] <Light-emitting layer 5> The light-emitting layer 5 is a layer that is excited by the recombination of holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between the pair of electrodes, and thus emits light.

[0248] The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9. When the hole injection layer 3 is present on the anode 2, the light-emitting layer 5 is formed between the hole injection layer 3 and the cathode 9. When the hole transport layer 4 is present on the anode 2, the light-emitting layer 5 is formed between the hole transport layer 4 and the cathode 9.

[0249] The thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effects of the present invention. A thicker layer is preferable in that defects are less likely to occur in the film, and a thinner layer is preferable in that a low driving voltage can be easily achieved. The thickness of the light-emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, and usually preferably 200 nm or less, more preferably 100 nm or less.

[0250] In the organic electroluminescent device of the present invention, the light-emitting layer 5 is formed using the composition for organic electroluminescent devices of the present invention, preferably by a wet film-forming method.

[0251] When a light-emitting layer is formed by a wet film-forming method using the composition for organic electroluminescent elements of the present invention, the composition for organic electroluminescent elements of the present invention may contain, in addition to the compound represented by formula (1), the polymer compound having the repeating unit (2), and the compound represented by formula (3), other light-emitting materials and charge-transporting materials.

[0252] Other light-emitting materials and charge-transporting materials will be described in detail below.

[0253] (luminescent material) The light-emitting material other than the compound represented by formula (1) is not particularly limited as long as it emits light at a desired emission wavelength and does not impair the effects of the present invention, and known light-emitting materials can be used. The light-emitting material may be a fluorescent material or a phosphorescent material, but a material with good luminous efficiency is preferred. From the viewpoint of internal quantum efficiency, a phosphorescent material is preferred.

[0254] Examples of fluorescent materials include the following materials:

[0255] Examples of fluorescent light-emitting materials that emit blue light (blue fluorescent light-emitting materials) include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis(2-phenylethenyl)benzene, and derivatives thereof.

[0256] Examples of fluorescent materials that emit green light (green fluorescent materials) include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al(C9H6NO)3.

[0257] Examples of fluorescent materials that emit yellow light (yellow fluorescent materials) include rubrene and perimidon derivatives.

[0258] Examples of fluorescent materials that emit red light (red fluorescent materials) include DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, and azabenzothioxanthene.

[0259] Examples of phosphorescent materials include organometallic complexes containing a metal selected from Groups 7 to 11 of the long periodic table (hereinafter, unless otherwise specified, the term "periodic table" refers to the long periodic table). Preferred examples of metals selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.

[0260] As the ligand of the organometallic complex, a ligand in which a (hetero)aryl group is linked to pyridine, pyrazole, phenanthroline, etc., such as a (hetero)arylpyridine ligand or a (hetero)arylpyrazole ligand, is preferred, and a phenylpyridine ligand or a phenylpyrazole ligand is particularly preferred. Here, (hetero)aryl represents an aryl group or a heteroaryl group.

[0261] Specific examples of preferred phosphorescent materials include phenylpyridine complexes 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; and porphyrin complexes such as octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethylpalladium porphyrin, and octaphenylpalladium porphyrin.

[0262] Examples of polymer-based light-emitting materials include polyfluorene-based materials such as poly(9,9-dioctylfluorene-2,7-diyl), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)], and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(1,4-benzo-2{2,1'-3}-triazole)], and polyphenylenevinylene-based materials such as poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene].

[0263] (Charge transport material) The charge transporting material is a material that has the ability to transport positive charges (holes) or negative charges (electrons). There are no particular limitations on the charge transporting material other than the compound represented by formula (3), and any known material can be used as long as it does not impair the effects of the present invention.

[0264] The charge transporting material may be a compound that has been used in the light-emitting layer of an organic electroluminescent device, and is particularly preferably a compound that has been used as a host material in the light-emitting layer.

[0265] Specific examples of the charge transporting material include the compounds exemplified as the hole transporting compound for the hole injection layer 3, such as aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which a tertiary amine is linked via a fluorene group, hydrazone compounds, silazane compounds, silanamine compounds, phosphamine compounds, and quinacridone compounds, as well as electron transporting compounds such as anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, and silole compounds.

[0266] Examples of charge transporting materials include aromatic diamines containing two or more tertiary amines, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, in which two or more condensed aromatic rings are substituted with nitrogen atoms (JP-A-5-234681), aromatic amine compounds having a starburst structure, such as 4,4',4''-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., vol. 72-74, p. 985, 1997), triphenylamines, and the like (J. Lumin., vol. 72-74, p. 985, 1997). Compounds exemplified as hole-transporting compounds for the hole-transport layer 4, such as aromatic amine compounds consisting of a tetramer of amine (Chem. Commun., p. 2175, 1996), fluorene compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997), and carbazole compounds such as 4,4'-N,N'-dicarbazolebiphenyl, can also be preferably used. Other examples include oxadiazole compounds such as 2-(4-biphenylyl)-5-(p-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD) and 2,5-bis(1-naphthyl)-1,3,4-oxadiazole (BND); silole compounds such as 2,5-bis(6'-(2',2''-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy); and phenanthroline compounds such as bathophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproine).

[0267] (Formation of light-emitting layer 5 by wet film formation method) The organic electroluminescent device of the present invention has a light-emitting layer formed by a wet film-forming method using the composition for organic electroluminescent devices of the present invention. The organic electroluminescent device of the present invention may have, as the light-emitting layer 5, a light-emitting layer other than the light-emitting layer formed by a wet film-forming method using the composition for organic electroluminescent devices of the present invention. The method for forming this light-emitting layer may be a vacuum deposition method or a wet film-forming method, but the wet film-forming method is preferred because of its excellent film-forming properties.

[0268] When the light-emitting layer 5 is formed by a wet film-forming method, the composition for organic electroluminescent elements of the present invention or a composition for forming a light-emitting layer prepared by mixing a material for the light-emitting layer 5 with a solvent (solvent for the light-emitting layer) in which the material is soluble is used in place of the composition for forming a hole-injection layer, in the same manner as in the case of forming the hole-injection layer 3 described above by a wet film-forming method.

[0269] Examples of the solvent include the ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents mentioned for forming 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 as exemplified for the composition for organic electroluminescent elements of the present invention. Specific examples of the solvent are listed below, but are not limited to these as long as they do not impair the effects of the present invention.

[0270] For example, 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, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether; aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, and 3-isopropyl biphenyl. Examples of suitable solvents include aromatic hydrocarbon solvents such as phenyl, 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, decalin, and bicyclohexane; 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 fenchone. Among these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

[0271] To obtain a more uniform film, it is preferable that the solvent evaporates at an appropriate rate from the liquid film immediately after film formation. Therefore, as described above, the boiling point of the solvent used is usually 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and usually 270°C or lower, preferably 250°C or lower, more preferably 230°C or lower.

[0272] The amount of solvent used is arbitrary as long as it does not significantly impair the effects of the present invention, but as mentioned above, a higher total content in the composition for forming an emitting layer, i.e., the composition for organic electroluminescent elements, is preferable in terms of facilitating film formation due to low viscosity, and a lower total content in terms of facilitating thick film formation. As mentioned 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, and preferably 99.99% by mass or less, more preferably 99.9% by mass or less, particularly preferably 99% by mass or less.

[0273] The solvent can be removed after the wet film formation by heating or reducing pressure. In the heating method, a clean oven or a hot plate is preferred as the heating means to apply heat uniformly to the entire film.

[0274] The heating temperature in the heating step may be any temperature as long as it does not significantly impair the effects of the present invention. However, a higher temperature is preferable in terms of shortening the drying time, and a lower temperature is preferable in terms of minimizing damage to the material. The upper limit of the heating temperature is usually 250°C or less, preferably 200°C or less, and more preferably 150°C or less. The lower limit of the heating temperature is usually 30°C or more, preferably 50°C or more, and more preferably 80°C or more. Heating temperatures exceeding the upper limit are not preferred because they exceed the heat resistance of commonly used charge transport materials or phosphorescent materials and may cause decomposition or crystallization. Heating temperatures below the lower limit are not preferred because they require a long time to remove the solvent. The heating time in the heating step is appropriately determined based on the boiling point and vapor pressure of the solvent in the composition for forming an emitting layer, the heat resistance of the material, and the heating conditions.

[0275] (Formation of the light-emitting layer 5 by vacuum deposition method) When forming the light-emitting layer 5 by vacuum deposition, one or more of the constituent materials of the light-emitting layer 5 (such as the above-mentioned light-emitting material and charge-transporting compound) are usually placed in a crucible installed in a vacuum chamber (when two or more materials are used, each is usually placed in a separate crucible), and the vacuum chamber is evacuated by a vacuum pump for 10 -4After evacuating the chamber to about 100 Pa, the crucible is heated (when two or more materials are used, each crucible is usually heated), and the materials in the crucible are evaporated while controlling the amount of evaporation (when two or more materials are used, each material is usually evaporated while controlling the amount of evaporation independently), to form the light-emitting layer 5 on the hole injection layer 3 or hole transport layer 4 placed opposite the crucible. When two or more materials are used, the light-emitting layer 5 can also be formed by placing a mixture of these materials in the crucible and heating and evaporating them.

[0276] The degree of vacuum during deposition is not limited as long as it does not significantly impair the effects of the present invention. -6 Torr (0.13 × 10 -4 Pa) or above, 9.0×10 -6 Torr (12.0 × 10 -4 The deposition rate is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The deposition temperature during deposition is not limited as long as it does not significantly impair the effects of the present invention, but is preferably 10°C or more and 50°C or less.

[0277] <Hole-blocking layer 6> A hole-blocking layer 6 may be provided between the light-emitting layer 5 and the electron-injecting layer 8 described below. The hole-blocking layer 6 is a layer laminated on the light-emitting layer 5 so as to be in contact with the interface of the light-emitting layer 5 on the cathode 9 side.

[0278] The hole-blocking layer 6 has the role of preventing holes migrating from the anode 2 from reaching the cathode 9, and the role of efficiently transporting electrons injected from the cathode 9 toward the light-emitting layer 5. Required physical properties of the material constituting the hole-blocking layer 6 include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1).

[0279] Examples of materials for the hole-blocking layer 6 that satisfy these conditions include mixed ligand complexes such as bis(2-methyl-8-quinolinolato)(phenolato)aluminum and bis(2-methyl-8-quinolinolato)(triphenylsilanolato)aluminum; metal complexes such as bis(2-methyl-8-quinolinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolinolato)aluminum binuclear metal complex; styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Laid-Open No. 11-242996); triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Laid-Open No. 7-41759); and phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297). Compounds having at least one pyridine ring substituted at the 2-, 4-, and 6-positions, as described in WO 2005 / 022962, are also preferred as materials for the hole-blocking layer 6.

[0280] There is no limitation on the method for forming the hole blocking layer 6, and it can be formed in the same manner as the method for forming the light emitting layer 5 described above.

[0281] The thickness of the hole blocking layer 6 is arbitrary as long as it does not significantly impair the effects of the present invention, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

[0282] <Electron transport layer 7> The electron transport layer 7 is provided between the light emitting layer 5 or the hole element layer 6 and the electron injection layer 8 for the purpose of further improving the current efficiency of the element.

[0283] The electron transport layer 7 is formed from a compound that can efficiently transport electrons injected from the cathode 9 between electrodes to which an electric field is applied, toward the light-emitting layer 5. The electron transporting compound used in the electron transport layer 7 is required to have a high efficiency of electron injection from the cathode 9 or the electron injection layer 8, and to have high electron mobility so that the injected electrons can be efficiently transported.

[0284] Examples of electron transporting compounds that satisfy these conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo[h]quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (U.S. Pat. No. 5,645,948), quinoxaline compounds (Japanese Patent Laid-Open No. 6-207169), phenanthroline derivatives (Japanese Patent Laid-Open No. 5-331459), 2-t-butyl-9,10-N,N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

[0285] The thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[0286] The electron transport layer 7 is formed by laminating it on the light emitting layer 5 or the hole blocking layer 6 by a wet film formation method or a vacuum deposition method, similar to the light emitting layer 5. Usually, the vacuum deposition method is used.

[0287] <Electron injection layer 8> The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the electron transport layer 7 or the light-emitting layer 5 .

[0288] To efficiently inject electrons, a metal with a low work function is preferable as the material for forming the electron injection layer 8. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium.

[0289] The thickness of the electron injection layer 8 is preferably 0.1 to 5 nm.

[0290] Inserting an ultrathin insulating film (with a film thickness of about 0.1 to 5 nm) made of LiF, MgF2, Li2O, Cs2CO3, or the like as an electron injection layer 8 at the interface between the cathode 9 and the electron transport layer 7 is also an effective method for improving the efficiency of the device (Appl. Phys. Lett., Vol. 70, p. 152, 1997; JP-A-10-74586; IEEE Trans. Electron. Devices, Vol. 44, p. 1245, 1997; SID 04 Digest, p. 154). Furthermore, doping organic electron-transporting materials, such as nitrogen-containing heterocyclic compounds such as bathophenanthroline or metal complexes such as aluminum complexes of 8-hydroxyquinoline, with alkali metals such as sodium, potassium, cesium, lithium, or rubidium (as described in JP-A Nos. 10-270171, 2002-100478, and 2002-100482, among others) is preferred because it improves electron injection and transport properties while also achieving excellent film quality. In this case, the film thickness is typically 5 nm or more, preferably 10 nm or more, and typically 200 nm or less, preferably 100 nm or less.

[0291] The electron injection layer 8 is formed by laminating it on the light-emitting layer 5 or the hole blocking layer 6 or electron transport layer 7 thereon by a wet film-forming method or a vacuum deposition method in the same manner as the light-emitting layer 5. The details of the wet film formation method are the same as those of the light-emitting layer 5 described above.

[0292] <Cathode 9> The cathode 9 serves to inject electrons into a layer (such as the electron injection layer 8 or the light-emitting layer 5) on the light-emitting layer 5 side. The material of the cathode 9 can be the same as that used for the anode 2. For efficient electron injection, it is preferable to use a metal with a low work function. Examples of materials that can be used for the cathode 9 include metals such as tin, magnesium, indium, calcium, aluminum, and silver, as well as alloys thereof. Examples of materials for the cathode 9 include alloy electrodes with a low work function, such as a magnesium-silver alloy, a magnesium-indium alloy, and an aluminum-lithium alloy.

[0293] From the viewpoint of device stability, it is preferable to protect the cathode 9 made of a metal having a low work function by laminating a metal layer having a high work function and being stable against the atmosphere on the cathode 9. Examples of the metal to be laminated include aluminum, silver, copper, nickel, chromium, gold, and platinum.

[0294] The thickness of the cathode is usually the same as that of the anode 2 .

[0295] <Other constituent layers> 1 has been described above, the organic electroluminescent device of the present invention may have any layer between the anode 2 and cathode 9 and the light-emitting layer 5 in addition to the layers described above, as long as the performance is not impaired. Any layer other than the light-emitting layer 5 may be omitted.

[0296] For example, it is also effective to provide an electron blocking layer between the hole transport layer 4 and the light emitting layer 5 for the same purpose as the hole blocking layer 8. The electron blocking layer prevents electrons moving from the light emitting layer 5 from reaching the hole transport layer 4, thereby increasing the probability of recombination with holes in the light emitting layer 5 and trapping the generated excitons within the light emitting layer 5, and also efficiently transporting holes injected from the hole transport layer 4 toward the light emitting layer 5.

[0297] The properties required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). When the light-emitting layer 5 is formed by a wet film-forming method, it is preferable to also form the electron-blocking layer by a wet film-forming method, since this facilitates device production. For this reason, it is preferable that the electron blocking layer also has compatibility with wet film formation, and examples of materials used for such electron blocking layers include copolymers of dioctylfluorene and triphenylamine, such as F8-TFB (International Publication No. 2004 / 084260).

[0298] 1, it is also possible to laminate the cathode 9, electron injection layer 8, electron transport layer 7, hole blocking layer 6, light-emitting layer 5, hole transport layer 4, hole injection layer 3, and anode 2 in this order on substrate 1. The organic electroluminescent device of the present invention can also be provided between two substrates, at least one of which is highly transparent.

[0299] It is also possible to create a structure in which multiple layers of the layer configuration shown in Figure 1 are stacked (a structure in which multiple light-emitting units are stacked). In this case, using, for example, V2O5 as a charge generation layer instead of the interfacial layer between the layers (between the light-emitting units) (when the anode is ITO and the cathode is Al, these two layers) reduces the barrier between the layers, which is preferable from the standpoints of luminous efficiency and driving voltage.

[0300] The present invention can be applied to any organic electroluminescent device, whether it is a single device, a device with a structure in which the devices are arranged in an array, or a structure in which the anodes and cathodes are arranged in an XY matrix.

[0301] [Display and lighting devices] The display device and lighting device of the present invention use the organic electroluminescent device of the present invention as described above. There are no particular limitations on the type or structure of the display device and lighting device of the present invention, and they can be assembled using the organic electroluminescent device of the present invention in accordance with a conventional method. For example, the display device of the present invention can be formed by a method such as that described in "Organic EL Display" (Ohmsha, published on August 20, 2004, by Tokito Shizuo, Adachi Chinaya, and Murata Hideyuki). [Example]

[0302] The present invention will be explained in more detail below with reference to examples. The present invention is not limited to the following examples, and the present invention can be practiced with any modifications without departing from the gist of the invention.

[0303] [Example 1] An organic electroluminescent device was fabricated in the following manner.

[0304] A 50-nm-thick indium tin oxide (ITO) transparent conductive film was deposited on a glass substrate and patterned into 2-mm-wide stripes using conventional photolithography and hydrochloric acid etching to form the anode. The ITO-patterned substrate was then ultrasonically cleaned with a surfactant solution, then rinsed with ultrapure water, then ultrasonically cleaned with ultrapure water, and finally rinsed with ultrapure water. It was then dried with compressed air and finally cleaned with ultraviolet light and ozone.

[0305] A composition for forming a hole injection layer was prepared by dissolving a hole transporting polymer compound represented by the following formula (P-1) at a concentration of 3.0 mass % and a compound represented by the following formula (HI-1) at a concentration of 0.3 mass % in ethyl benzoate.

[0306] [ka]

[0307] This composition for forming a hole injection layer was spin-coated onto the substrate in the atmosphere and dried on a hot plate in the atmosphere at 240° C. for 30 minutes to form a uniform thin film with a thickness of 40 nm, which was used as a hole injection layer.

[0308] Next, a composition for forming a hole transport layer was prepared by dissolving 3% by mass of a charge transport polymer compound represented by the following structural formula (HT-1) in cyclohexylbenzene. The composition was spin-coated onto the substrate on which the hole injection layer had been formed in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 230°C for 30 minutes to form a uniform thin film with a thickness of 43 nm, which served as the hole transport layer.

[0309] [ka]

[0310] Subsequently, as materials for the light-emitting layer, 75 parts by mass of a polymer compound (Mw=39000, Mw / Mn=1.41) represented by the following structural formula (H-1), 25 parts by mass of a compound represented by the following structural formula (H-2), and 20 parts by mass of a compound represented by the following structural formula (D-1) were weighed out, and these were dissolved in cyclohexylbenzene so that the total concentration was 6.0% by mass, to prepare a composition for forming a light-emitting layer.

[0311] [ka]

[0312] This composition for forming an emissive layer was spin-coated onto the substrate on which the hole transport layer had been formed in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 120°C for 20 minutes to form a uniform thin film with a thickness of 70 nm, which served as the emissive layer.

[0313] The substrate on which the light-emitting layer had been formed was placed in a vacuum deposition device, and the inside of the device was heated to 2 × 10 -4 The pressure was evacuated until it reached a pressure of 0.1 Pa or less.

[0314] Next, a compound represented by the following structural formula (HB-1) and 8-hydroxyquinolinolatolithium were co-deposited on the light-emitting layer at a thickness ratio of 2:3 by vacuum deposition at a rate of 1 Å / sec to form a hole-blocking layer with a thickness of 30 nm.

[0315] [ka]

[0316] Next, a 2 mm wide striped shadow mask was attached to the substrate as a mask for cathode deposition so that it was perpendicular to the ITO stripes of the anode, and the mask was placed in another vacuum deposition apparatus. Aluminum was heated in a molybdenum boat to form an 80 nm thick aluminum layer at a deposition rate of 1 to 8.6 Å / s to form the cathode.

[0317] Next, in a nitrogen glove box, a glass cap equipped with a moisture getter sheet was placed to cover the deposition area, and the periphery of the deposition area and the glass cap were bonded and sealed with UV-curable resin.

[0318] In this manner, an organic electroluminescent device having a light-emitting area measuring 2 mm×2 mm was obtained.

[0319] [Example 2] An element was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming the light-emitting layer was (H-1):(H-2):(D-1) = 50:50:20.

[0320] [Example 3] A device was fabricated in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming the light-emitting layer was (H-1):(H-3):(D-1)=75:25:20. The structural formula of (H-3) is shown below.

[0321] [ka]

[0322] [Comparative Example 1] A device was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming a light-emitting layer was (H-1):(D-1)=100:20.

[0323] [Element evaluation] The organic electroluminescent devices fabricated in Examples 1 to 3 and Comparative Example 1 were subjected to a luminance test of 1000 cd / m 2 The voltage (V) when light was emitted was measured, and the difference from the voltage of Comparative Example 1 (voltages of Examples 1 to 3 and Comparative Example 1 - voltage of Comparative Example 1) was calculated and taken as the voltage difference (V). The organic electroluminescent devices fabricated in Examples 1 to 3 and Comparative Example 1 were subjected to a luminance test of 1000 cd / m 2 The current luminous efficiency (cd / A) when the device was caused to emit light at 100 was measured, and the relative value when the current luminous efficiency of Comparative Example 1 was taken as 100 was determined to be the relative luminous efficiency. The organic electroluminescent devices fabricated in Examples 1 to 3 and Comparative Example 1 were tested to a brightness of 1000 cd / m 2 The external quantum efficiency (EQE) when light was emitted was determined, and the relative value when the EQE of Comparative Example 1 was taken as 100 was taken as the relative EQE. The evaluation results are shown in Table 1. As shown in Table 1, it was found that the organic electroluminescent device of the present invention had improved luminous efficiency and lower voltage than the organic electroluminescent device of the comparative example.

[0324] [Table 1]

[0325] [Example 4] An element was fabricated in the same manner as in Example 1, except that the compound represented by structural formula (H-2) was replaced with a compound represented by the following structural formula (H-4), and the material composition (parts by mass) contained in the composition for forming an emitting layer was (H-1):(H-4):(D-1) = 75:25:20.

[0326] [ka]

[0327] [Example 5] A device was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming the light-emitting layer was (H-1):(H-4):(D-1) = 50:50:20.

[0328] [Example 6] A device was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming a light-emitting layer was (H-1):(H-4):(D-1)=25:75:20.

[0329] [Example 7] An element was fabricated in the same manner as in Example 1, except that a compound represented by the following structural formula (H-5) was used instead of the structural formula represented by structural formula (H-2), and the material composition (parts by mass) contained in the composition for forming an emitting layer was (H-1):(H-5):(D-1) = 75:25:20.

[0330] [ka]

[0331] [Example 8] An element was fabricated in the same manner as in Example 1, except that a compound represented by the following structural formula (H-6) was used instead of the compound represented by structural formula (H-2), and the material composition (parts by mass) contained in the composition for forming an emitting layer was (H-1):(H-6):(D-1) = 75:25:20.

[0332] [ka]

[0333] Comparative Example 2 An element was fabricated in the same manner as in Comparative Example 1.

[0334] Comparative Example 3 An element was fabricated in the same manner as in Example 1, except that the compound represented by structural formula (H-2) was replaced with a compound represented by the following structural formula (H-7), and the material composition (parts by mass) contained in the composition for forming an emitting layer was (H-1):(H-7):(D-1) = 75:25:20.

[0335] [ka]

[0336] Comparative Example 4 An element was fabricated in the same manner as in Example 1, except that the compound represented by the following structural formula (D-2) was used instead of the compound represented by structural formula (D-1), and the material composition (parts by mass) contained in the composition for forming an emitting layer was (H-1):(H-4):(D-2) = 75:25:20.

[0337] [ka]

[0338] Comparative Example 5 A device was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming a light-emitting layer was (H-1):(H-5):(D-2)=75:25:20.

[0339] Comparative Example 6 A device was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming a light-emitting layer was (H-1):(H-6):(D-2)=75:25:20.

[0340] Comparative Example 7 A device was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming a light-emitting layer was (H-1):(H-7):(D-2)=75:25:20.

[0341] [Element evaluation] The organic electroluminescent devices fabricated in Examples 4 to 8 and Comparative Examples 2 to 7 were tested to a luminance of 1000 cd / m 2 The voltage (V) when light was emitted was measured, and the difference between the voltage of the device of Comparative Example 2 and the voltage of each device (voltages of Examples 4 to 8 and Comparative Examples 2 to 7 - voltage of Comparative Example 2) was calculated and used as the voltage difference (V). The organic electroluminescent devices fabricated in Examples 4 to 8 and Comparative Examples 2 to 7 were tested to a luminance of 1000 cd / m 2 The external quantum efficiency (EQE) was determined when the device was caused to emit light at 100°C, and the relative value of the EQE of each device was determined when the EQE of Comparative Example 2 was taken as 100, and this was taken as the relative EQE. The organic electroluminescent devices fabricated in Examples 4 to 8 and Comparative Examples 2 to 7 were driven at a constant current, and the initial luminance Lo was 3000 cd / m 2 The time until the luminance decreased to 95% of the initial luminance was calculated and taken as LT95 (hr). The LT95 of each element was calculated relative to the LT95 of Comparative Example 2, which was taken as 100, and this was taken as the relative driving life. These results are shown in Table 2. As shown in Table 2, the organic electroluminescent device of the present invention operates at a low voltage, has a high luminous efficiency (EQE), and has a long driving life.

[0342] [Table 2]

[0343] [Example 9] The device was fabricated in the same manner as in Example 1.

[0344] [Comparative Example 8] A device was produced in the same manner as in Example 1, except that the material composition (parts by mass) contained in the composition for forming a light-emitting layer was (H-1):(H-2):(D-2)=75:25:20.

[0345] Comparative Example 9 An element was fabricated in the same manner as in Example 1, except that a polymer compound represented by the following structural formula (H-8) was used instead of the polymer compound represented by structural formula (H-1), and the material composition (parts by mass) contained in the composition for forming an emitting layer was (H-8):(H-2):(D-1) = 75:25:20.

[0346] [ka]

[0347] [Element evaluation] The organic electroluminescent devices fabricated in Example 9, Comparative Example 8, and Comparative Example 9 were tested to have a brightness of 1000 cd / m 2The voltage (V) when light was emitted was measured, and the difference from the voltage of Comparative Example 2 (voltages of Examples 9, Comparative Examples 2, 8, and 9 - voltage of Comparative Example 2) was calculated and used as the voltage difference (V). The organic electroluminescent devices fabricated in Example 9, Comparative Example 8, and Comparative Example 9 were tested to have a brightness of 1000 cd / m 2 The external quantum efficiency (EQE) when light was emitted was determined, and the relative value when the EQE of Comparative Example 2 was taken as 100 was taken as the relative EQE. The organic electroluminescent devices fabricated in Example 9, Comparative Example 8, and Comparative Example 9 were driven at a constant current, and the initial luminance Lo was 3000 cd / m 2 The time until the luminance decreased to 95% of the initial luminance was calculated as LT95 (hr), and the relative value of LT95 of each element was calculated when the LT95 of Comparative Example 2 was set to 100, to give the relative driving life. These results are shown in Table 3. As shown in Table 3, the device of the present invention has a low voltage, a high luminous efficiency (EQE), and high driving durability. On the other hand, the device of Comparative Example 9, in which the polymer compound contained in the light-emitting layer does not contain the structure represented by formula (2) of the present invention, had a high voltage and a low luminous efficiency.

[0348] [Table 3]

[0349] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2019-110408 filed on June 13, 2019, the entire contents of which are incorporated by reference. [Explanation of symbols]

[0350] 1 board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6. Hole-blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent device

Claims

1. A compound represented by the following formula (1), a polymer compound having a repeating unit including a structure represented by the following formula (2); A composition for organic electroluminescent devices comprising a compound represented by the following formula (3) and a solvent: 【Chemical 1】 [In formula (1), R １ , R ２ are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent. R １ , R ２ If there are multiple R １ , R ２ may be the same or different. Adjacent R bonded to the benzene ring １ or R ２ may be bonded to each other to form a ring fused to the benzene ring. a is an integer of 0 to 4. b is an integer of 0 to 3. m is an integer from 1 to 20. n is an integer of 0 to 2. Ring A is any one of a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring, a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring. Ring A may have a substituent. The substituent is any one of a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 2 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 20 carbon atoms, or a combination thereof. Adjacent substituents bonded to ring A may be bonded to each other to form a ring fused to ring A. Z １ represents a direct bond or an m+1 valent aromatic linking group. L １ represents an auxiliary ligand, and l is an integer of 1 to 3. When there are multiple auxiliary ligands, they may be different from each other or the same.] 【Chemistry 2】 [In formula (2), R ３ , R ４ are each independently any one of an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, and a (hetero)aryl group having 3 to 30 carbon atoms, or a combination thereof. These groups may further have a substituent.] 【Chemistry 3】 [In formula (3), X １ represents N. R ５ are each independently a (hetero)aryl group having 3 to 30 carbon atoms. These groups may further have a substituent. ５ If there are multiple R ５ may be the same or different. Adjacent R bonded to the benzene ring ５ may be bonded to each other to form a ring fused to the benzene ring. R ６ , R ７ are each independently a group in which a plurality of groups selected from phenyl groups and carbazolyl groups are linked together. These groups may further have a substituent. The substituents which may be substituted include an alkyl group having 1 to 20 carbon atoms, a (hetero)aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a (hetero)aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, a (hetero)aryl group having 3 to 30 carbon atoms, and a bridging group. c is an integer of 0 to 5. R ５ ~R ７ The termini of each independently contain a phenyl group or a carbazolyl group. However, if c is 0, R ６ and R ７ is not an unsubstituted phenyl group.

2. Z in the formula (1) １ The composition for organic electroluminescent devices according to claim 1 , wherein is a direct bond.

3. 2. The composition for organic electroluminescent elements according to claim 1, wherein the compound represented by formula (1) is a compound represented by the following formula (1-1): 【Chemistry 4】 [In formula (1-1), Three Xs ２ represents C or N at the same time. Z ２ represents a direct bond or a p+1 valent aromatic linking group. Z ３ represents a direct bond or a q+1-valent aromatic linking group. p and q are integers of 1 to 10. R １ , R ２ , a, b, n, m, ring A, L １ , l is R in formula (1) １ , R ２ , a, b, m, n, ring A, L １ , 1.]

4. 3. The composition for organic electroluminescent elements according to claim 1, wherein the compound represented by formula (1) is a compound represented by formula (1-2): 【Chemistry 5】 [In formula (1-2), R １ , a, m, n, ring A, Z １ , L １ , l is R in formula (1) １ , a, m, n, ring A, Z １ , L １ , l. R １５ ~R １７ is a substituent.

5. 5. The composition for organic electroluminescent elements according to claim 1, wherein l in the formula (1) is 3.

6. The composition for organic electroluminescent elements according to any one of claims 1 to 5, wherein the polymer compound having a repeating unit including a structure represented by formula (2) includes a repeating unit represented by the following formula (2-1): 【Chemistry 6】 [In formula (2-1), Ar ２１ ~Ar ２３ each independently represents a divalent (hetero)arylene group having 3 to 30 carbon atoms which may have a substituent. Ar ２４ , Ar ２５ each independently represents a (hetero)aryl group having 3 to 30 carbon atoms which may have a substituent. and r represents an integer of 0 to 2.

7. In the compound represented by the formula (3), [phenylene-(R ５ ) c], R ６ and R ７ The composition for organic electroluminescent elements according to any one of claims 1 to 6, wherein the three partial structures, including the substituents if any, are not identical in structure.

8. A method for producing an organic electroluminescent device, comprising the step of forming a light-emitting layer by a wet film-forming method using the organic electroluminescent device composition according to any one of claims 1 to 7.

9. An organic electroluminescent device having a light-emitting layer formed using the organic electroluminescent device composition according to any one of claims 1 to 7.

10. A display device comprising the organic electroluminescent device according to claim 9.

11. A lighting device comprising the organic electroluminescent element according to claim 9.

Images