WO2016136847A1

WO2016136847A1 - Polymer, composition for organic electroluminescent element, organic electroluminescent element, organic el display device, and organic el illumination

Info

Publication number: WO2016136847A1
Application number: PCT/JP2016/055536
Authority: WO
Inventors: 飯田　宏一朗; 延軍李; 友和梅基
Original assignee: 三菱化学株式会社
Priority date: 2015-02-25
Filing date: 2016-02-24
Publication date: 2016-09-01
Also published as: JP6593432B2; CN107406588A; TWI753578B; KR20170125824A; TW201634532A; TWI708793B; TW202106758A; JPWO2016136847A1; KR102496777B1; CN107406588B

Abstract

Provided are a polymer having high hole injection/transport ability and high durability, a composition for an organic electroluminescent element which includes the polymer, an organic electroluminescent element having high luminous efficiency which is fabricated using the composition, and a display device and illumination device which use the organic electroluminescent element. This polymer contains units represented by formula (1) as repeating units. (In formula (1), Ar¹, R¹, and T¹ are each the same as defined in the specification.)

Description

Polymer, composition for organic electroluminescence device, organic electroluminescence device, organic EL display device and organic EL lighting

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

Examples of a method for forming an organic layer in an organic electroluminescent element include a vacuum deposition method and a wet film formation method. Since the vacuum deposition method is easy to stack, it has an advantage that the charge injection from the anode and / or the cathode is improved, and the exciton light-emitting layer is easily contained. On the other hand, the wet film formation method does not require a vacuum process, is easy to increase in area, and can be easily applied to a plurality of materials having various functions by using a coating liquid in which a plurality of materials having various functions are mixed. There is an advantage that a layer containing these materials can be formed.

However, since the wet film formation method is difficult to stack, the driving stability is inferior to that of the element by the vacuum vapor deposition method, and the current state is that it has not reached a practical level except for a part.

Therefore, in order to perform lamination by a wet film forming method, a charge transporting polymer having a crosslinkable group is desired and developed. For example, Patent Documents 1 to 3 disclose organic electroluminescent elements that contain a polymer having a specific repeating unit and are laminated by a wet film-forming method. For example, Patent Documents 4 to 6 disclose an arylamine polymer used as a charge transport material and an element using the same in order to form an organic electroluminescent device having excellent hole transport properties.

Japanese Unexamined Patent Publication No. 2010-155985 Japanese Unexamined Patent Publication No. 2013-045986 Japanese Unexamined Patent Publication No. 2013-170228 Japanese Unexamined Patent Publication No. 2012-102286 Japan Special Table 2007-518842 International Publication No. 2013/114976

However, these elements described in Patent Documents 1 to 3 have a problem that the drive voltage is high and the drive life is short. For this reason, there has been a demand for improvement in charge injection / transport capability and durability of the charge transport material.

Therefore, an object of the present invention is to provide a novel polymer having a high hole injecting and transporting ability and a high durability and a composition for an organic electroluminescence device containing the polymer. Another object of the present invention is to provide an organic electroluminescence device having high luminance and a long driving life.

As a result of intensive studies, the present inventors have found that a polymer having a specific repeating unit easily generates a cation radical, and that the above problem can be solved by efficiently transporting the cation radical, The present invention has been completed.

That is, the gist of the present invention is as follows [1] to [12].
[1] A polymer containing a unit represented by the following formula (1) as a repeating unit.

(In the formula (1), Ar ¹ each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R ¹ Each independently represents an alkyl group which may have a substituent, and T ¹ represents an aromatic hydrocarbon group or an aromatic heterocyclic group having a crosslinkable group as a substituent.
[2] The polymer according to [1], further including a unit represented by the following formula (2) as a repeating unit.

(In Formula (2), Ar ¹ each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R ¹ Each independently represents an optionally substituted alkyl group, and L ¹ represents an aromatic hydrocarbon group or an aromatic heterocyclic group.)
[3] The polymer has a unit represented by the formula (1) and a unit represented by the formula (2) in a total amount of 50 mol% or more based on 100 mol% of all monomer units. The polymer according to the above [2].
[4] The polymer according to any one of [1] to [3], wherein Ar ¹ is a 2-fluorenyl group which may have a substituent.
[5] In any one of the above [2] to [4], the L ¹ is 4,4′-biphenylene, that is, contains a unit represented by the following formula (3) as a repeating unit. The polymer described.

(In Formula (3), Ar ¹ each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R ¹ Each independently represents an optionally substituted alkyl group.)
[6] The polymer according to any one of [1] to [5], having a weight average molecular weight (Mw) of 20,000 or more and a dispersity (Mw / Mn) of 2.5 or less. .
[7] A composition for an organic electroluminescent device comprising the polymer according to any one of [1] to [6].

[8] An organic electroluminescence device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate, wherein the organic layer is the composition for an organic electroluminescence device according to the above [7] An organic electroluminescent element including a layer formed by a wet film-forming method using.
[9] The organic electroluminescence device 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] A hole injection layer, a hole transport layer and a light emitting layer are included between the anode and the cathode, and the hole injection layer, the hole transport layer and the light emitting layer are all formed by a wet film forming method. The organic electroluminescent element according to [8] or [9].
[11] An organic EL display device having the organic electroluminescent element as described in any one of [8] to [10].
[12] An organic EL illumination having the organic electroluminescent element as described in any one of [8] to [10].

In the N, N-bis (4-alkylphenyl) benzidine structure contained in the main chain of the polymer of the present invention, a phenyl group having an alkyl group as an electron donating group in the p-position is substituted with an N atom of benzidine. Therefore, it tends to be a cation radical and excels in hole injection from the anode.
The N atom present from the above N, N-bis (4-alkylphenyl) benzidine structure via a phenylene group has an aromatic hydrocarbon group or aromatic heterocyclic ring in which three or more rings are condensed. The group is substituted. In three or more condensed rings, orbitals are easily delocalized, and the hole transport between polymer chains is excellent.
Furthermore, since the polymer of this invention contains a crosslinkable group, it can be made insoluble 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 cracks and the like. According to the organic electroluminescent element of the present invention, the luminance is high and the driving life is long.

Further, since the polymer of the present invention is excellent in electrochemical stability, an element including a layer formed using the polymer is a flat panel display (for example, for OA computers or wall-mounted televisions), an in-vehicle display element. It can be applied to light sources (for example, light sources for copiers, backlight sources for liquid crystal displays and instruments), display boards, and indicator lamps that make use of the characteristics of cell phone displays and surface light emitters. Is a big one.

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

Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. It is not specified in the contents.
In the present specification, all percentages and parts expressed by mass are the same as percentages and parts expressed by weight.

<Polymer>
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.

(In the formula (1), Ar ¹ each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R ¹ Each independently represents an alkyl group which may have a substituent, and T ¹ represents an aromatic hydrocarbon group or an aromatic heterocyclic group having a crosslinkable group as a substituent.

[Substituent of repeating unit]
In Ar ¹ in the unit represented by the above formula (1), examples of the aromatic hydrocarbon group include an anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, Examples thereof include groups in which three or more 5- or 6-membered rings such as acenaphthene ring, fluoranthene ring, fluorene ring, and indenofluorene ring are condensed.

Examples of the aromatic heterocyclic group include groups in which three or more 5- or 6-membered rings such as a carbazole ring, an indenocarbazole ring, an indolocarbazole ring, a dibenzofuran ring, and a dibenzothiophene ring are condensed.

Ar ¹ is preferably an aromatic hydrocarbon group from the viewpoint of excellent charge transportability and durability, and more preferably a monovalent group of a fluorene ring, that is, a phenyl group or a fluorenyl group, more preferably a fluorenyl group. More preferred is a 2-fluorenyl group. Ar ¹ in the unit represented by the formula (1) may be the same or different, but is preferably the same.

In R ¹ in the unit represented by the above formula (1), examples of the alkyl group include a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec A linear, branched, or cyclic group having a carbon number of usually 1 or more and usually 24 or less, such as -butyl group, tert-butyl group, n-hexyl group, n-octyl group, cyclohexyl group, dodecyl group, etc. An alkyl group is mentioned.

Among them, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n- A linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, such as a hexyl group or a cyclohexyl group, is preferred, and a linear or branched alkyl group having 1 to 4 carbon atoms is more preferred. . Moreover, R ¹ in the unit represented by the formula (1) may be the same or different, but is preferably the same.

The substituent that the aromatic hydrocarbon group and aromatic heterocyclic group in Ar ¹ and the alkyl group in R ¹ may have is not particularly limited as long as the properties of the polymer are not significantly reduced. However, for example, a group selected from the following substituent group Z is exemplified, and an alkyl group, an alkoxy group, an aromatic hydrocarbon group, and an aromatic heterocyclic group are preferable, and an alkyl group is more preferable.

[Substituent group Z]
For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group, etc. A linear, branched or cyclic alkyl group having usually 1 or more carbon atoms and usually 24 or less, preferably 12 or less;
An alkenyl group having usually 2 or more carbon atoms and usually 24 or less, preferably 12 or less, such as a vinyl group;
An alkynyl group such as an ethynyl group, which usually has 2 or more carbon atoms and is usually 24 or less, preferably 12 or less;
For example, an alkoxy group having a carbon number of usually 1 or more and usually 24 or less, preferably 12 or less, such as a methoxy group or an ethoxy group;
For example, an aryloxy group having usually 4 or more, preferably 5 or more, and usually 36 or less, preferably 24 or less, such as a phenoxy group, a naphthoxy group, or a pyridyloxy group;
For example, an alkoxycarbonyl group having 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methoxycarbonyl group or an ethoxycarbonyl group;
For example, a dialkylamino group having 2 or more carbon atoms and usually 24 or less, preferably 12 or less, such as a dimethylamino group or a diethylamino group;
For example, a diarylamino group having usually 10 or more, preferably 12 or more, usually 36 or less, preferably 24 or less, such as a diphenylamino group, a ditolylamino group, or an N-carbazolyl group;
An arylalkylamino group having usually 7 or more carbon atoms, usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;
For example, an acetyl group, a benzoyl group, etc., an acyl group having usually 2 or more carbon atoms and usually 24 or less, preferably 12 or less;
For example, a halogen atom such as a fluorine atom or a chlorine atom;
A haloalkyl group having usually 1 or more and usually 12 or less, preferably 6 or less, such as a trifluoromethyl group;
For example, an alkylthio group having a carbon number of usually 1 or more and usually 24 or less, preferably 12 or less, such as a methylthio group or an ethylthio group;
For example, an arylthio group having a carbon number of usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less, such as a phenylthio group, a naphthylthio group, or a pyridylthio group;
For example, a silyl group having a carbon number of usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less, such as a trimethylsilyl group or a triphenylsilyl group;
For example, a siloxy group having 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less, such as trimethylsiloxy group or triphenylsiloxy group;
A cyano group;
For example, an aromatic hydrocarbon group having usually 6 or more carbon atoms, usually 36 or less, preferably 24 or less, such as a phenyl group or 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, such as thienyl group or pyridyl group.

In addition, each of the above substituents may further have a substituent, and examples of the substituent include the same ones as the above substituent (substituent group Z).

In T ¹ in the unit represented by the above formula (1), a plurality of aromatic hydrocarbon groups and aromatic heterocyclic groups may be bonded.

Examples of the aromatic hydrocarbon group include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring, and the like. , A 6-membered monocyclic ring or a divalent group having 2 to 5 condensed 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, and a pyrrolopyrazole ring. , Pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, A quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. 2 It includes the groups.

The substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have is not particularly limited, and examples thereof include a group selected from the substituent group Z, such as an alkyl group, an alkoxy group, and an aromatic group. An aromatic hydrocarbon group and an aromatic heterocyclic group are preferable, and an alkyl group is more preferable.

When T ¹ is a group in which a plurality of the aromatic hydrocarbon groups and aromatic heterocyclic groups are combined, 2 to 6 of these groups are linked from the viewpoint of excellent charge transportability and durability. It is preferable. The aromatic hydrocarbon group and aromatic heterocyclic group to be linked may be one kind or plural kinds.

Further, when T ¹ is a group in which a plurality of the aromatic hydrocarbon groups and aromatic heterocyclic groups are bonded, they may be bonded through a linking group. In this case, examples of the linking group include a group selected from the group consisting of —CR ¹ R ² —, —O—, —CO—, —NR ³ —, and —S—, and a group obtained by linking them in 2 to 10 groups. preferable. When two or more are connected, the linking group may be one kind or plural kinds. Here, R ¹ to R ³ each independently have a hydrogen atom or an alkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a substituent. Represents an aromatic heterocyclic group which may be substituted. As the linking group, —CR ¹ R ² — and a group in which 2 to 6 —CR ¹ R ² — are connected are more preferable, and —CR ¹ R ² — is particularly preferable.

[About the crosslinkable group]
T ¹ has a crosslinkable group as a substituent. By including a crosslinkable group, a large difference in solubility in an organic solvent can be produced before and after a reaction (slightly solubilizing reaction) caused by irradiation with heat and / or active energy rays.
A crosslinkable group is a group that reacts with a group constituting another molecule located in the vicinity of the crosslinkable group by irradiation with heat and / or active energy rays to form a new chemical bond. Say. In this case, the reacting group may be the same group as the crosslinkable group or a different group. Examples of the crosslinkable group include groups shown in the following crosslinkable group group T.

(In the above formula, R ⁷ to R ⁹ represent a hydrogen atom or an alkyl group. R ¹⁰ to R ¹² represent a hydrogen atom, an alkyl group, or an alkoxy group. Ar ⁴ may have a substituent. Represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent.)

As the alkyl group for R ⁷ to R ¹² , a linear or branched chain alkyl group having 6 or less carbon atoms is usually preferable. For example, a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, n -Butyl group, isobutyl group and the like. More preferred is a methyl group or an ethyl group. When the alkyl group of R ⁷ to R ¹² has 6 or less carbon atoms, the crosslinking reaction is not sterically hindered and the film tends to be insolubilized.

As the alkoxy group of R ¹⁰ to R ¹² , a linear or branched chain alkoxy group having 6 or less carbon atoms is usually preferable. For example, methoxy group, ethoxy group, n-propoxy group, 2-propoxy group, n -Butoxy group and the like. More preferred are a methoxy group and an ethoxy group. If the alkoxy group of R ¹⁰ to R ¹² has 6 or less carbon atoms, the crosslinking reaction is not sterically hindered and the film tends to be insolubilized.

Examples of the aromatic hydrocarbon group which may have a substituent of Ar ⁴ include, for example, a monocyclic 6-membered ring such as a benzene ring and a naphthalene ring having 2 free valences, or 2 to 5 A condensed ring is mentioned. In particular, a benzene ring having one free valence is preferable. Ar ⁴ may be a group in which two or more aromatic hydrocarbon groups which may have these substituents are bonded. Examples of such a group include a biphenylene group and a terphenylene group, and a 4,4′-biphenylene group is preferable.
Of these, a group that undergoes a crosslinking reaction by cationic polymerization, such as a cyclic ether group such as an epoxy group or an oxetane group, or a vinyl ether group, is preferable in terms of high reactivity and ease of insolubilization by crosslinking. Among these, an oxetane group is more preferable in terms of easy control of the rate of cationic polymerization, and a vinyl ether group is preferable in that a hydroxyl group that may cause deterioration of the device during cationic polymerization is difficult to generate.

Further, an arylvinylcarbonyl group such as a cinnamoyl group and a group that undergoes a cycloaddition reaction such as a benzocyclobutene ring having a monovalent free valence are preferable in terms of further improving the electrochemical stability of the device.

Of the crosslinkable groups, a benzocyclobutene ring having a monovalent free valence is particularly preferable in that the structure after crosslinking is particularly stable.

Examples of the aromatic heterocyclic group which may have a substituent for Ar ⁴ include, for example, a thienyl group, a pyridyl group and the like, and the number of carbon atoms is usually 3 or more, preferably 4 or more, and usually 36 or less, preferably An aromatic heterocyclic group having 24 or less is exemplified. In particular, a thienyl group and a pyridyl group are preferable.

[Another repeating unit]
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. Bis (4-alkylphenyl) benzidine structure, and the ratio of N atoms substituted with 3 or more condensed aromatic hydrocarbon groups or aromatic heterocyclic groups can be increased, hole injection and hole transport Is preferable.

(In Formula (2), Ar ¹ each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R ¹ Each independently represents an optionally substituted alkyl group, and L ¹ represents an aromatic hydrocarbon group or an aromatic heterocyclic group.)

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

In L ¹ in the unit represented by the above formula (2), a plurality of aromatic hydrocarbon groups and aromatic heterocyclic groups may be bonded.

When L ¹ is a group in which a plurality of the aromatic hydrocarbon groups and aromatic heterocyclic groups are combined, 2 to 6 of these groups are linked from the viewpoint of excellent charge transportability and durability. It is preferable. The aromatic hydrocarbon group and aromatic heterocyclic group to be linked may be one kind or plural kinds.

Further, when L ¹ is a group in which a plurality of the aromatic hydrocarbon groups and aromatic heterocyclic groups are bonded, they may be bonded through a linking group. In this case, examples of the linking group include a group selected from the group consisting of —CR ¹ R ² —, —O—, —CO—, —NR ³ —, and —S—, and a group obtained by linking them in 2 to 10 groups. preferable. When two or more are connected, the linking group may be one kind or plural kinds. Here, R ¹ to R ³ each independently have a hydrogen atom or an alkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a substituent. Represents an aromatic heterocyclic group which may be substituted. As the linking group, —CR ¹ R ² — and a group in which 2 to 6 —CR ¹ R ² — are connected are more preferable, and —CR ¹ R ² — is particularly preferable.

L ¹ is preferably any of 1,4-phenylene, 4,4′-biphenylene, and 4,4 ″ -p-terphenylene from the viewpoint of excellent hole injection / transport properties.

In particular, it is preferable that L ¹ is 4,4′-biphenylene, that is, a unit represented by the following formula (3) is contained as a repeating unit.

(In Formula (3), Ar ¹ each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R ¹ Each independently represents an optionally substituted alkyl group.)

[Repetition unit ratio]
In the polymer of the present invention, since hole injection and hole transport are enhanced, the units represented by the above formula (1) and the above formula (2) are included with respect to 100 mol% of all monomer units. In total, it is preferably 50 mol% or more, more preferably 80 mol% or more, and 100 mol% (that is, other than the units represented by the formula (1) and the formula (2)). Most preferably).

[Number of crosslinkable groups]
The crosslinkable group possessed by the polymer of the present invention is preferably larger in that it is sufficiently insolubilized by crosslinking, and other layers can be easily formed thereon by a wet film forming method. On the other hand, it is preferable that the number of crosslinkable groups is small from the viewpoint that cracks are not easily generated in the formed layer, unreacted crosslinkable groups hardly remain, and the organic electroluminescent element tends to have a long life.

The crosslinkable group present in one polymer chain in the polymer of the present invention is preferably usually an average of 1 or more, more preferably an average of 2 or more, and usually preferably 200 or less, more preferably 100 or less. is there.

Further, the number of crosslinkable groups possessed by the polymer of the present invention can be expressed by the number per 1000 molecular weight of the polymer.

When the number of crosslinkable groups of the polymer of the present invention is represented by the number per 1000 molecular weight of the polymer, it is usually 3.0 or less, preferably 2.0 or less, more preferably 1 per 1000 molecular weight. 0.0 or less, and usually 0.01 or more, preferably 0.05 or more.
When the number of crosslinkable groups is within the above range, cracks or the like hardly occur and a flat film can be easily obtained. In addition, since the crosslinking density is moderate, there are few unreacted crosslinking groups remaining in the layer after the crosslinking reaction, and it is difficult to affect the life of the resulting device.
Furthermore, since the poor solubility in an organic solvent after the crosslinking reaction is sufficient, a multilayer laminated structure can be easily formed by a wet film forming method.

Here, the number of crosslinkable groups per 1000 molecular weight of the polymer can be calculated from the molar ratio of the charged monomers at the time of synthesis and the structural formula, excluding the terminal group from the polymer.
For example, in the case of the polymer 1 synthesized in Example 1 to be described later, in the polymer 1, the average molecular weight of the repeating unit excluding the terminal group is 1688.46, and the crosslinkable group is 1 repeating unit. The average is 0.676 per hit. When this is calculated by simple proportion, the number of crosslinkable groups per 1000 molecular weight is calculated to be 0.40.

[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, still more preferably 200,000 or less, and usually 2, 500 or more, preferably 5,000 or more, more preferably 20,000 or more, and further preferably 30,000 or more.
If the weight average molecular weight of the polymer exceeds the above upper limit, the solubility in a solvent is lowered, so that the film formability may be impaired. Moreover, since the glass transition temperature, melting | fusing point, and vaporization temperature of a polymer will fall when the weight average molecular weight of a polymer is less than the said lower limit, heat resistance may fall.

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 usually 2,000 or more, preferably It is 4,000 or more, more preferably 8,000 or more, and still more preferably 20,000 or more.

Furthermore, 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 degree of dispersion is preferably as small as possible, the lower limit is ideally 1. When the degree of dispersion of the polymer is not more than the above upper limit, purification is easy, and solubility in a solvent and charge transporting ability are good.

Usually, the weight average molecular weight of a polymer is determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the elution time is shorter for higher molecular weight components and the elution time is longer for lower molecular weight components, but using the calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the elution time of the sample is changed to the molecular weight. The weight average molecular weight is calculated by conversion.

[Concrete example]
Specific examples of the polymer of the present invention are shown below, but the polymer of the present invention is not limited thereto. The numbers in the chemical formula represent the molar ratio of repeating units.
These polymers may be any of random copolymers, alternating copolymers, block copolymers, graft copolymers, and the like, and are not limited to the sequence of monomers.

[Method for producing polymer]
The method for producing the polymer of the present invention is not particularly limited, and is arbitrary as long as the polymer of the present invention is obtained. For example, it can be produced by a polymerization method using a Suzuki reaction, a polymerization method using a Grignard reaction, a polymerization method using a Yamamoto reaction, a polymerization method using an Ullmann reaction, a polymerization method using a Buchwald-Hartwig reaction, or the like.
In the case of the polymerization method by the Ullmann reaction and the polymerization method by the Buchwald-Hartwig reaction, for example, an aryl dihalide represented by the formula (1a), the formula (1b) and the formula (2b) (X is I, Br, Cl, F, etc.) And the primary aminoaryl represented by the formula (1c) is reacted to synthesize the polymer of the present invention.

(In the above formula, X represents a halogen atom, and Ar ¹ , R ¹ , T ¹ and L ¹ are as defined above.)

In the above polymerization method, the reaction for forming an N-aryl bond is usually carried out in the presence of a base such as potassium carbonate, tert-butoxy sodium, triethylamine or the like. Moreover, it can also carry out in presence of transition metal catalysts, such as copper and a palladium complex, for example.

<Organic electroluminescent material>
The polymer of the present invention can be particularly suitably used 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 an organic electroluminescent element material, it is preferably used as a material forming at least one of a hole injection layer and a hole transport layer in the organic electroluminescent element, that is, a charge transporting material.
When used as a charge transporting material, it may contain one type of the polymer of the present invention, or may contain two or more types in any combination and in any ratio.

When forming at least one of the hole injection layer and the hole transport layer of the organic electroluminescence device using the polymer of the present invention, the inclusion of the polymer of the present invention in the hole injection layer and / or the hole transport layer The amount is usually 1 to 100% by mass, preferably 5 to 100% by mass, and more preferably 10 to 100% by mass. The above range is preferable because the charge transport property of the hole injection layer and / or the hole transport layer is improved, the drive voltage is reduced, and the drive stability is improved.

When the polymer of the present invention is not 100% by mass in the hole injection layer and / or hole transport layer, the component constituting the hole injection layer and / or hole transport layer will be described later. Compound.
Moreover, since an organic electroluminescent element can be manufactured simply, it is preferable to use the polymer of this invention for the organic layer formed by a wet film-forming method.

<Composition for organic electroluminescence device>
The composition for organic electroluminescent elements of the present invention contains the polymer of the present invention. In addition, the composition for organic electroluminescent elements of the present invention may contain one type of the polymer of the present invention, or may contain two or more types in any combination and in any ratio. Good.

[Polymer content]
The content of the polymer of the present invention in the composition for organic electroluminescent elements of the present invention is usually 0.01 to 70% by mass, preferably 0.1 to 60% by mass, more preferably 0.5 to 50% by mass. %.
Within the above range, it is preferable because defects are hardly generated in the formed organic layer and unevenness in film thickness is hardly generated.

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

[solvent]
The composition for organic electroluminescent elements of the present invention usually contains a solvent. This solvent is preferably one that dissolves the polymer of the present invention. Specifically, a solvent that dissolves the polymer of the present invention at room temperature is usually 0.05% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more.

Specific examples of the solvent include aromatic solvents such as toluene, xylene, mesitylene and cyclohexylbenzene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene and o-dichlorobenzene; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene Aliphatic ethers such as glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, Ether solvents such as aromatic ethers such as 2,3-dimethylanisole and 2,4-dimethylanisole; aliphatic ester solvents such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; phenyl acetate Organic solvents such as aromatic solvents such as phenyl propionate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and n-butyl benzoate; And organic solvents used for the composition for forming a hole and the composition for forming a hole transport layer.
In addition, 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and arbitrary ratios.
Among them, as a solvent contained in the composition for organic electroluminescent elements of the present invention, a solvent having a surface tension at 20 ° C. of usually less than 40 dyn / cm, preferably 36 dyn / cm or less, more preferably 33 dyn / cm or less. Is preferred.

When a coating film is formed by a wet film-forming method using the composition for organic electroluminescent elements of the present invention, and the polymer of the present invention is crosslinked to form an organic layer, the affinity between the solvent and the base must be high. preferable. This is because the uniformity of film quality greatly affects the uniformity and stability of light emission of the organic electroluminescence device. Therefore, the composition for organic electroluminescent elements used for the wet film-forming method is required to have a low surface tension so that a uniform coating film with higher leveling property can be formed. Therefore, it is preferable to use a solvent having a low surface tension as described above 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 low surface tension solvent include the aforementioned aromatic solvents such as toluene, xylene, mesitylene and cyclohexylbenzene, ester solvents such as ethyl benzoate, ether solvents such as anisole, trifluoromethoxyanisole, penta Examples include fluoromethoxybenzene, 3- (trifluoromethyl) anisole, and ethyl (pentafluorobenzoate).

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

Specific examples of such a solvent include the above-mentioned aromatic solvents such as toluene, xylene and mesitylene, ether solvents and ester solvents.

By the way, moisture may cause deterioration of the performance of the organic electroluminescent device, and in particular, may promote a decrease in luminance during continuous driving. Therefore, in order to reduce the moisture remaining during wet film formation as much as possible, among the above-mentioned solvents, those having a water solubility of 1% by mass or less at 25 ° C. are preferred, and a solvent having a content of 0.1% by mass or less Is more preferable.

The content of the solvent contained in the composition for organic electroluminescent elements 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. . When the content of the solvent is not less than the above lower limit, the flatness and uniformity of the formed layer can be improved.

[Electron-accepting compound]
When the composition for organic electroluminescent elements of the present invention is used for forming a hole injection layer, it is preferable to further contain an electron-accepting compound from the viewpoint of reducing resistance.

As the electron-accepting compound, a compound having an oxidizing power and an ability to accept one electron from the polymer of the present invention is preferable. Specifically, a compound with an electron affinity of 4 eV or more is preferable, and a compound with a compound of 5 eV or more is more preferable.
Examples of such electron-accepting compounds include triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. 1 type, or 2 or more types of compounds chosen from the group which consists of are mentioned.

Specifically, an onium salt substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate (WO 2005/089024); High valence inorganic compounds such as iron (III) (Japanese Patent Laid-Open No. 11-251067) and ammonium peroxodisulfate; Cyano compounds such as tetracyanoethylene; Tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-2003) Aromatic boron compounds such as 31365); fullerene derivatives and iodine.

As such a compound, an element belonging to Groups 15 to 17 of a long-period periodic table (hereinafter, unless otherwise specified, the term “periodic table” refers to a long-period periodic table) In addition, an ionic compound having a structure in which at least one organic group is bonded by a carbon atom is preferable, and a compound represented by the following formula (4) is particularly preferable.

(In the formula (4), ^{R 9} is represents an organic group bound to _{A 1} and carbon ^{atom, R 10} is .R ⁹ and ^{R 10} represent any substituent may combine to form a ring May be.)

The type of R ⁹ is not particularly limited as long as it is an organic group having a carbon atom at the bonding portion with A ₁ as long as it is not contrary to the gist of the present invention. The molecular weight of R ⁹ is a value including a substituent and is usually 1000 or less, preferably 500 or less.
Preferable examples of R ⁹ include, for example, an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, and an aromatic heterocyclic group from the viewpoint of delocalizing a positive charge. Among them, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferable because it delocalizes positive charges and is thermally stable.

Examples of the alkyl group include linear, branched, or cyclic alkyl groups having a carbon number of usually 1 or more and usually 12 or less, preferably 6 or less. Specific examples include methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group and the like.
Examples of the alkenyl group include those having usually 2 or more, usually 12 or less, preferably 6 or less. Specific examples include vinyl group, allyl group, 1-butenyl group and the like.
Examples of the alkynyl group include those having usually 2 or more, usually 12 or less, preferably 6 or less. Specific examples include ethynyl group and propargyl group.

The aromatic hydrocarbon group is a 5-membered or 6-membered monocyclic ring or a 2-5 condensed ring having one free valence, and a positive charge is more delocalized on the group. Is mentioned. Specific examples thereof include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring and fluorene ring having one free valence. Etc.

The aromatic heterocyclic group is a 5-membered or 6-membered monocyclic ring having 2 free valences or a 2-4 condensed ring, and a positive charge is delocalized on the group. Is mentioned. 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, and a carbazole ring having one free valence. , Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine Ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

R ¹⁰ is not particularly limited as long as it is not contrary to the gist of the present invention. The molecular weight of R ¹⁰ is a value including a substituent and is usually 1000 or less, preferably 500 or less.
Examples of R ¹⁰ include, for example, alkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, aromatic heterocyclic group, amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl Group, alkylcarbonyloxy group, alkylthio group, arylthio group, sulfonyl group, alkylsulfonyl group, arylsulfonyl group, sulfonyloxy group, cyano group, hydroxyl group, thiol group, silyl group and the like.

Among them, like R ⁹ , an organic group having a carbon atom at the bonding portion to A ₁ is preferable because of its high electron accepting property. Examples include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, Aromatic heterocyclic groups are preferred. In particular, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferable because it has a large electron accepting property and is thermally stable.
Alkyl group, an alkenyl group of R ^10, alkynyl group, aromatic hydrocarbon group, the aromatic heterocyclic group include the same as described above for R ^9.

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

Examples of the arylamino group include arylamino groups having at least one aromatic hydrocarbon group or aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. It is done. Specific examples include phenylamino group, diphenylamino group, tolylamino group, pyridylamino group, thienylamino group and the like.
The acylamino group includes an acylamino group having one or more acyl groups having usually 2 or more carbon atoms and usually 25 or less, preferably 15 or less carbon atoms. Specific examples include an acetylamino group and a benzoylamino group.

The alkoxy group includes an alkoxy group having usually 1 or more carbon atoms and usually 12 or less, preferably 6 or less. Specific examples include a methoxy group, an ethoxy group, and a butoxy group.
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. Specific examples include phenyloxy group, naphthyloxy group, pyridyloxy group, thienyloxy group and the like.

Examples of the acyl group include acyl groups having usually 1 or more carbon atoms and usually 25 or less, preferably 15 or less. Specific examples include formyl group, acetyl group, benzoyl group and the like.
The alkoxycarbonyl group includes an alkoxycarbonyl group having usually 2 or more carbon atoms and usually 10 or less, preferably 7 or less. Specific examples include a methoxycarbonyl group and an ethoxycarbonyl group.

Examples of the aryloxycarbonyl group include those 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. Specific examples include a phenoxycarbonyl group and a pyridyloxycarbonyl group.
Examples of the alkylcarbonyloxy group include alkylcarbonyloxy groups having usually 2 or more carbon atoms and usually 10 or less, preferably 7 or less. Specific examples include an acetoxy group and a trifluoroacetoxy group.

The alkylthio group includes an alkylthio group having usually 1 or more carbon atoms and usually 12 or less, preferably 6 or less. Specific examples include a methylthio group and an ethylthio group.
The arylthio group includes an arylthio group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 14 or less. Specific examples include a phenylthio group, a naphthylthio group, and a pyridylthio group.

Specific examples of the alkylsulfonyl group and the arylsulfonyl group include a mesyl group and a tosyl group.
Specific examples of the sulfonyloxy group include a mesyloxy group and a tosyloxy group.
Specific examples of the silyl group include a trimethylsilyl group and a triphenylsilyl group.

As described above, the groups exemplified as R ⁹ and R ¹⁰ in the formula (4) may be further substituted with other substituents as long as not departing from the gist of the present invention. The type of the substituent is not particularly limited, and examples thereof include a halogen atom, a cyano group, a thiocyano group, and a nitro group in addition to the groups exemplified as R ⁹ and R ¹⁰ . Among these, from the viewpoint of not hindering the heat resistance and electron acceptability of the ionic compound (electron accepting compound), an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an aromatic hydrocarbon group, an aromatic heterocyclic ring. Groups are preferred.

In the formula (4), A ₁ is preferably an element belonging to Group 17 of the periodic table, and from the viewpoint of electron acceptability and availability, it is before the fifth period (third to fifth periods) of the periodic table. Element) is preferred. That is, as A1, any _one of an iodine atom, a bromine atom, and a chlorine atom is preferable.
In particular, from the viewpoint of electron acceptability and compound stability, an ionic compound in which A ₁ in Formula (4) is a bromine atom or an iodine atom is preferable, and an ionic compound in which an iodine atom is used is most preferable.

In formula (4), Z ₁ ^n1- represents a counter anion. The type of the counter anion is not particularly limited, and may be a monoatomic ion or a complex ion. However, the larger the size of the counter anion, the more the negative charge is delocalized, and the positive charge is also delocalized thereby increasing the electron accepting ability. Therefore, the complex ion is preferable to the monoatomic ion.
n ₁ is an arbitrary positive integer corresponding to the ionic value of the counter anion Z ₁ ⁿ¹⁻ . The value of n ₁ is not particularly limited, but is preferably 1 or 2, and most preferably 1.

Specific examples of Z ₁ ^n1- include hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, cyanide ion, nitrate ion, nitrite ion, sulfate ion, sulfite ion, perchloric acid. Ion, perbromate ion, periodate ion, chlorate ion, chlorite ion, hypochlorite ion, phosphate ion, phosphite ion, hypophosphite ion, borate ion, isocyanate ion, Hydrogen sulfide ion, tetrafluoroborate ion, hexafluorophosphate ion, hexachloroantimonate ion; carboxylate ion such as acetate ion, trifluoroacetate ion, benzoate ion; sulfone such as methanesulfonic acid, trifluoromethanesulfonate ion Acid ions; alkoxy ions such as methoxy ion and t-butoxy ion It is. Of these, tetrafluoroborate ions and hexafluoroborate ions are preferable.

Further, as the counter anion Z ₁ ^n1- , the negative charge is delocalized in view of the stability of the compound, the solubility in the solvent, and the large size, and the positive charge is also delocalized accordingly. A complex ion represented by the following formula (5) is particularly preferable because the electron accepting ability is increased.

(In Formula (5), each E ₃ independently represents an element belonging to Group 13 of the long-period periodic table, and Ar ⁵ to Ar ⁸ each independently represents an aromatic hydrocarbon group or an aromatic complex. Represents a cyclic group.)
E ₃ is preferably a boron atom, an aluminum atom, or a gallium atom, and more preferably a boron atom from the viewpoint of stability of the compound, ease of synthesis and purification.
Examples of the aromatic hydrocarbon group and the aromatic heterocyclic group represented by Ar ⁵ to Ar ⁸ include a 5-membered member having one free valence similar to those exemplified above for R ^{9 in} the formula (4). Examples thereof include a ring, a 6-membered monocyclic ring, or a 2-4 condensed ring. Among them, a benzene ring, naphthalene ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring and isoquinoline ring having one free valence are preferable from the viewpoint of stability and heat resistance of the compound. .

The aromatic hydrocarbon group and aromatic heterocyclic group exemplified as Ar ⁵ to Ar ⁸ may be further substituted with another substituent as long as not departing from the gist of the present invention. The type of the substituent is not particularly limited, and any substituent can be applied, but an electron-withdrawing group is preferable.
Examples of preferable electron-withdrawing groups as the substituent that Ar ⁵ to Ar ⁸ may have include halogen atoms such as fluorine atom, chlorine atom and bromine atom; cyano group; thiocyano group; nitro group; mesyl group Alkylsulfonyl groups such as tosyl group; arylsulfonyl groups such as tosyl group; acyl groups such as formyl group, acetyl group, benzoyl group and the like, usually having 1 or more, usually 12 or less, preferably 6 or less; methoxycarbonyl group, ethoxycarbonyl An alkoxycarbonyl group having 2 or more carbon atoms, usually 10 or less, preferably 7 or less; a phenoxycarbonyl group, a pyridyloxycarbonyl group or the like, and usually having 3 or more carbon atoms, preferably 4 or more and usually 25 or less. An aryloxycarbonyl group having an aromatic hydrocarbon group or an aromatic heterocyclic group of preferably 15 or less; Bonyl group; aminosulfonyl group; trifluoromethyl group, pentafluoroethyl group, etc., a fluorine atom in a linear, branched or cyclic alkyl group having usually 1 or more, usually 10 or less, preferably 6 or less carbon atoms And a haloalkyl group substituted with a halogen atom such as a chlorine atom.

In particular, it is more preferable that at least one group out of Ar ⁵ to Ar ⁸ has one or more fluorine atoms or chlorine atoms as substituents. In particular, it is most preferably a perfluoroaryl group in which all of the hydrogen atoms of Ar ⁵ to Ar ⁸ are substituted with fluorine atoms from the viewpoint of efficiently delocalizing negative charges and having an appropriate sublimation property. preferable. Specific examples of the perfluoroaryl group include a pentafluorophenyl group, a heptafluoro-2-naphthyl group, and a tetrafluoro-4-pyridyl group.

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 delocalized, the electron accepting ability is good, and it is preferable that the charge transport is not hindered.

Specific examples of the electron-accepting compound described in the following formula (4) suitable for the present invention are shown in the following Table 1, but the present invention is not limited thereto.

The composition for organic electroluminescent elements of the present invention may contain one of the electron accepting compounds as described above alone, or may contain two or more kinds in any combination and ratio.
When the composition for organic electroluminescent elements of the present invention contains an electron accepting compound, the content of the electron accepting compound in the composition for organic electroluminescent elements of the present invention is usually 0.0005% by mass or more, preferably 0. 0.001% by mass or more, usually 20% by mass or less, preferably 10% by mass or less. The ratio of the electron-accepting compound to the polymer of the present invention in the composition for organic electroluminescent elements is usually 0.5% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, Usually, it is 80 mass% or less, Preferably it is 60 mass% or less, More preferably, it is 40 mass% or less.

The content of the electron-accepting compound in the composition for organic electroluminescent elements is preferably not less than the above lower limit because the electron acceptor accepts electrons from the polymer and the formed organic layer is reduced in resistance. It is preferable that the organic layer formed is less likely to have defects and is less likely to cause film thickness unevenness.

[Cation radical compound]
The composition for organic electroluminescent elements of the present invention may further contain a cation radical compound.

As the cation radical compound, an ionic compound composed of a cation radical which is a chemical species obtained by removing one electron from a hole transporting compound and a counter anion is preferable. However, when the cation radical is derived from a hole transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.
Further, the cation radical is preferably a chemical species obtained by removing one electron from a hole transporting compound described later. A chemical species obtained by removing one electron from a compound preferable as a hole transporting compound is preferable in terms of amorphousness, visible light transmittance, heat resistance, solubility, and the like.

Here, the cation radical compound can be generated by mixing a hole transporting compound described later and the above-described electron accepting compound. That is, by mixing the hole-transporting compound and the electron-accepting compound, electron transfer occurs from the hole-transporting compound to the electron-accepting compound, and consists of a cation radical and a counter anion of the hole-transporting compound. A cation ion compound is formed.

When the composition for organic electroluminescent elements of the present invention contains a cation radical compound, the content of the cation radical compound in the composition for organic electroluminescent elements of the present invention is usually 0.0005% by mass or more, preferably 0.001. It is 40 mass% or less normally, Preferably it is 20 mass% or less. When the content of the cation radical compound is not less than the lower limit, the formed organic layer is preferably reduced in resistance, and when it is not more than the upper limit, the formed organic layer is less likely to have defects and is not likely to cause film thickness unevenness.

In addition to the above-mentioned components, the composition for organic electroluminescence device of the present invention contains the components contained in the composition for forming a hole injection layer and the composition for forming a hole transport layer, which will be described later. It may contain.

<Organic electroluminescent device>
The organic electroluminescent device of the present invention is an organic electroluminescent device having an anode and a cathode and an organic layer between the anode and the cathode on a substrate, wherein the organic layer contains the polymer of the present invention. And a layer formed by a wet film formation method using the composition for organic electroluminescence elements.

In the organic electroluminescence device of the present invention, the layer formed by the wet film formation method is preferably at least one of a hole injection layer and a hole transport layer. A hole transport layer and a light-emitting layer are provided, and all of the hole injection layer, the hole transport layer and the light-emitting layer are preferably formed by a wet film formation method.
In the present invention, the wet film forming method is a film forming method, that is, a coating method, for example, spin coating method, dip coating method, die coating method, bar coating method, blade coating method, roll coating method, spray coating method, capillary A method of forming a film by employing a wet film formation method such as a coating method, an ink jet method, a nozzle printing method, a screen printing method, a gravure printing method, or a flexographic printing method, and drying the coated film. Among these film forming methods, spin coating, spray coating, ink jet, nozzle printing, and the like are preferable.

As an example of the structure of the organic electroluminescent element of the present invention, FIG. 1 shows a schematic diagram (cross section) of a structural example of the organic electroluminescent element 10. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, 6 is a hole blocking layer, 7 is an electron transport layer, 8 is an electron injection layer, 9 represents each cathode.
Hereinafter, an example of an embodiment of the layer configuration of the organic electroluminescent element of the present invention and a general formation method thereof will be described with reference to FIG.

[substrate]
The substrate 1 serves as a support for the organic electroluminescent element, and a quartz or glass plate, a metal plate or a metal foil, a plastic film or a sheet is usually used. Of these, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferable. The substrate is preferably made of a material having a high gas barrier property since the organic electroluminescence device is hardly deteriorated by the outside air. For this reason, in particular, when a material having a low gas barrier property 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 property.

[anode]
The anode 2 has a function of injecting holes into the layer on the light emitting layer 5 side.
The anode 2 is usually made of a metal such as aluminum, gold, silver, nickel, palladium, or platinum; a metal oxide such as an oxide of indium and / or tin; a metal halide such as copper iodide; a carbon black and a poly (3 -Methylthiophene), conductive polymers such as polypyrrole and polyaniline, and the like.

The anode 2 is usually formed by a dry method such as a sputtering method or a vacuum evaporation method. In addition, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution is used. It can also be formed by dispersing and coating on a substrate. In the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or an anode can be formed by applying a conductive polymer on a substrate (Appl. Phys. Lett., 60). Volume, 2711, 1992).

The anode 2 usually has a single layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the first anode.
The thickness of the anode 2 may be determined according to required transparency and material. In particular, when high transparency is required, a thickness at which visible light transmittance is 60% or more is preferable, and a thickness at which 80% or more is more preferable. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably 500 nm or less. On the other hand, when transparency is unnecessary, the thickness of the anode 2 may be arbitrarily set according to the required strength, and in this case, the anode 2 may have the same thickness as the substrate.

In the case where another layer is formed on the surface of the anode 2, impurities on the anode 2 are removed by performing treatments such as ultraviolet / ozone, oxygen plasma, and argon plasma before the film formation, and the ionization potential thereof. It is preferable to improve the hole injection property by adjusting.

[Hole injection layer]
The layer responsible for transporting holes from the anode 2 side to the light emitting layer 5 side is usually called a hole injection transport layer or a hole transport layer. When there are two or more layers responsible for transporting holes from the anode 2 side to the light emitting layer 5 side, the layer closer to the anode side may be referred to as the hole injection layer 3. The hole injection layer 3 is preferably formed from the viewpoint of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5 side. When forming the hole injection layer 3, the hole injection layer 3 is usually formed on the anode 2.

The thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.
The formation method of the hole injection layer may be a vacuum deposition method or a wet film formation method. In terms of excellent film forming properties, it is preferable to form the film by a wet film forming method.
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 cation radical compound, and particularly preferably contains a cation radical compound and a hole transporting compound.

Hereinafter, a general method for forming a hole injection layer will be described. In the organic electroluminescence device of the present invention, the hole injection layer is formed by a wet film formation method using the composition for an organic electroluminescence device of the present invention. It is preferably formed by.

[Hole transporting compound]
The composition for forming a hole injection layer usually contains a hole transporting compound that becomes the hole injection layer 3. Moreover, in the case of the wet film-forming method, a solvent is usually further contained. It is preferable that the composition for forming a hole injection layer has high hole transportability and can efficiently transport injected holes. For this reason, it is preferable that the hole mobility is high and impurities that become traps are less likely to be generated during production or use. Moreover, it is preferable that it is excellent in stability, has a small ionization potential, and has high transparency to visible light. In particular, when the hole injection layer is in contact with the light emitting layer, those that do not quench the light emitted from the light emitting layer or those that form an exciplex with the light emitting layer and do not decrease the light emission efficiency are preferable.

The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier from the anode to the hole injection layer. Examples of hole transporting compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which tertiary amines are linked by a fluorene group, hydrazones Compounds, silazane compounds, quinacridone compounds, and the like.

Of the above-described exemplary compounds, an aromatic amine compound is preferable and an aromatic tertiary amine compound is particularly preferable from the viewpoint of amorphousness and visible light transmittance. Here, the aromatic tertiary amine compound is 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, but is a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (a polymerizable compound in which repeating units are linked) from the viewpoint of easily obtaining uniform light emission due to the surface smoothing effect. ) Is preferably used. 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, represented by the following formula (6). And a polymer compound containing a repeating unit as a repeating unit.

(In Formula (6), Ar ¹¹ and Ar ¹² each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Ar ¹³ to Ar ¹⁵ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. And represents a linking group selected from the group of linking groups shown, and two groups out of Ar ¹¹ to Ar ¹⁵ that are bonded to the same N atom may be bonded to each other to form a ring.

(In the above formula, Ar ¹⁶ to Ar ²⁶ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. ¹¹ and R ¹² each independently represents a hydrogen atom or an arbitrary substituent.)
The aromatic hydrocarbon group and aromatic heterocyclic group of Ar ¹⁶ to Ar ²⁶ have one or two free valences from the viewpoint of the solubility, heat resistance, and hole injection / transport properties of the polymer compound. , A benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, and a pyridine ring are preferable, and a benzene ring and a naphthalene ring having one or two free valences are more preferable.

Specific examples of the aromatic tertiary amine polymer compound containing the unit represented by the formula (6) as a repeating unit include those described in International Publication No. 2005/089024.
The hole injection layer 3 contains the above-described electron-accepting compound or the above-described cation radical compound because the conductivity of the hole-injection layer can be improved by oxidation of the hole-transporting compound. It is preferable.

Cation radical compounds derived from polymer compounds such as PEDOT / PSS (Adv. Mater., 2000, 12, 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, 94, 7716) It is also produced by oxidative polymerization (dehydrogenation polymerization).
Oxidative polymerization here refers to oxidation of a monomer chemically or electrochemically with peroxodisulfate in an acidic solution. In the case of this oxidative polymerization (dehydrogenation polymerization), the monomer is polymerized by oxidation, and a cation radical that is removed from the polymer repeating unit by using an anion derived from an acidic solution as a counter anion is removed. Generate.

[Formation of hole injection layer by wet film formation method]
When the hole injection layer 3 is formed by a wet film formation method, a material for forming the hole injection layer is usually mixed with a soluble solvent (a solvent for the hole injection layer) to form a film-forming composition (hole An injection layer forming composition), and applying the hole injection layer forming composition onto a layer (usually an anode) corresponding to the lower layer of the hole injection layer, forming a film, and then drying. Form.

The concentration of the hole transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effects of the present invention are not significantly impaired, but in terms of film thickness uniformity, the lower one is preferable. From the viewpoint that defects are less likely to occur in the hole injection layer, a higher value is preferable. Specifically, it is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and on the other hand, 70% by mass. The content is preferably less than 60% by mass, 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, amide solvents, and the like.
Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and anisole. , Aromatic ethers such as phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole and 2,4-dimethylanisole.

Examples of the ester 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, methylnaphthalene and the like. It is done.

Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide and the like.
In addition to these, dimethyl sulfoxide and the like can also be used.
Formation of the hole injection layer 3 by a wet film formation method is usually performed after preparing a composition for forming a hole injection layer, and then forming the composition on a layer (usually the anode 2) corresponding to the lower layer of the hole injection layer 3 The film is formed by coating and drying.
In general, the hole injection layer 3 is dried by heating or drying under reduced pressure after film formation.

[Formation of hole injection layer by vacuum evaporation]
When the hole injection layer 3 is formed by vacuum vapor deposition, one or more of the constituent materials of the hole injection layer 3 (the above-described hole transporting compound, electron accepting compound, etc.) are usually vacuumed. Put in a crucible installed in the container (if two or more kinds of materials are used, usually put each in separate crucibles), evacuate the vacuum container to about 10 ^-4 Pa with a vacuum pump, then heat the crucible (When using two or more types of materials, each crucible is usually heated) and evaporated while controlling the amount of evaporation of the material in the crucible (when using two or more types of materials, each is usually independent. The hole injection layer is formed on the anode on the substrate placed facing the crucible. When two or more kinds of materials are used, the hole injection layer can be formed by putting the mixture in a crucible and heating and evaporating the mixture.

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 ⁻⁶ Torr (0.13 × 10 ⁻⁴ Pa) or more and 9.0 × 10 ⁻⁶ Torr ( 12.0 × 10 ⁻⁴ Pa) or less. The deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 to 5.0 liters / second or more. The film forming temperature at the time of vapor deposition is not limited as long as the effects of the present invention are not significantly impaired, but it is preferably performed at 10 ° C. or higher and 50 ° C. or lower.
The hole injection layer 3 may be cross-linked similarly to the hole transport layer 4 described later.

[Hole transport layer]
The hole transport layer 4 is a layer having a function of transporting holes from the anode 2 side to the light emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescence device of the present invention, but it is preferable to form this layer in terms of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5. . When forming the hole transport layer 4, the hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. Further, when there is the hole injection layer 3 described above, it 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 5 nm or more, preferably 10 nm or more, and is usually 300 nm or less, preferably 100 nm or less.
The formation method of the hole transport layer 4 may be a vacuum deposition method or a wet film formation method. In terms of excellent film forming properties, it is preferable to form the film by a wet film forming method.
Hereinafter, a general method for forming a hole transport layer will be described.

The hole transport layer 4 usually contains a hole transport compound. Examples of the hole transporting compound contained in the hole transporting layer 4 include the compounds described above, and more specifically, in addition to the polymer of the present invention, 4,4′-bis [N— (1 -Naphthyl) -N-phenylamino] biphenyl, an aromatic diamine containing two or more tertiary amines and having two or more condensed aromatic rings substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234811) Gazette), aromatic amine compounds having a starburst structure such as 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine (J. Lumin., 72-74, 985, 1997). ), An aromatic amine compound consisting of a tetramer of triphenylamine (Chem. Commun., 2175, 1996), 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9 ′ Spiro compounds of spirobifluorene, etc. (Synth.Metals, 91 vol, 209 pp., 1997), 4,4'-N, such as a carbazole derivative such as N'- dicarbazole biphenyl as preferred. Also, for example, polyvinyl carbazole, polyvinyl triphenylamine (Japanese Unexamined Patent Publication No. 7-53953), polyarylene ether sulfone containing tetraphenylbenzidine (Polym. Adv. Tech., 7, 33, 1996). Etc. can also be preferably used.

[Formation of hole transport layer by wet film formation method]
When forming a hole transport layer by a wet film formation method, in general, in the same manner as in the case of forming the above-described hole injection layer by a wet film formation method, holes are used instead of the hole injection layer forming composition. It forms using the composition for transport layer formation.
When the hole transport layer is formed by a wet film formation method, the hole transport layer forming composition usually further contains a solvent. The solvent used for the composition for forming a hole transport layer can be the same solvent as the solvent used for the composition for forming a hole injection layer described above.

The concentration of the hole transporting compound in the composition for forming a hole transport layer can be in the same range as the concentration of the hole transporting compound in the composition for forming a hole injection layer.
Formation of the hole transport layer by a wet film formation method can be performed in the same manner as the hole injection layer film formation method described above.

[Formation of hole transport layer by vacuum evaporation]
When the hole transport layer is formed by the vacuum deposition method, the hole transport layer is usually used instead of the hole injection layer forming composition in the same manner as in the case of forming the hole injection layer by the vacuum deposition method. It can form using the composition for layer formation. The film formation conditions such as the degree of vacuum at the time of vapor deposition, the vapor deposition rate, and the temperature can be formed under the same conditions as those for the vacuum vapor deposition of the hole injection layer.

[Light emitting layer]
The light emitting layer 5 is a layer having a function of emitting light when excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between a pair of electrodes. . The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9, and the light-emitting layer is formed between the hole injection layer and the cathode when there is a hole injection layer on the anode. When there is a hole transport layer on the surface, it is formed between the hole transport layer and the cathode.

The film thickness of the light emitting layer 5 is arbitrary as long as the effects of the present invention are not significantly impaired. However, a thicker film is preferable in that the film is less likely to be defective. On the other hand, a thinner film is preferable in terms of easy driving voltage. . For this reason, it is preferably 3 nm or more, more preferably 5 nm or more, and on the other hand, it is usually preferably 200 nm or less, and more preferably 100 nm 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).

[Light emitting material]
The light emitting material emits light at a desired light 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, but a material having good light emission efficiency is preferred, and a phosphorescent light emitting material is preferred 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 gives blue light emission (blue fluorescent light emitting material) include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene, and derivatives thereof.
Examples of the fluorescent light-emitting material that gives green light emission (green fluorescent light-emitting material) include quinacridone derivatives, coumarin derivatives, aluminum complexes such as Al (C ₉ H ₆ NO) _{3, and the} like.

Examples of the fluorescent light-emitting material that gives yellow light (yellow fluorescent light-emitting material) include rubrene and perimidone derivatives.
Examples of fluorescent light-emitting materials (red fluorescent light-emitting materials) that emit red light include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) -based compounds, benzopyran derivatives, rhodamine derivatives. Benzothioxanthene derivatives, azabenzothioxanthene and the like.

Examples of the phosphorescent material include organometallic complexes 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, and gold.
As the ligand of the organometallic complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. In particular, a phenylpyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

Specific preferred phosphorescent materials include, for example, tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, tris And phenylpyridine complexes such as (2-phenylpyridine) osmium and tris (2-phenylpyridine) rhenium, and porphyrin complexes such as octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethylpalladium porphyrin, and octaphenylpalladium porphyrin.

Polymeric light-emitting materials include 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 the like, and polyphenylene vinylene materials such as poly [2-methoxy-5- (2-hexylhexyloxy) -1,4-phenylenevinylene].

[Charge transport materials]
The charge transport 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 or the like conventionally used in a light emitting layer of an organic electroluminescence device can be used, and a compound used as a host material of the light emitting layer is particularly preferable.

Specific examples of the charge transporting material include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and fluorene groups including the polymer of the present invention. In addition to the compounds exemplified as the hole transporting compound of the hole injection layer, such as a compound in which a tertiary amine is linked, a hydrazone compound, a silazane compound, a silanamine compound, a phosphamine compound, a quinacridone compound, and the like And electron transporting compounds such as benzene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, silole compounds, and the like.

Further, for example, two or more condensed aromatic rings including two or more tertiary amines typified by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are bonded to the nitrogen atom. Aromatic amine compounds having a starburst structure such as substituted aromatic diamines (Japanese Patent Laid-Open No. 5-234811), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine ( J. Lumin., 72-74, 985, 1997), an aromatic amine compound comprising a tetramer of triphenylamine (Chem. Commun., 2175, 1996), 2, 2 ′, 7 , 7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene and the like (Synth. Metals, 91, 209, 1997) , 4,4'-N, N'- compounds exemplified as hole-transporting compound of the positive hole transport layer of the carbazole-based compounds such as di-biphenyl, or the like can be preferably used.

In addition, 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl)- Oxadiazole compounds such as 1,3,4-oxadiazole (BND), 2,5-bis (6 ′-(2 ′, 2 ″ -bipyridyl))-1,1-dimethyl-3,4 Examples thereof include silole compounds such as diphenylsilole (PyPySPyPy) and phenanthroline compounds such as bathophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproin).

[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, but a wet film formation method is preferable and a spin coating method and an ink jet method are more preferable because of excellent film forming properties. In particular, when a hole injection layer or a hole transport layer, which is a lower layer of a light emitting layer, is formed using the composition for an organic electroluminescent element of the present invention, it is easy to form a layer by a wet film formation method. It is preferable to employ a membrane method. When the light emitting layer is formed by a wet film forming method, the light emitting layer is usually used instead of the hole injection layer forming composition in the same manner as in the case of forming the hole injection layer by the wet film forming method. The light-emitting layer forming composition prepared by mixing the material to be mixed with a soluble solvent (light-emitting layer solvent) is used.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, alkane solvents, halogenated aromatic hydrocarbon solvents, fats, and the like mentioned for the formation of the hole injection layer. An aromatic alcohol solvent, an alicyclic alcohol solvent, an aliphatic ketone solvent, an alicyclic ketone solvent, and the like. Although the specific example of a solvent is given to the following, as long as the effect of this invention is not impaired, it is not limited to these.

For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2 -Aromatic ether solvents such as methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, diphenyl ether; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic ester solvents such as ethyl, propyl benzoate, and n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-iropropylbiphenyl, 1,2,3,4 Aromatic hydrocarbon solvents such as tramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene and methylnaphthalene; amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide; n-decane, cyclohexane, Alkane solvents such as ethylcyclohexane, decalin and bicyclohexane; Halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene; Aliphatic alcohol solvents such as butanol and hexanol; Fats such as cyclohexanol and cyclooctanol Examples include cyclic alcohol solvents; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and Fencon. Of these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

[Hole blocking layer]
A 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 laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.
The hole blocking layer 6 has a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Have The 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 excited triplet level (T1). Is high.

Examples of the hole blocking layer material satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed ligand complexes of, such as metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyryl biphenyl derivatives, etc. Triazole derivatives such as styryl compounds (Japanese Patent Laid-Open No. 11-242996), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole ( Japanese Patent Laid-Open No. 7-41759), phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-7929) JP), and the like. Furthermore, a compound having at least one pyridine ring substituted at the 2,4,6-position described in International Publication No. 2005/022962 is also preferable as a material for the hole blocking layer.

There is no restriction | limiting in the formation method of the hole-blocking layer 6. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
The 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 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less. is there.

[Electron transport layer]
The 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 device.
The electron transport layer 7 is formed of a compound that can efficiently transport electrons injected from the cathode 9 between electrodes to which an electric field is applied in the direction of the light emitting layer 5. As an electron transporting compound used for the electron transport layer 7, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and it has high electron mobility and can efficiently transport the injected electrons. It must be a compound that can be made.

Specific examples of the electron transporting compound used in the electron transporting layer include, for example, metal complexes such as 8-hydroxyquinoline aluminum complex (Japanese Patent Laid-Open No. 59-194393), 10-hydroxybenzo [h]. Metal complexes of quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Patent No. No. 5645948), quinoxaline compounds (Japanese Unexamined Patent Publication No. 6-207169), phenanthroline derivatives (Japanese Unexamined Patent Publication No. 5-331459), 2-t-butyl-9,10-N, N′-dicyano. Anthraquinone diimine, n-type hydrogenated amorphous Silicon carbide, n-type zinc sulfide, n-type zinc selenide and the like.

The thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and is usually 300 nm or less, preferably 100 nm or less.
The electron transport layer 7 is formed by laminating on the hole blocking layer 6 by a wet film formation method or a vacuum deposition method in the same manner as described above. Usually, a vacuum deposition method is used.

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

In order to perform electron injection efficiently, the material for forming the electron injection layer 8 is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. The film thickness is usually preferably from 0.1 nm to 5 nm.
Furthermore, an organic electron transport material represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, rubidium ( (Described in Japanese Patent Laid-Open No. 10-270171, Japanese Patent Laid-Open No. 2002-1000047, Japanese Patent Laid-Open No. 2002-1000048, etc.), which improves electron injection / transport properties and achieves excellent film quality. It is preferable because it becomes possible.

The film thickness of the electron injection layer 8 is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.
The electron injection layer 8 is formed by laminating the light emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 thereon by a wet film formation method or a vacuum deposition method.
The details in the case of the wet film forming method are the same as those in the case of the light emitting layer described above.

[cathode]
The cathode 9 plays a role of injecting electrons into a layer (such as an electron injection layer or a light emitting layer) on the light emitting layer 5 side.
As the material of the cathode 9, the material used for the anode 2 can be used. However, in order to perform electron injection efficiently, it is preferable to use a metal having a low work function. , Metals such as indium, calcium, aluminum and silver, or alloys thereof. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

From the viewpoint of device stability, it is preferable to protect a cathode made of a metal having a low work function by laminating 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 thickness of the cathode is usually 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 other layer described above may be provided between the anode and the cathode.

[Other element configurations]
The organic electroluminescent device of the present invention has a structure opposite to that described above, that is, a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, a hole transport layer, and a hole injection layer on the substrate. It is also possible to laminate in the order of the anode.
When the organic electroluminescent element of the present invention is applied to an organic electroluminescent device, it may be used as a single organic electroluminescent element, or may be used in a configuration in which a plurality of organic electroluminescent elements are arranged in an array, The anode and the cathode may be used in a configuration in which they are arranged in an XY matrix.

<Organic EL display device>
The organic EL display device (organic electroluminescent element display device) of the present invention uses the above-described organic electroluminescent element of the present invention. There is no restriction | limiting in particular about the model and structure of the organic electroluminescent display apparatus of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element of this invention.
For example, the organic EL display device of the present invention can be obtained by the method described in “Organic EL display” (Ohm, published on Aug. 20, 2004, Shizushi Tokito, Chiba Adachi, Hideyuki Murata). Can be formed.

<Organic EL lighting>
The organic EL illumination (organic electroluminescence element illumination) of the present invention uses the above-described organic electroluminescence element of the present invention. There is no restriction | limiting in particular about the model and structure of the organic EL illumination of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element of this invention.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and the present invention can be arbitrarily modified and implemented without departing from the gist thereof.

<Example 1>
[Synthesis of Monomer (Compound 3)]
Compound 1 was synthesized as follows.
Monomer synthesis

4-sec-Butylaniline (37.36 g, 250.34 mmol), bromobenzene (38.52 g, 245.33 mmol), sodium tert-butoxy (57.77 g, 601.05 mmol), and toluene (500 ml) were charged into a flask. The system was sufficiently purged with nitrogen and heated to 60 ° C. (solution A). To a 25 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.52 g, 0.491 mmol) charged in another flask, 1,1′-bis (diphenylphosphino) ferrocene (1.09 g, 1. 96 mmol) was added and warmed to 60 ° C. (solution B). Solution B was added to solution A in a nitrogen stream and stirred at 100 ° C. for 4.0 hours. After allowing to cool to room temperature, ethyl acetate (300 ml) and brine (100 ml) were added to the reaction mixture, and the mixture was stirred and separated. The aqueous layer was extracted with ethyl acetate (100 ml x 2), and the organic layers were combined. , Dried over magnesium sulfate and concentrated. Further, purification by silica gel column chromatography (n-hexane / methylene chloride = 9/1) gave Compound 1 (40.2 g) as a pale yellow oil.

Compound 1 (40.0 g, 177.5 mmol), 4,4′-dibromobiphenyl (27.15 g, 87.02 mmol) and sodium tert-butoxy (42.6 g, 443.8 mmol), toluene (500 ml) were placed in a flask. The system was fully purged with nitrogen and heated to 60 ° C. (solution C). In another flask, tris (dibenzylideneacetone) dipalladium chloroform complex (0.92 g, 0.89 mmol), toluene (25 ml), 4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (1. 9 g, 7.12 mmol) was added and warmed to 60 ° C. (solution DB). Solution D was added to Solution C in a nitrogen stream and reacted at 100 ° C. for 5.5 hours. After allowing to cool to room temperature, toluene (300 ml) and brine (100 ml) were added to the reaction solution, and the mixture was stirred and separated. The aqueous layer was extracted with toluene (100 ml × 2 times), and the organic layers were combined. After drying with, it was treated with activated clay, and then concentrated. Further, purification by silica gel column chromatography (n-hexane / ethyl acetate = 9/1) gave Compound 2 (52.2 g) as a pale yellow oil.

N, N-dimethylformamide (300 ml) and methylene chloride (300 ml) were added to compound 2 (52.1 g, 86.71 mmol) and cooled in an ice bath. To this was added dropwise a solution of N-bromosuccinimide (38.87 g, 173.42 mmol) in N, N-dimethylformamide (100 ml) and methylene chloride (100 ml), and the mixture was warmed to room temperature over 4.5 hours with stirring. Warm up. Water was added to the reaction solution, extraction was carried out with methylene chloride, the organic layer was concentrated, and purified by column chromatography (developing solution: hexane / methylene chloride = 4/1) to give colorless solid compound 3 (23.23). 2 g) was obtained.

[Synthesis of Polymer 1]
Polymer 1 was synthesized according to the following reaction formula.

Compound 3 (5.00 g, 6.6 mmol), 2-amino-9,9-dihexylfluorene (4.61 g, 13.2 mmol), and sodium tert-butoxy (4.88 g, 50.8 mmol), toluene (100 g ) Was charged into the flask, the inside of the system was replaced with nitrogen, and the mixture was heated to 90 ° C. (solution E). In another flask, tris (dibenzylideneacetone) dipalladium complex (0.12 g, 1.1 mmol), toluene (7.8 ml), [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine ( 0.28 g, 0.11 mmol) was added and warmed to 60 ° C. (solution F). In a nitrogen stream, solution F was added to solution E, and heated to reflux for 1 hour. After confirming the disappearance of the raw material, 4,4′-dibromobiphenyl (0.60 g, 1.92 mmol) was added, and the mixture was heated to reflux for 1 hour. Further, 4- (4- {1,1-bis [4- (4-bromophenyl) phenyl] ethyl} phenyl) benzocyclobutene (2.69 g, 4.01 mmol) was added, and the mixture was heated and returned for 1 hour. , Bromobenzene (1.04 g, 6.6 mmol) was added, and the mixture was heated to reflux for 1.5 hours. The reaction solution was allowed to cool, toluene (100 g) was added, and the mixture was added dropwise to ethanol (5000 g) to obtain a crude polymer.
The crude polymer was dissolved in toluene and 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 polymer collected by filtration was purified by column chromatography to obtain polymer 1 (3.7 g).
Weight average molecular weight (Mw) = 45200
Number average molecular weight (Mn) = 32700
Dispersity (Mw / Mn) = 1.38

(Organic electroluminescence device)
<Example 2>
The organic electroluminescent element shown in FIG. 1 was produced.
An indium tin oxide (ITO) transparent conductive film deposited on the glass substrate 1 by sputtering is patterned into a 2 mm wide stripe using a normal photolithography technique and hydrochloric acid etching to form a film having a thickness of 70 nm. Anode 2 was formed. The patterned ITO substrate is cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, followed by drying with compressed air, and finally UV irradiation. Ozone cleaning was performed.

Next, hole injection containing the polymer 1 (P1) synthesized in Example 1, 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate represented by the structural formula (A1), and ethyl benzoate A layer forming coating solution was prepared. This coating solution was formed on the anode 2 by spin coating and heated under the following conditions to obtain a hole injection layer having a thickness of 35 nm.

<Coating liquid for hole injection layer formation>
Solvent Ethyl benzoate Coating solution concentration Polymer 7: 3.0% by mass
A1: 0.6% by mass

<Film formation conditions for hole injection layer 3>
Spin coat atmosphere In-air heating condition In-air 230 ° C 60 minutes

Subsequently, a coating solution for forming a hole transport layer containing the following (P2) is prepared, and a hole transport layer having a thickness of 40 nm is formed by spin coating on the hole injection layer 3 under the following conditions and heating. Formed.

<Coating liquid for hole transport layer formation>
Solvent Cyclohexylbenzene Coating solution concentration 1.5% by mass

<Film formation conditions for hole transport layer 4>
Spin coat atmosphere Nitrogen Heating conditions Nitrogen 230 ° C 60 min

Next, a coating solution for forming a light emitting layer containing the compounds (H1), (H2) and (D1) shown in the following structural formula is prepared, and film formation is performed by spin coating under the following conditions, followed by heating. A light emitting layer having a thickness of 56 nm was formed on the hole transport layer 4.

<Light emitting layer forming coating solution>
Solvent Cyclohexylbenzene Coating solution concentration H1: 2.25% by mass
H2: 2.75% by mass
D1: 1.00% by mass

<Film-forming conditions of the light emitting layer 5>
Spin coat atmosphere Nitrogen Heating conditions Nitrogen 130 ° C 10 min

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

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

Here, the element on which the electron transport layer 7 has been deposited is transferred to another vacuum deposition apparatus, and a 2 mm wide striped shadow mask is used as a mask for cathode deposition so that the ITO stripe of the anode 2 is orthogonal to the element. It was made to adhere to. As the electron injection layer 8, first, lithium fluoride (LiF) was formed on the electron transport layer 7 with a film thickness of 0.5 nm by a vacuum evaporation method using a molybdenum boat. Next, aluminum was similarly heated by a molybdenum boat as the cathode 9, and an aluminum layer having a thickness of 80 nm was formed by vacuum deposition. The substrate temperature during the above two-layer deposition was kept at room temperature.

Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, a sealing process was performed by the method described below.

In a nitrogen glove box, a photocurable resin (30Y-437 manufactured by Three Bond Fine Chemical Co., Ltd.) with a width of about 1 mm is applied to the outer periphery of a 23 mm × 23 mm glass plate, and a moisture getter sheet (Dynic Corporation) is applied to the center. Company). On this, the board | substrate which complete | finished cathode formation was bonded together so that the vapor-deposited surface might oppose a desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened.

As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained. Table 2 shows the characteristics of this element.

<Comparative Example 1>
An organic electroluminescent device was prepared in the same manner as in Example 2 except that the polymer used for the coating liquid for forming the hole injection layer was changed from the polymer 1 (P1) to the polymer (P3) represented by the following formula. . Table 2 shows the characteristics of this element.

<Comparative example 2>
An organic electroluminescent element was prepared in the same manner as in Example 2 except that the polymer used for the coating liquid for forming the hole injection layer was changed from the polymer 1 (P1) to the polymer (P4) represented by the following formula. . Table 2 shows the characteristics of this element.

<Comparative Example 3>
An organic electroluminescent element was prepared in the same manner as in Example 2 except that the polymer used for the coating liquid for forming the hole injection layer was changed from the polymer 1 (P1) to the polymer (P5) represented by the following formula. . Table 2 shows the characteristics of this element.

As is apparent from Table 2, it was found that the organic electroluminescent device using the polymer of the present invention had a low voltage.

Although the present invention has been described in detail and with reference to specific embodiments, 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 a Japanese patent application filed on Feb. 25, 2015 (Japanese Patent Application No. 2015-035607), the contents of which are incorporated herein by reference.

1 Substrate (glass substrate)
DESCRIPTION OF SYMBOLS 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

The polymer which contains the unit represented by following formula (1) as a repeating unit.

(In the formula (1), Ar 1 each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R 1 Each independently represents an alkyl group which may have a substituent, and T 1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group having a crosslinkable group as a substituent.
Furthermore, the polymer of Claim 1 which contains the unit represented by following formula (2) as a repeating unit.

(In Formula (2), Ar 1 each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R 1 Each independently represents an optionally substituted alkyl group, and L 1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group.)
The polymer has a unit represented by the formula (1) and a unit represented by the formula (2) in a total of 50 mol% or more based on 100 mol% of all monomer units. 2. The polymer according to 2.
The polymer according to any one of claims 1 to 3, wherein Ar 1 is a 2-fluorenyl group which may have a substituent.
The polymer according to any one of claims 2 to 4, wherein the L 1 is 4,4'-biphenylene, that is, contains a unit represented by the following formula (3) as a repeating unit.

(In Formula (3), Ar 1 each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group in which three or more rings optionally having a substituent are condensed. R 1 Each independently represents an optionally substituted alkyl group.)
The polymer according to any one of claims 1 to 5, having a weight average molecular weight (Mw) of 20,000 or more and a dispersity (Mw / Mn) of 2.5 or less.
A composition for an organic electroluminescent device comprising the polymer according to any one of claims 1 to 6.
An organic electroluminescent device comprising an anode, a cathode, and an organic layer between the anode and the cathode on a substrate, wherein the organic layer comprises the organic electroluminescent device composition according to claim 7, An organic electroluminescence device including a layer formed by a wet film formation method.
The organic electroluminescence device according to claim 8, wherein the layer formed by the wet film forming method is at least one of a hole injection layer and a hole transport layer.
A positive hole injection layer, a positive hole transport layer and a light emitting layer are included between the anode and the negative electrode, and the positive hole injection layer, the positive hole transport layer and the light emitting layer are all formed by a wet film formation method. Item 10. The organic electroluminescent device according to Item 8 or 9.
An organic EL display device having the organic electroluminescent element according to any one of claims 8 to 10.
An organic EL illumination comprising the organic electroluminescence device according to any one of claims 8 to 10.