TW202110997A - Composition for organic electroluminescent elements, organic electroluminescent element, display device and lighting device - Google Patents

Abstract

A composition for organic electroluminescent elements, said composition containing a compound represented by formula (1), a polymer compound having a repeating unit that contains a structure represented by formula (2), a compound represented by formula (3), and a solvent. An organic electroluminescent element which comprises a light emitting layer that is formed using this composition for organic electroluminescent elements.

Description

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

The present invention relates to a composition for an organic electroluminescence element useful for forming a light-emitting layer of an organic electroluminescence element (hereinafter sometimes referred to as an "organic EL (Electro-Luminescence) element"). The present invention also relates to an organic electroluminescence element having a light-emitting layer formed using the composition for an organic electroluminescence element, a method of manufacturing the same, and a display device and a lighting device having the organic electroluminescence element.

Various electronic devices using organic EL elements, such as organic EL lighting and organic EL displays, are being put into practical use. Organic electroluminescent elements consume little power due to low applied voltage and can emit light in three primary colors. Therefore, they have begun to be used not only in large-scale display monitors, but also in small and medium-sized displays such as mobile phones and smart phones.

Organic electroluminescent devices are manufactured by laminating multiple layers such as a light-emitting layer, a charge injection layer, and a charge transport layer. Currently, most organic electroluminescent devices are manufactured by evaporating organic materials under vacuum. In the vacuum evaporation method, the evaporation process is complicated and the productivity is poor. The organic electroluminescent element manufactured by the vacuum vapor deposition method is extremely difficult to realize the enlargement of the panel of the illumination or display.

In recent years, as a process for efficiently manufacturing organic electroluminescent elements that can be used for large-scale displays or lighting, a wet film formation method (coating method) has been studied. Compared with the vacuum vapor deposition method, the wet film formation method has the advantage of being able to easily form a stable layer, and therefore is expected to be applied to mass production of displays or lighting devices or large displays.

In order to manufacture an organic electroluminescent element by a wet film formation method, all the materials used need to be materials that can be dissolved in an organic solvent and used as an ink. When the solubility of the used material is poor, it requires long-term heating and other operations, so there is a possibility that the material will deteriorate before use. Furthermore, if the uniform state cannot be maintained in the solution state for a long period of time, precipitation of the material from the solution will occur, making it impossible to form a film using an inkjet device or the like. The material used in the wet film forming method requires solubility in the two senses of dissolving quickly in an organic solvent and maintaining a uniform state without precipitation after dissolution.

In recent years, compounds containing specific substituents introduced into organometallic complex structures with iridium as the central metal widely used as luminescent dopants to improve solubility in organic solvents, and compounds containing An attempt has been made to improve the performance of organic electroluminescent devices by using inks of macromolecular compounds having a phyllostructure to improve the luminous efficiency of organic electroluminescent devices or to lower the driving voltage (for example, Patent Literature 1 and Patent Literature 2).

As another advantage of the wet film formation method over the vacuum vapor deposition method, it is possible to use more kinds of materials in one layer. In the vacuum vapor deposition method, when the number of materials increases, it is difficult to control the vapor deposition rate to be constant. On the other hand, in the wet film forming method, even if the number of materials increases, as long as each material is dissolved in an organic solvent, it is possible to prepare an ink with a fixed composition ratio for layer formation.

In recent years, attempts have been made to use a specific compound containing a triazine ring or a pyrimidine ring as one of the multiple components contained in the ink for forming the light-emitting layer for the purpose of undertaking electron transport (for example, Patent Document 3 And Patent Document 4). [Prior Art Literature] [Patent Literature]

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

[The problem to be solved by the invention] However, in the above-mentioned prior art, although the solubility of the luminescent dopant is improved due to the introduction of a specific substituent, and the stability of the ink is improved, the introduction of the specific substituent increases the electron transport properties of the luminescent material. decline. Therefore, for display or lighting applications, the performance of the organic electroluminescent element cannot be said to be sufficient, and it is required to further reduce the driving voltage and improve the luminous efficiency and driving life.

[Means to solve the problem] The subject of the present invention is to provide a composition for an organic electroluminescence element that can produce an organic electroluminescence element with a lower driving voltage, higher luminous efficiency, and long driving life than conventional ones by a wet film forming method.

In order to flexibly apply the advantages of the wet film forming method that can use more materials in one layer, the inventors conducted intensive studies in view of the above-mentioned problems. As a result, it was found that by using iridium complexes with high solubility in organic solvents with specific substituents introduced as luminescent dopants, in addition to the use of polymers containing 茀 structure, they are also used for electron transport. The specific compound containing the triazine ring or the pyrimidine ring is used as the host material, and these are dissolved in the solvent to make the composition for the organic electroluminescence device, and use it to make the organic electroluminescence device, the performance of the organic electroluminescence device improve.

The composition for an organic electroluminescent element of the present invention uses a highly soluble iridium complex in an organic solvent into which a specific substituent is introduced as a light-emitting dopant, so it is less likely to cause precipitation of the light-emitting material and has excellent storage stability. In addition, since it contains a specific compound containing a triazine ring or a pyrimidine ring that is responsible for electron transport, it is possible to produce organic materials with improved electron transport ability in the light-emitting layer, low driving voltage, high luminous efficiency, and long driving life compared to the previous ones. Electroluminescent element.

The gist of the present invention is as follows.

[1] A composition for organic electroluminescent elements, including: The compound represented by the following formula (1); The polymer compound has a repeating unit including a structure represented by the following formula (2); A compound represented by the following formula (3) and a solvent.

[式（1）中，R¹ 、R² 分別獨立地為碳數1～20的烷基、碳數7～40的（雜）芳烷基、碳數1～20的烷氧基、碳數3～20的（雜）芳氧基、碳數1～20的烷基矽烷基、碳數6～20的芳基矽烷基、碳數2～20的烷基羰基、碳數7～20的芳基羰基、碳數1～20的烷基胺基、碳數6～20的芳基胺基、及碳數3～30的（雜）芳基中的任一者，或者該些的組合；該些基亦可進而具有取代基；於存在多個R¹ 、R² 的情況下，多個R¹ 、R² 可相同亦可不同；鍵結於苯環的相鄰的R¹ 或R² 可相互鍵結而形成縮合於所述苯環的環； a為0～4的整數；b為0～3的整數； m為1～20的整數； n為0～2的整數； 環A為吡啶環、吡嗪環、嘧啶環、咪唑環、噁唑環、噻唑環、喹啉環、異喹啉環、喹唑啉環、喹噁啉環、氮雜三伸苯環、咔啉環中的任一者； 環A亦可具有取代基；所述取代基為氟原子、氯原子、溴原子、碳數1～20的烷基、碳數7～40的（雜）芳烷基、碳數1～20的烷氧基、碳數3～20的（雜）芳氧基、碳數1～20的烷基矽烷基、碳數6～20的芳基矽烷基、碳數2～20的烷基羰基、碳數7～20的芳基羰基、碳數2～20的烷基胺基、碳數6～20的芳基胺基、及碳數3～20的（雜）芳基中的任一者，或者該些的組合；鍵結於環A的相鄰的取代基彼此可鍵結而形成縮合於環A的環； Z¹ 表示直接鍵或m+1價的芳香族連結基； L¹ 表示輔助配位子；l為1～3的整數；輔助配位子存在多個的情況下，可分別不同，亦可相同][化1]

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

[化2]

[In formula (2), R ³ and R ⁴ are each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, an alkoxy group having 1 to 20 carbons, and 3-20 (hetero)aryloxy groups, alkylsilyl groups having 1-20 carbons, arylsilyl groups having 6-20 carbons, alkylcarbonyl groups having 2-20 carbons, aryl groups having 7-20 carbons Any one of a carbonyl group, an alkylamino group having 1 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons, or a combination of these; the These groups may further have substituents]

[化3]

[In formula (3), X ¹ represents C or N; R ⁵ to R ⁷ are each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and 1 to 20 carbons. Alkoxy, (hetero)aryloxy with 3-20 carbons, alkylsilyl with 1-20 carbons, arylsilyl with 6-20 carbons, alkylcarbonyl with 2-20 carbons, Any one of an arylcarbonyl group having 7 to 20 carbons, an alkylamino group having 1 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons, Or a combination of these; these groups may further have substituents; when there are multiple R ^5s , the multiple R ^5s may be the same or different; adjacent R ^5s bonded to the benzene ring may bond to each other To form a ring condensed to the benzene ring; c is an integer from 0 to 5; wherein, when c is 0, R ⁶ and R ^{7 are} not unsubstituted phenyl at the same time]

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

[3] The composition for an organic electroluminescence element according to [1], wherein the compound represented by the formula (1) is a compound represented by the following formula (1-1).

[化4]

[In formula (1-1), three X ² represent 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 from 1 to 10; R ¹ , R ² , a, b, n, m, ring A, L ¹ , l and R ¹ , R ² , a, b, m in formula (1) , N, ring A, L ¹ , l have the same meaning]

[4] The composition for an organic electroluminescence element according to [1] or [2], wherein the compound represented by the formula (1) is a compound represented by the formula (1-2).

[化5]

[In formula (1-2), R ¹ , a, m, n, ring A, Z ¹ , L ¹ , l and R ¹ , a, m, n, ring A, Z ¹ , L ¹ and l have the same meaning; R ¹⁵ to R ¹⁷ are substituents]

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

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

[化6]

[In formula (2-1), Ar ²¹ to Ar ²³ each independently represent a bivalent (hetero) arylene group having 3 to 30 carbon atoms that may have a substituent; Ar ²⁴ and Ar ²⁵ each independently represent that they may have The substituent has a (hetero)aryl group having 3 to 30 carbon atoms; r represents an integer of 0 to 2]

[7] The composition for an organic electroluminescent device according to any one of [1] to [6], wherein in the compound represented by the formula (3), [phenylene-(R ⁵ )c ] ^{The three partial structures of R 6} and R ⁷ are not the same structure. When the partial structure has a substituent, the substituent is also included.

[8] The composition for an organic electroluminescent device according to any one of [1] to [7], wherein the ^{terminals of R 5} to R ⁷ in the compound represented by formula (3) each independently include Phenyl, naphthyl, stilbyl, carbazolyl, indolocarbazolyl, indenocarbazolyl, or indeno stilbyl.

[9] A method of manufacturing an organic electroluminescence element, including the step of forming a light-emitting layer by a wet film formation method using the organic electroluminescence element composition as described in any one of [1] to [8].

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

[11] A display device having the organic electroluminescent element as described in [10].

[12] A lighting device having the organic electroluminescence element as described in [10].

[Effects of the invention] According to the present invention, by the wet film forming method, it is possible to provide an organic electroluminescent device with lower driving voltage, higher luminous efficiency, and long driving life than before.

Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of its gist.

In this specification, (hetero)aralkyl, (hetero)aryloxy, and (hetero)aryl respectively represent an aralkyl group that may contain a heteroatom, an aryloxy group that may contain a heteroatom, and an aryl group that may contain a heteroatom. . "May contain heteroatoms" means that one or two or more of the carbon atoms forming the main skeleton of the aryl group, aralkyl group, or aryloxy group are substituted with heteroatoms. Examples of heteroatoms include nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms, silicon atoms, and the like. Among them, a nitrogen atom is preferred from the viewpoint of durability. The same is true for (hetero) aryl extensions.

In this specification, "aromatic linking group" means not only an aromatic hydrocarbon linking group, that is, a linking group having an aromatic hydrocarbon ring, but also a broad sense including a heteroaromatic linking group, that is, a linking group having a heteroaromatic ring. Aromatic linking group.

[Luminescent Dopant] The composition for an organic electroluminescent element of the present invention contains a compound represented by the following formula (1) as a light-emitting dopant.

[化7]

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

In formula (1), from the viewpoint of durability, R ¹ and R ^{2 are} preferably each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and An arylamino group having 6 to 20 or a (hetero)aryl group having 3 to 30 carbons, more preferably an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, or a carbon number 3-20 (hetero)aryl groups. Two adjacent R ² may be connected to each other to form a ring.

Regarding a, in terms of ease of manufacture, 0 is preferred, and in terms of improving solubility, 1 or 2 is preferred, and 1 is more preferred. Regarding b, 0 is preferable in terms of ease of manufacture, and 1 or 2 is more preferable, and 1 is more preferable in terms of improving durability and solubility. When two adjacent R ² are connected to each other to form a ring, b is preferably 2 or 3.

In order to improve the solubility of the phenyl group having a tertiary butyl group at the end in an organic solvent, m is preferably 2 or more. The phenyl group having a tertiary butyl group at the end has little involvement in charge transport or light emission. Therefore, if it is too large, the driving voltage may increase or the light emission efficiency may decrease. Therefore, m is preferably 8 or less, and more preferably 4 or less.

In terms of both solubility and low driving voltage and high luminous efficiency, the compound represented by formula (1) preferably has 4 or more such terminal tertiary butyl groups as a whole, especially 6 or more. , And 48 or less, especially 24 or less.

In terms of ease of manufacture, n is preferably 0 or 1. In terms of less fear of increasing the driving voltage, n is preferably zero. In terms of improving solubility, n is preferably 1 or 2.

In terms of durability, ring A is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring.

In terms of durability and improved solubility, the hydrogen atom on ring A is preferably substituted by an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and a carbon number of 3 ~20 (hetero)aryl substitution. In terms of ease of manufacture, the hydrogen atom on ring A is preferably unsubstituted. If the hydrogen atom on the ring A is substituted with a phenyl group or a naphthyl group which may have a substituent, excitons are easily generated when used in an organic electroluminescent device, and therefore, it is preferable in terms of improving luminous efficiency.

If in ring A, the substituents on ring A are bonded to each other to form a condensed ring condensed to ring A, thereby forming a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, and an aza tertiary The benzene ring and the carboline ring have a longer emission wavelength, and therefore are useful for red emission applications. Among them, it is preferable that the ring A is formed with a quinoline ring, an isoquinoline ring, or a quinazoline ring in terms of durability and the point of exhibiting red light emission.

In terms of ease of manufacture, Z ^{1 is} preferably a direct bond. In terms of less fear that the drive voltage will increase, Z ^{1 is} preferably an m+1 valent aromatic linking group.

In the case of m being 1, in terms of durability, Z ^{1 is} preferably phenylene, biphenylene, terphenylene, terphenylene (terphenylene), or terphenylene diyl, and particularly preferably paraphenylene base.

When m is 2 or more, in terms of durability, Z ¹ preferably includes a benzene ring with 1,3,5-position as the bonding position or 2,4,6-position as the bonding position. Triazine ring.

Z ¹ preferably includes a trivalent group represented by the following formula (1-2A) or (1-2B).

[化8]

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

[化9]

[In formula (1-1), three X ² represent 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 from 1 to 10; R ¹ , R ² , a, b, n, m, ring A, L ¹ , l and R ¹ , R ² , a, b, m in formula (1) , N, ring A, L ¹ , l have the same meaning]

In the formula (1-1), Z ² and Z ^{3 are} preferably direct bonds in terms of ease of manufacture.

In terms of less fear that the driving voltage will increase, Z ² and Z ^{3 are} preferably p+1-valent and q+1-valent aromatic linking groups. In this case, for example, when p and q are 1, in terms of durability, Z ² and Z ^{3 are} preferably phenylene, biphenylene, terphenylene, or diphenylene, especially It is preferably p-phenylene.

In terms of durability, Z ^{2 when p is 2 or more and Z 3} when q is 2 or more preferably includes a benzene ring with 1,3,5-position as the bonding position or 2,4,6- The position is the triazine ring at the bonding position. That is, Z ² and Z ³ preferably include a trivalent group represented by the following formula (1-2A) or (1-2B).

[化10]

L ¹ is an auxiliary ligand. Although not particularly limited, L ^{1 is} preferably a monovalent bidentate ligand, and more preferably selected from the ligands represented by the following formula (1A), formula (1B), and formula (1C). The dotted lines in the following formulas (1A) to (1C) indicate coordination bonds. When l is 1 and there are two auxiliary ligands L ¹ , the auxiliary ligands L ¹ may be the same as each other or may have different structures. When l is 3, L ¹ does not exist.

[化11]

In the formulas (1A) and (1B), R ⁹ and R ^{10 are} selected from the same group as the R ¹ and R ² , and preferred examples are also the same. g is an integer of 0-4. h is an integer of 0-4. Regarding g and h, 0 is preferred in terms of ease of production, and 1 or 2 is preferred in terms of improving solubility, and 1 is more preferred.

Ring B is 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 benzoxaline ring. Any of the azole rings may have a substituent. In terms of durability, ring B is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring.

In terms of durability and improved solubility, the hydrogen atom on ring B is preferably an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and a carbon number of 3 ~20 (hetero)aryl substitution. In terms of ease of manufacture, the hydrogen atom on ring B is preferably unsubstituted. If the hydrogen atom on the ring B is substituted with a phenyl group or a naphthyl group which may have a substituent, excitons are easily generated when used in an organic electroluminescent device, and therefore, it is preferable in terms of improving luminous efficiency.

If in ring B, the substituents on ring B are bonded to each other to form a condensed ring condensed to ring B, thereby forming a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, and an aza tertiary The benzene ring and the carboline ring tend to generate excitons on the auxiliary dopant, and are therefore preferable in terms of improving the luminous efficiency. Among them, it is preferable that the ring B is formed with a quinoline ring, an isoquinoline ring, and a quinazoline ring in terms of durability and the point of exhibiting red light emission.

In the formula (1C), R ¹¹ to R ¹³ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted by a fluorine atom, a phenyl group which may be substituted by an alkyl group having 1 to 20 carbon atoms, or halogen atom. More preferably, R ¹¹ and R ¹³ are a methyl group or a tertiary butyl group, and R ¹² is a hydrogen atom, an alkyl group having 1 to 20 carbons, or a phenyl group.

The compound represented by the formula (1) is also preferably a compound represented by ^{the following formula (1-2) in which adjacent R 2} are bonded to each other to form a sulphur ring.

[化12]

[In formula (1-2), R ¹ , a, m, n, ring A, Z ¹ , L ¹ , l and R ¹ , a, m, n, ring A, Z ¹ , L ¹ and l have the same meaning; R ¹⁵ to R ¹⁷ are substituents]

Examples of R ¹⁵ include substituents that the above- ^{mentioned R 2 may have.} More preferably, R ¹⁵ is an alkyl group having 1 to 20 carbons, or an aromatic hydrocarbon group having 6 to 30 carbons which may be substituted with one or two alkyl groups having 1 to 20 carbons. Here, the aromatic hydrocarbon group having 6 to 30 carbon atoms refers to a group formed by connecting a plurality of monocyclic rings, bicyclic condensed rings, or tricyclic condensed rings, or monocyclic, bicyclic condensed rings, or tricyclic condensed rings. R ^{15 is more} preferably an alkyl group having 1 to 20 carbons, and particularly preferably an alkyl group having 1 to 8 carbons.

R ^16, R ¹⁷ or is a part of the ² R R ² may have a substituent, preferably each independently an alkyl group having 1 to 12 carbon atoms, and may be one or two carbon atoms of 1 to 12 An alkyl substituted aromatic hydrocarbon group with 6 to 20 carbons, an alkoxy group with 1 to 12 carbons, or an aromatic with 6 to 20 carbons which may be substituted by one or two alkoxy groups with 1 to 12 carbons Group hydrocarbon group. Here, the aromatic hydrocarbon group having 6 to 20 carbon atoms refers to a group formed by connecting a plurality of monocyclic rings, bicyclic condensed rings, or tricyclic condensed rings, or monocyclic, bicyclic condensed rings, or tricyclic condensed rings. R ¹⁶ and R ¹⁷ are more preferably each independently an alkyl group having 1 to 8 carbons, or an aromatic hydrocarbon group having 6 or 12 carbons which may be substituted with one or two alkyl groups having 1 to 8 carbons, particularly preferably It is an alkyl group having 1 to 8 carbons, or an aromatic hydrocarbon group having 6 carbons which may be substituted with one or two alkyl groups having 1 to 8 carbons. Here, the aromatic hydrocarbon structure with carbon number 6 is a benzene structure, and the aromatic hydrocarbon structure with carbon number 12 is a biphenyl structure.

Hereinafter, preferred specific examples of the compound represented by formula (1) which are the light-emitting dopant contained in the composition for an organic electroluminescent element of the present invention are shown. The present invention is not limited to these.

[化13]

[化14]

[化15]

[Polymer compound] The composition for an organic electroluminescent device of the present invention includes a polymer compound having a repeating unit including a structure represented by the following formula (2) (hereinafter, sometimes referred to as "repeating unit (2)") .

[化16]

[In formula (2), R ³ and R ⁴ are each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, an alkoxy group having 1 to 20 carbons, and 3-20 (hetero)aryloxy groups, alkylsilyl groups having 1-20 carbons, arylsilyl groups having 6-20 carbons, alkylcarbonyl groups having 2-20 carbons, aryl groups having 7-20 carbons Any one of a carbonyl group, an alkylamino group having 1 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons, or a combination of these; the These groups may further have substituents]

In formula (2), in terms of self-solubility, R ³ and R ⁴ are each independently preferably an alkyl group having 1 to 20 carbon atoms and a (hetero)aralkyl group having 7 to 40 carbon atoms. In terms of heat resistance, R ³ and R ⁴ are each independently preferably a (hetero)aryl group having 3 to 30 carbon atoms.

In terms of improving the charge transportability, the polymer compound contained in the composition for an organic electroluminescent device of the present invention preferably includes a repeating unit (2) and a polymer compound having the following formula (2). -1) Repeating unit of the structure shown (hereinafter, sometimes referred to as "repeating unit (2-1)"). In this case, the repeating unit (2) may be included in the following repeating unit (2-1).

[化17]

[In formula (2-1), Ar ²¹ to Ar ²³ each independently represent a bivalent (hetero) arylene group having 3 to 30 carbon atoms that may have a substituent; Ar ²⁴ and Ar ²⁵ each independently represent that they may have The substituent has a (hetero)aryl group having 3 to 30 carbon atoms; r represents an integer of 0 to 2]

In terms of durability, Ar ²¹ to Ar ²³ are each independently preferably a phenylene group, a biphenylene group, a terphenylene group, a stilbene diyl group, or an arbitrarily selected carbon number formed by connecting these groups The divalent group of 30 or less is particularly preferably p-phenylene and biphenylene. These groups may have a substituent. When formula (2-1) includes the structure represented by formula (2), when Ar ²¹ , Ar ²² or r is 1 or more, at least one selected from at least one Ar ²³ is represented by formula (2) A stilbene group that may have a substituent at the 9, 9'position.

In terms of durability, Ar ²⁴ and Ar ²⁵ are each independently preferably a phenyl group, a biphenyl group, a terphenyl group, and a stilbene group, and particularly preferably a phenyl group and a stilbene group. These groups may have a substituent.

The polymer compound contained in the composition for an organic electroluminescence element of the present invention may include only one type of repeating unit (2), or two or more types. In addition, only one type of repeating unit (2-1) may be included, or two or more types may be included.

The weight average molecular weight (Mw) of the polymer compound contained in the composition for an organic electroluminescent element of the present invention is usually 2,000,000 or less, preferably 500,000 or less, more preferably 100,000 or less, still more preferably 50,000 or less, and usually 2,500 Above, it is preferably 5,000 or more, more preferably 10,000 or more, and still more preferably 20,000 or more.

If the weight average molecular weight is less than or equal to the upper limit, the solubility to the solvent is excellent, and the film-forming properties are also excellent. If the weight average molecular weight is more than the above lower limit, the glass transition temperature, melting point, and vaporization temperature of the polymer compound are high, and the heat resistance is excellent.

The number average molecular weight (Mn) of the polymer compound contained in the composition for an organic electroluminescent element of the present invention is usually 1,000,000 or less, preferably 250,000 or less, more preferably 50,000 or less, still more preferably 25,000 or less, and usually 2,000 Above, it is preferably 4,000 or more, more preferably 8,000 or more, and still more preferably 15,000 or more.

The degree of dispersion (Mw/Mn) of the polymer compound contained in the composition for an organic electroluminescent element of the present invention is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. The smaller the value of the degree of dispersion, the better, so the lower limit is desirably 1. If the degree of dispersion of the polymer compound is less than or equal to the above upper limit, it is easy to purify, and the solubility to the solvent or the charge transport ability is good.

Generally, the weight average molecular weight of a polymer compound is determined by the determination of size exclusion chromatography (SEC). In the 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 the molecular weight using a calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight. The number average molecular weight is also calculated in the same way.

The method for producing the polymer compound contained in the composition for an organic electroluminescence element of the present invention is not particularly limited, and it is arbitrary as long as the polymer compound having the repeating unit (2) can be obtained. For example, the polymerization method based on Suzuki reaction, the polymerization method based on Grignard reaction, the polymerization method based on Yamamoto reaction, the polymerization method based on Ullmann reaction, the polymerization method based on Ullmann reaction, the polymerization method based on Grignard reaction, the polymerization method based on Ullmann reaction, the polymerization method based on Buchwald-Hartwig (Buchwald-Hartwig) reaction polymerization method.

Hereinafter, preferred specific examples of the repeating unit of the polymer compound having the repeating unit (2) contained in the composition for an organic electroluminescent element of the present invention other than those shown in the examples and the combination thereof are shown. The present invention is not limited to these.

[化18]

[Charge Transport Material] The composition for an organic electroluminescent element of the present invention contains a compound represented by the following formula (3) as a charge-transporting material.

[化19]

[In formula (3), X ¹ represents C or N; R ⁵ to R ⁷ are each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and 1 to 20 carbons. Alkoxy, (hetero)aryloxy with 3-20 carbons, alkylsilyl with 1-20 carbons, arylsilyl with 6-20 carbons, alkylcarbonyl with 2-20 carbons, Any one of an arylcarbonyl group having 7 to 20 carbons, an alkylamino group having 1 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons, Or a combination of these; these groups may further have substituents; when there are multiple R ^5s , the multiple R ^5s may be the same or different; adjacent R ^5s bonded to the benzene ring may bond to each other To form a ring condensed to the benzene ring; c is an integer from 0 to 5; wherein, when c is 0, R ⁶ and R ^{7 are} not unsubstituted phenyl at the same time]

In formula (3), in terms of durability, R ⁵ to R ⁷ are each independently preferably an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and 6 carbon atoms. -20 arylamino group, or (hetero)aryl group having 3 to 30 carbons, more preferably alkyl having 1 to 20 carbons, (hetero)aralkyl having 7 to 40 carbons, or carbon number of 3 to The (hetero)aryl group of 20 is more preferably an aryl group having 6 to 20 carbons.

In terms of charge transportability, R ⁵ to R ^{7 are} preferably (hetero)aryl groups each independently having 3 to 20 carbon atoms. The (hetero) aryl group having 3 to 20 carbon atoms includes a monocyclic or condensed ring aryl group, a monocyclic or condensed ring heteroaryl group, a structure in which multiple monocyclic or condensed ring aryl groups are connected, monocyclic or A structure in which a plurality of heteroaryl groups in a condensed ring are connected, and a structure in which a plurality of monocyclic or condensed ring aryl groups or a monocyclic or condensed ring heteroaryl group are arbitrarily connected. More preferably, R ⁵ to R ⁷ are each independently a group selected from the group consisting of phenyl, naphthyl, stilbene, carbazolyl, indolocarbazolyl, indenocarbazolyl, indeno lanyl, or A group having 3 to 20 carbons is formed by arbitrarily connecting a plurality of groups selected from the group consisting of phenyl, naphthyl, stilbene, and carbazolyl. Particularly preferred is an indolocarbazolyl, indenocarbazolyl, indenophosphoryl, phenyl or phenyl group formed by linking two or three of them. These groups may further have a substituent.

From the aspects of charge transportability, luminous efficiency of the device, and driving life of the device, it ^{is more preferable that the ends of R 5} to R ⁷ independently include a phenyl group, a naphthyl group, a stilbene group, a carbazolyl group, and an indolocarb The oxazolyl, indenocarbazolyl or indenosulfyl group, when these groups are present, are preferably in the form of (i) below, more preferably in the form of (ii) below, and still more preferably The following (iii) aspect. (I) When c is 1 or more ^{, at least one of one or more of R 5} , R ⁶ and R ⁷ contains a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenopyranyl group at the end . (Ii) When c is 1 or more of one or more of R ⁵ , R ⁶ and R ⁷ , only one or two of the ends contain naphthyl, stilbene, carbazolyl, indolocarbazolyl, indeno Carbazolyl or indenosulfonyl. (Iii) When c is 1 or more of one or more of R ⁵ , R ⁶ and R ⁷ , only one or two of the ends contain naphthyl, stilbene or carbazolyl, or only one contains indolocarbazole Group, indenocarbazolyl, or indeno guanyl. He said terminal where R ⁵ ~ R ⁷ may be R ⁵ ~ R ⁷ has a substituent.

These structures may further have a substituent. As an example of these terminal structures, the structure shown in the figure below can be cited.

[化20]

[In the structure, * represents the bonding position; Ar ²⁰ represents an aromatic hydrocarbon group with 6 to 20 carbon atoms; R ¹⁴ represents a substituent; these structures may further have a substituent]

The substituents that these structures may have are the same as the substituents that R ⁵ to R ⁷ may have.

Ar ^{20 is} preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms, more preferably a phenyl group or a biphenyl group, and still more preferably a phenyl group.

In the structure having two R ¹⁴ , the two R ¹⁴ may be the same or different. R ^{14 is} preferably alkyl having 1 to 20 carbons, aralkyl having 7 to 40 carbons, alkoxy having 1 to 20 carbons, aryloxy having 6 to 20 carbons, or having 1 to 20 carbons. Alkylsilyl group, arylsilyl group having 6 to 20 carbons, aryl group having 6 to 30 carbons which may be substituted with alkyl group having 1 to 8 carbons, or aryl group having 6 to 30 carbons which may be substituted with alkyl group having 1 to 8 carbons Heteroaryl group having 3 to 30 carbons, more preferably alkyl having 1 to 20 carbons, aralkyl having 7 to 40 carbons, alkoxy having 1 to 20 carbons, aryloxy having 6 to 20 carbons Group, an aryl group with 6 to 30 carbons which may be substituted with an alkyl group with 1 to 8 carbons, more preferably an alkyl group with 1 to 8 carbons, an aralkyl group with 7 to 20 carbons, and 1 to 8 carbons An alkoxy group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, and an aryl group having 6 to 14 carbon atoms that may be substituted with an alkyl group having 1 to 8 carbon atoms.

From the viewpoint of improving the solubility in the solvent and the amorphous property, it is preferable that when c is 1 or more, at least one of ^{R 5} , R ⁶ and R ^{7 has 1,2-phenylene} In terms of ease of synthesis, it is preferred that at least one contains 1,3-phenylene group or 1,3-phenylene group.

From the viewpoint of durability, c is preferably an integer of 0-2.

In the compound represented by the formula (3), the ^{three partial structures of Bz-(R 5} )c, R ⁶ and R ^{7 when the benzene ring having R 5} is represented by "Bz", all three may be the same The structure of, or only one is a different structure, or all three are different structures. When the partial structure has a substituent, its substituent is also included. It is preferably only one different structure or three all different structures, and more preferably three all different structures. The reason will be described later.

The compound represented by formula (3) contained as a charge transporting material is a low-molecular compound, and its molecular weight is preferably 400 or more, more preferably 450 or more, still more preferably 500 or more, particularly preferably 600 or more, and more preferably 3000 or less, more preferably 2000 or less, still more preferably 1500 or less, particularly preferably 1200 or less.

Hereinafter, preferable specific examples of the compound represented by formula (3) contained in the composition for an organic electroluminescence element of the present invention as a charge transporting material other than those shown in the examples are shown. The present invention is not limited to these.

[化21]

[Specific examples of each structure] Hereinafter, as formula (1), formula (1-1), formula (1-2), formula (1A) to formula (1C), formula (2), and formula (2-1) ), specific examples and preferred structures of various structures of ^{R 1} to R ⁷ , R ⁹ to R ¹³ , Ar ²¹ to Ar ²⁵ , ring A, and ring B in formula (3).

The alkyl group having 1 to 20 carbon atoms may be any of linear, branched, or cyclic alkyl groups. Specifically, methyl, ethyl, n-propyl, n-butyl, N-pentyl, n-hexyl, n-octyl, isopropyl, isobutyl, isopentyl, tertiary butyl, cyclohexyl, etc. Among them, preferred are linear alkyl groups having 1 to 8 carbon atoms such as methyl, ethyl, n-butyl, n-hexyl, and n-octyl.

The (hetero)aralkyl group having 7 to 40 carbon atoms refers to a group in which a part of hydrogen atoms constituting a linear, branched, or cyclic alkyl group is substituted with a (hetero)aryl group. Specifically, 2-phenyl-1-ethyl, cumyl, 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, 7-phenyl-1-heptyl, tetrahydro Naphthyl etc. Among them, preferred are 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, and 7-phenyl-1-heptyl.

Specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a hexyloxy group, a cyclohexyloxy group, and an octadecyloxy group. Wait. Among them, hexyloxy is preferred.

Specific examples of the (hetero)aryloxy group having 3 to 20 carbon atoms include a phenoxy group and a 4-methylphenyloxy group. Among them, phenoxy is preferred.

Specific examples of the alkylsilyl group having 1 to 20 carbon atoms include trimethylsilyl group, triethylsilyl group, triisopropylsilyl group, dimethylphenyl group, and tert-butyldimethylsilyl group. Base silyl group, tertiary butyl diphenyl silyl group, etc. Among them, a triisopropylsilyl group, a tertiary butyldimethylsilyl group, and a tertiary butyldiphenylsilyl group are preferred.

Specific examples of the arylsilyl group having 6 to 20 carbon atoms include a diphenylpyridylsilyl group and a triphenylsilyl group. Among them, a triphenylsilyl group is preferred.

Specific examples of the alkylcarbonyl group having 2 to 20 carbon atoms include an acetyl group, a propionyl group, a trimethyl acetyl group, a hexyl group, a decyl group, and a cyclohexyl carbonyl group. Among them, acetyl and trimethyl acetyl are preferred.

Specific examples of the arylcarbonyl group having 7 to 20 carbon atoms include a benzyl group, a naphthyl group, an anthryl group, and the like. Among them, a benzyl group is preferred.

Specific examples of the alkylamino group having 1 to 20 carbon atoms include methylamino, dimethylamino, diethylamino, ethylmethylamino, dihexylamino, and dioctylamino. Amino, dicyclohexylamino, etc. Among them, dimethylamino and dicyclohexylamino are preferred.

Specific examples of the arylamino group having 6 to 20 carbon atoms include phenylamino group, diphenylamino group, bis(4-tolyl)amino group, and bis(2,6-dimethylbenzene). Group) amine group and so on. Among them, diphenylamino and bis(4-tolyl)amino are preferred.

The (hetero)aryl group with 3 to 30 carbon atoms refers to an aromatic hydrocarbon group and an aromatic heterocyclic group having one free valence, or a connected aromatic hydrocarbon group formed by connecting a plurality of aromatic hydrocarbon groups, and a plurality of aromatic hydrocarbon groups. A linked aromatic heterocyclic group formed by linking a heterocyclic group, or a group formed by arbitrarily linking one or more aromatic hydrocarbon groups and one or more aromatic heterocyclic groups.

Specific examples of (hetero)aryl groups having 3 to 30 carbon atoms include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, fused tetraphenyl ring, pyrene ring, and benzopyrene having one free valence. Ring, tri-ring, terphenylene ring, fluoranthene ring, furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole Ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring , Thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Cinnoline ring, quinoxaline ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and other groups. Examples of the connected aromatic hydrocarbon group formed by connecting a plurality of aromatic hydrocarbons include biphenyl group, terphenyl group, and the like.

Among the (hetero)aryl groups, from the viewpoint of durability, a benzene ring, a naphthalene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, and a pyridine ring having a valence of one free atom are preferred. , Pyrimidine ring, triazine ring. Among them, it is more preferable to have one free valence, and an aryl group with 6 to 18 carbons such as a benzene ring, a naphthalene ring or a phenanthrene ring that can be substituted by an alkyl group having 1 to 8 carbons, or one free valence, The pyridine ring which may be substituted by an alkyl group having 1 to 4 carbons is more preferably a benzene ring, a naphthalene ring or a phenanthrene ring which has a free valence and may be substituted by an alkyl group having 1 to 8 carbons. The number of aryl groups from 6 to 18.

The divalent (hetero)aryl group having 3 to 30 carbon atoms is the same as the exemplified material of the (hetero)aryl group having 3 to 30 carbon atoms except that it has two free valences, and the preferred examples are also the same .

As a combination of these substituents, for example, 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, an alkyl group, or an aralkyl group can be used. As a combination of an aryl group and an aralkyl group, for example, a combination of a phenyl group, a biphenyl group or a terphenyl group and a 5-phenyl-1-pentyl group or a 6-phenyl-1-hexyl group can be used.

[Specific examples of substituents] Below, formula (1), formula (1-1), formula (1-2), formula (1A) to formula (1C), formula (2), formula (2-1), ^{The substituents that R 1} to R ⁷ , R ⁹ to R ¹³ , Ar ²¹ to Ar ²⁵ , ring A and ring B in formula (3) may have are alkyl groups with 1 to 20 carbons, and those with 7 to 40 carbons (Hetero)aralkyl, alkoxy with 1-20 carbons, (hetero)aryloxy with 3-20 carbons, alkylsilyl with 1-20 carbons, arylsilane with 6-20 carbons Group, C2-C20 alkylcarbonyl group, C7-20 arylcarbonyl group, C1-C20 alkylamino group, C6-C20 arylamino group, C3-C30 (Hetero)aryl or crosslinking group. Specific examples of various substituents are listed.

The alkyl group having 1 to 20 carbon atoms may be any of linear, branched, or cyclic alkyl groups. Specifically, methyl, ethyl, n-propyl, n-butyl, N-pentyl, n-hexyl, n-octyl, isopropyl, isobutyl, isopentyl, tertiary butyl, cyclohexyl, etc. Among them, preferred are linear alkyl groups having 1 to 8 carbon atoms such as methyl, ethyl, n-butyl, n-hexyl, and n-octyl.

The (hetero)aralkyl group having 7 to 40 carbon atoms refers to a group in which a part of the hydrogen atoms constituting a linear, branched or cyclic alkyl group is substituted with a (hetero)aryl group. Specifically, 2- Phenyl-1-ethyl, cumyl, 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, 7-phenyl-1-heptyl, tetrahydronaphthyl and the like. Among them, preferred are 5-phenyl-1-pentyl, 6-phenyl-1-hexyl, and 7-phenyl-1-heptyl.

Specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a hexyloxy group, a cyclohexyloxy group, and an octadecyloxy group. Wait. Among them, hexyloxy is preferred.

Specific examples of the (hetero)aryloxy group having 3 to 20 carbon atoms include a phenoxy group and a 4-methylphenyloxy group. Among them, phenoxy is preferred.

Specific examples of the alkylsilyl group having 1 to 20 carbon atoms include trimethylsilyl group, triethylsilyl group, triisopropylsilyl group, dimethylphenyl group, and tert-butyldimethylsilyl group. Base silyl group, tertiary butyl diphenyl silyl group, etc. Among them, a triisopropylsilyl group, a tertiary butyldimethylsilyl group, and a tertiary butyldiphenylsilyl group are preferred.

Specific examples of the arylsilyl group having 6 to 20 carbon atoms include a diphenylpyridylsilyl group and a triphenylsilyl group. Among them, a triphenylsilyl group is preferred.

Specific examples of the alkylcarbonyl group having 2 to 20 carbon atoms include an acetyl group, a propionyl group, a trimethyl acetyl group, a hexyl group, a decyl group, and a cyclohexyl carbonyl group. Among them, acetyl and trimethyl acetyl are preferred.

Specific examples of the arylcarbonyl group having 7 to 20 carbon atoms include a benzyl group, a naphthyl group, an anthryl group, and the like. Among them, a benzyl group is preferred.

Specific examples of the alkylamino group having 1 to 20 carbon atoms include methylamino, dimethylamino, diethylamino, ethylmethylamino, dihexylamino, and dioctylamino. Amino, dicyclohexylamino, etc. Among them, dimethylamino and dicyclohexylamino are preferred.

Specific examples of the arylamino group having 6 to 20 carbon atoms include phenylamino group, diphenylamino group, bis(4-tolyl)amino group, and bis(2,6-dimethylbenzene). Group) amine group and so on. Among them, diphenylamino and bis(4-tolyl)amino are preferred.

The (hetero)aryl group with 3 to 30 carbon atoms refers to an aromatic hydrocarbon group and an aromatic heterocyclic group having one free valence, or a connected aromatic hydrocarbon group formed by connecting a plurality of aromatic hydrocarbon groups, and a plurality of aromatic hydrocarbon groups. A linked aromatic heterocyclic group formed by linking a heterocyclic group, or a group formed by arbitrarily linking one or more aromatic hydrocarbon groups and one or more aromatic heterocyclic groups.

Specific examples of (hetero)aryl groups having 3 to 30 carbon atoms include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, fused tetraphenyl ring, pyrene ring, and benzopyrene having one free valence. Ring, tri-ring, terphenylene ring, fluoranthene ring, furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole Ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring , Thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Cinnoline ring, quinoxaline ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and other groups. Examples of the connected aromatic hydrocarbon group formed by connecting a plurality of aromatic hydrocarbons include biphenyl group, terphenyl group, and the like.

Among the (hetero)aryl groups, from the viewpoint of durability, a benzene ring, a naphthalene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, and a pyridine ring having a valence of one free atom are preferred. , Pyrimidine ring, triazine ring. Among them, it is more preferable to have one free valence, and an aryl group with 6 to 18 carbons such as a benzene ring, a naphthalene ring or a phenanthrene ring that can be substituted by an alkyl group having 1 to 8 carbons, or one free valence, The pyridine ring which may be substituted by an alkyl group having 1 to 4 carbons is more preferably a benzene ring, a naphthalene ring or a phenanthrene ring which has a free valence and may be substituted by an alkyl group having 1 to 8 carbons. The number of aryl groups from 6 to 18.

As a combination of these substituents, for example, 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, an alkyl group, or an aralkyl group can be used. As a combination of an aryl group and an aralkyl group, for example, a combination of a phenyl group, a biphenyl group or a terphenyl group and a 5-phenyl-1-pentyl group or a 6-phenyl-1-hexyl group can be used.

Among these substituents, preferred are alkyl groups having 1 to 20 carbons, aralkyl groups having 7 to 40 carbons, alkoxy groups having 1 to 20 carbons, aryloxy groups having 3 to 20 carbons, and An alkylsilyl group having 1-20, an arylsilyl group having 6-20 carbons, an arylamino group having 6-20 carbons, and a (hetero)aryl group having 3-30 carbons. Further preferred are alkyl groups having 1 to 20 carbons, alkoxy groups having 1 to 20 carbons, alkylsilyl groups having 1 to 20 carbons, arylsilyl groups having 6 to 20 carbons, and 6 to 20 carbons. Arylamino and (hetero)aryl groups having 3 to 30 carbon atoms. Particularly preferred are an alkyl group having 1 to 20 carbons, an alkoxy group having 1 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons. The specific structures and preferred carbon numbers of these preferred substituents are as described in the specific examples of the substituents.

When these substituents further have a substituent, as this substituent, the said exemplified substituent can be mentioned.

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

In the light-emitting layer of the organic electroluminescent device of the present invention, the polymer compound having the repeating unit (2) mainly undertakes hole transport. In the case of a structure in which the repeating unit (2) is included in the repeating unit (2-1), since it has an arylamine structure, the hole transportability is greatly improved. The compound represented by formula (3) has high electron transport properties. Therefore, the charge transportability in the light-emitting layer is improved, and the voltage is reduced. In addition, it is considered that the charge balance between holes and electrons becomes better, and luminous efficiency is improved. Here, the light-emitting dopant represented by formula (1) has an alkyl group containing a tertiary butyl group. The tertiary butyl group is bulky and therefore becomes a steric hindrance. Therefore, the charge-transporting compound usually exists at a certain distance from the charge-receiving part of the light-emitting dopant, and the charge is not easy to move from the charge-transporting compound to the light-emitting dopant. Here, in the present invention, the material responsible for the transmission of holes is mainly a polymer compound, and the holes are easy to move on the polymer chain, so there are holes in a relatively wide area of the polymer chain. It is considered that in a wide range of polymer chains with holes, there are holes that are relatively easy to move to the part of the light-emitting dopant represented by formula (1), and the holes will move from the part to the part of formula (1). Represents the luminescent dopant. As such, in the light-emitting layer of the organic electroluminescent device of the present invention, it is considered that the holes move to the neutral light-emitting dopant first. It is considered that secondly, electrons move from the compound represented by formula (3) to the light-emitting dopant, and recombine to emit light. It is considered that the light-emitting dopant represented by formula (1) has low durability against electrons, but high durability against holes, and therefore the device life will be prolonged.

Furthermore, in the compound represented by the formula (3), the ^{three partial structures of [phenylene-(R 5} )c], R ⁶ and R ⁷ (including their substituents (when they have) ) It is preferable that these three are not the same structure. Furthermore, it is preferable that the three partial structures are different from each other. In the present invention, such a structure is called an asymmetric structure.

The compound represented by the formula (3) is more ^{preferably R 5} to R ⁷ in which only one or two of the ends contain naphthyl, stilbene, carbazolyl, indolocarbazolyl, and indenocarbazolyl , The asymmetric structure of indeno tungsten group. By adopting this asymmetric structure, the amorphous quality is improved to form a uniform and stable film, and it is easy to form a film uniformly mixed with other materials. In addition, the self-solubility in the solvent is improved, and the stability in the solution is improved. From the point of view, better. In particular, the aspect of being easy to uniformly mix with other materials is particularly effective when a polymer material is further included as a charge transport material.

It is thought that the reason is that the composition for organic electroluminescent device, which is formed by dissolving the compound represented by the formula (3) and the polymer compound having the repeating unit (2) in a solvent, is used as a light-emitting layer formation When the composition is used for wet film formation, the solvent volatilizes during drying and the composition for forming the light-emitting layer is being concentrated. By making the compound represented by the formula (3) asymmetric, it is easy to interact with The polymer chain ring of the polymer compound having the repeating unit (2) is directly formed into a film in a state in which the polymer chain rings are uniformly mixed.

In particular, at least one of one or more (if present) R ⁵ , R ⁶ and R ⁷ contains a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group or an indenopyranyl group at the end In the case of the base, it is considered that the carbazolyl, indolocarbazolyl, indenocarbazolyl, or indenocarbazolyl group has the hole-transporting ability (although the degree is different), so it is different from the hole-transporting polymer compound It has high affinity and is easy to be uniformly mixed with the hole-transporting polymer compound to become a stable film. Among these, the carbazole group is considered to have a moderately small structure and is easier to mix with a polymer compound, so it is preferable.

In addition, it is considered that since the compound represented by the formula (3) as a charge transport material is asymmetric, the luminous efficiency of the compound represented by the formula (1) as a light-emitting dopant can be improved. The reason is described below.

The light-emitting dopant represented by formula (1) has an alkyl group containing a tertiary butyl group. Generally, since the tertiary butyl group becomes a steric hindrance, the charge-transporting material exists at a certain distance from the light-emitting dopant represented by the formula (1). In the present invention, since the material responsible for hole transport is mainly a polymer compound, there are holes in a relatively wide area on the polymer chain, so the holes are easily moved to the light-emitting dopant represented by formula (1) Agent. On the other hand, since the tertiary butyl group of the light-emitting dopant represented by the formula (1) is a steric hindrance, the low-molecular compound usually exists at a certain distance from the light-emitting dopant, and the charge is not easy to emit light from the low-molecular compound. The dopant moves. However, when the electron-transporting material represented by the formula (3) of the present invention has an asymmetric structure, the distribution of LUMO is uneven, and it is considered that there are places where electrons easily move. Therefore, it is considered that electrons are easily transferred to a light-emitting dopant having a steric hindrance such as a tertiary butyl group to lower the voltage, emit light with high efficiency, and prolong the life of the device.

^{In addition, in the case where at least one of the terminals of R 5} to R ⁷ in the compound represented by the formula (3) contains a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenoguanyl group It is considered that the compound represented by the formula (3) easily accepts electrons as well as holes, and thus easily accepts both electrons and holes to form an excited state. In this case, it is considered that the excitation energy directly transfers to the light-emitting dopant, and it is considered that even if it is a light-emitting dopant having a tertiary butyl group as in the formula (1), the excitation energy transfers efficiently. As a result, it is considered that the luminous efficiency becomes higher and the driving life of the element becomes longer.

Furthermore, even if the compound represented by the formula (3) is a symmetrical type, when ^{all the terminals of R 5} to R ⁷ are carbazolyl groups, the luminous efficiency increases for the same reason and the device is driven The life is longer, so it is better. The molecular structure of the carbazolyl group is relatively small. Therefore, even if ^{all the terminals of R 5} to R ⁷ have a carbazolyl group, the influence on the three-dimensional structure of the compound represented by the formula (3) is small, which is preferable. The compound represented by the formula (3) is a symmetric type means that in the compound represented by the formula (3), c=1, and [phenylene-R ⁵ ], R ⁶ and R ^{7 are} three Partial structure (including the substituent when it has a substituent) when all three have the same structure.

[Synthesis method of compound represented by formula (1)] The compound represented by formula (1) contained as a light-emitting dopant in the composition for an organic electroluminescence element of the present invention is an iridium complex. The synthesis method of this iridium complex is shown below.

The ligand of the iridium complex can be synthesized by a combination of known methods and the like. Ligands can be carried out by Suzuki-Miyaura coupling reaction between aryl boronic acids and halogenated heteroaryls, with 2-methanyl or anilines, or acyl-aminopyridines located in the ortho position with each other, etc. Friedlaender cyclization reaction (Chem. Rev. 2009, 109, 2652 or Organic Reactions, 28(2), 37-201) and other known reactions are synthesized.

＜Synthesis method of iridium complexes＞ The iridium complex can be synthesized by a combination of known methods using ligands and iridium chloride n-hydrate as raw materials. This will be explained below.

As a synthesis method of iridium complexes, for easy understanding, a method of crosslinking iridium binuclear complexes (MG Colombo) through a chlorine-crosslinked iridium binuclear complex shown in the following formula [A] using a phenylpyridine ligand as an example , TC Brunold, T. Riedener, HU Gudel, Inorganic Chemistry (Inorg. Chem.) 1994, 33, 545-550); from the following formula [B] dinuclear complex compound to further exchange chlorine with acetone, The method of obtaining the target after being transformed into a mononuclear complex (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) etc., but not limited to these.

For example, the typical reaction conditions represented by the following formula [A] are as follows.

As the first stage, a chlorine-crosslinked iridium binuclear complex is synthesized by the reaction of 2 equivalents of the first ligand and 1 equivalent of iridium chloride n-hydrate. The solvent is usually a mixed solvent of 2-ethoxyethanol and water, but solvent-free or other solvents can also be used. It is also possible to use excessive amounts of ligands, or use additives such as bases to promote the reaction. Other cross-linking anionic ligands such as bromine can also be used instead of chlorine.

The reaction temperature is not particularly limited, but it is generally preferably 0°C or higher, more preferably 50°C or higher, preferably 250°C or lower, and more preferably 150°C or lower. By setting the reaction temperature within this temperature range, only the target reaction can be carried out without accompanying by-products or decomposition reactions, and there is a tendency to obtain high selectivity.

[化22]

In the second stage, a halide ion trap like silver triflate is added to contact the second ligand to obtain the target complex. The solvent usually uses ethoxyethanol or diglyme, but depending on the type of ligand, it can be solvent-free or other solvents, or a mixture of multiple solvents can be used. Even if the halogen ion trapping agent is not added, the reaction may sometimes proceed, so it is not necessarily necessary. However, in order to increase the reaction yield, selectively synthesize facial isomers with higher quantum yields and add the trapping agent. The agent is advantageous. The reaction temperature is not particularly limited, and it is usually carried out in the range of 0°C to 250°C.

The typical reaction conditions represented by the following formula [B] will be described.

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

In the second stage, the activity of the 1,3-diketone compound can be extracted by combining the binuclear complex with 1 equivalent or more of acetone-like 1,3-diketone compound and 1 equivalent or more of sodium carbonate. The basic hydrogen compound reacts and transforms into a mononuclear complex coordinated by 1,3-diketone ligands. Generally, a solvent such as ethoxyethanol or methylene chloride that can dissolve the binuclear complex as a raw material is used, and it can be carried out without a solvent when the ligand is in a liquid state. The reaction temperature is not particularly limited, and it is usually carried out within the range of 0°C to 200°C.

[化23]

In the third stage, 1 equivalent or more of the second ligand is reacted. The type and amount of the solvent are not particularly limited. When the second ligand is liquid at the reaction temperature, it can also be solvent-free. The reaction temperature is also not particularly limited, but since the reactivity is slightly insufficient, the reaction is usually carried out at a relatively high temperature of 100°C to 300°C. Therefore, a solvent with a high boiling point such as glycerin can be preferably used.

After the final reaction, purification is performed to remove unreacted raw materials, reaction by-products, and solvents. The refining operations in general organic synthetic chemistry can be applied, but as described in the non-patent literature, the refining is mainly performed by the phase-phase silica gel column chromatography method. The developing solution can be a single or mixed solution of hexane, heptane, dichloromethane, chloroform, ethyl acetate, toluene, methyl ethyl ketone, and methanol. Refining can also be carried out many times under changing conditions. Other chromatographic techniques (reverse phase silica gel chromatography, size exclusion chromatography, paper chromatography) or separation cleaning, reprecipitation, recrystallization, powder suspension cleaning, vacuum drying, etc. can be implemented as needed operating.

[Solvent] The composition for an organic electroluminescent element of the present invention contains a solvent.

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

As long as the solvent is a compound represented by formula (1) as a solute as a light-emitting dopant, a polymer compound having a repeating unit (2), a compound represented by formula (3), or the following which may be contained as necessary The solvent that dissolves other luminescent materials or charge-transporting materials well is not particularly limited.

As a preferable solvent, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; toluene, xylene, mesitylene, cyclohexylbenzene (phenyl Cyclohexane), tetralin and other aromatic hydrocarbons; chlorobenzene, dichlorobenzene, trichlorobenzene and other halogenated aromatic hydrocarbons; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene , Anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole , Diphenyl ether and other aromatic ethers; phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate and other aromatic esters; cyclohexanone, ring Alicyclic ketones such as octanone and fenchone; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; butanol and hexanol Aliphatic alcohols; aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), etc. Among them, alkanes or aromatic hydrocarbons are preferred. In particular, cyclohexylbenzene has better viscosity and boiling point in the wet film forming process.

These solvents may be used singly, or two or more of them may be used in any combination and ratio.

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

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

The content of the compound represented by the formula (1) as a light-emitting dopant in the composition for an organic electroluminescence element is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 20% by mass or less. Preferably, it is 10% by mass or less. By setting the content of the compound represented by the formula (1) within this range, when the composition is used in an organic electroluminescent device, the excitation energy is directed to the adjacent layer (for example, a hole transport layer or a hole The barrier layer) is less likely to move, and less extinction due to the interaction of excitons, so that the luminous efficiency can be improved.

The composition for an organic electroluminescence element of the present invention may include only one compound represented by the formula (1), or may include two or more in combination.

The content of the polymer compound having the repeating unit (2) in the composition for an organic electroluminescence element of the present invention is usually 0.01% by mass or more, preferably 0.1% by mass or more, usually 20% by mass or less, preferably 10 Less than mass%. By setting the content of the polymer compound within this range, when the composition is used in an organic electroluminescent device, the excitation energy can move to an adjacent layer (for example, a hole transport layer or a hole blocking layer). There are few cases, and there are fewer cases of extinction due to the interaction of excitons, so the luminous efficiency can be improved.

The composition for an organic electroluminescence element of the present invention may include only one polymer compound having a repeating unit (2), or may include two or more types in combination.

The content of the compound represented by the formula (3) in the composition for an organic electroluminescent element of the present invention is usually 0.005% by mass or more, preferably 0.05% by mass or more, usually 10% by mass or less, preferably 5% by mass the following. By setting the content of the compound represented by the formula (3) in this range, when the composition is used in an organic electroluminescent device, it can be moved from the adjacent cathode side layer (for example, hole blocking layer) to The light-emitting layer efficiently injects electrons, so that the driving voltage can be reduced.

The composition for an organic electroluminescence element of the present invention may include only one compound represented by the formula (3), or may include two or more in combination.

From the viewpoint of luminous efficiency, the composition for an organic electroluminescent device of the present invention preferably contains 100 parts by mass of the polymer compound having the repeating unit (2) and the compound represented by formula (3) in total The compound represented by the formula (1) is 5 parts by mass to 100 parts by mass, particularly 15 parts by mass to 60 parts by mass. If the compound represented by the formula (1) that is responsible for light emission is too small, the efficiency will be reduced, and if it is too large, the light will be easily extinct and the efficiency will be reduced.

From the viewpoint of reasonable charge balance and improved efficiency, the composition for an organic electroluminescent device of the present invention is preferably 100 masses in total of the polymer compound having the repeating unit (2) and the compound represented by the formula (3) In parts, 20 parts by mass to 98 parts by mass, particularly 50 parts by mass to 90 parts by mass of the polymer compound having the repeating unit (2) are contained.

The content of the solvent in the composition for an organic electroluminescent element of the present invention is preferably 10 parts by mass or more in 100 parts by mass of the composition, more preferably 50 parts by mass or more, particularly preferably 80 parts by mass or more, and preferably 99.95 parts by mass Parts or less, more preferably 99.9 parts by mass or less, particularly preferably 99.8 parts by mass or less.

As described later, the thickness of the light-emitting layer is generally about 3 nm to 200 nm, but if the content of the solvent is more than the above 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 less than or equal to the above upper limit, after the film formation, the thickness of the film obtained by removing the solvent can be obtained, so there is a tendency that the film formation becomes easier.

As described above, the composition for an organic electroluminescent element of the present invention may contain only one solvent, or may contain two or more in combination.

[Organic electroluminescent element] The organic electroluminescence element of the present invention includes a light-emitting layer formed by a wet film formation method using the composition for an organic electroluminescence element of the present invention.

The organic electroluminescence 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 using the composition for the organic electroluminescence device of the present invention by a wet film forming method. The formed light-emitting layer serves as at least one of the organic layers.

In the present invention, the so-called wet film forming method refers to the use of, for example, spin coating, dip coating, die coating, bar coating, blade coating, roll coating, spray coating, capillary coating, inkjet The method, the nozzle printing method, the screen printing method, the gravure printing method, the flexographic printing method, etc., uses a wet method to form a film as the film forming method, that is, the coating method, and the film formed by these methods is dried To carry out the method of film formation.

FIG. 1 is a schematic diagram showing a cross-section of a preferred configuration example of the organic electroluminescent element 10 of the present invention. In Figure 1, the symbol 1 indicates the substrate, the symbol 2 indicates the anode, the symbol 3 indicates the hole injection layer, the symbol 4 indicates the hole transport layer, the symbol 5 indicates the light-emitting layer, the symbol 6 indicates the hole blocking layer, and the symbol 7 indicates the electron transport layer , Symbol 8 indicates an electron injection layer, and symbol 9 indicates a cathode.

As the materials applied to these structures, well-known materials can be used, and there is no particular limitation. The following describes representative materials or manufacturing methods for each layer as an example. Hereinafter, in the case of citing publications or papers, etc., the corresponding content can be appropriately adapted and applied within the scope of the common sense of those skilled in the art.

＜Board 1＞ The substrate 1 serves as a support for the organic electroluminescence element, and a quartz or glass plate, a metal plate or metal foil, a plastic film or a sheet, etc. are usually used. Among these, a glass plate or a plate made of transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, and polycure is preferred. It is preferable that the substrate 1 is made of a material with high gas barrier properties from the viewpoint that deterioration of the organic electroluminescent element due to external air is unlikely to occur. In particular, in the case of 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 side of the substrate 1 to improve the gas barrier properties.

＜Anode 2＞ The anode 2 has a function of injecting holes into the layer on the light-emitting layer side. The anode 2 usually contains: metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium and/or tin oxides; halogenated metals such as copper iodide; carbon black or poly(3-methylthiophene) , Polypyrrole, polyaniline and other conductive polymers.

The formation of the anode 2 is usually performed by a dry method such as a sputtering method or a vacuum vapor deposition method. When the anode 2 is formed using metal particles such as silver, copper iodide particles, carbon black, conductive metal oxide particles, conductive polymer fine powder, etc., it can also be dispersed in an appropriate binder resin The solution is applied to the substrate to form. In the case of conductive polymer, it is also possible to directly form a thin film on the substrate by electrolytic polymerization, or coat a conductive polymer on the substrate to form the anode 2 (Appl. Phys. Lett.), 60 Vol. 2711, 1992).

The anode 2 usually has a single-layer structure, but a layered structure may be appropriately adopted. When the anode 2 has a laminated structure, different conductive materials may be laminated on the anode of the first layer.

The thickness of the anode 2 may be determined according to the required transparency, material, and the like. In particular, when high transparency is required, it is preferable to make the visible light transmittance a thickness of 60% or more, and more preferably to have a thickness of 80% or more. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, usually 1000 nm or less, and preferably 500 nm or less. When transparency is not required, the thickness of the anode 2 may be any thickness according to the required strength and the like. In this case, the anode 2 may have the same thickness as the substrate 1.

When forming a film on the surface of the anode 2, it is preferable to perform treatments such as ultraviolet light + ozone, oxygen plasma, argon plasma, etc. before film formation to remove impurities on the anode and adjust its ionization potential to make the holes Improved injectability.

＜Hole injection layer 3＞ The layer that performs the function of transporting holes from the anode 2 side to the light emitting layer 5 side is generally called a hole injection transport layer or a hole transport layer. When there are two or more layers that perform the function of transporting holes from the anode 2 side to the light emitting layer 5 side, the layer closer to the anode 2 side may be referred to as the hole injection layer 3. In terms of enhancing the function of transporting holes from the anode 2 to the light-emitting layer 5 side, it is preferable to use the hole injection layer 3. When the hole injection layer 3 is used, the hole injection layer 3 is usually formed on the anode 2.

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

The method for forming the hole injection layer 3 may be a vacuum evaporation method or a wet film forming method. In terms of excellent film-forming properties, it is preferably formed by a wet film-forming method.

The hole injection layer 3 preferably includes a hole-transporting compound, and more preferably includes a hole-transporting compound and an electron-accepting compound. Furthermore, it is preferable to include a cationic radical compound in the hole injection layer 3, and it is particularly preferable to include a cationic radical compound and a hole transporting compound.

(Hole-transporting compound) The composition for forming a hole injection layer usually contains a hole transporting compound that becomes the hole injection layer 3.

In the case of the wet film forming method, it usually contains a solvent. The composition for forming the hole injection layer preferably has high hole transport properties and can efficiently transport the injected holes. Therefore, it is preferable that the hole mobility is high, and impurities that become traps are not easily generated during manufacturing or use. In addition, it is preferably excellent in stability, low in ionization potential, and high in transparency to visible light. Especially when the hole injection layer 3 is in contact with the light-emitting layer 5, it is preferable not to extinct the light emitted from the light-emitting layer 5 or to form an exciplex with the light-emitting layer 5 without reducing the luminous efficiency. By.

As the hole-transporting compound, from the viewpoint of inhibiting charge injection from the anode 2 to the hole injection layer 3, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferred. Examples of hole-transporting compounds include aromatic amine-based compounds, phthalocyanine-based compounds, porphyrin-based compounds, oligothiophene-based compounds, polythiophene-based compounds, benzylphenyl-based compounds, and triphenylene-based compounds. Compounds formed by linking graded amines, hydrazone-based compounds, silazane-based compounds, quinacridone-based compounds, etc.

Among the exemplified compounds, in terms of amorphous properties and visible light transmittance, aromatic amine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred. The aromatic tertiary amine compound also includes a compound having an aromatic tertiary amine structure and having a group derived from an aromatic tertiary amine.

The type of aromatic tertiary amine compound is not particularly limited. In terms of easily obtaining uniform light emission due to the surface smoothing effect, it is preferable to use a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (repeat Polymeric compounds with connected units). As a preferable example of the aromatic tertiary amine polymer compound, a polymer compound having a repeating unit represented by the following formula (I) and the like can be cited.

[化24]

[In formula (I), Ar ¹ and Ar ² each independently represent an optionally substituted aromatic group or an optionally substituted heteroaromatic group; Ar ³ to Ar ⁵ each independently represent an optionally substituted aromatic group A group or a heteroaromatic group which may have a substituent; Q represents a linking group selected from the following linking group group; In addition, in Ar ¹ to Ar ⁵ , two groups bonded to the same N atom may be bonded to each other Knot to form a ring]

The linking group is shown below.

[化25]

[In the formulas, Ar ⁶ ~ Ar ¹⁶ each independently represents an aromatic group may have a substituent or a hetero aromatic substituent; R ^a ~ R ^b each independently represent a hydrogen atom or an optionally substituted base]

The aromatic group and heteroaromatic group of Ar ¹ to Ar ¹⁶ are preferably derived from a benzene ring, a naphthalene ring, and a phenanthrene ring in terms of the solubility, heat resistance, and hole injection and transport properties of the polymer compound. The group of thiophene ring and pyridine ring is more preferably a group derived from a benzene ring or a naphthalene ring.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by formula (I) include compounds described in the International Publication No. 2005/089024 pamphlet, and the like.

(Electron-accepting compound) The hole injection layer 3 preferably contains an electron-accepting compound, so that the conductivity of the hole injection layer 3 can be improved by oxidation of the hole-transporting compound.

The electron-accepting compound is preferably a compound having an oxidizing ability and an ability to accept a single electron from the hole transporting compound. Specifically, a compound having an electron affinity of 4 eV or more is preferable, and a compound having an electron affinity of 5 eV or more is more preferable.

Examples of such electron-accepting compounds include those selected from the group consisting of triaryl boron compounds, metal halide, Lewis acid, organic acid, onium salt, salt of arylamine and metal halide, and salt of arylamine and Lewis acid. One or two or more compounds in the group, etc. Specifically, examples include onium salts substituted with organic groups such as 4-isopropyl-4'-methyldiphenyl iodotetrakis (pentafluorophenyl) borate and triphenyl sulfonium tetrafluoroborate ( International Publication No. 2005/089024); iron(III) chloride (Japanese Patent Laid-Open No. 11-251067), high valence inorganic compounds such as ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; three (Pentafluorophenyl)borane (Japanese Patent Laid-Open No. 2003-31365) and other aromatic boron compounds; fullerene derivatives, iodine, etc.

(Cation free radical compound) The cationic radical compound is preferably an ionic compound containing a cationic radical which is a chemical species in which one electron is removed from the hole transporting compound, and a counter anion. When the cationic radical is derived from a hole-transporting polymer compound, the cationic radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

The cationic radical is preferably a chemical species in which one electron has been removed from the compound described above as the hole-transporting compound. From the aspects of amorphousness, visible light transmittance, heat resistance, solubility, etc., a chemical species in which one electron is removed from a compound that is preferable as a hole-transporting compound is preferable.

The cationic radical compound can be produced by mixing the hole-transporting compound and the electron-accepting compound. By mixing the hole-transporting compound and the electron-accepting compound, electrons move from the hole-transporting compound to the electron-accepting compound to generate cation radicals containing the hole-transporting compound and counter anions. Compound.

PEDOT/PSS (Adv. Mater., 2000, vol. 12, page 481) or emeraldine hydrochloride (J. Phys. Chem., 1990, vol. 94, Page 7716) and other cationic radical compounds derived from polymer compounds can also be generated by oxidative polymerization (dehydrogenation polymerization). The oxidative polymerization mentioned here is to chemically or electrochemically oxidize the monomer in an acid solution using peroxodisulfate or the like. In the case of this oxidative polymerization (dehydrogenation polymerization), the monomer is polymerized by oxidation, and an anion derived from an acidic solution is used as a counter anion, and a cation with one electron removed from the repeating unit of the polymer is generated Free radicals.

(Formation of hole injection layer 3 by wet film forming method) In the case of forming the hole injection layer 3 by a wet film formation method, the material for the hole injection layer 3 is usually mixed with a soluble solvent (a solvent for the hole injection layer) to prepare a film-forming composition (A composition for forming a hole injection layer), the composition for forming a hole injection layer is formed on a layer corresponding to the lower layer of the hole injection layer 3 (usually the anode 2) by a wet film forming method , And let it dry to form. The drying of the formed film can be performed in the same manner as the drying method in the formation of the light-emitting layer 5 by the wet film formation method.

The concentration of the hole-transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired. Regarding the concentration, in terms of the uniformity of the film thickness, it is better to be low, and to the point that defects are less likely to occur in the hole injection layer 3, it is more preferable to be high. The concentration of the hole-transporting 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, particularly preferably 0.5% by mass or more, preferably 70% by mass or less, and further It is preferably 60% by mass or less, and particularly preferably 50% by mass or less.

Examples of the solvent include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents.

As ether solvents, for example, aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA) and 1,2-dimethoxybenzene, 1,3-Dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2 , 4-dimethyl anisole and other aromatic ethers.

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

Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, and 1,4-diisopropylbenzene. , Methyl naphthalene and so on.

Examples of amide-based solvents include N,N-dimethylformamide, N,N-dimethylacetamide, and the like.

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

The formation of the hole injection layer 3 by the wet film formation method is usually by preparing the composition for forming the hole injection layer, and then coating it to form a film to the lower layer corresponding to the hole injection layer 3 (usually The anode 2) is applied and dried to proceed. The hole injection layer 3 is usually dried by heating or drying under reduced pressure after forming the film.

(Formation of the hole injection layer 3 by the vacuum evaporation method) In the case of forming the hole injection layer 3 by the vacuum evaporation method, the constituent material of the hole injection layer 3 (the hole transportability Put one or two or more of compounds, electron-accepting compounds, etc.) into a crucible set in a vacuum container (when two or more materials are used, they are usually put into different crucibles), using a vacuum pump After exhausting the vacuum vessel to about 10 ^-4 Pa, heat the crucible (in the case of using two or more materials, the crucible is usually heated separately), while controlling the evaporation of the material in the crucible, make it Evaporation (when two or more materials are used, the amount of evaporation is usually controlled independently to evaporate), and a hole injection layer 3 is formed on the anode 2 on the substrate placed facing the crucible. In the case of using two or more materials, the mixture of these may be put into a crucible and heated to evaporate to form the hole injection layer 3.

As long as the effect of the present invention is not significantly impaired, the degree of vacuum during vapor deposition is not particularly limited, and it is usually 0.1×10 ^-6 Torr (0.13×10 ^-4 Pa) or more and 9.0×10 ^-6 Torr (12.0×10 ^-4 Pa) or less. As long as the effect of the present invention is not significantly impaired, the vapor deposition rate is not limited, and it is usually 0.1 Å/sec or more and 5.0 Å/sec or less. As long as the effect of the present invention is not significantly impaired, the film formation temperature during vapor deposition is not limited, and it is preferably performed at 10°C or higher and 50°C or lower.

＜Hole transport layer 4＞ The hole transport layer 4 is a layer that performs the function of transporting holes from the anode 2 side to the light emitting layer 5 side. The hole transport layer 4 is not an essential layer for the organic electroluminescent element of the present invention, but it is preferable to provide this layer in terms of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5. When the hole transport layer 4 is provided, the hole transport layer 4 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.

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

The method of forming the hole transport layer 4 may be a vacuum evaporation method or a wet film forming method. In terms of excellent film-forming properties, it is preferably formed by a wet film-forming method.

The hole transport layer 4 usually contains a hole transport compound that forms the hole transport layer 4. Examples of the hole-transporting compound contained in the hole-transporting layer 4 include, in particular, those represented by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl Two or more tertiary amines and an aromatic diamine in which two or more condensed aromatic rings are substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), 4,4',4''-tri(1- Naphthylphenylamino) triphenylamine and other aromatic amine compounds with a Starburst structure (J. Lumin., Volume 72-74, Page 985, 1997), containing triphenylamine Aromatic amine compound of amine tetramer (Chem. Commun., 2175 page, 1996), 2,2',7,7'-tetra-(diphenylamino)-9,9 Spirocyclic compounds such as'-spirobifen (Synth. Metals, Volume 91, page 209, 1997), 4,4'-N,N'-dicarbazole biphenyl and other carbazole derivatives, etc. It is also preferable to use polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Laid-Open No. 7-53953), and poly(arylene ether) containing tetraphenyl benzidine (advanced technology for polymerization (Polym. Adv. Tech.), Volume 7, 33 pages, 1996) and so on.

(Formation of hole transport layer 4 by wet film formation method) In the case of forming the hole transport layer 4 by a wet film formation method, generally, the same as when the hole injection layer 3 is formed by the wet film formation method, a composition for forming a hole transport layer is used instead of the holes. The injection layer forming composition is formed.

In the case of forming the hole transport layer 4 by a wet film formation method, the composition for forming the hole transport layer generally contains a solvent. The solvent used in the composition for forming the hole transport layer can be the same solvent as the solvent used in the composition for forming the hole injection layer. 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.

The formation of the hole transport layer 4 by the wet film formation method can be performed in the same manner as the film formation method of the hole injection layer 3 described above.

(Formation of hole transport layer 4 by vacuum evaporation method) In the case of forming the hole transport layer 4 by a vacuum vapor deposition method, it is usually the same as when the hole injection layer 3 is formed by the wet film formation method, and the constituent material of the hole transport layer 4 can be used instead of the electricity. The hole is formed by injecting the constituent material of the layer 3. Regarding the film forming conditions such as the degree of vacuum during the vapor deposition, the vapor deposition rate, and the temperature, the film can be formed under the same conditions as those during the vacuum vapor deposition of the hole injection layer 3.

＜Light-emitting layer 5＞ The light-emitting layer 5 is a layer that performs the function of being excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 to emit light when an electric field is applied between a pair of electrodes.

The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9. Regarding the light-emitting layer 5, when the hole injection layer 3 exists on the anode 2, it is formed between the hole injection layer 3 and the cathode 9. When the hole transport layer 4 exists on the anode 2, the light-emitting layer 5 is formed between the hole transport layer 4 and the cathode 9.

As long as the effect of the present invention is not significantly impaired, the film thickness of the light-emitting layer 5 is arbitrary. However, in terms of preventing defects in the film, it is better to be thick, and in terms of easily achieving a low driving voltage, it is better to be thin. The thickness of the light-emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, usually 200 nm or less, and more preferably 100 nm or less.

In the organic electroluminescence device of the present invention, the light-emitting layer 5 is formed by using the composition for the organic electroluminescence device of the present invention, and is preferably formed by a wet film forming method.

When the composition for an organic electroluminescence element of the present invention is used to form a light-emitting layer by a wet film formation method, the composition for an organic electroluminescence element of the present invention has the compound represented by the formula (1), In addition to the polymer compound of the repeating unit (2) and the compound represented by the formula (3), other light-emitting materials and charge-transporting materials may also be included.

Hereinafter, other luminescent materials and charge-transporting materials will be described in detail.

(Luminescent material) The luminescent material other than the compound represented by formula (1) emits light at a desired emission wavelength, and as long as the effect of the present invention is not impaired, there is no particular limitation, and a known luminescent material can be applied. The luminescent material may be a fluorescent luminescent material or a phosphorescent luminescent material, but it is preferably a material with good luminous efficiency. From the viewpoint of internal quantum efficiency, a phosphorescent light-emitting material is preferred.

Examples of the fluorescent material include the following materials.

As the fluorescent light emitting material (blue fluorescent light emitting material) that provides blue light emission, for example, naphthalene, perylene, pyrene, anthracene, coumarin, cha, p-bis(2-phenylvinyl)benzene and these Derivatives and so on.

Examples of fluorescent materials that provide green light emission (green fluorescent light-emitting materials) include quinacridone derivatives, coumarin derivatives, aluminum complexes such as _{Al(C 9} H ₆ NO) _{3, and the like.}

As a fluorescent light emitting material (yellow fluorescent light emitting material) that provides yellow light emission, for example, fluorescein, perimidone derivatives, and the like can be cited.

As the fluorescent light-emitting material (red fluorescent light-emitting material) that provides red light emission, for example, DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl) )-4H-pyran) compounds, benzopyran derivatives, rose bengal derivatives, benzothioxanthone derivatives, azabenzothioxanthones, etc.

Examples of phosphorescent materials include Groups 7 to 11 selected from the long-period periodic table (hereinafter referred to as the "periodic table" unless otherwise specified). Organometallic complexes of metals in the group. Preferred examples of metals selected from Group 7 to Group 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold, and the like.

As the ligands of the organometallic complexes, (hetero)arylpyridine ligands, (hetero)arylpyrazole ligands and other (hetero)aryl groups are preferably linked to pyridine, pyrazole, phenanthroline, etc. The ligands formed are particularly preferably phenylpyridine ligands and phenylpyrazole ligands. Here, the (hetero)aryl group means an aryl group or a heteroaryl group.

As preferred phosphorescent luminescent materials, specific examples include: tris(2-phenylpyridine)iridium, tris(2-phenylpyridine)ruthenium, tris(2-phenylpyridine)palladium, bis(2-phenylpyridine) Pyridine)platinum, tris(2-phenylpyridine)osmium, tris(2-phenylpyridine)rhenium and other phenylpyridine complexes and octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin Porphyrin complexes such as phyrin, octaphenyl palladium porphyrin, etc.

Examples of polymer-based luminescent materials include: poly(9,9-dioctyl -2,7-diyl), poly[(9,9-dioctyl -2,7-diyl)-co -(4,4'-(N-(4-Second-butylphenyl))diphenylamine)], poly[(9,9-dioctyl -2,7-diyl)-co- (1,4-Benzo-2{2,1'-3}-triazole)] and other polytetrafluoroethylene materials, poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-styrene ethylene] and other polystyrene ethylene-based materials.

(Charge transport material) The charge-transporting material is a material having positive charge (hole) or negative charge (electron) transport properties. As a charge-transporting material other than the compound represented by formula (3), as long as the effect of the present invention is not impaired, It is not particularly limited, and known materials can be used.

As the charge-transporting material, compounds previously used for the light-emitting layer of organic electroluminescent elements, etc. can be used. In particular, a compound used as a host material of the light-emitting layer is preferable.

Specific examples of charge-transporting materials include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzyl phenyl compounds, and connection with stilbene groups. Compounds made of tertiary amines, hydrazone-based compounds, silazane-based compounds, silanamine-based compounds, phosphamide-based compounds, quinacridone-based compounds, etc. are exemplified as hole-transporting compounds in the hole injection layer 3 In addition, electron-transporting compounds such as anthracene-based compounds, pyrene-based compounds, carbazole-based compounds, pyridine-based compounds, phenanthroline-based compounds, oxadiazole-based compounds, and silole-based compounds can also be cited.

As a charge-transporting material, it can also be preferably used: 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl containing two or more tertiary amines and Aromatic diamines in which two or more condensed aromatic rings are substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), 4,4',4''-tris(1-naphthylphenylamino) three Aromatic amine compounds with starburst structure such as phenylamine (J. Lumin., Volume 72-74, Page 985, 1997), aromatic amines containing tetramers of triphenylamine Compounds (Chem. Commun.), 2175 pages, 1996), 2,2',7,7'-tetra-(diphenylamino)-9,9'-spirobifen and other stilbene compounds (Synth. Metals, Vol. 91, p. 209, 1997), 4,4'-N,N'-dicarbazole biphenyl and other carbazole-based compounds as hole transport in the hole transport layer 4 Exemplified compounds and the like. In addition, you can also cite: 2-(4-biphenyl)-5-(p-tertiary butylphenyl)-1,3,4-oxadiazole (tBu-PBD), 2,5-bis(1 -Naphthyl)-1,3,4-oxadiazole (BND) and other oxadiazole compounds; 2,5-bis(6'-(2',2''-bipyridyl))-1,1 -Dimethyl-3,4-diphenylsilole (PyPySPyPy) and other silole compounds; 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline, BPhen), 2,9-dimethyl -4,7-Diphenyl-1,10-phenanthroline (bathocuproin, BCP) and other phenanthroline compounds, etc.

(Formation of light-emitting layer 5 by wet film forming method) The organic electroluminescent element of the present invention has a light-emitting layer formed by a wet film forming method using the composition for an organic electroluminescent element of the present invention. The organic electroluminescent element of the present invention may have a light-emitting layer other than a light-emitting layer formed by a wet film formation method using the composition for an organic electroluminescent element of the present invention as the light-emitting layer 5. The method for forming the light-emitting layer may be a vacuum deposition method or a wet film formation method. However, in terms of excellent self-film formation properties, the wet film formation method is preferred.

In the case of forming the light-emitting layer 5 by a wet film formation method, as in the case of forming the hole injection layer 3 by a wet film formation method, the composition for an organic electroluminescent device of the present invention, or A composition for forming a light-emitting layer prepared by mixing a material as the light-emitting layer 5 with a soluble solvent (solvent for a light-emitting layer) is formed instead of the composition for forming a hole injection layer.

As the solvent, for example, in addition to the ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents listed for the formation of the hole injection layer 3, alkane-based solvents, halogenated aromatic hydrocarbon-based solvents, Aliphatic alcohol-based solvents, alicyclic alcohol-based solvents, aliphatic ketone-based solvents, alicyclic ketone-based solvents, etc. The solvent used is also exemplified as the solvent of the composition for an organic electroluminescent device of the present invention. Specific examples of solvents are listed below, but they are not limited to these as long as the effects of the present invention are not impaired.

For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3 -Dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4- Aromatic ether solvents such as dimethyl anisole and diphenyl ether; aromatics such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, etc. Ester solvent; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropyl Aromatic hydrocarbon solvents such as benzene and methylnaphthalene; amine solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; n-decane, cyclohexane, ethyl ring Alkane solvents such as hexane, decahydronaphthalene, and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; cyclohexane Alicyclic alcohol-based solvents such as alcohol and cyclooctanol; aliphatic ketone-based solvents such as methyl ethyl ketone and dibutyl ketone; alicyclic ketone-based solvents such as cyclohexanone, cyclooctanone, and fenchone. Among these, particularly preferred are an alkane-based solvent and an aromatic hydrocarbon-based solvent.

In order to obtain a more uniform film, it is preferable that the solvent evaporate from the liquid film immediately after film formation at an appropriate speed. Therefore, the boiling point of the solvent used is as described above, usually 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, usually 270°C or lower, preferably 250°C or lower, and more preferably a boiling point of 230 ℃ below.

As long as the effect of the present invention is not significantly impaired, the amount of solvent used is arbitrary. However, as described above, the total content in the composition for forming the light-emitting layer, that is, the composition for the organic electroluminescent element, is due to low viscosity. In terms of ease of film formation, more is better, and in terms of ease of forming a thick film, lower is better. As described above, the content of the solvent in the composition for an organic electroluminescent device is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, preferably 99.99% by mass or less, and more preferably It is 99.9% by mass or less, particularly preferably 99% by mass or less.

As a method for removing the solvent after wet film formation, heating or reduced pressure can be used. As the heating means used in the heating method, in terms of uniformly supplying heat to the entire film, it is preferable to clean an oven or a hot plate.

As long as the effect of the present invention is not significantly impaired, the heating temperature in the heating step is arbitrary, but in terms of shortening the drying time, the temperature is preferably high, and in terms of less damage to the material, the temperature is lower. Better. The upper limit of the heating temperature is usually 250°C or lower, preferably 200°C or lower, and more preferably 150°C or lower. The lower limit of the heating temperature is usually 30°C or higher, preferably 50°C or higher, and more preferably 80°C or higher. The temperature at which the heating temperature exceeds the upper limit has higher heat resistance than the charge transport material or phosphorescent material generally used, and may decompose or crystallize, so it is not preferable. If the heating temperature is less than the lower limit, it takes a long time to remove the solvent, which is not preferable. The heating time in the heating step can be reasonably determined according to the boiling point or vapor pressure of the solvent in the composition for forming the light-emitting layer, the heat resistance of the material, and the heating conditions.

(Formation of the light-emitting layer 5 by the vacuum evaporation method) When the light-emitting layer 5 is formed by the vacuum evaporation method, the constituent materials of the light-emitting layer 5 (the light-emitting material, charge-transporting compound, etc.) are usually One or two or more are put into the crucible set in the vacuum container (when two or more materials are used, they are usually put into different crucibles), and the vacuum container is evacuated to 10 ^{-by using a vacuum pump After about 4} Pa, heat the crucible (when two or more materials are used, the crucible is usually heated separately), while controlling the evaporation of the material in the crucible, evaporate it (when using more than two materials) In the case of, the amount of evaporation is usually controlled independently to evaporate), and the light-emitting layer 5 is formed on the hole injection layer 3 or the hole transport layer 4 placed facing the crucible. When two or more kinds of materials are used, the mixture of these may be put into a crucible and heated to evaporate to form the light-emitting layer 5.

That does not significantly impair the effects of the present invention, the degree of vacuum during the deposition is not limited, but is usually ^{0.1 × 10 -6 Torr (0.13 ×} 10 -4 Pa) or more and ^{9.0 × 10 -6 Torr (12.0 ×} 10 - ⁴ Pa) or less. As long as the effect of the present invention is not significantly impaired, the vapor deposition rate is not limited, and it is usually 0.1 Å/sec or more and 5.0 Å/sec or less. As long as the effect of the present invention is not significantly impaired, the film formation temperature during vapor deposition is not limited, and it is preferably performed at 10°C or higher and 50°C or lower.

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

The hole blocking layer 6 has a function of blocking holes moved from the anode 2 from reaching the cathode 9 and a function of efficiently transporting electrons injected from the cathode 9 to the direction of the light-emitting layer 5. The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility, low hole mobility, large energy gap (difference between HOMO and LUMO), and high excited triplet energy level (T1).

As a material of the hole blocking layer 6 that satisfies such conditions, for example, bis(2-methyl-8-hydroxyquinoline) (phenol)aluminum, bis(2-methyl-8-hydroxyquinoline) ( Triphenylsilanol) aluminum (bis(2-methyl-8-quinolinolato)(triphenyl silanolato)aluminum) and other mixed ligand complexes, bis(2-methyl-8-quinolinolato)aluminum-μ- Metal complexes such as oxo-bis-(2-methyl-8-hydroxyquinoline) aluminum dinuclear metal complexes, and styryl compounds such as stilbene biphenyl derivatives (Japanese Patent Laid-Open No. 11- 242996), 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole and other triazole derivatives (Japanese Patent Special Kaihei 7-41759), phenanthroline derivatives such as bathocuproin (Japanese Patent Laid-open No. 10-79297), etc. The compounds described in International Publication No. 2005/022962 having at least one substituted pyridine ring at positions 2, 4, and 6 are also preferable as the material of the hole blocking layer 6.

The method of forming the hole blocking layer 6 is not limited, and it can be formed in the same manner as the method of forming the light-emitting layer 5 described above.

As long as the effect of the present invention is not significantly impaired, the film thickness of the hole blocking layer 6 is arbitrary, and is usually 0.3 nm or more, preferably 0.5 nm or more, usually 100 nm or less, preferably 50 nm or less.

＜Electron transport layer 7＞ For the purpose of further improving the current efficiency of the device, 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.

The electron transport layer 7 is formed of a compound capable of efficiently transporting electrons injected from the cathode 9 to the direction of the light emitting layer 5 between electrodes to which an electric field is applied. The electron-transporting compound used in the electron-transporting layer 7 needs to be a compound that has high electron injection efficiency from the cathode 9 or the electron injection layer 8, has high electron mobility, and can efficiently transport the injected electrons.

Examples of electron-transporting compounds satisfying such conditions include: 8-hydroxyquinoline (8-hydroxyquinoline) aluminum complexes and other metal complexes (Japanese Patent Laid-Open No. 59-194393), 10- Metal complexes of hydroxybenzo[h]quinoline, oxadiazole derivatives, stilbene biphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone Metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, tribenzimidazolylbenzene (U.S. Patent No. 5645948 specification), quinoxaline compounds (Japanese Patent Laid-Open No. 6-207169) Bulletin), phenanthroline derivatives (Japanese Patent Laid-Open No. 5-331459), 2-tert-butyl-9,10-N,N'-dicyanoanthraquinone diimide, n-type hydrogenated amorphous Silicon carbide, n-type zinc sulfide, n-type zinc selenide, etc.

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

The electron transport layer 7 is formed by laminating the light emitting layer 5 or the hole blocking layer 6 by a wet film formation method or a vacuum vapor deposition method, similarly to the light emitting layer 5. Generally, a vacuum evaporation method is used.

＜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.

In order to perform electron injection efficiently, the material forming the electron injection layer 8 is preferably a metal with a low work function. As examples, alkali metals such as sodium or cesium, alkaline earth metals such as barium or calcium, and the like can be used.

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

Inserting an extremely thin insulating film (with a thickness of about 0.1 nm to 5 nm) such as _{LiF, MgF 2} , Li ₂ O, Cs ₂ CO ₃ and the like at the interface between the cathode 9 and the electron transport layer 7 as the electron injection layer 8 is also to improve the device Effective methods for efficiency (Appl. Phys. Lett.), Vol. 70, 152 pages, 1997; Japanese Patent Laid-Open No. 10-74586; IEEE Trans. Electron. Devices, Vol. 44 , 1245 pages, 1997; Society for Information Display (SID) 04 Digest, 154 pages). Furthermore, organic electron transport represented by nitrogen-containing heterocyclic compounds such as 4,7-diphenyl-1,10-phenanthroline or metal complexes such as aluminum complexes of 8-hydroxyquinoline The material is doped with alkali metals such as sodium, potassium, cesium, lithium, rubidium (described in Japanese Patent Laid-Open No. 10-270171, Japanese Patent Laid-Open No. 2002-100478, Japanese Patent Laid-Open No. 2002-100482, etc.), It is preferable because it has excellent film quality with improved electron injection properties and improved transport properties. The film thickness in this case is usually 5 nm or more, preferably 10 nm or more, usually 200 nm or less, and preferably 100 nm or less.

The electron injection layer 8 is formed by laminating the light emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 on the light emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 similarly to the light emitting layer 5 by a wet film formation method or a vacuum evaporation method. The details in the case of the wet film formation method are the same as in the case of the light-emitting layer 5 described above.

＜Cathode 9＞ The cathode 9 plays a role of injecting electrons into the layer on the light-emitting layer 5 side (the electron injection layer 8 or the light-emitting layer 5, etc.). As the material of the cathode 9, the material used in the anode 2 can be used. However, in terms of efficiently performing electron injection, it is preferable to use a metal with a low work function. As the material of the cathode 9, for example, metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys of these can be used. Examples of the material of the cathode 9 include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In terms of device stability, it is preferable to laminate a metal layer with a high work function and stable with respect to the atmosphere on the cathode 9 to protect the cathode 9 containing a metal with a low work function. Examples of the laminated metal include metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.

The film thickness of the cathode is usually the same as that of the anode 2.

＜Other constituent layers＞ The above description focuses on the element with the layer structure shown in FIG. 1, but between the anode 2 and cathode 9 and the light-emitting layer 5 of the organic electroluminescent element of the present invention, as long as its performance is not impaired, all the elements are not included. You may have arbitrary layers other than the layers in the description. Any layers other than the light-emitting layer 5 may be omitted.

For example, for the same purpose as the hole blocking layer 8, it is also effective to provide an electron blocking layer between the hole transport layer 4 and the light-emitting layer 5. The electron blocking layer has the following function: by blocking the electrons moving from the light-emitting layer 5 from reaching the hole transport layer 4, the probability of recombination with holes in the light-emitting layer 5 is increased, and the generated excitons are enclosed in the light-emitting layer 5 The role of; and the role of efficiently transporting holes injected from the hole transport layer 4 in the direction of the light emitting layer 5.

The characteristics required for the electron blocking layer include high hole transportability, large energy gap (difference between HOMO and LUMO), and high excited triplet energy level (T1). In the case where the light-emitting layer 5 is formed by a wet film formation method, the electron blocking layer is also formed by a wet film formation method, which facilitates device manufacturing, which is therefore preferable. Therefore, the electron blocking layer is also preferably suitable for wet film formation. As the material used in this type of electron blocking layer, a copolymer of dioctyl fluoride and triphenylamine represented by F8-TFB can be cited. (International Publication No. 2004/084260) and so on.

It may also have a structure opposite to that of FIG. 1, that is, a cathode 9, an electron injection layer 8, an electron transport layer 7, a hole blocking layer 6, a light emitting layer 5, a hole transport layer 4, and a hole are sequentially laminated on the substrate 1. Injection layer 3, anode 2. The organic electroluminescent element of the present invention may also be provided between at least one of two substrates with high transparency.

It may also be a structure in which the layer configuration shown in FIG. 1 is stacked in multiple stages (a structure in which a plurality of light-emitting units are stacked). At this time, if, for example, V ₂ O _{5 is} used as a charge generation layer instead of the interface layer between the levels (between light-emitting units) (the anode is indium tin oxide (ITO), and the cathode is Al, it means The two layers), the barriers between the stages are reduced, and the self-luminous efficiency and the driving voltage are better.

The present invention can be applied to any one of the organic electroluminescent element is a single element, the element has a structure arranged in an array, and the anode and the cathode are arranged in an X-Y matrix.

[Display Device and Lighting Device] The display device and the lighting device of the present invention use the organic electroluminescent element of the present invention. There is no particular limitation on the form or structure of the display device and the lighting device of the present invention, and the organic electroluminescent element of the present invention can be used and assembled according to conventional methods. For example, the display device of the present invention can be formed by the method described in "Organic EL Display" (Ohmsha (Ohmsha), issued on August 20, 2004, by then Seishi Shi, Chinami Adachi, Hideyuki Murata). . Example

Hereinafter, examples are shown to explain the present invention more specifically. The present invention is not limited to the following examples, and can be arbitrarily modified and implemented as long as it does not deviate from the gist of the present invention.

[Example 1] The organic electroluminescent element was produced by the following method.

For the glass substrate, the transparent conductive film of indium-tin oxide (ITO) is deposited to a thickness of 50 nm, and the anode is formed by patterning into 2 mm wide stripes using common photolithography technology and hydrochloric acid etching. The substrate patterned with ITO is cleaned in the order of ultrasonic cleaning with surfactant aqueous solution, ultrapure water, ultrasonic cleaning with ultrapure water, and water washing with ultrapure water, and then compressed It is dried by air, and finally cleaned by ultraviolet ozone.

As a composition for forming a hole injection layer, a hole-transporting polymer compound represented by the following formula (P-1) at a concentration of 3.0% by mass and a compound represented by the following formula (HI-1) was prepared The composition is dissolved in ethyl benzoate at a concentration of 0.3% by mass.

[化26]

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

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

[化27]

Then, as the material of the light-emitting layer, weigh 75 parts by mass of the polymer compound represented by the following structural formula (H-1) (Mw=39000, Mw/Mn=1.41), as represented by the following structural formula (H-2) 25 parts by mass of the compound represented by the following structural formula (D-1) and 20 parts by mass of the compound represented by the following structural formula (D-1) were dissolved in cyclohexylbenzene so as to be 6.0% by mass in total to prepare a composition for forming a light-emitting layer.

[化28]

The composition for forming a light-emitting layer was spin-coated in a nitrogen glove box on the substrate on which the hole transport layer was formed, and dried on a heating plate in a nitrogen glove box at 120°C for 20 minutes to form a film thickness of 70 nm The uniform film is used as the light-emitting layer.

The substrate on which the light-emitting layer has been formed is set in a vacuum vapor deposition apparatus, and the inside of the apparatus is exhausted to 2×10 ^-4 Pa or less.

Next, the compound represented by the following structural formula (HB-1) and lithium 8-quinolinolate were co-evaporated on the light-emitting layer at a film thickness ratio of 2:3 at a rate of 1 Å/sec by a vacuum evaporation method Above, a hole blocking layer with a thickness of 30 nm is formed.

[化29]

Then, as a mask for cathode vapor deposition, a 2 mm wide striped shadow mask was closely attached to the substrate in a manner orthogonal to the ITO stripes of the anode, and set in another vacuum vapor deposition device as a cathode. , The aluminum is heated by the molybdenum boat to form an aluminum layer with a thickness of 80 nm at a deposition rate of 1 Å/sec to 8.6 Å/sec to form a cathode.

Then, in a nitrogen glove box, a glass cap (Glass cap) provided with a dewatering sheet was installed so as to cover the vapor deposition part, and the periphery of the vapor deposition part and the glass cap were bonded and sealed with UV curing resin.

By performing the operation as described above, an organic electroluminescent element having a light-emitting area portion having a size of 2 mm×2 mm was obtained.

[Example 2] The composition (parts by mass) of the material contained in the composition for forming a light-emitting layer is set to (H-1): (H-2): (D-1)=50:50:20. 1 The components are produced in the same way.

[Example 3] The material composition (parts by mass) contained in the composition for forming a light-emitting layer is set to (H-1): (H-3): (D-1)=75:25:20. Otherwise, the same as in the examples 1 The components are produced in the same way. The structural formula of (H-3) is shown below.

[化30]

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

[Evaluation of the device] The voltage (V) when the organic electroluminescent device produced in Examples 1 to 3 and Comparative Example 1 emits light with a luminance of 1000 cd/m ^{2 was} measured, and the voltage difference from that of Comparative Example 1 was determined. (The voltage of Examples 1 to 3 and Comparative Example 1-the voltage of Comparative Example 1) was taken as the voltage difference (V). The current luminous efficiency (cd/A) when the organic electroluminescent elements produced in Examples 1 to 3 and Comparative Example 1 emit light at a luminance of 1000 cd/m ^{2 was} measured, and the current luminous efficiency of Comparative Example 1 was determined. The relative value at 100 is used as the relative luminous efficiency. Calculate the external quantum efficiency (referred to as EQE) when the organic electroluminescent elements produced in Examples 1 to 3 and Comparative Example 1 emit light at a luminance of 1000 cd/m ^{2 and set the EQE of Comparative Example 1 to 100} The relative value of is set to relative EQE. Table 1 shows these evaluation results. As shown in Table 1, it can be seen that the organic electroluminescence element of the present invention has higher luminous efficiency and lower voltage than the organic electroluminescence element of the comparative example.

[Table 1] Light-emitting layer material composition (parts by mass) Voltage difference (V) Relative luminous efficiency Relative EQE Example 1 H-1: H-2: D-1 = 75: 25: 20 -0.13 110 107 Example 2 H-1: H-2: D-1 = 50: 50: 20 -0.14 110 107 Example 3 H-1: H-3: D-1 = 75: 25: 20 -0.16 100 99 Comparative example 1 H-1: D-1 =100: 20 0 100 100

[Example 4] The compound represented by the following structural formula (H-4) is used instead of the compound represented by the structural formula (H-2), and the material composition (parts by mass) contained in the composition for forming a light-emitting layer is set as (H- 1): (H-4): (D-1)=75:25:20, except for this, an element was produced in the same manner as in Example 1.

[化31]

[Example 5] The material composition (parts by mass) contained in the composition for forming a light-emitting layer is set to (H-1): (H-4): (D-1)=50:50:20. Otherwise, the same as in the examples 1 The components are produced in the same way.

[Example 6] The composition (parts by mass) of the material contained in the composition for forming the light-emitting layer is set to (H-1): (H-4): (D-1)=25:75:20. Otherwise, the same as in the examples 1 The components are produced in the same way.

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

[化32]

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

[化33]

[Comparative Example 2] The device was produced in the same manner as in Comparative Example 1.

[Comparative Example 3] The compound represented by the following structural formula (H-7) is used instead of the compound represented by the structural formula (H-2), and the material composition (parts by mass) contained in the composition for forming a light-emitting layer is set as (H- 1): (H-7): (D-1)=75:25:20, and other than that, an element was produced in the same manner as in Example 1.

[化34]

[Comparative Example 4] The compound represented by the following structural formula (D-2) is used instead of the compound represented by the structural formula (D-1), and the material composition (parts by mass) contained in the composition for forming a light-emitting layer is set as (H- 1): (H-4): (D-2)=75:25:20, and other than that, an element was produced in the same manner as in Example 1.

[化35]

[Comparative Example 5] The material composition (parts by mass) contained in the composition for forming a light-emitting layer is set to (H-1): (H-5): (D-2)=75:25:20. Otherwise, the same as in the examples 1 The components are produced in the same way.

[Comparative Example 6] The material composition (parts by mass) contained in the composition for forming a light-emitting layer is set to (H-1): (H-6): (D-2)=75:25:20. Otherwise, the same as in the examples 1 The components are produced in the same way.

[Comparative Example 7] The material composition (parts by mass) contained in the composition for forming a light-emitting layer is set to (H-1): (H-7): (D-2)=75:25:20. Otherwise, the same as in the examples 1 The components are produced in the same way.

[Evaluation of the element] The voltage (V) at which the organic electroluminescent element produced in Example 4 to Example 8 and Comparative Example 2 to Comparative Example 7 emits light at a luminance of 1000 cd/m ^{2 was} measured, and the value of Comparative Example 2 was determined. The difference between the voltage of the element and the voltage of each element (the voltage of Examples 4 to 8 and Comparative Examples 2 to 7-the voltage of Comparative Example 2) was taken as the voltage difference (V). The external quantum efficiency (referred to as EQE) when the organic electroluminescent element produced in Example 4 to Example 8 and Comparative Example 2 to Comparative Example 7 emit light at a luminance of 1000 cd/m ^{2 was determined, and the comparative example 2 was determined.} The relative value of the EQE of each element when the EQE is set to 100 is used as the relative EQE. The organic electroluminescent elements prepared in Example 4 to Example 8 and Comparative Example 2 to Comparative Example 7 were driven with constant current, ^{converted to the initial luminance Lo=3000 cd/m 2} , and the luminance decreased to 95 of the initial luminance. The time to% is taken as LT95 (hr), and the relative value of LT95 of each element when the LT95 of Comparative Example 2 is set to 100 is obtained as the relative drive life. These results are shown in Table 2. As shown in Table 2, it can be seen that the organic electroluminescent element of the present invention has a low voltage, a high luminous efficiency (EQE), and a long driving life.

[Table 2] Light-emitting layer material composition (parts by mass) Voltage difference (V) Relative EQE Relative drive life Example 4 H-1: H-4: D-1 = 75: 25: 20 -0.14 114 442 Example 5 H-1: H-4: D-1 = 50: 50: 20 -0.26 127 802 Example 6 H-1: H-4: D-1 = 25: 75: 20 +0.05 155 1040 Example 7 H-1: H-5: D-1 = 75: 25: 20 -0.24 110 420 Example 8 H-1: H-6: D-1 = 75: 25: 20 -0.18 132 272 Comparative example 2 H-1: D-1 =100: 20 0 100 100 Comparative example 3 H-1: H-7: D-1 = 75: 25: 20 -0.03 117 135 Comparative example 4 H-1: H-4: D-2 = 75: 25: 20 +2.83 94 0.3 Comparative example 5 H-1: H-5: D-2 = 75: 25: 20 +2.62 94 0.2 Comparative example 6 H-1: H-6: D-2 = 75: 25: 20 +9.12 twenty two 9 Comparative example 7 H-1: H-7: D-2 = 75: 25: 20 +6.86 27 0.01

[Example 9] In the same manner as in Example 1, an element was produced.

[Comparative Example 8] The material composition (parts by mass) contained in the composition for forming the light-emitting layer is set to (H-1): (H-2): (D-2)=75:25:20. Otherwise, the same as in the examples 1 The components are produced in the same way.

[Comparative Example 9] Use the polymer compound represented by the following structural formula (H-8) instead of the polymer compound represented by the structural formula (H-1), and set the material composition (parts by mass) contained in the composition for forming the light-emitting layer Except for (H-8):(H-2):(D-1)=75:25:20, an element was produced in the same manner as in Example 1.

[化36]

[Evaluation of the device] The voltage (V) when the organic electroluminescent device produced in Example 9, Comparative Example 8 and Comparative Example 9 was made to emit light with a luminance of 1000 cd/m ^{2 was} measured, and the voltage difference from that of Comparative Example 2 was determined. (Example 9, Comparative Example 2, Comparative Example 8, and Comparative Example 9-Voltage of Comparative Example 2) was taken as the voltage difference (V). Calculate the external quantum efficiency (referred to as EQE) when the organic electroluminescent elements produced in Example 9, Comparative Example 8 and Comparative Example 9 emit light at a luminance of 1000 cd/m ^{2 and set the EQE of Comparative Example 2 to 100} The relative value of is set to relative EQE. The organic electroluminescent elements produced in Example 9, Comparative Example 8 and Comparative Example 9 were driven with constant current, ^{converted to the initial luminance Lo=3000 cd/m 2} , and the time until the luminance decreased to 95% of the initial luminance was calculated As LT95 (hr), the relative value of the LT95 of each element when the LT95 of Comparative Example 2 is set to 100 is obtained as the relative drive life. These results are shown in Table 3. As shown in Table 3, it can be seen that the device of the present invention has low voltage, high luminous efficiency (EQE), and high driving durability. On the other hand, the element of Comparative Example 9 in which the polymer compound contained in the light-emitting layer does not include the structure represented by the formula (2) of the present invention has a high voltage and low luminous efficiency.

[table 3] Light-emitting layer material composition (parts by mass) Voltage difference (V) Relative EQE Relative drive life Example 9 H-1: H-2: D-1 = 75: 25: 20 -0.13 107 305 Comparative example 2 H-1: D-1 =100: 20 0 100 100 Comparative example 8 H-1: H-2: D-2 = 75: 25: 20 +3.28 85 205 Comparative example 9 H-8: H-2: D-1 = 75: 25: 20 +0.00 98 369

Although the present invention has been described in detail using a specific aspect, it is obvious to those skilled in the art that various changes can be made without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application 2019-110408 filed on June 13, 2019, and is incorporated by reference in its entirety.

1: substrate 2: anode 3: hole injection layer 4: hole transport layer 5: Light-emitting layer 6: Hole barrier 7: Electron transport layer 8: Electron injection layer 9: Cathode 10: Organic electroluminescent element

FIG. 1 is a cross-sectional view schematically showing an example of the structure of the organic electroluminescent element of the present invention.

1: substrate

2: anode

3: hole injection layer

4: hole transport layer

5: Light-emitting layer

6: Hole barrier

7: Electron transport layer

8: Electron injection layer

9: Cathode

10: Organic electroluminescent element

Claims (12)

A composition for an organic electroluminescent device, comprising: a compound represented by the following formula (1); a polymer compound having a repeating unit including a structure represented by the following formula (2); represented by the following formula (3) Compounds, and solvents;

In formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, an alkoxy group having 1 to 20 carbons, and 3 ～20 (hetero)aryloxy groups, C1-C20 alkylsilyl groups, C6-C20 arylsilyl groups, C2-C20 alkylcarbonyl groups, C7-20 aryl groups Any one of a carbonyl group, an alkylamino group having 1 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons, or a combination of these; these The group may further have a substituent; when there are multiple R ¹ and R ² , the multiple R ¹ and R ² may be the same or different; adjacent R ¹ or R ² bonded to the benzene ring may be mutually Bond to form a ring condensed to the benzene ring; a is an integer from 0 to 4; b is an integer from 0 to 3; m is an integer from 1 to 20; n is an integer from 0 to 2; ring A is a pyridine ring , Pyrazine ring, pyrimidine ring, imidazole ring, oxazole ring, thiazole ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azatriphenylene ring, carboline ring One; Ring A may have a substituent; the substituent is a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and a carbon number of 1 ～20 alkoxy group, (hetero)aryloxy group with 3-20 carbons, alkylsilyl group with 1-20 carbons, arylsilyl group with 6-20 carbons, alkyl group with 2-20 carbons Any of a carbonyl group, an arylcarbonyl group having 7 to 20 carbons, an alkylamino group having 2 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 20 carbons Or a combination of these; adjacent substituents bonded to ring A may be bonded to each other to form a ring condensed to ring A; Z ¹ represents a direct bond or an m+1 valent aromatic linking group; L ¹ Represents an auxiliary ligand; l is an integer from 1 to 3; when there are multiple auxiliary ligands, they may be different or the same;

In formula (2), R ³ and R ⁴ are each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, an alkoxy group having 1 to 20 carbons, and 3 ～20 (hetero)aryloxy groups, C1-C20 alkylsilyl groups, C6-C20 arylsilyl groups, C2-C20 alkylcarbonyl groups, C7-20 aryl groups Any one of a carbonyl group, an alkylamino group having 1 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons, or a combination of these; these The group may further have a substituent;

In the formula (3), X ¹ represents C or N; R ⁵ to R ⁷ are each independently an alkyl group having 1 to 20 carbons, a (hetero)aralkyl group having 7 to 40 carbons, and one having 1 to 20 carbons. Alkoxy, (hetero)aryloxy with 3 to 20 carbons, alkylsilyl with 1 to 20 carbons, arylsilyl with 6 to 20 carbons, alkylcarbonyl with 2 to 20 carbons, carbon Any one of an arylcarbonyl group having 7 to 20, an alkylamino group having 1 to 20 carbons, an arylamino group having 6 to 20 carbons, and a (hetero)aryl group having 3 to 30 carbons, or The combination of these; these groups may further have substituents; when there are multiple R ^5s , the multiple R ^5s may be the same or different; adjacent R ^5s bonded to the benzene ring may be bonded to each other A ring condensed to the benzene ring is formed; c is an integer from 0 to 5; wherein, when c is 0, R ⁶ and R ^{7 are} not both unsubstituted phenyl groups at the same time. The composition for an organic electroluminescent element according to claim 1, wherein Z ¹ in the formula (1) is a direct bond. The composition for an organic electroluminescence element according to claim 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (1-1);

In formula (1-1), three X ² represent 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 from 1 to 10; R ¹ , R ² , a, b, n, m, ring A, L ¹ , l and R ¹ , R ² , a, b, m, n, ring A, L ¹ , and l have the same meaning. The composition for an organic electroluminescent element according to claim 1 or 2, wherein the compound represented by formula (1) is a compound represented by formula (1-2);

In the formula ^{(1-2), R 1, a} , m, n, Ring ^{A, Z 1, L 1,} l and the formula R (1) is ^1, a, m, n, Ring A, Z ^1, L ¹ and l have the same meaning; R ¹⁵ to R ¹⁷ are substituents. The composition for an organic electroluminescent element according to any one of claims 1 to 4, wherein l in the formula (1) is 3. The composition for an organic electroluminescent device according to any one of claims 1 to 5, wherein the polymer compound having a repeating unit including the structure represented by the formula (2) includes the following formula (2- 1) The repeating unit represented;

In the formula (2-1), Ar ²¹ to Ar ²³ each independently represent a bivalent (hetero) arylene group having 3 to 30 carbon atoms that may have a substituent; Ar ²⁴ and Ar ²⁵ each independently indicate that they may be substituted (Hetero)aryl group having 3 to 30 carbon atoms in the group; r represents an integer of 0-2. The composition for an organic electroluminescent device according to any one of claims 1 to 6, wherein in the compound represented by the formula (3), [phenylene-(R ⁵ )c], R ^{The three partial structures of 6} and R ⁷ are not the same structure, and when the partial structure has a substituent, its substituent is also included. The composition for an organic electroluminescent device according to any one of claims 1 to 7, wherein the ^{ends of R 5} to R ⁷ in the compound represented by the formula (3) each independently include a phenyl group, Naphthyl, stilbene, carbazolyl, indolocarbazolyl, indenocarbazolyl, or indeno carbazolyl. A method for manufacturing an organic electroluminescent element includes the step of forming a light-emitting layer by a wet film forming method using the organic electroluminescent element composition according to any one of claims 1 to 8. An organic electroluminescence element having a light-emitting layer formed using the organic electroluminescence element composition according to any one of claims 1 to 8. A display device having the organic electroluminescence element according to claim 10. A lighting device having the organic electroluminescence element according to claim 10.

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