CN107406588B

CN107406588B - Polymer, composition for organic electroluminescent element, organic EL display device, and organic EL lighting

Info

Publication number: CN107406588B
Application number: CN201680011444.2A
Authority: CN
Inventors: 饭田宏一朗; 李延军; 梅基友和
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2015-02-25
Filing date: 2016-02-24
Publication date: 2020-06-23
Anticipated expiration: 2036-02-24
Also published as: WO2016136847A1; TW202106758A; KR20170125824A; KR102496777B1; TWI708793B; TWI753578B; TW201634532A; JP6593432B2; JPWO2016136847A1; CN107406588A

Abstract

The invention provides a polymer with high hole injection and transmission capacity and high durability, a composition for an organic electroluminescent element containing the polymer, an organic electroluminescent element with high luminous efficiency manufactured by using the composition, and a display device and a lighting device using the organic electroluminescent element. The polymer of the present invention contains a unit represented by formula (1) as a repeating unit. (wherein Ar is¹、R¹、T¹The definitions are the same as those described in the specification. )

Description

Polymer, composition for organic electroluminescent element, organic EL display device, and organic EL lighting

Technical Field

The present invention relates to a polymer, and more particularly, to a polymer useful as a charge transporting material for an organic electroluminescent element, a composition for an organic electroluminescent element containing the polymer, an organic electroluminescent element including a layer formed using the composition, and an organic EL (Electro Luminescence) display device and an organic EL lighting having the organic electroluminescent element.

Background

Examples of the method for forming an organic layer in an organic electroluminescent element include a vacuum vapor deposition method and a wet film formation method. The vacuum deposition method has an advantage that since lamination is easy, injection of charges from the anode and/or the cathode is easily improved, and excitons are easily confined in the light-emitting layer. On the other hand, the wet film forming method does not require a vacuum process, and is easy to increase the area, and by using a coating liquid in which a plurality of materials having various functions are mixed, there is an advantage that a layer containing a plurality of materials having various functions can be easily formed.

However, wet film formation methods are difficult to form into a multilayer structure, and therefore, they are inferior in driving stability to elements obtained by vacuum deposition methods, and at present, they are not at a practical level except for a part.

Therefore, in order to form a laminate by a wet film formation method, a charge transporting polymer having a crosslinkable group is required and developed. For example, patent documents 1 to 3 disclose organic electroluminescent elements containing a polymer having a specific repeating unit, which are laminated by a wet film forming method. In addition, in order to form an organic electroluminescent device having excellent hole-transporting properties, for example, patent documents 4 to 6 disclose arylamine polymers used as charge-transporting materials and devices using the same.

Documents of the prior art

Patent document

Patent document 1: japanese patent application laid-open No. 2010-155985

Patent document 2: japanese patent laid-open publication No. 2013-045986

Patent document 3: japanese patent laid-open publication No. 2013-170228

Patent document 4: japanese patent laid-open No. 2012 and 102286

Patent document 5: japanese Kokai publication No. 2007-518842

Patent document 6: international publication No. 2013/114976

Disclosure of Invention

Problems to be solved by the invention

However, the devices described in patent documents 1 to 3 have a problem that the driving voltage is high and the driving life is short. Therefore, improvement in charge injection transport ability and durability of the charge transport material is required.

Accordingly, an object of the present invention is to provide a novel polymer having high hole injection transport ability and high durability, and a composition for an organic electroluminescent element comprising the polymer. Another object of the present invention is to provide an organic electroluminescent element having high luminance and a long driving life.

Means for solving the problems

The present inventors have conducted extensive studies and, as a result, have found that a polymer having a specific repeating unit is likely to generate a cationic radical, and that the above-mentioned problems can be solved by efficiently transporting the cationic radical, thereby completing the present invention.

That is, the gist of the present invention is as shown in the following [1] to [12 ].

[1] A polymer containing a unit represented by the following formula (1) as a repeating unit.

[ solution 1]

(in the formula (1), Ar¹Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group formed by fusing 3 or more rings with or without a substituent. R¹Each independently represents an alkyl group with or without a substituent. T is¹Represents an aromatic hydrocarbon group or an aromatic heterocyclic group having a crosslinkable group as a substituent. )

[2] The polymer according to the above [1], which further contains a unit represented by the following formula (2) as a repeating unit.

[ solution 2]

(in the formula (2), Ar¹Each independently represent havingOr an unsubstituted aromatic hydrocarbon group or aromatic heterocyclic group obtained by fusing 3 or more rings. R¹Each independently represents an alkyl group with or without a substituent. L is¹Represents an aromatic hydrocarbon group or an aromatic heterocyclic group. )

[3] The polymer according to the above [2], wherein the polymer has a total of 50 mol% or more of the unit represented by the above formula (1) and the unit represented by the above formula (2) with respect to 100 mol% of all monomer units.

[4]As described above [1]～[3]The polymer according to any one of the above, wherein Ar is¹Is a 2-fluorenyl group with or without a substituent.

[5]As described above [2]～[4]The polymer according to any one of the above, wherein L is¹Is 4, 4' -biphenylene, that is, the polymer contains a unit represented by the following formula (3) as a repeating unit.

[ solution 3]

(in formula (3), Ar¹Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group formed by fusing 3 or more rings with or without a substituent. R¹Each independently represents an alkyl group with or without a substituent. )

[6] The polymer according to any one of the above [1] to [5], wherein the weight average molecular weight (Mw) is 20,000 or more and the dispersity (Mw/Mn) is 2.5 or less.

[7] A composition for an organic electroluminescent element, which comprises the polymer according to any one of the above [1] to [6 ].

[8] An organic electroluminescent element comprising an anode, a cathode and an organic layer disposed between the anode and the cathode on a substrate, wherein the organic layer comprises a layer formed by a wet film-forming method using the composition for an organic electroluminescent element according to [7 ].

[9] The organic electroluminescent element according to [8], wherein the layer formed by the wet film formation method is at least one of a hole injection layer and a hole transport layer.

[10] The organic electroluminescent element according to the above [8] or [9], wherein a hole injection layer, a hole transport layer, and a light-emitting layer are provided between the anode and the cathode, and all of the hole injection layer, the hole transport layer, and the light-emitting layer are formed by a wet film formation method.

[11] An organic EL display device having the organic electroluminescent element according to any one of [8] to [10 ].

[12] An organic EL lighting having the organic electroluminescent element as recited in any one of [8] to [10 ].

ADVANTAGEOUS EFFECTS OF INVENTION

The N, N-bis (4-alkylphenyl) benzidine structure included in the main chain of the polymer of the present invention is a structure in which a phenyl group having an alkyl group as an electron-donating group in the para position is substituted on the N atom of benzidine, and therefore, a cationic radical is easily formed and hole injection from the anode is excellent.

Further, an aromatic hydrocarbon group or an aromatic heterocyclic group obtained by condensing 3 or more rings is substituted on the N atom existing in the N, N-bis (4-alkylphenyl) benzidine structure via a phenylene group. Orbitals in condensed rings of 3 or more rings are easily delocalized, and hole transport between polymer chains is excellent.

In addition, since the polymer of the present invention contains a crosslinkable group, it can be insolubilized by crosslinking after coating.

The layer obtained by wet film formation using the composition for organic electroluminescent elements containing the polymer of the present invention is flat without causing cracks and the like. The organic electroluminescent element of the present invention has high luminance and long driving life.

Further, since the polymer of the present invention is excellent in electrochemical stability, it is considered that an element including a layer formed using the polymer is applied to a flat panel display (for example, OA computers or wall-mounted televisions), a display device for vehicles, a display of a mobile phone, a light source utilizing characteristics as a flat light emitting body (for example, a light source of a copier, a backlight of a liquid crystal display or a gauge, etc.), a display panel, and a marker lamp, and its technical value is high.

Drawings

Fig. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent element of the present invention.

Detailed Description

The embodiments of the present invention will be described in detail below, but the technical features described below are merely examples (representative examples) of the embodiments of the present invention, and the present invention is not particularly limited to these contents as long as the features do not exceed the gist thereof.

All percentages or parts expressed by mass in this specification are the same as percentages or parts expressed by weight.

< polymers >

The polymer of the present invention has a repeating unit represented by the following formula (1), that is, contains a unit represented by the following formula (1) as a repeating unit.

[ solution 4]

[ substituent of repeating Unit ]

Ar in the unit represented by the above formula (1)¹Among them, as the aromatic hydrocarbon group, there may be mentioned, for example, an anthracycline, phenanthrylene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring, 1, 2-benzophenanthrylene ring, benzo [9,10] benzo]Phenanthrene ring, acenaphthene ring, fluoranthene ring, fluorene ring, indenofluorene ring, etc. which are fused by more than 3 rings from 5-or 6-membered ring.

Examples of the aromatic heterocyclic group include groups obtained by fusing 3 or more rings of 5-or 6-membered rings, such as carbazole ring, indenocarbazole ring, indolocarbazole ring, dibenzofuran ring, and dibenzothiophene ring.

Ar is excellent in charge transport property and durability¹Preferred are aromatic hydrocarbon groups, and among them, phenyl groups or fluorene groups having a valence of 1 in the fluorene ring, that is, fluorenyl groups are more preferred, and 2-fluorenyl groups are particularly preferred. Ar in the unit represented by formula (1)¹May be the same or different, but are preferably the same.

R in the unit represented by the above formula (1)¹Examples of the alkyl group include a linear, branched or cyclic alkyl group having usually not less than 1 carbon atom and usually not more than 24 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-hexyl group, a n-octyl group, a cyclohexyl group and a dodecyl group.

Among them, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclohexyl group, and the like is preferable, and a linear or branched alkyl group having 1 to 4 carbon atoms is more preferable. R in the unit represented by the formula (1)¹May be the same or different, but are preferably the same.

As Ar¹Aromatic hydrocarbon group and aromatic heterocyclic group in (1), and R¹The alkyl group in (b) is not particularly limited as long as the characteristics of the polymer are not significantly deteriorated, and examples thereof include groups selected from the following substituent group Z, preferably alkyl groups, alkoxy groups, aromatic hydrocarbon groups, aromatic heterocyclic groups, and more preferably alkyl groups.

[ substituent group Z ]

A straight-chain, branched or cyclic alkyl group having usually 1 or more carbon atoms, usually 24 or less carbon atoms, preferably 12 or less carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group, etc.;

an alkenyl group having usually 2 or more carbon atoms, usually 24 or less carbon atoms, and preferably 12 or less carbon atoms such as a vinyl group;

an alkynyl group having usually 2 or more carbon atoms, usually 24 or less carbon atoms, and preferably 12 or less carbon atoms such as an ethynyl group;

an alkoxy group having usually 1 or more, usually 24 or less, and preferably 12 or less carbon atoms such as a methoxy group and an ethoxy group;

an aryloxy group having usually 4 or more carbon atoms, preferably 5 or more carbon atoms, usually 36 or less carbon atoms, preferably 24 or less carbon atoms such as a phenoxy group, naphthoxy group, pyridyloxy group, etc.;

an alkoxycarbonyl group having usually 2 or more, usually 24 or less, and preferably 12 or less carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group;

for example, a dialkylamino group having usually 2 or more carbon atoms, usually 24 or less carbon atoms, and preferably 12 or less carbon atoms such as a dimethylamino group and a diethylamino group;

a diarylamino group having usually 10 or more, preferably 12 or more, usually 36 or less, preferably 24 or less carbon atoms such as a diphenylamino group, a ditolylamino group, and an N-carbazolyl group;

an aralkylamino group having usually 7 or more carbon atoms, usually 36 or less carbon atoms, preferably 24 or less carbon atoms such as a phenylmethylamino group;

an acyl group having usually 2 or more carbon atoms, usually 24 or less carbon atoms, and preferably 12 or less carbon atoms such as an acetyl group and a benzoyl group;

a halogen atom such as a fluorine atom or a chlorine atom;

a haloalkyl group having a carbon number of usually 1 or more, usually 12 or less, preferably 6 or less, such as a trifluoromethyl group;

alkylthio groups having usually 1 or more, usually 24 or less, and preferably 12 or less carbon atoms such as methylthio and ethylthio;

an arylthio group having usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less carbon atoms such as a phenylthio group, a naphthylthio group, a pyridylthio group and the like;

a silyl group having usually 2 or more, preferably 3 or more, usually 36 or less, and preferably 24 or less carbon atoms such as a trimethylsilyl group or a triphenylsilyl group;

a siloxy group having usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less carbon atoms such as trimethylsiloxy group, triphenylsiloxy group and the like;

a cyano group;

an aromatic hydrocarbon group having usually 6 or more carbon atoms, usually 36 or less carbon atoms, and preferably 24 or less carbon atoms such as a phenyl group and a naphthyl group;

for example, an aromatic heterocyclic group having 3 or more, preferably 4 or more, usually 36 or less, preferably 24 or less carbon atoms such as a thienyl group or a pyridyl group.

Each of the substituents may further have a substituent, and examples of the substituents include the same substituents as those of the above-mentioned substituent (substituent group Z).

T in the unit represented by the above formula (1)¹In the above, the aromatic hydrocarbon group and the aromatic heterocyclic group may be bonded to each other by 2 or more.

Examples of the aromatic hydrocarbon group include a 6-membered monocyclic ring such as a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzopyrene ring, a1, 2-benzophenanthrene ring, a benzo [9,10] phenanthrene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring, and a 2-valent group of a condensed ring having 2 to 5 rings.

Examples of the aromatic heterocyclic group include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, an azulene ring and other monocyclic 5-or 6-membered rings or fused rings of 2-to 4 rings.

The substituent that the aromatic hydrocarbon group or aromatic heterocyclic group may have is not particularly limited, and examples thereof include groups selected from the above substituent group Z, preferably an alkyl group, an alkoxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an alkyl group.

T¹In the case where 2 or more aromatic hydrocarbon groups and aromatic heterocyclic groups are bonded, it is preferable that 2 to 6 of these groups are bonded together from the viewpoint of excellent charge transport properties and durability. The number of the aromatic hydrocarbon groups and aromatic heterocyclic groups to be linked may be 1, or 2 or more.

In addition, T¹When the number of the aromatic hydrocarbon group and the aromatic heterocyclic group is 2 or more, the bonding may be performed through a linking group. In this case, the linking group is preferably selected from the group consisting of-CR¹R²―、―O―、―CO―、―NR³A group of-and-S-; and a group formed by connecting 2 to 10 of them. When 2 or more linking groups are present, the number of linking groups may be 1 or 2 or more. Here, R¹～R³Each independently represents a hydrogen atom, an alkyl group with or without a substituent, an aromatic hydrocarbon group with or without a substituent, or an aromatic heterocyclic group with or without a substituent. As the linking group, more preferred is-CR¹R²And 2-6-CR¹R²The group bonded is particularly preferably-CR¹R²―。

[ crosslinkable group ]

T¹Has a crosslinkable group as a substituent. By containing a crosslinkable group, the solubility in an organic solvent can be greatly different between before and after a reaction (hardly dissolving reaction) by irradiation with heat and/or active energy rays.

The crosslinkable group means the following group: the group which forms a new chemical bond is reacted with a group constituting another molecule located in the vicinity of the crosslinkable group by irradiation with heat and/or active energy rays. In this case, the group to be reacted may be the same as the crosslinkable group or may be a different group. Examples of the crosslinkable group include groups shown in the following crosslinkable group T.

< crosslinkable group set T >

[ solution 5]

(in the above formula, R⁷～R⁹Represents a hydrogen atom or an alkyl group. R¹⁰～R¹²Represents a hydrogen atom, an alkyl group or an alkoxy group. Ar (Ar)⁴Represents an aromatic hydrocarbon group with or without substituents or an aromatic heterocyclic group with or without substituents. )

As R⁷～R¹²The alkyl group (b) is preferably a linear or branched chain alkyl group having 6 or less carbon atoms, for example, a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, an n-butyl group, an isobutyl group, etc. More preferably methyl or ethyl. If R is⁷～R¹²The alkyl group (2) has a carbon number of 6 or less, and tends to facilitate insolubilization of the film without sterically hindering the crosslinking reaction.

As R¹⁰～R¹²The alkoxy group (b) is preferably a linear or branched chain alkoxy group having 6 or less carbon atoms, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, a 2-propoxy group, and an n-butoxy group. More preferably methoxy group or ethoxy group. If R is¹⁰～R¹²The alkoxy group (2) has a carbon number of 6 or less, and tends to be easily insolubilized without sterically hindering the crosslinking reaction.

In addition, as Ar⁴Examples of the substituted or unsubstituted aromatic hydrocarbon group of (2) include a monocyclic ring having a 6-membered ring such as a benzene ring or naphthalene ring having a free valence of 1, and a condensed ring having 2 to 5 rings. Benzene rings having a valence of 1 free atom are particularly preferred. In addition, Ar⁴It may be a group obtained by bonding 2 or more of these aromatic hydrocarbon groups with or without substituents. Examples of such a group include biphenylene group and terphenylene group, and 4, 4' -biphenylene group is preferableA biphenyl group.

Among these, a cyclic ether group such as an epoxy group or an oxetane group is preferable in terms of high reactivity and easiness of insolubilization by crosslinking; a vinyl ether group; and the like, which undergo a crosslinking reaction by cationic polymerization. Among them, an oxetanyl group is more preferable from the viewpoint of easiness in controlling the rate of cationic polymerization, and a vinyl ether group is preferable from the viewpoint of easiness in generating a hydroxyl group which may cause deterioration of a device at the time of cationic polymerization.

In addition, from the viewpoint of further improving the electrochemical stability of the device, a group capable of undergoing a cycloaddition reaction, such as an arylvinylcarbonyl group such as cinnamoyl group, or a benzocyclobutene ring having a valence of 1 free atom, is preferable.

Among the crosslinkable groups, benzocyclobutene rings having a valence of 1 free atom are particularly preferable in terms of particularly stable structure after crosslinking.

As Ar⁴Examples of the substituted or unsubstituted aromatic heterocyclic group in (b) include an aromatic heterocyclic group having usually 3 or more, preferably 4 or more, usually 36 or less, preferably 24 or less carbon atoms such as a thienyl group and a pyridyl group. Thienyl and pyridyl are particularly preferred.

[ other repeating units ]

When the polymer of the present invention further contains a repeating unit represented by the following formula (2), that is, a unit represented by the following formula (2) as a repeating unit, it is preferable because the proportion of N atoms substituted with an N, N-bis (4-alkylphenyl) benzidine structure and an aromatic hydrocarbon group or an aromatic heterocyclic group formed by fusion of 3 or more rings in the polymer can be increased, and the hole injection and hole transport can be improved.

[ solution 6]

(in the formula (2), Ar¹Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group formed by fusing 3 or more rings with or without a substituent. R¹Each of which isIndependently represents an alkyl group with or without a substituent. L is¹Represents an aromatic hydrocarbon group or an aromatic heterocyclic group. )

Further, the number of crosslinkable groups of the polymer described later can be adjusted by adjusting the ratio of the unit of formula (1) to the unit of formula (2).

L in the unit represented by the above formula (2)¹In the above, the aromatic hydrocarbon group and the aromatic heterocyclic group may be bonded to each other by 2 or more.

L¹In the case where 2 or more aromatic hydrocarbon groups and aromatic heterocyclic groups are bonded, it is preferable that 2 to 6 of these groups are bonded together from the viewpoint of excellent charge transport properties and durability. The aromatic hydrocarbon group and the aromatic heterocyclic group to be linked may be 1,the number of the cells may be 2 or more.

In addition, L¹When the number of the aromatic hydrocarbon group and the aromatic heterocyclic group is 2 or more, the bonding may be performed through a linking group. In this case, the linking group is preferably selected from the group consisting of-CR¹R²―、―O―、―CO―、―NR³A group of-and-S-; and a group formed by connecting 2 to 10 of them. When 2 or more linking groups are present, the number of linking groups may be 1 or 2 or more. Here, R¹～R³Each independently represents a hydrogen atom, an alkyl group with or without a substituent, an aromatic hydrocarbon group with or without a substituent, or an aromatic heterocyclic group with or without a substituent. As the linking group, more preferred is-CR¹R²And 2-6-CR¹R²The group bonded is particularly preferably-CR¹R²―。

L is excellent in hole injection transport property¹Any of 1, 4-phenylene, 4 '-biphenylene, and 4, 4' -terphenylene is preferable.

Particularly preferably L¹Is 4, 4' -biphenylene, that is, contains a unit represented by the following formula (3) as a repeating unit.

[ solution 7]

[ ratio of repeating units ]

The polymer of the present invention is improved in hole injection and hole transport, and therefore the total of the units represented by the above formulae (1) and (2) is preferably 50 mol% or more, more preferably 80 mol% or more, and most preferably 100 mol% with respect to 100 mol% of the total monomer units (that is, units other than the units represented by the above formulae (1) and (2) are not included).

[ number of crosslinkable groups ]

The polymer of the present invention preferably has a large number of crosslinkable groups in terms of being sufficiently insoluble by crosslinking and facilitating formation of another layer thereon by a wet film-forming method. On the other hand, however, the number of crosslinkable groups is preferably small because cracks are not easily generated in the formed layer, unreacted crosslinkable groups are not easily left, and the organic electroluminescent element is easily prolonged in life.

The crosslinkable group present in 1 polymer chain in the polymer of the present invention is preferably generally 1 or more on average, more preferably 2 or more on average, and is generally preferably 200 or less, more preferably 100 or less.

The number of crosslinkable groups contained in the polymer of the present invention can be expressed as the number per 1000 molecular weight of the polymer.

When the number of crosslinkable groups contained in the polymer of the present invention is expressed as the number per 1000 molecular weight of the polymer, the number is usually 3.0 or less, preferably 2.0 or less, more preferably 1.0 or less, and usually 0.01 or more, preferably 0.05 or more per 1000 molecular weight.

When the number of crosslinkable groups is within the above range, cracks or the like are less likely to occur, and a flat film is easily obtained. In addition, since the crosslinking density is moderate, the number of unreacted crosslinkable groups remaining in the layer after the crosslinking reaction is small, and the lifetime of the obtained device is hardly affected.

Furthermore, the crosslinking reaction is sufficiently insoluble in an organic solvent, and therefore, a multilayer structure can be easily formed by a wet film formation method.

Here, the number of crosslinkable groups per 1000 molecular weight of the polymer can be calculated from the molar ratio of the monomers charged at the time of synthesis and the structural formula by subtracting the terminal group from the polymer.

For example, when the case of the polymer 1 synthesized in example 1 described later is described, the molecular weight of the repeating unit excluding the terminal group in the polymer 1 is 1688.46 on average, and the number of crosslinkable groups per 1 repeating unit is 0.676 on average. When this is calculated by a simple ratio, the number of crosslinkable groups per 1000 molecular weight is calculated to be 0.40.

[ solution 8]

Polymer 1

[ molecular weight of Polymer ]

The weight average molecular weight of the polymer of the present invention is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less, further preferably 200,000 or less, and is usually 2,500 or more, preferably 5,000 or more, more preferably 20,000 or more, further preferably 30,000 or more.

When the weight average molecular weight of the polymer exceeds the above upper limit, the solubility in a solvent is lowered, and thus the film-forming property may be impaired. When the weight average molecular weight of the polymer is less than the above lower limit, the glass transition temperature, melting point and vaporization temperature of the polymer decrease, and therefore the heat resistance may decrease.

In addition, the number average molecular weight (Mn) in the polymer of the present invention is usually 2,500,000 or less, preferably 750,000 or less, more preferably 400,000 or less, and is usually 2,000 or more, preferably 4,000 or more, more preferably 8,000 or more, further preferably 20,000 or more.

The dispersity (Mw/Mn) in the polymer of the present invention is preferably 3.5 or less, more preferably 2.5 or less, and still more preferably 2.0 or less. Since the smaller the value of the dispersion degree, the better, the lower limit value is desirably 1. When the degree of dispersion of the polymer is not more than the above upper limit, the polymer can be easily purified and has good solubility in a solvent and good charge transport ability.

Typically, the weight average molecular weight of the polymer is determined by SEC (size exclusion chromatography) determination. In the SEC measurement, the elution time of a component having a higher molecular weight is shorter, and the elution time of a component having a lower molecular weight is longer, and the elution time of a sample is converted into a molecular weight using a calibration curve calculated from the elution time of polystyrene (standard sample) having a known molecular weight, thereby calculating a weight average molecular weight.

[ specific examples ]

Specific examples of the polymer of the present invention are shown below, but the polymer of the present invention is not limited to these. The numbers in the chemical formula represent the molar ratio of the repeating units.

These polymers may be any of random copolymers, alternating copolymers, block copolymers, graft copolymers, and the like, and the order of arrangement of the monomers is not limited.

[ solution 9]

[ method for producing Polymer ]

The method for producing the polymer of the present invention is not particularly limited, and any method may be used as long as the polymer of the present invention can be obtained. For example, they can be produced by a polymerization method based on Suzuki (Suzuki) reaction, a polymerization method based on Grignard (Grignard) reaction, a polymerization method based on Yamamoto (Yamamoto) reaction, a polymerization method based on Ullmann (Ullmann) reaction, a polymerization method based on Buchwald-Hartwig (Buchwald-Hartwig) reaction, and the like.

In the case of a polymerization method based on the Ullmann (Ullmann) reaction and a polymerization method based on the Buchwald-hartwigh (Buchwald-Hartwig) reaction, for example, the polymer of the present invention is synthesized by reacting a dihalogenated aryl group represented by the formula (1a), the formula (1b), the formula (2b) (X represents a halogen atom such as I, Br, Cl, F, etc.) with a primary aminoaryl group represented by the formula (1 c).

[ solution 10]

(in the above formula, X represents a halogen atom,Ar¹、R¹、T¹、L¹the same as above. )

In the above-mentioned polymerization method, the reaction for forming an N-aryl bond is usually carried out in the presence of a base such as potassium carbonate, sodium tert-butoxide, or triethylamine. In addition, the reaction may be carried out in the presence of a transition metal catalyst such as copper or a palladium complex.

< organic electroluminescent device Material >

The polymer of the present invention is particularly suitable for use as an organic electroluminescent element material. That is, the polymer of the present invention is preferably an organic electroluminescent element material.

When the polymer of the present invention is used as a material for an organic electroluminescent element, the polymer is preferably used as a charge-transporting material which is a material for forming at least one of a hole injection layer and a hole transport layer in the organic electroluminescent element.

When used as a charge transporting material, the polymer may contain 1 kind of the polymer of the present invention, or may contain 2 or more kinds in any combination and in any ratio.

When at least one of the hole injection layer and the hole transport layer of the organic electroluminescent element is formed using the polymer of the present invention, the content of the polymer of the present invention in the hole injection layer and/or the hole transport layer is usually 1 to 100% by mass, preferably 5 to 100% by mass, and more preferably 10 to 100% by mass. When the amount is within the above range, the charge transporting property of the hole injection layer and/or the hole transport layer is improved, the driving voltage is reduced, and the driving stability is improved, which is preferable.

When the content of the polymer of the present invention in the hole injection layer and/or the hole transport layer is not 100% by mass, examples of the component constituting the hole injection layer and/or the hole transport layer include a hole-transporting compound described later.

In addition, since an organic electroluminescent element can be easily manufactured, the polymer of the present invention is preferably used for an organic layer formed by a wet film formation method.

< composition for organic electroluminescent element >

The composition for an organic electroluminescent element of the present invention contains the polymer of the present invention. The composition for an organic electroluminescent element of the present invention may contain 1 kind of the polymer of the present invention, or may contain 2 or more kinds thereof in any combination and in any ratio.

[ content of Polymer ]

The content of the polymer of the present invention in the composition for an organic electroluminescent element of the present invention is usually 0.01 to 70% by mass, preferably 0.1 to 60% by mass, and more preferably 0.5 to 50% by mass.

Within the above range, the organic layer formed is less likely to have defects and less likely to have uneven film thickness, which is preferable.

The composition for an organic electroluminescent element of the present invention may contain a solvent or the like in addition to the polymer of the present invention.

[ solvent ]

The composition for an organic electroluminescent element of the present invention usually contains a solvent. The solvent preferably dissolves the polymer of the present invention. Specifically, a solvent that dissolves the polymer of the present invention at room temperature usually in an amount of 0.05% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass or more is suitable.

Specific examples of the solvent include aromatic solvents such as toluene, xylene, trimethylbenzene, cyclohexylbenzene, and the like; halogen-containing solvents such as 1, 2-dichloroethane, chlorobenzene, o-dichlorobenzene, and the like; ether solvents such as aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA), and aromatic ethers such as 1, 2-dimethoxybenzene, 1, 3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2, 3-dimethylanisole, and 2, 4-dimethylanisole; aliphatic ester solvents such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; ester solvents such as aromatic esters including phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and n-butyl benzoate; and the like, and an organic solvent used in a composition for forming a hole injection layer or a composition for forming a hole transport layer, which will be described later.

The solvent may be used in 1 kind, or 2 or more kinds may be used in any combination and in any ratio.

Among these, the solvent contained in the composition for an organic electroluminescent element of the present invention is preferably a solvent having a surface tension of usually less than 40dyn/cm, preferably 36dyn/cm or less, more preferably 33dyn/cm or less at 20 ℃.

When a coating film is formed by a wet film-forming method using the composition for an organic electroluminescent element of the present invention and the polymer of the present invention is crosslinked to form an organic layer, the composition preferably has high affinity between a solvent and a substrate. This is because the uniformity of the film quality greatly affects the uniformity and stability of light emission of the organic electroluminescent element. Therefore, the composition for an organic electroluminescent element used in the wet film formation method is required to have a low surface tension in order to form a more uniform coating film with higher leveling property. Therefore, the use of a solvent having a low surface tension as described above is preferable because a uniform layer containing the polymer of the present invention can be formed and a uniform crosslinked layer can be formed.

Specific examples of the solvent having a low surface tension include aromatic solvents such as toluene, xylene, trimethylbenzene, cyclohexylbenzene, etc., ester solvents such as ethyl benzoate, ether solvents such as anisole, trifluoromethoxybenzene, pentafluoromethoxybenzene, 3- (trifluoromethyl) anisole, ethyl (pentafluorobenzoate), etc., as described above.

On the other hand, the solvent contained in the composition for an organic electroluminescent element of the present invention is preferably a solvent having a vapor pressure of usually 10mmHg or less, preferably 5mmHg or less, and usually 0.1mmHg or more at 25 ℃. By using such a solvent, a composition for an organic electroluminescent element suitable for the properties of the polymer of the present invention can be prepared in a process suitable for producing an organic electroluminescent element by a wet film formation method.

Specific examples of such solvents include the aromatic solvents, ether solvents and ester solvents described above, such as toluene, xylene and trimethylbenzene.

However, moisture may cause deterioration in the performance of the organic electroluminescent element, and particularly, may promote a decrease in luminance during continuous driving. Therefore, in order to reduce the residual moisture in wet film formation as much as possible, the solubility of water at 25 ℃ in the solvent is preferably 1 mass% or less, and more preferably 0.1 mass% or less.

The content of the solvent contained in the composition for an organic electroluminescent element of the present invention is usually 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, and particularly preferably 80% by mass or more. By setting the content of the solvent to the lower limit or more, the flatness and uniformity of the formed layer can be improved.

< Electron-accepting Compound >

When the composition for an organic electroluminescent element of the present invention is used for forming a hole injection layer, it is preferable that the composition further contains an electron-accepting compound in order to reduce the resistance.

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

Examples of such electron-accepting compounds include 1 or 2 or more compounds selected from the group consisting of triarylboron compounds, metal halides, lewis acids, organic acids, onium salts, salts of arylamines with metal halides, and salts of arylamines with lewis acids.

Specifically, examples thereof include onium salts substituted with an organic group such as 4-isopropyl-4' -methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (International publication No. 2005/089024); high-valence inorganic compounds such as iron (III) chloride (Japanese patent application laid-open No. 11-251067) and ammonium persulfate; cyano compounds such as tetracyanoethylene; aromatic boron compounds such as tris (pentafluorophenyl) borane (Japanese patent application laid-open No. 2003-31365); fullerene derivatives and iodine, etc.

As such a compound, an ionic compound having a structure in which at least one organic group is bonded to a carbon atom in an element belonging to groups 15 to 17 of the long-period periodic table (hereinafter, unless otherwise noted, referred to as "periodic table") is preferable, and a compound represented by the following formula (4) is particularly preferable.

[ solution 11]

(in the formula (4), R⁹Represents a carbon atom with A₁A bonded organic radical, R¹⁰Represents an arbitrary substituent. R⁹And R¹⁰May be bonded to each other to form a ring. )

As R⁹If it is in the same position as A₁The bonding portion of (2) is not particularly limited as long as it does not depart from the gist of the present invention. With respect to R⁹The molecular weight of (b) is usually 1000 or less, preferably 500 or less in terms of a value including a substituent.

As R⁹Preferable examples of the positive charge include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, and an aromatic heterocyclic group, in view of non-localization of the positive charge. Among them, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferable because it is thermally stable while a positive charge is not localized.

Examples of the alkyl group include linear, branched or cyclic alkyl groups having usually 1 or more carbon atoms, usually 12 or less carbon atoms, and preferably 6 or less carbon atoms. Specific examples thereof include methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, tert-butyl, and cyclohexyl.

Examples of the alkenyl group include alkenyl groups having usually 2 or more carbon atoms, usually 12 or less carbon atoms, and preferably 6 or less carbon atoms. Specific examples thereof include a vinyl group, an allyl group, and a 1-butenyl group.

Examples of the alkynyl group include an alkynyl group having usually 2 or more carbon atoms, usually 12 or less carbon atoms, and preferably 6 or less carbon atoms. Specific examples thereof include ethynyl and propargyl.

Examples of the aromatic hydrocarbon group include the following groups: the group is a monocyclic ring having 1 free valence of 5-or 6-membered ring or a condensed ring having 2 to 5 rings, and is a group in which positive charges are further delocalized on the group. Specific examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzopyrene ring, a1, 2-benzophenanthrene ring, a benzo [9,10] phenanthrene ring, an acenaphthene ring, a fluorene ring, and the like, each having a free valence of 1.

Examples of the aromatic heterocyclic group include the following groups: the group is a monocyclic or 2-4-membered ring having 1 free valence 5-or 6-membered ring, and is a group in which positive charges are further delocalized on the group. Specific examples thereof include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, a azulene ring and the like having a free valence of 1.

For R unless the gist of the present invention is not violated¹⁰There is no particular limitation. R¹⁰The molecular weight of (b) is usually 1000 or less, preferably 500 or less, in terms of a value including a substituent.

As R¹⁰Examples of the (b) include alkyl, alkenyl, alkynyl, aromatic hydrocarbon, aromatic heterocyclic group, amino, alkoxy, aryloxy, acyl, alkoxycarbonyl, aryloxycarbonyl, alkylcarbonyloxy, alkylthio, arylthio, sulfonyl, alkylsulfonyl, arylsulfonyl, sulfonyloxy, cyano, hydroxyl, thiol, and silyl groups.

Wherein, with R⁹Similarly, from the viewpoint of high electron accepting property, the compound is preferably the same as A₁The organic group having a carbon atom at the bonding portion of (2) is preferably an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group or an aromatic heterocyclic group, as an example. In particular, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferable because of its high electron-accepting property and thermal stability.

As R¹⁰The alkyl, alkenyl, alkynyl, aromatic hydrocarbon group and aromatic heterocyclic group of (A) include those mentioned above for R⁹The same substances as those described above.

Examples of the amino group include alkylamino, arylamino, and acylamino.

Examples of the alkylamino group include an alkylamino group having an alkyl group of 1 or more carbon atoms, usually 1 or more, and usually 12 or less, preferably 6 or less. Specific examples thereof include methylamino, dimethylamino, diethylamino, and dibenzylamino.

Examples of the arylamino group include arylamino groups having an aromatic hydrocarbon group or an aromatic heterocyclic group, in which the number of carbon atoms is usually not less than 3, preferably not less than 4, and usually not more than 25, preferably not more than 15. Specific examples thereof include phenylamino, diphenylamino, tolylamino, pyridylamino and thienylamino groups.

Examples of the acylamino group include acylamino groups having an acyl group having 1 or more carbon atoms of usually 2 or more, and usually 25 or less, preferably 15 or less. Specific examples thereof include acetylamino group, benzoylamino group and the like.

Examples of the alkoxy group include an alkoxy group having usually 1 or more carbon atoms, usually 12 or less, and preferably 6 or less. Specific examples thereof include methoxy group, ethoxy group, butoxy group and the like.

Examples of the aryloxy group include aryloxy groups having an aromatic hydrocarbon group or an aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less carbon atoms. Specific examples thereof include a phenyloxy group, a naphthyloxy group, a pyridyloxy group, and a thienyloxy group.

Examples of the acyl group include an acyl group having usually 1 or more carbon atoms, usually 25 or less, and preferably 15 or less. Specific examples thereof include formyl, acetyl and benzoyl.

Examples of the alkoxycarbonyl group include an alkoxycarbonyl group having a carbon number of usually 2 or more, usually 10 or less, and preferably 7 or less. Specific examples thereof include methoxycarbonyl and ethoxycarbonyl.

Examples of the aryloxycarbonyl group include an aromatic hydrocarbon group or an aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less carbon atoms. Specific examples thereof include phenoxycarbonyl and pyridyloxycarbonyl.

Examples of the alkylcarbonyloxy group include an alkylcarbonyloxy group having a carbon number of usually 2 or more, usually 10 or less, and preferably 7 or less. Specific examples thereof include acetoxy group and trifluoroacetyloxy group.

The alkylthio group includes an alkylthio group having usually 1 or more carbon atoms, usually 12 or less carbon atoms, and preferably 6 or less carbon atoms. Specific examples thereof include methylthio and ethylthio.

Examples of the arylthio group include arylthio groups having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 14 or less carbon atoms. Specific examples thereof include phenylthio, naphthylthio and pyridylthio.

Specific examples of the alkylsulfonyl group and the arylsulfonyl group include a methylsulfonyl group and a tosyl group.

Specific examples of the sulfonyloxy group include a methanesulfonyloxy group, a toluenesulfonyloxy group and the like.

Specific examples of the silyl group include a trimethylsilyl group and a triphenylsilyl group.

As mentioned above, R in the formula (4) is⁹And R¹⁰The groups shown in the examples may be those which do not depart from the gist of the inventionTo be further substituted with other substituents. The kind of the substituent is not particularly limited, but is exemplified by the above-mentioned R⁹And R¹⁰Examples of the groups include a halogen atom, a cyano group, a thiocyano group, and a nitro group. Among them, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups are preferable from the viewpoint of not hindering the heat resistance and electron-accepting properties of the ionic compound (electron-accepting compound).

In the formula (4), A₁The element belonging to group 17 of the periodic table is preferable, and elements before the 5 th period (3 rd to 5 th periods) of the periodic table are preferable in terms of electron-accepting property and availability. I.e. as A₁Preferably, any of an iodine atom, a bromine atom and a chlorine atom is used.

In particular, A in the formula (4) is preferable from the viewpoints of electron accepting property and stability of the compound₁Is an ionic compound of a bromine atom or an iodine atom, most preferably A in the formula (4)₁Is an ionic compound of an iodine atom.

In the formula (4), Z₁ ^n1-Represents a counter anion. The counter anion is not particularly limited in kind, and may be a monoatomic ion or a complex ion. However, the larger the size of the counter anion, the less localized the negative charge, and the less localized the positive charge, and the greater the electron accepting ability, and therefore, the complex ion is more preferable than the monoatomic ion.

n₁Is with a counter anion Z₁ ^n1-Any positive integer corresponding to the ion valence of (a). To n₁The value of (b) is not particularly limited, but is preferably 1 or 2, and most preferably 1.

As Z₁ ^n1-Specific examples thereof include hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, cyanide ion, nitrate ion, nitrite ion, sulfate ion, sulfite ion, perchlorate ion, perbromate ion, periodate ion, chlorate ion, chlorite ion, hypochlorite ion, phosphate ion, phosphite ion, hypophosphite ion, borate ion, and the like,Isocyanate ion, hydrogen sulfide ion, tetrafluoroborate ion, hexafluorophosphate ion, hexachloroantimonate ion; carboxylate ions such as acetate ions, trifluoroacetate ions, benzoate ions and the like; sulfonate ions such as methanesulfonate ion and trifluoromethanesulfonate ion; alkoxy ions such as methoxy ion and t-butoxy ion. Among them, tetrafluoroborate ion and hexafluoroborate ion are preferable.

In addition, as a counter anion Z₁ ^n1-From the viewpoint of stability of the compound, solubility in a solvent, and large size, the complex ion represented by the following formula (5) is particularly preferable because the negative charge is not localized and the positive charge is also not localized, resulting in an increase in electron accepting ability.

[ solution 12]

(in the formula (5), E₃Each independently represents an element belonging to group 13 of the long form periodic Table, Ar⁵～Ar⁸Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group. )

As E₃Boron atom, aluminum atom, gallium atom are preferred, and boron atom is preferred from the viewpoint of stability of the compound and easiness of synthesis and purification.

As Ar⁵～Ar⁸The aromatic hydrocarbon group and the aromatic heterocyclic group of (3) include, for example, the above-mentioned R of the formula (4)⁹The exemplified substances are similar to the above, and each of them has a single ring of 5-or 6-membered ring having a free valence of 1 or a condensed ring of 2 to 4 rings. Among them, benzene rings, naphthalene rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, and isoquinoline rings having a valence of 1 free atom are preferable from the viewpoint of stability and heat resistance of the compound.

Ar is used as Ar unless the gist of the present invention is violated⁵～Ar⁸The aromatic hydrocarbon group and the aromatic heterocyclic group may be further substituted with another substituent. To substituentThe kind of (b) is not particularly limited, and any substituent may be applied, but an electron-withdrawing group is preferable.

If exemplified as Ar⁵～Ar⁸Preferred examples of the electron-withdrawing group as the substituent which may be contained include: a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, etc.; a cyano group; thiocyano; a nitro group; alkylsulfonyl such as methylsulfonyl; arylsulfonyl such as tosyl; an acyl group having usually 1 or more, usually 12 or less, and preferably 6 or less carbon atoms such as a formyl group, an acetyl group, and a benzoyl group; an alkoxycarbonyl group having usually 2 or more, usually 10 or less, and preferably 7 or less carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; an aryloxycarbonyl group having an aromatic hydrocarbon group or an aromatic heterocyclic group having usually 3 or more, preferably 4 or more, usually 25 or less, preferably 15 or less carbon atoms such as a phenoxycarbonyl group or a pyridyloxycarbonyl group; an aminocarbonyl group; an aminosulfonyl group; a halogenated alkyl group in which a halogen atom such as a fluorine atom or a chlorine atom is substituted on a linear, branched or cyclic alkyl group having usually 1 or more, usually 10 or less, preferably 6 or less carbon atoms, such as a trifluoromethyl group or a pentafluoroethyl group.

Among them, Ar is more preferable⁵～Ar⁸At least 1 group of (a) has 1 or 2 or more fluorine atoms or chlorine atoms as substituents. In particular, Ar is most preferable from the viewpoint of effectively non-localizing negative charges and having appropriate sublimability⁵～Ar⁸A perfluoroaryl group in which all hydrogen atoms of (A) are replaced by fluorine atoms. Specific examples of the perfluoroaryl group include a pentafluorophenyl group, a heptafluoro-2-naphthyl group, a tetrafluoro-4-pyridyl group and the like.

The molecular weight of the electron-accepting compound in the present invention is usually 100 to 5000, preferably 300 to 3000, and more preferably 400 to 2000.

Within the above range, the positive charge and the negative charge are sufficiently non-localized, have good electron accepting ability, and hardly interfere with charge transport, which is preferable.

Specific examples of electron-accepting compounds represented by the following formula (4) which are preferred in the present invention are shown in the following table 1, but the present invention is not limited thereto.

[ solution 13]

[ TABLE 1]

TABLE 1

[ TABLE 2]

TABLE 1 (continuation)

[ TABLE 3]

TABLE 1 (continuation)

[ TABLE 4]

TABLE 1 (continuation)

[ TABLE 5]

TABLE 1 (continuation)

[ TABLE 6]

TABLE 1 (continuation)

[ TABLE 7]

TABLE 1 (continuation)

The composition for an organic electroluminescent element of the present invention may contain 1 kind of the electron-accepting compound alone, or may contain 2 or more kinds in any combination and ratio.

When the composition for an organic electroluminescent element of the present invention contains an electron-accepting compound, the content of the electron-accepting compound in the composition for an organic electroluminescent element of the present invention is usually 0.0005 mass% or more, preferably 0.001 mass% or more, usually 20 mass% or less, preferably 10 mass% or less. In the composition for an organic electroluminescent element, the proportion of the electron-accepting compound to the polymer of the present invention is usually 0.5% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, usually 80% by mass or less, preferably 60% by mass or less, and more preferably 40% by mass or less.

When the content of the electron-accepting compound in the composition for an organic electroluminescent element is not less than the lower limit, the electron acceptor accepts electrons from the polymer, and the resistance of the organic layer formed is preferably lowered; if the content is less than the upper limit, defects are less likely to occur in the formed organic layer, and film thickness unevenness is less likely to occur, which is preferable.

[ cationic radical Compound ]

The composition for an organic electroluminescent element of the present invention may further contain a cationic radical compound.

The cationic radical compound is preferably an ionic compound composed of a cationic radical and a counter anion, which are chemical species obtained by removing a single electron from a hole-transporting compound. However, in the case where the cationic radical is derived from a hole-transporting polymer compound, the cationic radical has a structure obtained by removing a single electron from a repeating unit of the polymer compound.

The cation radical is preferably a chemical species obtained by removing a single electron from a hole-transporting compound described later. A chemical species obtained by removing a single electron from a compound preferable as the hole transporting compound is suitable from the viewpoints of amorphousness, visible light transmittance, heat resistance, solubility, and the like.

Here, the cationic radical compound can be produced by mixing a hole-transporting compound described later with the electron-accepting compound. That is, by mixing the hole-transporting compound and the electron-accepting compound, electrons move from the hole-transporting compound to the electron-accepting compound, and a cationic compound composed of a cationic radical of the hole-transporting compound and a counter anion is generated.

When the composition for an organic electroluminescent element of the present invention contains a cationic radical compound, the content of the cationic radical compound in the composition for an organic electroluminescent element of the present invention is usually 0.0005 mass% or more, preferably 0.001 mass% or more, usually 40 mass% or less, preferably 20 mass% or less. When the content of the cationic radical compound is not less than the lower limit, the resistance of the formed organic layer is preferably lowered; if the content is less than the upper limit, defects are less likely to occur in the formed organic layer, and film thickness unevenness is less likely to occur, which is preferable.

In addition to the above components, the composition for an organic electroluminescent element of the present invention may contain components contained in a composition for forming a hole injection layer or a composition for forming a hole transport layer, which will be described later, in a content which will be described later.

< organic electroluminescent element >

The organic electroluminescent element of the present invention is an organic electroluminescent element having an anode and a cathode on a substrate, and an organic layer located between the anode and the cathode, and is characterized in that the organic layer contains a layer formed by a wet film-forming method using the composition for an organic electroluminescent element of the present invention containing the polymer of the present invention.

In the organic electroluminescent element according to the present invention, the layer formed by a wet film formation method is preferably at least one of a hole injection layer and a hole transport layer, and particularly preferably, the organic layer includes a hole injection layer, a hole transport layer, and a light emitting layer, and all of the hole injection layer, the hole transport layer, and the light emitting layer are formed by a wet film formation method.

The wet film-forming method in the present invention refers to a film-forming method, that is, a method of forming a film by drying the coating film by using a wet film-forming method such as a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, a capillary coating method, an ink jet method, a nozzle printing method, a screen printing method, a gravure printing method, a flexographic printing method, or the like as a coating method. Among these film forming methods, spin coating, spray coating, inkjet method, nozzle printing method, and the like are preferable.

Fig. 1 shows a schematic view (cross section) of a structural example of an organic electroluminescent element 10 as an example of the structure of the organic electroluminescent element of the present invention. In fig. 1,1 denotes a substrate, 2 denotes an anode, 3 denotes a hole injection layer, 4 denotes a hole transport layer, 5 denotes a light emitting layer, 6 denotes a hole blocking layer, 7 denotes an electron transport layer, 8 denotes an electron injection layer, and 9 denotes a cathode.

Next, an example of an embodiment of the layer structure of the organic electroluminescent element of the present invention, a general formation method thereof, and the like will be described with reference to fig. 1.

[ base plate ]

The substrate 1 is a support for an organic electroluminescent element, and is generally a quartz or glass plate, a metal plate or foil, a plastic film or sheet, or the like. Among these, a glass plate or a plate of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, polysulfone is preferable. Since the organic electroluminescent element is less likely to be deteriorated by the external air, the substrate is preferably made of a material having a high gas barrier property. Therefore, particularly when a material having low gas barrier properties such as a synthetic resin substrate is used, it is preferable to provide a dense silicon oxide film or the like on at least one surface of the substrate to improve the gas barrier properties.

[ Anode ]

The anode 2 has a function of injecting holes into a layer on the light-emitting layer 5 side.

The anode 2 is typically composed of the following materials: metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as oxides of indium and/or tin; halogenated metals such as copper iodide; carbon black, and conductive polymers such as poly (3-methylthiophene), polypyrrole, and polyaniline.

The anode 2 is generally formed by a dry method such as a sputtering method or a vacuum deposition method. When the anode is formed using fine metal particles such as silver, fine particles such as copper iodide, carbon black, fine conductive metal oxide particles, fine conductive polymer powder, or the like, the anode may be formed by dispersing the fine metal particles in an appropriate binder resin solution and coating the solution on a substrate. Further, in the case of a conductive polymer, a thin film may be formed directly on a substrate by electrolytic polymerization, or a conductive polymer may be applied on a substrate to form an anode (appl. phys. lett., volume 60, page 2711, 1992).

The anode 2 is generally a single-layer structure, but may be a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the anode of the layer 1.

The thickness of the anode 2 may be determined according to the required transparency, material, and the like. Particularly when high transparency is required, the visible light transmittance is preferably 60% or more, more preferably 80% or more. The thickness of the anode 2 is usually 5nm or more, preferably 10nm or more, and usually 1000nm or less, preferably 500nm or less. On the other hand, when transparency is not required, the thickness of the anode 2 may be any thickness depending on the required strength or the like, and in this case, the anode 2 may be the same thickness as the substrate.

When another layer is formed on the surface of the anode 2, it is preferable to perform treatment such as ultraviolet ray/ozone, oxygen plasma, or argon plasma before the film formation to remove impurities on the anode 2 and adjust the ionization potential thereof to improve the hole injection property.

[ hole injection layer ]

A layer that serves a 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 the layer having the function of transporting holes from the anode 2 side to the light-emitting layer 5 side is 2 or more layers, the layer closer to the anode side may be referred to as a hole injection layer 3. The hole injection layer 3 is preferably formed in order to enhance the function of transporting holes from the anode 2 to the light-emitting layer 5. In the case of forming the hole injection layer 3, the hole injection layer 3 is usually formed on the anode 2.

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

The method for forming the hole injection layer may be a vacuum deposition method or a wet film formation method. The film is preferably formed by a wet film forming method in view of excellent film forming properties.

The hole injection layer 3 preferably contains a hole-transporting compound, and more preferably contains a hole-transporting compound and an electron-accepting compound. Further, the hole injection layer preferably contains a cationic radical compound, and particularly preferably contains a cationic radical compound and a hole-transporting compound.

In the organic electroluminescent element of the present invention, the hole injection layer is preferably formed by a wet film formation method using the composition for an organic electroluminescent element of the present invention.

[ hole-transporting Compound ]

The composition for forming a hole injection layer generally contains a hole-transporting compound for forming the hole injection layer 3. In the case of a wet film formation method, the solvent is usually further contained. The composition for forming a hole injection layer preferably has a high hole-transporting property and can efficiently transport injected holes. Therefore, it is preferable that the hole mobility is high, and impurities which become traps are less likely to be generated at the time of manufacturing, use, or the like. Further, it is preferable that the stability is excellent, the ionization potential is small, and the transparency to visible light is high. In particular, when the hole injection layer is in contact with the light-emitting layer, it is preferable that the hole injection layer does not quench light emission from the light-emitting layer or form an exciplex with the light-emitting layer to lower light emission efficiency.

The hole-transporting compound is preferably a compound having an ionization potential of 4.5eV to 6.0eV, from the viewpoint of a charge injection barrier (electric charge injection barrier) from the anode to the hole injection layer. Examples of the hole-transporting compound include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which tertiary amines are linked via fluorenyl groups, hydrazone compounds, silazane compounds, quinacridone compounds, and the like.

Among the above exemplified compounds, aromatic amine compounds are preferable, and aromatic tertiary amine compounds are particularly preferable, from the viewpoint of amorphousness and visible light transmittance. Here, the aromatic tertiary amine compound refers to a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.

The type of the aromatic tertiary amine compound is not particularly limited, and a polymer compound (a polymerizable compound in which repeating units are linked) having a weight average molecular weight of 1000 or more and 1000000 or less is preferably used in terms of facilitating uniform light emission by the surface smoothing effect. Preferred examples of the aromatic tertiary amine polymer compound include, in addition to the polymer of the present invention, a polymer compound having a repeating unit represented by the following formula (6), that is, a polymer compound containing a unit represented by the following formula (6) as a repeating unit.

[ solution 14]

(in formula (6), Ar¹¹And Ar¹²Each independently represents an aromatic hydrocarbon group with or without substituents or an aromatic heterocyclic group with or without substituents. Ar (Ar)¹³～Ar¹⁵Each independently represents an aromatic hydrocarbon group with or without substituents or an aromatic heterocyclic group with or without substituents. Y represents a linking group selected from the linking group shown below. In addition, in Ar¹¹～Ar¹⁵In (b), two groups bonded to the same N atom may be bonded to each other to form a ring. )

< linker group >

[ solution 15]

(in the above formula, Ar¹⁶～Ar²⁶Each independently represents an aromatic hydrocarbon group with or without substituents or an aromatic heterocyclic group with or without substituents. R¹¹And R¹²Each independently represents a hydrogen atom or an optional substituent. )

As Ar¹⁶～Ar²⁶The aromatic hydrocarbon group and the aromatic heterocyclic group of (1) are preferably a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, or a pyridine ring having a free valence of 1 or 2, and more preferably a benzene ring or a naphthalene ring having a free valence of 1 or 2, from the viewpoint of solubility, heat resistance, and hole injection transport properties of the polymer compound.

Specific examples of the aromatic tertiary amine polymer compound containing a unit represented by formula (6) as a repeating unit include those described in international publication No. 2005/089024.

The hole injection layer 3 preferably contains the electron-accepting compound and the cationic radical compound because the oxidation of the hole-transporting compound can increase the conductivity of the hole injection layer.

Cationic radical compounds derived from high molecular weight compounds such as PEDOT/PSS (adv.mater.,2000, vol. 12, p. 481) and emeraldine hydrochloride (j.phys.chem.,1990, vol. 94, p. 7716) can also be produced by oxidative polymerization (dehydropolymerization).

The oxidative polymerization here means that a monomer is chemically or electrochemically oxidized in an acidic solution by using persulfate or the like. In the case of the oxidative polymerization (dehydrogenation polymerization), the monomer is oxidized to be polymerized, and a cationic radical in which a single electron is removed from a repeating unit of the polymer with an anion derived from an acidic solution as a counter anion is generated.

[ formation of hole injection layer by Wet film formation method ]

In the case of forming the hole injection layer 3 by a wet film formation method, a composition for film formation (composition for hole injection layer formation) is usually prepared by mixing a material to be the hole injection layer with a soluble solvent (solvent for hole injection layer), and the composition for hole injection layer formation is applied to a layer (usually an anode) corresponding to a lower layer of the hole injection layer to form a film and dried, thereby forming the hole injection layer 3.

The concentration of the hole-transporting compound in the composition for forming a hole-injecting layer is arbitrary as long as the effect of the present invention is not significantly impaired, and is preferably low from the viewpoint of film thickness uniformity; on the other hand, the concentration is preferably high because defects are less likely to occur in the hole injection layer. Specifically, it is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.5% by mass or more, and on the other hand, it is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

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

Examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA), and aromatic ethers such as 1, 2-dimethoxybenzene, 1, 3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2, 3-dimethylanisole, and 2, 4-dimethylanisole.

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

Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3, 4-tetramethylbenzene, 1, 4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene.

Examples of the amide solvent include N, N-dimethylformamide and N, N-dimethylacetamide.

In addition, dimethyl sulfoxide or the like can be used.

The formation of the hole injection layer 3 by a wet film formation method is generally performed by preparing a composition for forming a hole injection layer, applying the composition to a layer (typically, the anode 2) corresponding to a lower layer of the hole injection layer 3, forming a film, and drying the film.

The hole injection layer 3 is usually formed, and then the coating film is dried by heating, drying under reduced pressure, or the like.

[ formation of hole injection layer by vacuum deposition method ]

In the case of forming the hole injection layer 3 by the vacuum deposition method, it is common to charge 1 or 2 or more kinds of constituent materials of the hole injection layer 3 (the hole-transporting compound, the electron-accepting compound, and the like described above) into a crucible provided in a vacuum container (in the case of using 2 or more kinds of materials, each material is generally charged into each crucible), and the vacuum container is evacuated to 10 degrees by a vacuum pump^-4Pa or so, and then the crucible is heated (in the case of using 2 or more materials, each crucible is usually heated), the evaporation amount of the material in the crucible is controlled and the material is evaporated (in the case of using 2 or more materials, evaporation amount is usually independently controlled and the material is evaporated), and a hole injection layer is formed on the anode on the substrate placed opposite to the crucible. When 2 or more materials are used, a mixture of these materials may be put into a crucible, heated, and evaporated to form a hole injection layer.

The degree of vacuum at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10^- ⁶Torr(0.13×10^-4Pa) above, 9.0 × 10^-6Torr(12.0×10^-4Pa) or less. The deposition rate is not limited as long as the effects of the present invention are not significantly impaired, and is usually

More than one second,

And less than second. The film formation temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, and is preferably 10 ℃ to 50 ℃.

The hole injection layer 3 may be crosslinked in the same manner as the hole transport layer 4 described later.

[ hole transport layer ]

The hole transport layer 4 is a layer that functions to transport holes from the anode 2 side to the light-emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescent element of the present invention, but is preferably formed from the viewpoint of enhancing the function of transporting holes from the anode 2 to the light-emitting layer 5. In the case of forming the hole transport layer 4, the hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. In the case of having the hole injection layer 3, the hole injection layer is formed between the hole injection layer 3 and the light-emitting layer 5.

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

The method for forming the hole transport layer 4 may be a vacuum deposition method or a wet film formation method. The film is preferably formed by a wet film forming method in view of excellent film forming properties.

Next, a general method for forming the hole transport layer will be described.

The hole transport layer 4 generally contains a hole transporting compound. Examples of the hole-transporting compound contained in the hole-transporting layer 4 include the above-mentioned compounds, and more specifically, in addition to the polymer of the present invention, an aromatic diamine represented by 4, 4' -bis [ N- (1-naphthyl) -N-phenylamino ] biphenyl, which contains 2 or more tertiary amines and in which 2 or more fused aromatic rings are substituted on a nitrogen atom (japanese patent application laid-open No. 5-234681); aromatic amine compounds having a starburst structure such as 4, 4', 4 ″ -tris (1-naphthylphenylamino) triphenylamine (j.lumin., volume 72-74, page 985, 1997); aromatic amine compounds formed from tetramers of triphenylamine (chem. commu., page 2175, 1996); spiro compounds such as 2,2 ', 7,7 ' -tetrakis (diphenylamino) -9,9 ' -spirobifluorene (synth. metals, vol. 91, p. 209, 1997); carbazole derivatives such as 4,4 '-N, N' -dicarbazole biphenyl are preferable. In addition, for example, polyvinylcarbazole, polyvinyltriphenylamine (jp 7-53953 a), and polyarylene ether sulfone containing tetraphenylbenzidine (polym. adv. tech., volume 7, page 33, 1996) can also be preferably used.

[ formation of hole transport layer by Wet film formation method ]

In the case of forming the hole transport layer by a wet film formation method, the hole transport layer is usually formed using a composition for forming a hole transport layer instead of the composition for forming a hole injection layer, as in the case of forming the hole injection layer by a wet film formation method.

In the case of forming the hole transport layer by a wet film formation method, the composition for forming a hole transport layer usually further contains a solvent. As the solvent used for the composition for forming a hole transport layer, the same solvents as those used for the composition for forming a hole injection layer can be used.

The concentration of the hole-transporting compound in the composition for forming a hole-transporting layer may be in the same range as the concentration of the hole-transporting compound in the composition for forming a hole-injecting layer.

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

[ formation of hole transport layer by vacuum deposition method ]

In the case where the hole transport layer is formed by a vacuum vapor deposition method, the hole transport layer can be formed by using a composition for forming a hole transport layer instead of the composition for forming a hole injection layer, in general, similarly to the case where the hole injection layer is formed by a vacuum vapor deposition method. The film formation conditions such as the degree of vacuum, the deposition rate, and the temperature during the deposition can be the same as those during the vacuum deposition of the hole injection layer.

[ luminescent layer ]

The light-emitting layer 5 is a layer that performs the following functions: when an electric field is applied between the pair of electrodes, holes injected from the anode 2 are recombined with electrons injected from the cathode 9, and are excited to emit light. The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9, and is formed between the hole injection layer and the cathode when the hole injection layer is provided on the anode, and is formed between the hole transport layer and the cathode when the hole transport layer is provided on the anode.

The thickness of the light-emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is preferably thick in view of the difficulty in generating defects in the film; on the other hand, the film thickness is preferably thin in view of ease of low driving voltage. Therefore, it is preferably 3nm or more, more preferably 5nm or more, and on the other hand, it is usually preferably 200nm or less, more preferably 100nm or less.

The light-emitting layer 5 contains at least a material having a light-emitting property (light-emitting material), and preferably contains a material having a charge-transporting property (charge-transporting material).

[ luminescent Material ]

The light-emitting material emits light at a desired emission wavelength, and is not particularly limited as long as the effect of the present invention is not impaired, and a known light-emitting material can be applied. The light-emitting material may be a fluorescent light-emitting material or a phosphorescent light-emitting material, and a material having good emission efficiency is preferable, and a phosphorescent light-emitting material is preferable from the viewpoint of internal quantum efficiency.

Examples of the fluorescent light-emitting material include the following materials.

Examples of the fluorescent light-emitting material that emits blue light (blue fluorescent light-emitting material) include naphthalene, perylene, pyrene, anthracene, coumarin, 1, 2-triphenylene, p-bis (2-phenylvinyl) benzene, and derivatives thereof.

Examples of the fluorescent light-emitting material that emits green light (green fluorescent light-emitting material) include quinacridone derivatives, coumarin derivatives, and Al (C)₉H₆NO)₃And aluminum complexes.

Examples of the fluorescent light-emitting material that emits yellow light (yellow fluorescent light-emitting material) include rubrene and a naphthyridinone derivative.

Examples of the fluorescent light-emitting material that emits red light (red fluorescent light-emitting material) include DCM (4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran) based compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothiatonne, and the like.

Examples of the phosphorescent material include an organometallic complex containing a metal selected from groups 7 to 11 of the long-period periodic table. Preferred examples of the metal selected from groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold, and the like.

The ligand of the organometallic complex is preferably a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand is linked to pyridine, pyrazole, phenanthroline, or the like, and particularly preferably a phenylpyridine ligand or a phenylpyrazole ligand. Here, (hetero) aryl means aryl or heteroaryl.

Specific examples of preferable phosphorescent light-emitting materials include phenylpyridine complexes such as tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, tris (2-phenylpyridine) osmium, and tris (2-phenylpyridine) rhenium, and porphyrin complexes such as platinum octaethylporphyrin, platinum octaphenylporphyrin, palladium octaethylporphyrin, and palladium octaphenylporphyrin.

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

[ Charge-transporting Material ]

The charge transporting material is a material having a positive charge (hole) or negative charge (electron) transport property, and is not particularly limited as long as the effect of the present invention is not impaired, and a known light emitting material can be applied.

As the charge transporting material, a compound used in a light-emitting layer of an organic electroluminescent element and the like can be used conventionally, and a compound used as a host material of a light-emitting layer is particularly preferable.

Specific examples of the charge transporting material include compounds exemplified as hole transporting compounds of the hole injection layer, such as aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which tertiary amines are linked via fluorenyl groups, hydrazone compounds, silazane compounds, phosphoramide compounds, and quinacridone compounds, which include the polymer of the present invention, and in addition, electron transporting compounds such as anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, and thiapyrrole compounds.

Further, for example, an aromatic diamine containing 2 or more tertiary amines and 2 or more fused aromatic rings substituted on the nitrogen atom, as represented by 4, 4' -bis [ N- (1-naphthyl) -N-phenylamino ] biphenyl, can be preferably used (japanese patent application laid-open No. 5-234681); aromatic amine compounds having a starburst structure such as 4, 4', 4 ″ -tris (1-naphthylphenylamino) triphenylamine (j.lumin., volume 72-74, page 985, 1997); aromatic amine-based compounds formed from tetramers of triphenylamine (chem.commun.,2175 page, 1996); fluorene compounds such as 2,2 ', 7,7 ' -tetrakis- (diphenylamino) -9,9 ' -spirobifluorene (synth. metals, volume 91, page 209, 1997); examples of the hole-transporting compound include carbazole-based compounds such as 4,4 '-N, N' -dicarbazole biphenyl, and the like.

In addition, oxadiazole compounds such as 2- (4-biphenyl) -5- (p-tert-butylphenyl) -1,3, 4-oxadiazole (tBu-PBD) and 2, 5-bis (1-naphthyl) -1,3, 4-oxadiazole (BND); silole-based compounds such as 2, 5-bis (6 '- (2', 2 "-bipyridine)) -1, 1-dimethyl-3, 4-diphenylsilole (pypespypy); phenanthroline compounds such as bathophenanthroline (BPhen) and 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP, bathocuproine).

[ formation of light-emitting layer by Wet film formation method ]

The method for forming the light-emitting layer may be a vacuum deposition method or a wet film formation method, and a wet film formation method is preferable because of its excellent film formation property, and a spin coating method and an ink jet method are more preferable. In particular, when the composition for an organic electroluminescent element of the present invention is used to form a hole injection layer or a hole transport layer as a lower layer of a light-emitting layer, lamination by a wet film formation method is easy, and thus the wet film formation method is preferably used. In the case of forming the light-emitting layer by a wet film-forming method, in general, as in the case of forming the hole-injecting layer by a wet film-forming method, a light-emitting layer is formed by using a light-emitting layer-forming composition prepared by mixing a material to be the light-emitting layer with a soluble solvent (light-emitting layer solvent) instead of the hole-injecting layer-forming composition.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, alkane solvents, halogenated aromatic hydrocarbon solvents, aliphatic alcohol solvents, alicyclic alcohol solvents, aliphatic ketone solvents, and alicyclic ketone solvents, which are listed for forming the hole injection layer. Specific examples of the solvent are given below, but the solvent is not limited to these examples as long as the effects of the present invention are not impaired.

Examples thereof include aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); aromatic ether solvents such as 1, 2-dimethoxybenzene, 1, 3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2, 3-dimethylanisole, 2, 4-dimethylanisole, and diphenyl ether; aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; aromatic hydrocarbon solvents such as toluene, xylene, trimethylbenzene, cyclohexylbenzene, tetrahydronaphthalene, 3-isopropylbiphenyl, 1,2,3, 4-tetramethylbenzene, 1, 4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene; amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide; alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, trichlorobenzene and the like; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohol solvents such as cyclohexanol and cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone solvents such as cyclohexanone, cyclooctanone and fenchone. Among these, alkane solvents and aromatic hydrocarbon solvents are particularly preferable.

[ hole-blocking layer ]

The hole blocking layer 6 may be provided between the light emitting layer 5 and an electron injection layer 8 described later. The hole blocking layer 6 is a layer stacked on the light emitting layer 5 so as to contact the interface on the cathode 9 side of the light emitting layer 5.

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

Examples of the material of the hole-blocking layer satisfying the above conditions include metal complexes such as mixed ligand complexes of aluminum bis (2-methyl-8-quinolinolato) (phenol) and aluminum bis (2-methyl-8-quinolinolato) (triphenylsilanol) and the like, metal complexes such as aluminum bis (2-methyl-8-quinolinolato) - μ -oxo-bis- (2-methyl-8-quinolinolato) aluminum binuclear metal complexes and the like, styryl compounds such as distyrylbiphenyl derivatives and the like (Japanese patent application laid-open No. 11-242996), triazole derivatives such as 3- (4-biphenyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2, 4-triazole and the like (Japanese patent application laid-open No. 7-41759), and the like, Phenanthroline derivatives such as bathocuproine (Japanese patent application laid-open No. 10-79297). Further, a compound having at least 1 pyridine ring substituted in the 2-, 4-or 6-position as described in international publication No. 2005/022962 is also preferable as a material for the hole-blocking layer.

There is no limitation on the method of forming the hole stopper layer 6. Therefore, the film can be formed by a wet film formation method, an evaporation method, or other methods.

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

[ Electron transport layer ]

An electron transport layer 7 is provided between the light-emitting layer 5 and the electron injection layer 8 for the purpose of further improving the current efficiency of the element.

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 the electrodes to which an electric field is applied. As the electron transporting compound used in the electron transporting layer 7, a compound which has high electron injection efficiency from the cathode 9 or the electron injecting layer 8, has high electron mobility, and can efficiently transport injected electrons is required.

Specific examples of the electron transporting compound used in the electron transporting layer include metal complexes such as aluminum complexes of 8-hydroxyquinoline (JP 59-194393A), metal complexes of 10-hydroxybenzo [ h ] quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, triphenylimidazolylbenzene (see U.S. Pat. No. 5645948), quinoxaline compounds (JP 6-207169A), phenanthroline derivatives (JP 5-331459A), 2-tert-butyl-9, 10-N, N' -dicyanoanthraquinone diimine, N-type hydrogenated amorphous silicon carbide, silicon nitride, and the like, n-type zinc sulfide, n-type zinc selenide, and the like.

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

The electron transport layer 7 is formed by being laminated on the hole blocking layer 6 by a wet film formation method or a vacuum evaporation method as described above. Vacuum evaporation is generally used.

[ Electron injection layer ]

The electron injection layer 8 functions to efficiently inject electrons injected from the cathode 9 into the electron transport layer 7 or the light emitting layer 5.

In order to efficiently inject electrons, the material forming the electron injection layer 8 is preferably a metal having a low work function. For example, alkali metal such as sodium or cesium, alkaline earth metal such as barium or calcium, or the like can be used. The film thickness is usually 0.1nm or more, preferably 5nm or less.

Further, it is preferable that the organic electron transport material represented by a nitrogen-containing heterocyclic compound such as bathophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium (described in japanese patent application laid-open nos. 10-270171, 2002-100478, 2002-100482, and the like), since the electron injection/transport properties can be improved and the film quality is excellent at the same time.

The thickness of the electron injection layer 8 is usually 5nm or more, preferably 10nm or more, and usually 200nm or less, preferably 100nm or less.

The electron injection layer 8 can be formed by being laminated on the light-emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 thereon by a wet film formation method or a vacuum evaporation method.

The details of the wet film formation method are the same as those of the light-emitting layer.

[ cathode ]

The cathode 9 functions to inject electrons into a layer (an electron injection layer, a light-emitting layer, or the like) on the light-emitting layer 5 side.

As the material of the cathode 9, the material used in the above-described anode 2; for efficient electron injection, a metal having a low work function is preferably used, and for example, a metal such as tin, magnesium, indium, calcium, aluminum, or silver, or an alloy thereof can be used. Specific examples thereof include low work function alloy electrodes such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys.

In view of stability of the device, it is preferable to protect the cathode made of a low work function metal by stacking a metal layer having a high work function and stable to the atmosphere on the cathode. Examples of the metal to be laminated include metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.

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

[ other layers ]

The organic electroluminescent element of the present invention may further have other layers as long as the effects of the present invention are not significantly impaired. That is, any layer other than the above may be provided between the anode and the cathode.

[ other component constitution ]

The organic electroluminescent element of the present invention may have a structure reverse to the above description, that is, a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, a hole transport layer, a hole injection layer, and an anode may be sequentially stacked on a substrate.

When the organic electroluminescent element of the present invention is applied to an organic electroluminescent device, the organic electroluminescent element may be used as a single organic electroluminescent element, or may be used in a configuration in which 2 or more organic electroluminescent elements are arranged in an array, or may be used in a configuration in which an anode and a cathode are arranged in an X-Y matrix.

< organic EL display device >

The organic EL display device (organic electroluminescence element display device) of the present invention uses the organic electroluminescence element of the present invention. The type and structure of the organic EL display device of the present invention are not particularly limited, and the organic EL display device can be assembled by a conventional method using the organic electroluminescent element of the present invention.

For example, the organic EL display device of the present invention can be formed by a method described in "organic EL display" (Ohmsha, published 8/20 (16) years, wainsch, yadak-kyo, cuntian-kangxi).

< organic EL illumination >

The organic EL lighting (organic EL element lighting) of the present invention uses the organic EL element of the present invention described above. The type and structure of the organic EL lighting device of the present invention are not particularly limited, and the organic EL lighting device of the present invention can be assembled by a conventional method using the organic electroluminescent element of the present invention.

Examples

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and can be carried out by arbitrarily changing the invention without departing from the gist thereof.

< example 1>

[ Synthesis of monomer (Compound 3) ]

Compound 1 was synthesized as follows.

Synthesis of monomers

[ solution 16]

In a flask, 4-sec-butylaniline (37.36g, 250.34mmol), bromobenzene (38.52g, 245.33mmol), sodium tert-butoxide (57.77g, 601.05mmol) and toluene (500ml) were charged, nitrogen gas was replaced, the system was heated to 60 ℃ (solution a), 1' -bis (diphenylphosphino) ferrocene (1.09g, 1.96mmol) was added to a toluene 25ml solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.52g, 0.491mmol) charged in another flask, the solution was heated to 60 ℃ (solution B) in a nitrogen gas flow, solution B was added to solution a, the mixture was stirred at 100 ℃ for 4.0 hours, naturally cooled to room temperature, ethyl acetate (300ml) and brine (100ml) were added to the reaction solution, followed by stirring, liquid separation was performed, the aqueous layer was extracted with ethyl acetate (100ml × 2 times), the organic layers were combined, dried, and concentrated, and the aqueous layer was purified by chromatography (magnesium sulfate; 9/1 g) to obtain a pale yellow oily compound (dichloromethane 672).

[ solution 17]

Compound 1(40.0g, 177.5mmol), 4' -dibromobiphenyl (27.15g, 87.02mmol), sodium tert-butoxide (42.6g, 443.8mmol), and toluene (500ml) were charged into a flask, the system was purged with nitrogen, and heated to 60 ℃ (solution C), tris (dibenzylideneacetone) dipalladium chloroform complex (0.92g, 0.89mmol), toluene (25ml), and 4- (N, N-dimethylamino) phenyl ] di-tert-butylphosphine (1.9g, 7.12mmol) were added to another flask, heated to 60 ℃ (solution D) in a nitrogen stream, solution D was added to solution C, reacted at 100 ℃ for 5.5 hours, cooled to room temperature naturally, toluene (300ml) and brine (100ml) were added to the reaction solution, followed by stirring, liquid separation, the aqueous layer was extracted with toluene (100ml × times), the organic layers were combined, dried with activated clay, treated with magnesium sulfate, concentrated with ethyl acetate (9/1 g), and purified by column chromatography (3652.35 g).

[ solution 18]

To compound 2(52.1g, 86.71mmol), N-dimethylformamide (300ml) and dichloromethane (300ml) were added, and the mixture was cooled in an ice bath. A solution of N, N-dimethylformamide (100ml) and methylene chloride (100ml) were added dropwise to the mixture, and the mixture was allowed to warm to room temperature over 4.5 hours while stirring. Water was added to the reaction solution, followed by extraction with dichloromethane, and the organic layer was concentrated and purified by column chromatography (developing solution: hexane/dichloromethane ═ 4/1), whereby compound 3(23.2g) was obtained as a colorless solid.

[ Synthesis of Polymer 1]

Polymer 1 was synthesized according to the following reaction scheme.

[ solution 19]

Polymer 1

A flask was charged with compound 3(5.00g, 6.6mmol), 2-amino-9, 9-dihexylfluorene (4.61g, 13.2mmol), sodium tert-butoxide (4.88g, 50.8mmol) and toluene (100g), and the system was heated to 90 ℃ under nitrogen substitution (solution E). To the other flask were added tris (dibenzylideneacetone) dipalladium complex (0.12g, 1.1mmol), toluene (7.8ml), and [4- (N, N-dimethylamino) phenyl ] di-t-butylphosphine (0.28g, 0.11mmol), and the mixture was heated to 60 deg.C (solution F). Solution F was added to solution E in a nitrogen stream, and the reaction was heated under reflux for 1 hour. After confirming the disappearance of the starting material, 4' -dibromobiphenyl (0.60g, 1.92mmol) was added and the mixture was refluxed for 1 hour. Further, 4- (4- {1, 1-bis [4- (4-bromophenyl) phenyl ] ethyl } phenyl) benzocyclobutene (2.69g, 4.01mmol) was added thereto, and after refluxing with heating for 1 hour, bromobenzene (1.04g, 6.6mmol) was added thereto, and the reaction was refluxed with heating for 1.5 hours. The reaction solution was naturally cooled, toluene (100g) was added thereto, and the mixture was added dropwise to ethanol (5000g) to obtain a crude polymer.

The crude polymer was dissolved in toluene, reprecipitated in acetone, and the precipitated polymer was collected by filtration. The obtained polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated in ammonia-containing ethanol. The filtered polymer was purified by column chromatography to give polymer 1(3.7 g).

Weight average molecular weight (Mw) 45200

Number average molecular weight (Mn) 32700

Dispersity (Mw/Mn) of 1.38

(organic electroluminescent element)

< example 2>

The organic electroluminescent element shown in fig. 1 was produced.

An Indium Tin Oxide (ITO) transparent conductive film was deposited on the glass substrate 1 by sputtering, and then a 2mm wide stripe was patterned by a general photolithography technique and hydrochloric acid etching, thereby forming an anode 2 having a film thickness of 70 nm. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with a surfactant aqueous solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, then dried with compressed air, and finally subjected to ultraviolet ozone cleaning.

Subsequently, a coating liquid for forming a hole injection layer containing polymer 1(P1) synthesized in example 1, 4-isopropyl-4' -methyldiphenyliodonium tetrakis (pentafluorophenyl) borate represented by the structural formula (a1), and ethyl benzoate was prepared. This coating solution was applied to the anode 2 by spin coating to form a film, and the film was heated under the following conditions to obtain a hole injection layer having a thickness of 35 nm.

[ solution 20]

< coating liquid for Forming Positive hole injection layer >

Solvent ethyl benzoate

Coating liquid concentration polymer 7: 3.0% by mass

A1: 0.6% by mass

< conditions for Forming hole-injecting layer 3>

In atmosphere of spin coating

Heating at 230 deg.C for 60 min

Next, a coating liquid for forming a hole transport layer containing (P2) below was prepared, and a film was formed on the hole injection layer 3 by spin coating under the following conditions, followed by heating to form a hole transport layer having a film thickness of 40 nm.

[ solution 21]

< coating liquid for Forming hole transport layer >

Solvent cyclohexylbenzene

Coating solution concentration 1.5% by mass

< conditions for Forming hole transport layer 4 >

In a spin coating atmosphere of nitrogen

Heating at 230 ℃ for 60 minutes in nitrogen

Next, a coating liquid for forming a light-emitting layer containing the compounds (H1), (H2), and (D1) represented by the following structural formulae was prepared, and a light-emitting layer having a film thickness of 56nm was formed on the hole transport layer 4 by spin coating under the following conditions and heating.

[ solution 22]

< coating liquid for Forming light-emitting layer >

Solvent cyclohexylbenzene

Coating liquid concentration H1: 2.25% by mass

H2: 2.75% by mass

D1: 1.00% by mass

< conditions for Forming light-emitting layer 5 >

In a spin coating atmosphere of nitrogen

Heating at 130 deg.C for 10 min in nitrogen

Here, the substrate on which the light-emitting layer was formed was transferred into a vacuum vapor deposition apparatus, and an organic compound (E1) having a structure shown below was laminated on the light-emitting layer 5 by a vacuum vapor deposition method, thereby forming the hole-blocking layer 6 having a film thickness of 10 nm.

[ solution 23]

Next, an organic compound (E2) having a structure shown below was laminated on the hole-blocking layer 6 by a vacuum evaporation method to form an electron-transporting layer 7 having a thickness of 10 nm.

[ solution 24]

Here, the element subjected to vapor deposition to the electron transport layer 7 was transferred to another vacuum vapor deposition apparatus, and a 2mm wide stripe shadow mask as a mask for cathode vapor deposition was brought into close contact with the element so as to be orthogonal to the ITO stripes of the anode 2. First, lithium fluoride (LiF) was formed as the electron injection layer 8 on the electron transport layer 7 by a vacuum evaporation method using a molybdenum boat in a film thickness of 0.5 nm. Subsequently, aluminum was heated by a molybdenum boat in the same manner, and an aluminum layer having a film thickness of 80nm was formed as the cathode 9 by a vacuum evaporation method. The substrate temperature during the 2-layer deposition was kept at room temperature.

Next, in order to prevent the deterioration of the device due to moisture in the atmosphere or the like during storage, a packaging process was performed by the following method.

In a nitrogen glove box, a photocurable resin (30Y-437, manufactured by Three Bond Fine Chemical) was applied to the outer periphery of a 23mm × 23mm size glass plate with a width of about 1mm, and a moisture-absorbing sheet (manufactured by dynic) was provided in the central portion.

An organic electroluminescent element having a light-emitting area portion of 2mm × 2mm in size was obtained as described above, and characteristics of the element are shown in table 2.

< comparative example 1>

An organic electroluminescent element was produced in the same manner as in example 2, except that the polymer used in the coating liquid for forming a hole injection layer was changed from the polymer 1(P1) to a polymer (P3) represented by the following formula. The characteristics of the element are shown in table 2.

[ solution 25]

< comparative example 2>

An organic electroluminescent element was produced in the same manner as in example 2, except that the polymer used in the coating liquid for forming a hole injection layer was changed from the polymer 1(P1) to a polymer (P4) represented by the following formula. The characteristics of the element are shown in table 2.

[ solution 26]

< comparative example 3>

An organic electroluminescent element was produced in the same manner as in example 2, except that the polymer used in the coating liquid for forming a hole injection layer was changed from the polymer 1(P1) to a polymer (P5) represented by the following formula. The characteristics of the element are shown in table 2.

[ solution 27]

[ TABLE 8]

TABLE 2

As is clear from Table 2, the voltage of the organic electroluminescent element using the polymer of the present invention is low.

The present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese patent application (Japanese patent application 2015-035607) filed on 25.2.2015, the contents of which are incorporated into this specification by reference.

Description of the symbols

1 substrate (glass substrate)

2 anode

3 hole injection layer

4 hole transport layer

5 light-emitting layer

6 hole blocking layer

7 electron transport layer

8 electron injection layer

9 cathode

10 organic electroluminescent element

Claims

1. A polymer containing a unit represented by the following formula (1) as a repeating unit,

[ solution 1]

In the formula (1), Ar¹Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group formed by fusing 3 or more rings with or without a substituent; r¹Each independently represents a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms, which may have a substituent; t is¹An aromatic hydrocarbon group or an aromatic heterocyclic group having a crosslinkable group as a substituent;

ar is¹In (1),

the aromatic hydrocarbon group is anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring, 1, 2-benzophenanthrene ring, benzo [9,10] phenanthrene ring, acenaphthene ring, fluoranthene ring, fluorene ring or indenofluorene ring,

the aromatic heterocyclic group is carbazole ring, indenocarbazole ring, indole carbazole ring, dibenzofuran ring or dibenzothiophene ring;

Ar¹aromatic hydrocarbon group and aromatic heterocyclic group in (1), and R¹The alkyl group in (1) may have a substituent selected from the following substituent group Z,

substituent group Z is:

a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms,

An alkenyl group having 2 to 24 carbon atoms,

An alkynyl group having 2 to 24 carbon atoms,

An alkoxy group having 1 to 24 carbon atoms,

An aryloxy group having 4 to 36 carbon atoms,

An alkoxycarbonyl group having 2 to 24 carbon atoms,

A dialkylamino group having 2 to 24 carbon atoms,

A diarylamino group having 10 to 36 carbon atoms,

An aralkylamino group having 7 to 36 carbon atoms,

An acyl group having 2 to 24 carbon atoms,

A halogen atom,

A haloalkyl group having 1 to 12 carbon atoms,

An alkylthio group having 1 to 24 carbon atoms,

An arylthio group having 4 to 36 carbon atoms,

A silyl group having 2 to 36 carbon atoms,

A siloxy group having 2 to 36 carbon atoms,

A cyano group,

An aromatic hydrocarbon group having 6 to 36 carbon atoms,

An aromatic heterocyclic group having 3 to 36 carbon atoms,

these substituents may further have the same substituent as the substituent group Z;

the T is¹In (1),

the aromatic hydrocarbon group is a 6-membered ring including a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzopyrene ring, a1, 2-benzophenanthrene ring, a benzo [9,10] phenanthrene ring, an acenaphthene ring, a fluoranthene ring, a fluorene ring or a 2-valent group of a condensed ring of 2-5 rings,

the aromatic heterocyclic group is a 2-valent group of a single ring of 5-or 6-membered ring including furan ring, benzofuran ring, thiophene ring, benzothiophene 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, 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, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring,

the aromatic hydrocarbon group and the aromatic heterocyclic group may be bonded together at 2 to 6,

the aromatic hydrocarbon group and the aromatic heterocyclic group may have a substituent selected from the substituent group Z.

2. The polymer of claim 1, wherein Ar is Ar¹Is an aromatic hydrocarbon group.

3. The polymer of claim 2, wherein Ar is Ar¹Is phenyl or fluorenyl.

4. As claimed in claim 3The polymer of (1), wherein Ar is¹Is fluorenyl.

5. The polymer of claim 4, wherein Ar is Ar¹Is 2-fluorenyl.

6. The polymer according to claim 1, wherein R in the unit represented by the formula (1)¹Is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms.

7. The polymer according to claim 6, wherein R in the unit represented by the formula (1)¹Is a linear or branched alkyl group having 1 to 4 carbon atoms.

8. The polymer according to claim 6, wherein R in the unit represented by the formula (1)¹The same is true.

9. The polymer of claim 1, wherein Ar is Ar¹Aromatic hydrocarbon group and aromatic heterocyclic group in (1), and R¹The substituent which the alkyl group in (1) may have is:

a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms,

An alkoxy group having 1 to 24 carbon atoms,

An aromatic hydrocarbon group having 6 to 36 carbon atoms,

An aromatic heterocyclic group having 3 to 36 carbon atoms.

10. The polymer of claim 9, wherein Ar is¹Aromatic hydrocarbon group and aromatic heterocyclic group in (1), and R¹The substituent which the alkyl group in (1) may have is:

a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms.

11. The polymer of any one of claims 1 to 8, whereinSaid T is¹The crosslinkable group is a group represented by the following crosslinkable group T,

crosslinkable group T:

in the above-mentioned formula, the compound of formula,

R⁷～R⁹represents a hydrogen atom or a linear or branched chain alkyl group having 6 or less carbon atoms,

R¹⁰～R¹²represents a hydrogen atom, a linear or branched chain alkyl group having 6 or less carbon atoms, or a linear or branched chain alkoxy group having 6 or less carbon atoms,

Ar⁴the aromatic heterocyclic group is a monocyclic or 2-5-ring fused aromatic hydrocarbon group having 1 free-valence 6-membered ring with or without a substituent, a group obtained by bonding 2 or more of these monocyclic or 2-5-ring fused aromatic hydrocarbon groups having 1 free-valence 6-membered ring with or without a substituent, or an aromatic heterocyclic group having 3 or more and 36 or less carbon atoms with or without a substituent.

12. The polymer according to claim 1, wherein the polymer has a weight average molecular weight Mw of 20,000 or more and a dispersity Mw/Mn of 2.5 or less.

13. The polymer according to any one of claims 1 to 8, which further comprises a unit represented by the following formula (2) as a repeating unit,

in the formula (2), Ar¹Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group formed by fusing 3 or more rings with or without a substituent;

R¹each independently represents with or without an accessAlkyl of a substituent;

L¹represents an aromatic hydrocarbon group or an aromatic heterocyclic group,

the aromatic hydrocarbon group is a 2-valent group of a 6-membered ring monocyclic ring or a 2-to 5-membered fused ring,

the aromatic heterocyclic group is a monocyclic group having 5 or 6 membered rings or a 2-valent group having 2 to 4 condensed rings,

said L¹The aromatic hydrocarbon group and the aromatic heterocyclic group in (1) may have a substituent of:

a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms,

An alkoxy group having 1 to 24 carbon atoms,

An aromatic hydrocarbon group having 6 to 36 carbon atoms,

An aromatic heterocyclic group having 3 to 36 carbon atoms.

14. The polymer of claim 13, wherein said L is¹The aromatic hydrocarbon group and the aromatic heterocyclic group in (1) may have a substituent of:

a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms.

15. The polymer of claim 13, wherein said L is¹Is any one of 1, 4-phenylene, 4 '-biphenylene and 4, 4' -terphenylene.

16. The polymer of claim 15, wherein said L is¹Is 4, 4' -biphenylene, that is, the polymer contains a unit represented by the following formula (3) as a repeating unit,

in the formula (3), Ar¹、R¹And Ar in formula (2)¹、R¹Are identical to each other。

17. The polymer of claim 13, wherein Ar is¹Is 2-fluorenyl.

18. The polymer according to claim 13, wherein the polymer has a weight average molecular weight Mw of 20,000 or more and a dispersity Mw/Mn of 2.5 or less.

19. The polymer according to claim 13, wherein the polymer has a total of 50 mol% or more of the unit represented by the formula (1) and the unit represented by the formula (2) with respect to 100 mol% of all monomer units.

20. A composition for an organic electroluminescent element, which comprises the polymer as defined in any one of claims 1 to 19.

21. An organic electroluminescent element comprising an anode, a cathode, and an organic layer located between the anode and the cathode on a substrate, wherein the organic layer comprises a layer formed by a wet film formation method using the composition for an organic electroluminescent element according to claim 20.

22. The organic electroluminescent element according to claim 21, wherein the layer formed by the wet film formation method is at least one of a hole injection layer and a hole transport layer.

23. The organic electroluminescent element according to claim 21 or 22, wherein a hole injection layer, a hole transport layer, and a light-emitting layer are included between the anode and the cathode, and all of the hole injection layer, the hole transport layer, and the light-emitting layer are formed by a wet film-forming method.

24. An organic EL display device having the organic electroluminescent element as claimed in any one of claims 21 to 23.

25. An organic EL lighting having the organic electroluminescent element as claimed in any one of claims 21 to 23.