JP2019218550A - Polymer, composition for organic electroluminescent element, organic electroluminescent element, organic el display device and organic el illumination - Google Patents

Abstract

To provide a polymer having a high hole injection transporting ability and high durability.SOLUTION: The polymer has a repeating unit represented by formula (1). In the formula, Arand Arrepresent a six-membered monocyclic or 2 to 5 condensed ring monovalent hydrocarbon group, or a five- or six-membered monocyclic or 2 to 4 condensed ring aromatic heterocyclic group; Arrepresents a six-membered monocyclic or 2 to 5 condensed ring divalent aromatic hydrocarbon group, or a five- or six-membered monocyclic or 2 to 4 condensed ring divalent aromatic heterocyclic group, where at least one of Ar, Arand Arhas a crosslinking group as a substituent; and n represents an integer of 4 or more. The aromatic hydrocarbon groups and the aromatic heterocyclic groups may be connected in a plurality of numbers directly or via a connecting group.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polymer, in particular, a polymer useful as a hole injection layer and a hole transport layer of an organic electroluminescent device, a composition for an organic electroluminescent device containing the polymer, and the organic electroluminescent device And an organic EL display having the same.

As a method for forming an organic layer in an organic electroluminescent element, there are a vacuum deposition method and a wet film formation method. The vacuum vapor deposition method has an advantage that the lamination is easy, so that the charge injection from the anode and / or the cathode can be improved and the light emitting layer of the exciton can be easily contained. On the other hand, the wet film formation method does not require a vacuum process, is easy to increase the area, and easily uses a coating solution in which a plurality of materials having various functions are mixed, thereby easily providing a plurality of functions having various functions. There is an advantage that a layer containing the above material can be formed.
However, since the wet film forming method is difficult to laminate, the driving stability is inferior to the device formed by the vacuum vapor deposition method, and at present, it is not at a practical level except for a part.
Therefore, a charge transporting polymer having a crosslinkable group is desired for lamination by a wet film formation method, and its development is being carried out. For example, Patent Literatures 1 to 5 disclose organic electroluminescent elements containing a polymer having a specific repeating unit and stacked by a wet film-forming method.

International Publication No. 2009/123269 International Publication No. 2010/018813 International Publication No. 2011/078387 International Publication No. 2011/093428 Japanese Patent No. 5246386

However, these devices described in Patent Documents 1 to 5 have a problem that the driving voltage is high, the emission luminance is low, and the driving life is short. Therefore, there has been a demand for an improvement in the charge injection / transport ability and durability of the charge transport material.
Accordingly, an object of the present invention is to provide a polymer having high hole injection / transport ability and high durability, and a composition for an organic electroluminescent device containing the polymer. Another object of the present invention is to provide an organic electroluminescent device having a high luminance and a long driving life.

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above problem can be solved by using a polymer having a specific repeating unit, and have completed the present invention.
That is, the present invention relates to the following.
[1] A polymer having a repeating unit represented by the following formula (1).

(Wherein, Ar ¹ , Ar ² and Ar ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, and n is an integer of 4 or more. The aromatic hydrocarbon group and the aromatic heterocyclic group may be linked to each other directly or via a linking group.)
[2]
The polymer according to [1], wherein at least one of Ar ¹ , Ar ² and Ar ³ has a crosslinkable group as a substituent.
[3]
The polymer according to [2], wherein the crosslinkable group is a group containing a benzocyclobutene ring.
[4]
[2] having at least two types of repeating units represented by the above formula (1), at least one type of repeating unit containing a crosslinkable group, and at least one type of repeating unit containing no crosslinkable group; Or the polymer according to [3].
[5]
The polymer according to any one of [1] to [4], wherein at least one of Ar ¹ and Ar ² is a 2-fluorenyl group which may have a substituent.
[6]
The polymer according to any one of [1] to [5], wherein Ar ³ is a group represented by the following formula (2).

(In the formula, m represents an integer of 1 to 3.)
[7]
Ar ³ is an aromatic hydrocarbon group or an aromatic heterocyclic group that is linked to a plurality of groups via a linking group represented by the following formula (3): Polymer.

(In the formula, p represents an integer of 1 to 10. R ¹ and R ² each independently represent a hydrogen atom or an optionally substituted alkyl group, aromatic hydrocarbon group, or aromatic group. Represents a group heterocyclic group. When a plurality of R ¹ and R ² are present, they may be the same or different.)
[8]
The polymer according to any one of [1] to [7], wherein the polymer has a weight average molecular weight (Mw) of 20,000 or more and a degree of dispersion (Mw / Mn) of 2.5 or less.
[9]
A composition for an organic electroluminescent device, comprising the polymer according to any one of [1] to [8].
[10]
On a substrate, an anode, a cathode, and an organic electroluminescent device having an organic layer between the anode and the cathode,
An organic electroluminescent device, wherein the organic layer includes a layer formed by a wet film formation method using the composition for an organic electroluminescent device according to [9].
[11]
The organic electroluminescent device according to [10], wherein the layer formed by the wet film forming method is at least one of a hole injection layer and a hole transport layer.
[12]
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 formation method. [10] The organic electroluminescent device according to [11].
[13]
An organic EL display device having the organic electroluminescent element according to any one of [10] to [12].
[14]
[10] An organic EL lighting device having the organic electroluminescent element according to any one of [12] to [12].

  The polymer of the present invention has four or more continuous p-phenylene groups between nitrogen atoms having an unshared electron pair, and HOMO is sufficiently widely delocalized to form holes. Excellent transportability. If the p-phenylene group has a substituent, steric hindrance increases the dihedral angle between each p-phenylene group and hinders orbital delocalization, so that a high hole transport ability cannot be obtained. Since the p-phenylene group in the polymer of the present invention has no substituent, the orbit is sufficiently delocalized and has a high hole transporting ability.

  Further, since the polymer of the present invention has four or more p-phenylene groups between two nitrogen atoms, the interaction between nitrogen atoms is smaller than that of three or less p-phenylene groups, and the ionization potential And the hole injection into the light emitting layer is excellent. When the hole injection from the hole transport layer to the light emitting layer is improved, the accumulation of holes between the hole transport layer and the light emitting layer is suppressed, so that the durability of the organic electroluminescent device is improved.

  In addition, the polymer of the present invention has four or more continuous p-phenylene groups and LUMO is sufficiently delocalized widely, so that it has excellent durability against electrons and excitons. By distributing LUMO to two or more continuous p-phenylene groups located far from two nitrogen atoms among four or more continuous p-phenylene groups, around a nitrogen atom that is weak to electrons and excitons, Is excellent in durability because LUMO is relatively not distributed. When the p-phenylene group has a substituent, steric hindrance increases the dihedral angle between each p-phenylene group and hinders delocalization of the orbit, so that high durability cannot be obtained. Since the p-phenylene group in the polymer has no substituent, the orbit is sufficiently delocalized, and the polymer has high durability.

  Further, the layer obtained by wet film formation using the composition for an organic electroluminescent device containing the polymer of the present invention is flat without cracks or the like. According to the organic electroluminescent device 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, devices including a layer formed using the polymer include flat panel displays (for example, for OA computers and wall-mounted televisions), and in-vehicle display devices. It can be applied to light sources (such as light sources for copiers, backlight sources for liquid crystal displays and instruments), display boards, and sign lights that make use of the features of mobile phone displays and surface light emitters. Is big.

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

Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited thereto unless it exceeds the gist thereof. Is not specified.
In the present specification, “% by mass” and “% by weight” are synonymous.
The polymer of the present invention is a polymer having a repeating unit represented by the following formula (1).

(Wherein, Ar ¹ , Ar ² and Ar ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, and n is an integer of 4 or more. The aromatic hydrocarbon group and the aromatic heterocyclic group may be linked to each other directly or via a linking group.)

[About Ar ¹ and Ar ² ]
Ar ¹ and Ar ² represent a monovalent aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent.
Examples of the aromatic hydrocarbon group include, for example, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring. , A 6-membered monocyclic or 2 to 5 condensed ring monovalent group.

  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 pyrroleimidazole ring, and a pyrrolopyrazole ring. , Pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, floppyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, A 5- or 6-membered monocyclic or 2-4 condensed ring such as a quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring and azulene ring 1 Include the groups.

Ar ¹ and Ar ² are preferably an aromatic hydrocarbon group from the viewpoint of excellent charge transportability and durability, and more preferably a monovalent group of a benzene ring and a fluorene ring, that is, a phenyl group and a fluorenyl group. Preferably, a fluorenyl group is more preferred, and a 2-fluorenyl group is particularly preferred.

  The aromatic hydrocarbon group and the substituent which the aromatic heterocyclic group may have are not particularly limited as long as they do not significantly reduce the properties of the present polymer. A selected group is mentioned, 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, usually 24 or less, preferably 12 or less;
An alkenyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a vinyl group;
An alkynyl group having usually 2 or more carbon atoms and usually 24 or less, preferably 12 or less, such as an ethynyl group;
An alkoxy group having usually 1 or more, usually 24 or less, preferably 12 or less carbon atoms, such as a methoxy group and an ethoxy group;
An aryloxy group having usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less carbon atoms, such as a phenoxy group, a naphthoxy group, and a pyridyloxy group;
An alkoxycarbonyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methoxycarbonyl group and an ethoxycarbonyl group;
A dialkylamino group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a dimethylamino group and a diethylamino group;
A diarylamino group having usually 10 or more, preferably 12 or more, usually 36 or less, preferably 24 or less carbon atoms, such as a diphenylamino group, a ditolylamino group, and an N-carbazolyl group;
An arylalkylamino group having usually 7 or more carbon atoms, usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;
Acyl groups having usually 2 or more, usually 24 or less, preferably 12 or less carbon atoms, such as acetyl and benzoyl;
A halogen atom such as a fluorine atom and a chlorine atom;
A haloalkyl group having usually 1 or more, usually 12 or less, preferably 6 or less, such as a trifluoromethyl group;
An alkylthio group having usually 1 or more, usually 24 or less, preferably 12 or less carbon atoms, such as a methylthio group and an ethylthio group;
An arylthio group having usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less carbon atoms, such as a phenylthio group, a naphthylthio group, and a pyridylthio group;
A silyl group having usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less carbon atoms, such as a trimethylsilyl group and a triphenylsilyl group;
A siloxy group having usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less carbon atoms, such as a trimethylsiloxy group and a triphenylsiloxy group;
A cyano group;
Aromatic hydrocarbon groups having usually 6 or more carbon atoms, usually 36 or less, preferably 24 or less, such as phenyl and naphthyl;
An aromatic heterocyclic group having 3 or more carbon atoms, preferably 4 or more, and usually 36 or less, preferably 24 or less, such as a thienyl group and a pyridyl group.
Among these substituents, an alkyl group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms are preferable from the viewpoint of solubility.
Further, each of the above substituents may further have a substituent, and examples thereof are selected from the groups exemplified in the above section (Substituent group Z).

[About Ar ³ ]
Ar ³ represents a divalent aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. A plurality of the aromatic hydrocarbon groups and the aromatic heterocyclic groups may be bonded.
Examples of the aromatic hydrocarbon group include, for example, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring. And a 6-membered monocyclic or 2 to 5 condensed ring divalent group.

  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 pyrroleimidazole ring, and a pyrrolopyrazole ring. , Pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, floppyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, A 5- or 6-membered monocyclic or 2-4 condensed ring such as a quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring and azulene ring 2 Include the groups.

From the viewpoint of excellent charge transportability and durability, Ar ³ is preferably an aromatic hydrocarbon group, and among them, a divalent group of a benzene ring and a fluorene ring, that is, a phenylene group and a fluorenylene group are more preferable. A 1,3-phenylene group, a 1,4-phenylene group, and a 2,7-fluorenyl group are more preferred.

  The aromatic hydrocarbon group and the substituent that the aromatic heterocyclic group may have are not particularly limited as long as they do not significantly reduce the properties of the present polymer, and for example, are selected from the substituent group Z. The alkyl group, the alkoxy group, the aromatic hydrocarbon group, and the aromatic heterocyclic group are preferable, and the alkyl group is more preferable.

When Ar ³ is a group in which a plurality of the aromatic hydrocarbon groups and aromatic heterocyclic groups are bonded, two to six of those groups are connected from the viewpoint of excellent charge transportability and durability. Is preferred. The aromatic hydrocarbon group and the aromatic heterocyclic group to be linked may be one kind or plural kinds.

Ar ³ is a group in which 1 to 3 p-phenylene groups represented by the following formula (2) are bonded, which is excellent in charge transporting property, durability and hole injection from the anode side. Are particularly preferred.

(In the formula, m represents an integer of 1 to 3.)

When Ar ³ is a group in which a plurality of the aromatic hydrocarbon groups and the aromatic heterocyclic groups are bonded, they may be bonded via a linking group. In this case, as the linking group, 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 2 to 10 are exemplified. preferable. When two or more groups are linked, the linking group may be one type or a plurality of types. Here, R ^{1 to} R ³ each independently represent 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 alkyl group, the aromatic hydrocarbon group, or the aromatic heterocyclic group, the same groups as the groups described in the aforementioned substituent group Z are preferable. The linking group, ^-CR 1 ^{R 2} in terms of durability -, and, ^-CR 1 ^{R 2} which is 2 to 6 linked - are particularly preferred, ^-CR 1 ^{R 2} - is more preferable.
Ar ³ is particularly preferably an aromatic hydrocarbon group and an aromatic heterocyclic group connected to each other via a linking group represented by the following formula (3) from the viewpoint of durability.

(In the formula, p represents an integer of 1 to 10. R ¹ and R ² each independently represent a hydrogen atom or an optionally substituted alkyl group, aromatic hydrocarbon group, or aromatic group. The alkyl group, the aromatic hydrocarbon group, or the aromatic heterocyclic group is preferably the same group as the group described in the above-mentioned substituent group Z. R ¹ and R ² are preferably When there are a plurality, they may be the same or different.)

[About n]
n represents an integer of 4 or more. N is preferably 4 from the viewpoint of high hole transport ability and excellent hole injection from the anode side. N is preferably 5 from the viewpoint of high hole transport ability and excellent hole injection into the light emitting layer.

[About crosslinkable groups]
The polymer of the present invention preferably has a crosslinkable group as a substituent on at least one of Ar ¹ , Ar ² and Ar ³ . By having a crosslinkable group, it is possible to cause a large difference in solubility in an organic solvent before and after a reaction caused by irradiation with heat and / or active energy rays (resolvability reaction). From the viewpoint of durability, it is more preferable to have a crosslinkable group as a substituent of Ar ³ .

A crosslinkable group is a group that, upon irradiation with heat and / or active energy rays, reacts with a group constituting another molecule located near the crosslinkable group to form a new chemical bond. Say. In this case, the reactive group may be the same or different from the crosslinkable group. Examples of the crosslinkable group include groups shown in the following crosslinkable group group T.
<Crosslinkable group T>

(Wherein, R ^{1 to} R ³ represent a hydrogen atom or an alkyl group; R ⁴ and R ⁵ represent a hydrogen atom, an alkyl group or an alkoxy group; and Ar ⁷ is an aromatic group which 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 ^{1 to} R ⁵ , 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, a -Butyl group, isobutyl group and the like. More preferably, it is a methyl group or an ethyl group. When the carbon number of R ^{1 to} R ⁵ is 6 or less, there is a tendency that the film is easily insolubilized without sterically inhibiting the crosslinking reaction.

As the alkoxy group for R ⁴ and R ⁵ , usually, a linear or branched chain alkoxy group having 6 or less carbon atoms is 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. When the number of carbon atoms of R ⁴ and R ⁵ is 6 or less, there is a tendency that the film is not easily insolubilized without sterically inhibiting the crosslinking reaction.

Examples of the aromatic hydrocarbon group optionally having a substituent of Ar ⁷ include a single-membered 6-membered ring such as a benzene ring and a naphthalene ring having one free valence, or a 2- to 5-membered ring. And fused rings. Particularly, a benzene ring having one free valence is preferable. Ar ⁷ may be a group obtained by bonding two or more aromatic hydrocarbon groups which may have these substituents. 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 cross-linking 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 preferred because it has high reactivity and is easily insolubilized by crosslinking. Among them, an oxetane group is more preferable in that the rate of cationic polymerization can be easily controlled, and a vinyl ether group is more preferable in that a hydroxyl group which may cause deterioration of the element during the cationic polymerization is hardly generated.
Further, a group that undergoes a cycloaddition reaction such as an arylvinylcarbonyl group such as a cinnamoyl group and a benzocyclobutene ring having a monovalent free valence is preferable in that the electrochemical stability of the device is further improved.
Further, among the crosslinkable groups, a benzocyclobutene ring having a monovalent free valence is particularly preferable because the structure after crosslinking is particularly stable.

In the polymer of the present invention, the crosslinkable group may be directly bonded to an aromatic hydrocarbon group, an aromatic heterocyclic group, and / or a linking group, or may be an aromatic hydrocarbon group and / or an aromatic hydrocarbon group. It may be directly bonded to a group other than the heterocyclic group, or may be bonded to these groups via an arbitrary divalent group. Examples of the arbitrary divalent group include a group selected from a —O— group, a —C (＝ O) — group, and a (optionally substituted) —CH ₂ — group in any order from 1 to A group formed by linking 30 is preferable.

  It is preferable that the number of the crosslinkable groups contained in the polymer of the present invention is large, in that the crosslinkable groups are sufficiently insolubilized by crosslinking and another layer is easily formed thereon by a wet film formation method. On the other hand, the number of crosslinkable groups is preferably small from the viewpoint that cracks hardly occur in the formed layer, unreacted crosslinkable groups hardly remain, and the organic electroluminescent element (organic EL element) tends to have a long life.

  In the polymer of the present invention, the number of crosslinkable groups present in one polymer chain is usually 1 or more, preferably 2 or more, and usually 200 or less, preferably 100 or less.

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

  When the number of the crosslinkable groups in 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 1.0 or less, more preferably 0 per 1000 molecular weight. 0.5 or less, more preferably 0.2 or less, and usually 0 or more, preferably 0.01 or more, more preferably 0.02 or more, and still more preferably 0.05 or more.

  When the number of crosslinkable groups is within the above range, cracks and the like hardly occur, and a flat film is easily obtained. In addition, since the crosslink density is appropriate, the number of unreacted crosslinkable groups remaining in the layer after the crosslink reaction is small, and the life of the obtained device is hardly affected.

  Furthermore, since the insoluble property in the organic solvent after the crosslinking reaction is sufficient, a multilayer laminated structure is easily formed by a wet film formation method.

Here, the number of crosslinkable groups per 1000 molecular weight of the polymer can be calculated from the molar ratio of the charged monomers at the time of synthesis and the structural formula, excluding the terminal groups from the polymer.
For example, in the case of the target polymer 1 synthesized in Synthesis Example 1 described below, in the target polymer 1, the molecular weight of the repeating unit excluding the terminal group is 1148.69 on average, and the crosslinkable group has one repeating unit. The average is 0.1156 pieces. When this is calculated by simple proportion, the number of crosslinkable groups per molecular weight of 1000 is calculated to be 0.10.

[About the molecular weight of the polymer]
The weight average molecular weight of the polymer of the present invention is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less, further more preferably 200,000 or less, and usually 2,000 or less. It is at least 500, preferably at least 5,000, more preferably at least 10,000, even more preferably at least 30,000.

  When the weight average molecular weight of the polymer exceeds the above upper limit, the solubility in a solvent is reduced, and thus the film formability may be impaired. When the weight average molecular weight of the polymer is below the lower limit, the glass transition temperature, the melting point and the vaporization temperature of the polymer are lowered, so that the heat resistance may be lowered.

  The number average molecular weight (Mn) of the polymer of the present invention is generally 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.

  Further, the degree of dispersion (Mw / Mn) in the polymer of the present invention is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. Since the smaller the value of the degree of dispersion is, the better, the lower limit is ideally 1. When the degree of dispersion of the polymer is equal to or less than the upper limit, purification is easy, and solubility in a solvent and charge transport ability are good.

  Usually, the weight average molecular weight of a polymer is determined by SEC (size exclusion chromatography) measurement. In the SEC measurement, the elution time of the higher molecular weight component is shorter and the elution time of the lower molecular weight component is longer. However, 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 converted to the molecular weight. By conversion, the weight average molecular weight is calculated.

[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 formulas represent the molar ratio of the repeating unit.
The number in the chemical formula relates to the molar ratio of the repeating unit. For example, in the above formula (1), in the case of a polymer containing a repeating unit having a crosslinking group and a repeating unit having no crosslinking group, the molar ratio is The repeating unit having no crosslinkable group is usually 0 or more, preferably 1 or more, more preferably 2 or more, further preferably 5 or more, and usually 100 or less, preferably 100 or less. Is 50 or less, more preferably 20 or less, and still more preferably 10 or less. If the molar ratio of the repeating unit having a crosslinkable group is too small, after the crosslinking reaction, poor solubility in an organic solvent is not sufficient, and the multilayer laminate structure in a wet film-forming method tends to be difficult, and if too large, cracks occur. Tend to occur, and it is difficult to obtain a flat film.
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 combining a CC bond forming reaction such as a Suzuki reaction, a Grignard reaction, a Ullmann reaction, a Buchwald-Hartwig reaction, and a CN bond forming reaction. However, since a portion of four or more continuous p-phenylene groups, which is a feature of the polymer of the present invention, has a poorly soluble structure, a substituent that enhances solubility in Ar ¹ and / or Ar ² is added. After the introduction, it is preferable to devise a method of constructing a portion of four or more continuous p-phenylene groups. By such a measure, the purity of the monomer (repeating unit) is increased, and a polymer having a desired degree of polymerization and molecular weight distribution is easily obtained.
Specifically, after a highly soluble primary amine such as 9,9-dialkyl-2-aminofluorene is reacted with bromobenzene to obtain a secondary amine, the p-position of the amino group is changed to N-bromo. It is preferable to construct the intermediate 1 by brominating with succinimide or the like, and further reacting with 4,4'-biphenyldiboronic acid, 4,4 "-p-terphenyldiboronic acid or an ester derivative thereof. The polymer of the present invention can be obtained by reacting the intermediate 1 with a dihalide.

The reaction of 4,4′-biphenyldiboronic acid, 4,4 ″ -p-terphenyldiboronic acid or an ester derivative thereof and a bromide with bromide is performed one by one to convert two Ar ¹ of the intermediate ¹ into two Ar ¹ . The groups can be different from each other.

  Further, a highly soluble primary amine such as 9,9-dialkyl-2-aminofluorene and 4,4′-dibromobiphenyl are reacted to obtain a monobromide having a secondary amine moiety, and then bis (pinacolato) is obtained. ) Conversion into a boronic acid ester with diboron or the like to obtain an intermediate 2, and a highly soluble primary amine and a dihalide such as 4,4′-dibromobiphenyl or 4,4 ″ -dibromo-p-terphenyl To obtain Intermediate 3, and Intermediate 2 and Intermediate 3 are preferably reacted to construct Intermediate 4. By reacting Intermediate 4 with a dihalide, the polymer of the present invention is obtained. Is obtained.

Usually, the step of reacting the primary or secondary amine compound with the halide is carried out in the presence of a base such as potassium carbonate, sodium tert-butoxy, triethylamine and the like. Further, the reaction can be performed in the presence of a transition metal catalyst such as copper or a palladium complex.
Usually, the reaction step between the boron derivative and the halide is carried out in the presence of a base such as potassium carbonate, sodium tert-butoxy, triethylamine and the like. If necessary, the reaction can be carried out in the presence of a transition metal catalyst such as a copper or palladium complex. Further, the reaction step with the boron derivative can be performed, for example, in the presence of a base such as potassium carbonate, potassium phosphate, sodium tert-butoxy, triethylamine, or a transition metal catalyst such as a palladium complex.

<Organic electroluminescent device material>
The polymer of the present invention is preferably used as an organic electroluminescent device material. That is, the polymer of the present invention is preferably an organic electroluminescent device material.
When the polymer of the present invention is used as an organic electroluminescent device material, it is preferably used as a material for forming at least one of the hole injection layer and the hole transport layer in the organic electroluminescent device, that is, as a charge transport material.
When used as a charge transporting material, the polymer of the present invention may contain one kind or two or more kinds in any combination and in any ratio.

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

When the polymer according to the present invention is not 100% by mass in the hole injecting layer and / or the hole transporting layer, the components constituting the hole injecting layer and / or the hole transporting layer include holes described later. And a transportable compound.
In addition, the polymer of the present invention is preferably used for an organic layer formed by a wet film formation method, since an organic electroluminescent element can be easily manufactured.

[Composition for organic electroluminescent device]
The composition for an organic electroluminescent device of the present invention contains the polymer of the present invention. The composition for an organic electroluminescent device of the present invention may contain one kind of the polymer of the present invention, or may contain two or more kinds thereof in an optional combination and an optional ratio. Good.

｛Polymer content｝
The content of the polymer of the present invention in the composition for an organic electroluminescent device of the present invention is usually 0.01 to 70% by mass, preferably 0.1 to 60% by mass, and more preferably 0.5 to 50% by mass. %.
It is preferable for the thickness to be within the above range because defects are unlikely to occur in the formed organic layer and unevenness in film thickness is unlikely to occur.
The composition for an organic electroluminescent device in the present invention can contain a solvent and the like in addition to the polymer according to the present invention.

{solvent}
The composition for an organic electroluminescent device of the present invention usually contains a solvent. This solvent preferably dissolves the polymer of the present invention. Specifically, a solvent that dissolves the polymer of the present invention at room temperature, usually at least 0.05% by mass, preferably at least 0.5% by mass, more preferably at least 1% by mass is suitable.
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, and 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 esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; Organic solvents such as aromatic esters such as phenyl onate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and n-butyl benzoate; and other organic solvent such as hole injection layer described below. Solvents used in the composition for forming a hole transport layer.
One type of solvent may be used, or two or more types may be used in any combination and in any ratio.

  Among them, as the solvent contained in the composition for an organic electroluminescent device 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 an organic electroluminescent device of the present invention and an organic layer is formed by crosslinking the polymer of the present invention, the affinity between the solvent and the base may be high. preferable. This is because the uniformity of the film quality greatly affects the uniformity and stability of light emission of the organic electroluminescent device. Therefore, the composition for an organic electroluminescent element used in the wet film forming method is required to have a higher leveling property and a lower surface tension so that a uniform coating film can be formed. Therefore, it is preferable to use a solvent having a low surface tension as described above, since 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 above-mentioned aromatic solvents such as toluene, xylene, mesitylene, and cyclohexylbenzene, ester solvents such as ethyl benzoate, ether solvents such as anisole, trifluoromethoxyanisole, and pentane. Examples include fluoromethoxybenzene, 3- (trifluoromethyl) anisole, and ethyl (pentafluorobenzoate).

  On the other hand, as the solvent contained in the composition for an organic electroluminescent device of the present invention, those 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 are preferable. . By using such a solvent, a composition for an organic electroluminescent device suitable for a process for producing an organic electroluminescent device by a wet film formation 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 the wet film formation as much as possible, among the above solvents, those having a solubility of water of 1% by mass or less at 25 ° C. are preferable, and those having a solubility of 0.1% by mass or less are preferable. Is more preferred.

  The content of the solvent contained in the composition for an organic electroluminescent device 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 equal to or more than the lower limit, the flatness and uniformity of the formed layer can be improved.

<Electron-accepting compound>
When used for forming a hole injection layer, the composition for an organic electroluminescent device of the present invention preferably further contains an electron accepting compound from the viewpoint of lowering the resistance.

  As the electron-accepting compound, a compound having oxidizing power and capable of accepting one electron from the polymer of the present invention is preferable. Specifically, a compound having an electron affinity of 4 eV or more is preferable, and a compound having an electron affinity of 5 eV or more is more preferable.

  Such electron accepting compounds include, for example, triaryl boron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. One or more compounds selected from the group consisting of:

  Specifically, onium salts in which an organic group is substituted, such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (WO 2005/089024); Iron (III) (Japanese Patent Application Laid-Open No. Hei 11-251067), high-valent inorganic compounds such as ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; tris (pentafluorophenyl) borane (Japanese Patent Application Publication No. 2003-2003). And aromatic boron compounds, such as fullerene derivatives and iodine.

  As such a compound, an element belonging to Groups 15 to 17 of the long-period periodic table (hereinafter, unless otherwise specified, the “periodic table” refers to the long-periodic table). In particular, 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 ⁶ represents an organic group bonded to A ₁ at a carbon atom, and R ⁷ represents an arbitrary substituent. R ⁶ and R ⁷ may combine with each other to form a ring.
The type of R ⁶ 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 does not contradict the purpose of the present invention. The molecular weight of R ⁶ is a value including the substituent, and is usually 1000 or less, preferably 500 or less.

Preferred examples of R ⁶ include 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. Above all, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferable because it delocalizes a positive charge and is thermally stable.

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

  The aromatic heterocyclic group is a 5-membered or 6-membered monocyclic or 2-4 condensed ring having one free valence, and a group capable of delocalizing a positive charge on the group. Is mentioned. Specific examples thereof include a furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, triazole ring, imidazole ring, oxadiazole ring, indole ring, and carbazole ring having one free valence. , Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, flopyrrole 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, cinnoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

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

  The alkynyl group includes those having usually 2 or more, usually 12 or less, preferably 6 or less. Specific examples include an ethynyl group and a propargyl group.

R ⁷ is not particularly limited as long as it does not depart from the gist of the present invention. The molecular weight of R ⁷ is a value including the substituent and is usually in the range of 1,000 or less, preferably 500 or less.

Examples of R ⁷ include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, and an alkyl group. Examples include carbonyloxy, alkylthio, arylthio, sulfonyl, alkylsulfonyl, arylsulfonyl, cyano, hydroxyl, thiol, and silyl groups.

Among them, similar to R ⁶ , an organic group having a carbon atom at the bonding portion to A ₁ is preferable from the viewpoint of high electron accepting property. Examples thereof 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 of its high electron accepting property and thermal stability.

Alkyl group, an alkenyl group of R ^7, alkynyl group, aromatic hydrocarbon group, the aromatic heterocyclic group include the same as those described for R ⁶ above.

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

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

  Examples of the arylamino group include an arylamino group having one or more aromatic hydrocarbon groups or aromatic heterocyclic groups having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less carbon atoms. Can be Specific examples include a phenylamino group, a diphenylamino group, a tolylamino group, a pyridylamino group, and a thienylamino group.

  As the acylamino group, an acylamino group having at least one acyl group having usually 2 or more, usually 25 or less, preferably 15 or less carbon atoms can be mentioned. Specific examples include an acetylamino group and a benzoylamino group.

  Examples of the alkoxy group include an alkoxy group having usually 1 or more, 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 an aryloxy group 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 phenyloxy group, a naphthyloxy group, a pyridyloxy group, and a thienyloxy group.

  As the acyl group, an acyl group having usually 1 or more, usually 25 or less, preferably 15 or less is exemplified. Specific examples include a formyl group, an acetyl group, a benzoyl group and the like.

  Examples of the alkoxycarbonyl group include an alkoxycarbonyl group having usually 2 or more, 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.

  Examples of the alkylthio group include 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.

  Examples of the arylthio group include 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 ⁶ and R ⁷ may be further substituted with other substituents, as long as they do not depart from the gist of the present invention. Although the type of the substituent is not particularly limited, examples thereof include a halogen atom, a cyano group, a thiocyano group, and a nitro group, in addition to the groups exemplified above as R ⁶ and R ⁷ . Among them, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, aromatic hydrocarbon groups, and aromatic heterocycles from the viewpoint of not hindering the heat resistance and electron acceptability of the ionic compound (electron accepting compound). Groups are preferred.

Wherein (4), A ₁ is preferably an element belonging to Group 17 of the periodic table, from the viewpoint of electron accepting property and ease of availability, the fifth period previous periodic table (third to fifth cycle Element) is preferred. That is, A ₁ is preferably any _one of an iodine atom, a bromine atom and a chlorine atom.

In particular, an ionic compound in which A ₁ in the formula (4) is a bromine atom or an iodine atom is preferable, and an ionic compound in which i is an iodine atom is most preferable in terms of electron acceptability and stability of the compound.

In the 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 is, the more delocalized the negative charge is, the more delocalized the positive charge is, and the larger the electron accepting ability becomes. Thus, a complex ion is preferable to a monatomic ion.

n ₁ is any positive integer corresponding to the counter anion _Z ^{1 n1-} valency. Although the value of n ₁ is not particularly limited, it is preferably 1 or 2, and most preferably 1.

Specific examples of Z ₁ ^n1-, hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, cyanide ion, nitrate ion, nitrite ion, sulfate ion, sulfite ion, perchlorate Ion, perbromate ion, periodate ion, chlorate ion, chlorite ion, hypochlorite ion, phosphate ion, phosphite ion, hypophosphite ion, borate ion, isocyanate ion, Hydrogen sulfide ion, tetrafluoroborate ion, hexafluorophosphate ion, hexachloroantimonate ion; carboxylate ion such as acetate ion, trifluoroacetate ion and benzoate ion; sulfone such as methanesulfonic acid and trifluoromethanesulfonic acid ion Acid ions; methoxy ions, alkoxy ions such as t-butoxy ion, etc. Gerare, tetrafluoroborate periodate ion and hexafluoro boronic acid ion.

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

In the formula (5), E ₃ independently represents an element belonging to Group 13 of the long period periodic table. Among them, a boron atom, an aluminum atom, and a gallium atom are preferable, and a boron atom is preferable in terms of stability of the compound, and ease of synthesis and purification.

In the formula (5), Ar ^{6 to} Ar ⁹ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group. Examples of the aromatic hydrocarbon group and the aromatic heterocyclic group include a 5-membered or 6-membered monocyclic or 2- to 5-membered ring having one free valence as described above for R ⁶ . And 4 fused rings. Among them, a benzene ring, a naphthalene ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, and an isoquinoline ring having one free valence are preferable from the viewpoint of stability and heat resistance of the compound. .

The aromatic hydrocarbon group and the aromatic heterocyclic group exemplified as Ar ^{6 to} Ar ⁹ may be further substituted with another substituent as long as it does not depart from the gist of the present invention. The type of the substituent is not particularly limited, and any substituent can be applied. However, the substituent is preferably an electron-withdrawing group.

Preferred examples of the electron-withdrawing group as a substituent which Ar ^{6 to} Ar ⁹ may have include a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom; a cyano group; a thiocyano group; a nitro group; Arylsulfonyl groups such as tosyl group; acyl groups having usually 1 or more, usually 12 or less, preferably 6 or less carbon atoms, such as formyl group, acetyl group and benzoyl group; methoxycarbonyl group and ethoxycarbonyl An alkoxycarbonyl group having usually 2 or more, usually 10 or less, preferably 7 or less carbon atoms such as a group; a phenoxycarbonyl group, a pyridyloxycarbonyl group or the like, usually having 3 or more carbon atoms, preferably 4 or more, usually 25 or less. An aryloxycarbonyl group having preferably 15 or less aromatic hydrocarbon groups or aromatic heterocyclic groups; A fluorine atom to a linear, branched or cyclic alkyl group having usually 1 or more, usually 10 or less, preferably 6 or less carbon atoms, such as a bonyl group; an aminosulfonyl group; a trifluoromethyl group and a pentafluoroethyl group. And a haloalkyl group substituted by a halogen atom such as a chlorine atom.

Above all, it is more preferable that at least one of Ar ^{6 to} Ar ⁹ has one or more fluorine or chlorine atoms as a substituent. In particular, from the viewpoint of delocalizing the negative charge efficiently and having an appropriate sublimation property, it is most preferable that all of the hydrogen atoms of Ar ^{6 to} Ar ⁹ are perfluoroaryl groups substituted with fluorine atoms. 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 from 100 to 5,000, preferably from 300 to 3,000, and more preferably from 400 to 2,000.

Within the above range, the positive charge and the negative charge are sufficiently delocalized, the electron accepting ability is good, and the charge transport is hardly hindered.
Hereinafter, specific examples of the electron-accepting compound suitable for the present invention are shown, but the present invention is not limited thereto.

  The composition for an organic electroluminescent device of the present invention may contain one kind of the above-described electron accepting compound alone, or may contain two or more kinds in any combination and in any ratio.

  When the composition for an organic electroluminescent device of the present invention contains an electron-accepting compound, the content of the electron-accepting compound in the composition for an organic electroluminescent device of the present invention is usually 0.0005% by mass or more, preferably 0.1% by mass. It is at least 001% by mass and usually at most 20% by mass, preferably at most 10% by mass. The ratio of the electron accepting compound to the polymer of the present invention in the composition for an organic electroluminescent device is usually 0.5% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more. It is 80% by mass or less, preferably 60% by mass or less, more preferably 40% by mass or less.

  When the content of the electron-accepting compound in the composition for an organic electroluminescent device is at least the lower limit, the electron acceptor accepts electrons from the polymer, and the formed organic layer is preferably low-resistance, and the upper limit is not more than the upper limit. This is preferable because defects are less likely to occur in the formed organic layer and unevenness in film thickness is less likely to occur.

<Cation radical compound>
The composition for an organic electroluminescent device of the present invention may further contain a cation radical compound.
As the cation radical compound, an ionic compound comprising 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 polymer compound having a hole-transporting property, the cation radical has a structure in which one electron is removed from a repeating unit of the polymer compound.

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

  Here, the cation radical compound can be generated by mixing the above-described hole transporting compound and the above-described electron accepting compound. That is, by mixing the above-described hole-transporting compound and the above-described electron-accepting compound, electron transfer from the hole-transporting compound to the electron-accepting compound occurs, and the cation radical of the hole-transporting compound is paired with the cation radical. A cationic ion compound consisting of an anion is formed.

When the composition for an organic electroluminescent device of the present invention contains a cation radical compound, the content of the cation radical compound in the composition for an organic electroluminescent device of the present invention is usually 0.0005% by mass or more, preferably 0.001% by mass. % Or less, usually 40% by mass or less, preferably 20% by mass or less. When the content of the cation radical compound is equal to or more than the lower limit, the formed organic layer is preferably reduced in resistance, and when the content is less than or equal to the upper limit, defects are hardly generated in the formed organic layer, and unevenness in film thickness is hardly generated. .
The composition for an organic electroluminescent device of the present invention contains, in addition to the above components, components contained in a composition for forming a hole injection layer or a composition for forming a hole transport layer described below, and a content described below. May be contained.

[Organic electroluminescent device]
The organic electroluminescent device of the present invention is an organic electroluminescent device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, wherein the organic layer contains the polymer of the present invention. And a layer formed by a wet film-forming method using the composition for an organic electroluminescent device.
In the organic electroluminescent device of the present invention, the layer formed by the wet film forming method is preferably at least one of a hole injection layer and a hole transport layer. It is preferable that a hole transport layer and a light emitting layer are provided, and that all of the hole injection layer, the hole transport layer, and the light emitting layer are layers formed by a wet film formation method.

  In the present invention, the wet film forming method means a film forming method, that is, as a coating method, for example, a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, or a capillary method. A method in which a film is formed by a wet method such as a coating method, an ink jet method, a nozzle printing method, a screen printing method, a gravure printing method, and a flexographic printing method, and a method of forming a film by drying the applied film. Among these film forming methods, a spin coating method, a spray coating method, an ink jet method, a nozzle printing method and the like are preferable.

Hereinafter, an example of an embodiment, such as a layer structure of an organic electroluminescent device of the present invention and a general forming method thereof, will be described with reference to FIG.
FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent device 10 of the present invention. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, Represents a light emitting layer, 6 represents a hole blocking layer, 7 represents an electron transport layer, 8 represents an electron injection layer, and 9 represents a cathode.

{substrate}
The substrate 1 serves as a support for the organic electroluminescent element, and is usually a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, or the like. Of these, a glass plate and a plate of a transparent synthetic resin 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 electroluminescent element is unlikely to be deteriorated by outside air. For this reason, particularly when a material having low gas barrier properties such as a synthetic resin substrate is used, it is preferable to provide a dense silicon oxide film or the like on at least one surface of the substrate to improve the gas barrier properties.

{anode}
The anode 2 has a function of injecting holes into 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, and platinum; a metal oxide such as an oxide of indium and / or tin; a metal halide such as copper iodide; -Methylthiophene), conductive polymers such as polypyrrole and polyaniline.

  The formation of the anode 2 is usually performed by a dry method such as a sputtering method or a vacuum evaporation method in many cases. Further, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., an appropriate binder resin solution may be used. It can also be formed by dispersing and applying on a substrate. In the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or a conductive polymer can be applied on the substrate to form an anode (Appl. Phys. Lett., 60). Vol., 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, a different conductive material may be laminated on the first layer anode.
The thickness of the anode 2 may be determined according to the required transparency and material. When particularly high transparency is required, the thickness is preferably such that the visible light transmittance is at least 60%, more preferably at least 80%. The thickness of the anode 2 is usually at least 5 nm, preferably at least 10 nm, and is usually at most 1,000 nm, preferably at most 500 nm. On the other hand, when transparency is not required, the thickness of the anode 2 may be arbitrarily set according to the required strength and the like. In this case, the anode 2 may have the same thickness as the substrate.

  When another layer is formed on the surface of the anode 2, impurities such as ultraviolet / ozone, oxygen plasma, and argon plasma are removed before the film is formed to remove impurities on the anode 2 and ionization potential thereof. Is preferably adjusted to improve the hole injection property.

｛Hole injection layer｝
The layer having a function of 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 having a function of transporting holes from the anode 2 side to the light emitting layer 5 side, a layer closer to the anode side may be referred to as a hole injection layer 3. The hole injection layer 3 is preferably formed in order to enhance the function of transporting holes from the anode 2 to the light emitting layer 5 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 at least 1 nm, preferably at least 5 nm, and usually at most 1,000 nm, preferably at most 500 nm.

The method for forming the hole injection layer may be a vacuum evaporation method or a wet film formation method. From the viewpoint 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 electroluminescent device of the present invention, the hole injection layer is formed by a wet film forming method using the composition for an organic electroluminescent device of the present invention. Is preferably formed.

<Hole transport compound>
The composition for forming a hole injection layer usually contains a hole transporting compound that becomes the hole injection layer 3. In the case of the wet film forming method, a solvent is usually further contained. The composition for forming a hole injection layer preferably has a high hole transporting property, and can efficiently transport injected holes. For this reason, it is preferable that the hole mobility be large and impurities serving as traps hardly occur at the time of manufacture or use. Further, it is preferable that the composition has excellent stability, a small ionization potential, and high transparency to visible light. In particular, when the hole injection layer is in contact with the light emitting layer, a material that does not quench light emitted from the light emitting layer or a material that does not decrease the light emission efficiency by forming an exciplex with the light emitting layer is preferable.
As the hole transporting compound, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferable 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 fluorene groups, hydrazones Compounds, silazane compounds, quinacridone compounds and the like.

Among the above exemplified 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 also includes a compound having a group derived from an aromatic tertiary amine.
The kind of the aromatic tertiary amine compound is not particularly limited, but from the viewpoint that uniform light emission is easily obtained due to the surface smoothing effect, a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (polymerizable compound having repeating units connected in series) ) Is preferably used. Preferred examples of the aromatic tertiary amine polymer include a polymer having a repeating unit represented by the following formula (6).

(In the 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 represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. represents a linking group selected from the group of linkage groups shown. in addition, of the Ar ¹¹ to Ar ^15, two groups bonded to the same N atom may bond to each other to form a ring.)

(In the above formulas, Ar ^{16 to} Ar ²⁶ each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. R ⁸ and R ⁹ each independently represent a hydrogen atom or an optional substituent.)

The aromatic hydrocarbon group and the aromatic heterocyclic group represented by Ar ^{16 to} Ar ²⁶ each have one or two free valences in view of the solubility, heat resistance, and hole injection / transport properties of the polymer compound. And 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 having a repeating unit represented by the formula (4) include those described in WO 2005/089024.

  The hole injection layer 3 contains the above-described electron accepting compound and the above-described cation radical compound because the conductivity of the hole injection layer can be improved by oxidation of the hole transporting compound. Is preferred.

  Cationic radical compounds derived from high molecular compounds such as PEDOT / PSS (Adv. Mater., 2000, Vol. 12, p. 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, Vol. 94, p. 7716) are known. It is also produced by oxidative polymerization (dehydrogenation polymerization).

  The oxidative polymerization referred to here is a method in which a monomer is oxidized chemically or electrochemically in an acidic solution using a peroxodisulfate or the like. In the case of this oxidative polymerization (dehydrogenation polymerization), a monomer is oxidized to become a polymer, and a cation radical which has one electron removed from a polymer repeating unit having an anion derived from an acidic solution as a counter anion is formed. Generate.

<Formation of hole injection layer by wet film formation method>
When the hole injecting layer 3 is formed by a wet film forming method, a material for forming a hole injecting layer is usually mixed with a soluble solvent (solvent for a hole injecting layer) to form a film forming composition (hole). An injection layer forming composition) is prepared, and the hole injection layer forming composition is applied on a layer (usually, an anode) corresponding to a lower layer of the hole injection layer to form a film, followed by drying. Form.

The concentration of the hole-transporting compound in the composition for forming a hole-injecting layer is arbitrary as long as the effect of the present invention is not significantly impaired. However, in terms of uniformity of the film thickness, a lower concentration is preferable. In view of the fact that defects are unlikely to occur in the hole injection layer, the higher is preferable. Specifically, it is preferably at least 0.01% by mass, more preferably at least 0.1% by mass, particularly preferably at least 0.5% by mass, and on the other hand, 70% by mass. Is preferably not more than 60% by mass, more preferably not more than 60% by mass, and particularly preferably not more than 50% by mass.
Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like.

  Examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), and 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and anisole. And phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and aromatic ethers such as 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, and methylnaphthalene. Can be Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide and the like.
Besides these, dimethyl sulfoxide and the like can also be used.

The formation of the hole injection layer 3 by the wet film formation method is usually performed by preparing a composition for forming a hole injection layer 3 and then forming the composition on a layer corresponding to the lower layer of the hole injection layer 3 (normally, the anode 2). It is performed by applying a film on the substrate and drying it.
After the formation of the hole injection layer 3, the coating film is usually dried by heating, drying under reduced pressure, or the like.

<Formation of hole injection layer by vacuum evaporation>
When the hole injection layer 3 is formed by a vacuum evaporation method, usually, one or two or more of the constituent materials of the hole injection layer 3 (the above-described hole transport compound, electron accepting compound, and the like) are vacuum-evaporated. Put in a crucible installed in a container (when using two or more types of materials, usually put them in separate crucibles), evacuate the vacuum container to about 10 ⁻⁴ Pa with a vacuum pump, and then heat the crucible. (When two or more types of materials are used, the respective crucibles are usually heated) and evaporated while controlling the amount of evaporation of the materials in the crucibles (When two or more types of materials are used, they are usually independent of each other). To form a hole injection layer on the anode on the substrate placed opposite to the crucible. When two or more types of materials are used, a mixture thereof can be placed in a crucible, heated and evaporated to form a hole injection layer.

The degree of vacuum at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10 ⁻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 ° / sec or more and 5.0 ° / sec or less. The film forming temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is preferably from 10 ° C. to 50 ° C.
In addition, the hole injection layer 3 may be crosslinked like the hole transport layer 4 described later.

｛Hole transport layer｝
The hole transport layer 4 has 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 electroluminescent device of the present invention, but is preferably formed from the viewpoint of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5. . 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. When the above-described hole injection layer 3 is provided, it is formed between the hole injection layer 3 and the light emitting layer 5.
The thickness of the hole transport layer 4 is usually at least 5 nm, preferably at least 10 nm, and is usually at most 300 nm, preferably at most 100 nm.
The method for forming the hole transport layer 4 may be a vacuum evaporation method or a wet film formation method. From the viewpoint of excellent film forming properties, it is preferable to form the film by a wet film forming method.

  The general method of forming a hole transport layer will be described below.In the organic electroluminescent device of the present invention, the hole transport layer is formed by a wet film forming method using the composition for an organic electroluminescent device of the present invention. It is preferably formed.

  The hole transporting layer 4 usually contains a hole transporting compound. The hole transporting compound contained in the hole transporting layer 4 is, in particular, two or more tertiary compounds represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl. Aromatic diamines containing an amine and two or more condensed aromatic rings substituted by nitrogen atoms (Japanese Patent Application Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triamine Aromatic amine compounds having a starburst structure such as phenylamine (J. Lumin., Vol. 72-74, p. 985, 1997), and aromatic amine compounds composed of tetramers of triphenylamine (Chem. Commun., 2175, 1996), and spiro compounds such as 2,2 ', 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals). Vol. 91, 209 pp., 1997), 4,4'-N, carbazole derivatives such as N'- dicarbazole biphenyl. Further, for example, polyarylene ether sulfone containing polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Application Laid-Open No. 7-53953), and tetraphenylbenzidine (Polym. Adv. Tech., Vol. 7, p. 33, 1996). Etc. can also be preferably used.

<Formation of hole transport layer by wet film formation method>
When the hole transport layer is formed by a wet film formation method, the hole injection layer is usually replaced with the hole injection layer forming composition in the same manner as in the case of forming the hole injection layer by the wet film formation method. It is formed using a composition for forming a transport layer.
When the hole transport layer is formed by a wet film forming method, the composition for forming a hole transport layer usually further contains a solvent. As the solvent used for the composition for forming a hole transport layer, the same solvent as the solvent used for the composition for forming a hole injection layer described above can be used.
The concentration of the hole transporting compound in the composition for forming a hole transporting layer can be in the same range as the concentration of the hole transporting compound in the composition for forming a hole injecting layer.
The hole transport layer can be formed by a wet film formation method in the same manner as the above-described hole injection layer film formation method.

<Formation of hole transport layer by vacuum evaporation method>
In the case where the hole transport layer is formed by the vacuum evaporation method, the hole transport layer is usually replaced with the hole injection layer forming composition in the same manner as the case where the hole injection layer is formed by the vacuum evaporation method. It can be formed using a layer forming composition. The film formation conditions such as the degree of vacuum, the vapor deposition rate and the temperature during the vapor deposition can be formed under the same conditions as in 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 by being excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between the pair of electrodes. . The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9. The light-emitting layer is formed between the hole injection layer and the cathode when there is a hole injection layer on the anode. If there is a hole transport layer on the cathode, it is formed between the hole transport layer and the cathode.
The thickness of the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired. However, a thicker film is preferable in that defects are less likely to occur in the film, and a thinner film is preferable in that a low driving voltage is easily obtained. . For this reason, it is preferably at least 3 nm, more preferably at least 5 nm, and usually, preferably at most 200 nm, more preferably at most 100 nm.
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 (a 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 effects of the present invention are not impaired, and a known light emitting material can be used. The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material. However, a material having good light emitting efficiency is preferable, and a phosphorescent light emitting material is preferable from the viewpoint of internal quantum efficiency.
Examples of the fluorescent light emitting material include the following materials.
Examples of the fluorescent light emitting material that emits blue light (blue fluorescent light emitting material) include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene, and derivatives thereof.
Examples of the fluorescent light emitting material that emits green light (green fluorescent light emitting material) include quinacridone derivatives, coumarin derivatives, aluminum complexes such as Al (C ₉ H ₆ NO) _3, and the like.
Examples of the fluorescent material that emits yellow light (yellow fluorescent material) include rubrene and perimidone derivatives.
Examples of the fluorescent light emitting material that emits red light (red fluorescent light emitting material) include, for example, DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostylyl) -4H-pyran) -based compound, benzopyran derivative, rhodamine derivative Benzothioxanthene derivatives, azabenzothioxanthenes and the like.

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

  As the ligand of the organometallic complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand is linked to pyridine, pyrazole, phenanthroline, or the like is preferable. Particularly, a phenylpyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

  Specific examples of preferred phosphorescent materials include, for example, tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, and tris (2-phenylpyridine) platinum. Examples thereof include 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.

  Polymer-based light-emitting materials include poly (9,9-dioctylfluorene-2,7-diyl) and 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 polyphenylenevinylene materials such as poly [2-methoxy-5- (2-hexylhexyloxy) -1,4-phenylenevinylene].

<Charge transporting material>
The charge transporting material is a material having a positive charge (hole) or negative charge (electron) transporting 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 electroluminescent element can be used, and a compound used as a host material of a light emitting layer is particularly preferable.
Specific examples of the charge transporting material include an aromatic amine compound, a phthalocyanine compound, a porphyrin compound, an oligothiophene compound, a polythiophene compound, a benzylphenyl compound, and a compound in which a tertiary amine is linked by a fluorene group. , Hydrazone-based compounds, silazane-based compounds, silanamin-based compounds, phosphamine-based compounds, quinacridone-based compounds and other compounds exemplified as the hole-transporting compound of the hole injection layer, and the like, anthracene-based compounds, pyrene-based compounds, Examples thereof include carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, and electron transporting compounds such as silole compounds.

  Further, for example, two or more condensed aromatic rings containing two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are added to a nitrogen atom. Aromatic amine compounds having a starburst structure such as substituted aromatic diamines (JP-A-5-234681) and 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine ( J. Lumin., 72-74, 985, 1997), aromatic amine compounds composed of a tetramer of triphenylamine (Chem. Commun., 2175, 1996), 2, 2 ', 7 , Fluorene-based compounds such as 7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, 91, 209, 1997) 4,4'-N, N'compounds exemplified as hole-transporting compound of the positive hole transport layer of the carbazole compounds such as di-biphenyl, or the like can be preferably used. In addition, 2- (4-biphenylyl) -5- (p-tert-butylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl)- Oxadiazole compounds such as 1,3,4-oxadiazole (BND) and 2,5-bis (6 ′-(2 ′, 2 ″ -bipyridyl))-1,1-dimethyl-3,4 And phenanthroline compounds such as -diphenylsilole (PyPySPyPy) and other silole compounds, 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 light-emitting layer may be formed by a vacuum deposition method or a wet film formation method. However, a wet film formation method is preferable, and a spin coating method and an ink jet method are more preferable because of excellent film formability. In particular, when a hole injecting layer or a hole transporting layer, which is a lower layer of a light emitting layer, is formed using the composition for an organic electroluminescent device of the present invention, lamination by a wet film formation method is easy. It is preferable to employ a membrane method. When the light-emitting layer is formed by a wet film-forming method, usually, in the same manner as in the case of forming the above-described hole-injection layer by a wet film-forming method, instead of the composition for forming a hole-injection layer, Is formed using a composition for forming a light-emitting layer prepared by mixing a material with a soluble solvent (solvent for a light-emitting layer).
Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, alkane solvents, halogenated aromatic hydrocarbon solvents, and fats, in addition to the above-mentioned ether solvents, ester solvents, aromatic hydrocarbon solvents, and amide solvents. Aliphatic alcohol-based solvents, alicyclic alcohol-based solvents, aliphatic ketone-based solvents, and alicyclic ketone-based solvents. Specific examples of the solvent will be given below, but the solvent is not limited thereto as long as the effects of the present invention are not impaired.

  For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, Aromatic ether solvents such as -methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole and diphenylether; phenylacetate, phenylpropionate, methylbenzoate, benzoic acid Aromatic ester solvents such as ethyl, propyl benzoate and n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylpropylbiphenyl, 1,2,3,4-te Aromatic hydrocarbon solvents such as lamethylbenzene, 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 Cyclic alcohol-based solvents; aliphatic ketone-based solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone-based 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 preventing 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. Having. The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and an excited triplet level (T1). Is high.
Examples of the material of the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed ligand complexes, metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolylato) aluminum binuclear metal complex, distyrylbiphenyl derivatives and the like Triazole derivatives such as styryl compounds (JP-A-11-242996) and 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (Japan) Phenanthroline derivatives such as bathocuproine (Japanese Patent Application Laid-Open No. 10-79297). Broadcast), and the like. Further, the compound having at least one pyridine ring substituted at the 2,4,6-position described in WO 2005/022962 is also preferable as the material of the hole blocking layer.

The method for forming the hole blocking layer 6 is not limited. Therefore, it can be formed by a wet film forming method, an evaporation method, or another method.
The thickness of the hole blocking layer 6 is optional 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 the electrodes to which an electric field is applied in the direction of the light emitting layer 5. The electron transporting compound used in the electron transporting layer 7 has a high electron injection efficiency from the cathode 9 or the electron injection layer 8 and a high electron mobility, and can efficiently transport injected electrons. It must be a compound that can be used.
As the electron transporting compound used in the electron transporting layer, specifically, for example, a metal complex such as an aluminum complex of 8-hydroxyquinoline (JP-A-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, trisbenzimidazolylbenzenes (US Pat. No. 5,645,948), a quinoxaline compound (Japanese Patent Application Laid-Open No. Hei 6-207169), a phenanthroline derivative (Japanese Patent Application Laid-Open No. 5-331559), 2-t-butyl-9,10-N, N'-dicyanoanthraquinone. Diimine, n-type hydrogenated amorphous coal Silicon nitride, 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 evaporation method in the same manner as described above. Usually, a vacuum evaporation method is used.

｛Electron injection layer｝
The electron injection layer 8 plays a role of efficiently injecting the electrons injected from the cathode 9 into the electron transport layer 7 or the light emitting layer 5.
For efficient electron injection, the material forming the electron injection layer 8 is preferably a metal having a low work function. Examples thereof include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. The film thickness is usually preferably 0.1 nm or more and 5 nm or less.
Further, an organic electron transporting material such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, and rubidium ( JP-A-10-270171, JP-A-2002-100478, JP-A-2002-100482, etc.) also improve electron injection / transportability and achieve excellent film quality. This is preferable because it becomes possible.
The 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 and the electron transporting layer 7 on the light emitting layer 5 by a wet film forming method or a vacuum evaporation method.
The details of the wet film forming method are the same as those of the above-described light emitting layer.

{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, it is possible to use the material used for the above-mentioned anode 2, but for efficient electron injection, it is preferable to use a metal having a low work function. , Indium, calcium, aluminum, silver, and other metals or alloys thereof. Specific examples include, for example, alloy electrodes having a low work function such as a magnesium-silver alloy, a magnesium-indium alloy, and an aluminum-lithium alloy.
From the viewpoint of the stability of the device, it is preferable to protect the cathode made of a metal having a low work function by laminating a metal layer having a high work function and being 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 device of the present invention may have another layer 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 configuration｝
The organic electroluminescent device of the present invention has a structure reverse 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 a substrate. , And an anode.
When the organic electroluminescent device of the present invention is applied to an organic electroluminescent device, it may be used as a single organic electroluminescent device, or may be used in a configuration in which a plurality of organic electroluminescent devices are arranged in an array. A configuration in which the anode and the cathode are arranged in an XY matrix may be used.

[Organic EL display]
The organic electroluminescent device display device (organic EL display device) of the present invention uses the above-described organic electroluminescent device of the present invention. The type and structure of the organic EL display device of the present invention are not particularly limited, and the organic EL display device can be assembled using the organic electroluminescent device of the present invention according to a conventional method.
For example, the organic EL display device of the present invention can be manufactured by a method described in “Organic EL Display” (Ohmsha, issued on August 20, 2004, Shizushi Tokito, Chihaya Adachi, Hideyuki Murata). Can be formed.

[Organic EL lighting]
The organic electroluminescent device lighting (organic EL lighting) of the present invention uses the above-described organic electroluminescent device of the present invention. The type and structure of the organic EL lighting of the present invention are not particularly limited, and can be assembled according to a conventional method using the organic electroluminescent device of the present invention.

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

  Compound 1 (10.0 g, 28.61 mmol), bromobenzene (4.27 g, 27.18 mmol), sodium tert-butoxide (7.4 g, 77.25 mmol), and toluene (150 ml) were charged, and the system was purged with nitrogen. Then, the mixture was heated to 60 ° C. (solution A). To a solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.089 g, 0.086 mmol) in 15 ml of toluene was added 1,1′-bis (diphenylphosphino) ferrocene (0.19 g, 0.344 mmol), and Warmed to ° C. (Solution B). The solution B was added to the solution A in a nitrogen stream, and the mixture was heated under reflux for 3.0 hours. After cooling to room temperature, the reaction mixture was added with ethyl acetate (300 ml) and brine (100 ml), stirred, separated, and the aqueous layer was extracted with ethyl acetate (100 ml × 2). After drying over magnesium sulfate, the mixture was concentrated. Further, the residue was purified by silica gel column chromatography (n-hexane / methylene chloride = 3/1) to obtain Compound 2 (10.4 g) as a pale yellow oil.

  N, N-dimethylformamide (200 ml) and methylene chloride (200 ml) were added to compound 2 (10.4 g, 24.43 mmol), and the mixture was cooled in an ice bath. A solution of N-bromosuccinimide (4.35 g, 24.43 mmol) in N, N-dimethylformamide (50 ml) and methylene chloride (50 ml) was added dropwise thereto, and the temperature was raised to room temperature over 3 hours with stirring. Water was added to the reaction solution, and extracted with methylene chloride. The organic layer was concentrated and purified by column chromatography (developing solution: hexane / methylene chloride = 3/1) to obtain a pale yellow oily compound 3 (10.8 g).

  Compound 3 (15.95 g, 31.61 mmol), 4,4'-biphenyldiboronic acid (3.9 g, 16.13 mmol), potassium carbonate (10.9 g, 79.03 mmol), and toluene (120 ml), ethanol (60 ml) and water (40 ml) were charged into a flask, and the system was sufficiently purged with nitrogen and heated to 80 ° C. Tetrakis (triphenylphosphine) palladium (1.8 g, 1.58 mmol) was added, and the mixture was stirred at 80 ° C for 4 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was concentrated and purified by column chromatography (developing solution: hexane / toluene = 2/1). Subsequently, the product was purified again by column chromatography (developing solution: THF / acetonitrile = 1/2). Compound 4 (8.5 g, yield 52.6%) was obtained. Compound 4 had an HPLC purity of 99.7 area%.

  4- (3-Aminophenyl) benzocyclobutene (8.77 g, 45 mmol) and N-methylpyrrolidone (60 ml) were mixed and cooled to -5C. Concentrated hydrochloric acid (8.59 ml, 99 mmol) and demineralized water (30 ml) were added, and the mixture was stirred for 30 minutes. Subsequently, an aqueous solution (30 ml) of sodium nitrite (3.20 g, 46.35 mmol) cooled to −5 ° C. was added at 5 ° C. or lower, and stirred for 30 minutes to obtain a diazonium salt solution. The above diazonium salt solution was added dropwise to an aqueous solution (400 ml) of potassium iodide (2263 g, 136.35 mmol) heated to 60 ° C., and the mixture was stirred for 2 hours. Dichloromethane was added to the reaction solution for extraction, washed with water, washed with a sodium thiosulfate solution, added with magnesium sulfate, stirred, filtered, and the filtrate was concentrated. Purification by silica gel column chromatography (developing solvent: n-hexane) gave 4- (3-iodophenyl) benzocyclobutene (7.8 g, yield 56.6%).

Under a nitrogen stream, dimethyl sulfoxide (100 ml), 4- (3-iodophenyl) benzocyclobutene (5.00 g, 16.3 mmol), bis (pinacolato) diboron (5.39 g, 21.2 mmol), potassium acetate (4 .00 g, 40.8 mmol) was charged into a flask and stirred at 60 ° C. for 30 minutes. Subsequently, 1,1′-bis (diphenylphosphino) ferrocene-palladium (II) dichloride-dichloromethane [PdCl ₂ (dppf) CH ₂ Cl ₂ ] (0.33 g, 0.41 mmol) was added, and 85 ° C. was added. The mixture was heated and stirred for hours. Toluene was added to the reaction solution, washed with water, magnesium sulfate was added, and the mixture was stirred and filtered. Activated clay was added to the filtrate, and the mixture was stirred and filtered. The filtrate was concentrated to obtain a colorless solid compound 6 (4.71 g, yield 94.2%).

  Under a nitrogen stream, toluene (100 ml), ethanol (50 ml), compound 6 (4.00 g, 13.1 mmol), 1,3,5-tribromobenzene (4.11 g, 13.1 mmol), 2M aqueous sodium carbonate solution (50 ml) was charged into a flask and heated and stirred at 60 ° C. for 30 minutes. Subsequently, tetrakis (triphenylphosphine) palladium (0.30 g, 0.26 mmol) was added, and the mixture was refluxed for 2 hours. Water was added to the reaction solution, extracted with toluene, magnesium sulfate and activated clay were added, and the mixture was stirred, filtered, and the filtrate was concentrated. Purification by silica gel column chromatography (developing solvent: n-hexane: toluene = 5: 1) gave compound 7 (3.89 g, yield 71.9%) as a colorless oil.

  Under a nitrogen stream, dimethylsulfoxide (300 ml), 4,4 "-dibromo-p-terphenyl, 3.0 g (7.73 mmol), bis (pinacolato) diboron 4.71 g (18.55 mmol), potassium acetate 4.55 g (46.38 mmol), the system was purged with nitrogen, and the mixture was stirred for 30 minutes at 60 ° C. Subsequently, 1,1′-bis (diphenylphosphino) ferrocenepalladium (II) dichloride dichloromethane adduct 0.32 g. (0.387 mmol) and reacted for 4 hours at 83 ° C. The reaction solution was filtered under reduced pressure, water was added to the filtrate, and extracted with toluene, anhydrous magnesium sulfate and activated clay were added to the organic layer, and the mixture was stirred. Thereafter, the filtrate was concentrated under reduced pressure, the filtrate was concentrated, and the precipitated solid was suspended and washed with methanol to obtain a colorless solid compound 7 (yield 2.8 g). 75% yield).

  Compound 3 (4.95 g, 9.95 mmol), Compound 7 (2.36 g, 4.97 mmol), potassium carbonate (5.53 g, 40.0 mmol), toluene (60 ml), ethanol (20 ml), water (20 ml) ), And the system was sufficiently purged with nitrogen and heated to 60 ° C. Tetrakis (triphenylphosphine) palladium (0.29 g, 0.25 mmol) was added, and the mixture was stirred at 80 ° C for 4 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was concentrated and purified by column chromatography (developing solution: hexane / methylene chloride = 2/1) to obtain Compound 8 (2.77 g, yield: 51.7%).

<Synthesis of Polymer 1>

Compound 4 (2.0 g, 1.997 mmol), compound 6 (0.095 g, 0.2296 mmol), sodium tert-butoxide (1.48 g, 15.38 mmol), and toluene (30 ml) were charged, and the system was purged with nitrogen. Replace and warm to 60 ° C. (Solution A). [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.085 g) was added to a toluene solution (5 ml) of tris (dibenzylideneacetone) dipalladium chloroform complex (0.042 g, 0.0399 mmol). , 0.3195 mmol) and heated to 60 ° C. (Solution B). Solution B was added to Solution A in a nitrogen stream, and the mixture was heated under reflux for 1.0 hour. Subsequently, 4,4′-dibromobiphenyl (0.52 g, 1.667 mmol) was added. After heating under reflux for 1.0 hour, 4,4'-dibromobiphenyl (0.025 g, 0.08 mmol) was additionally added. After 30 minutes, the reaction solution was allowed to cool, and the reaction solution was dropped into 500 ml of ethanol to crystallize a crude polymer.
The obtained crude polymer was dissolved in toluene (90 ml), N, N-diphenylamine (0.068 g, 0.403 mmol) and sodium tert-butoxy (0.74 g, 7.7 mmol) were charged, and the system was purged with nitrogen. Then, the mixture was heated to 60 ° C. (solution C). [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.043 g) was added to a toluene solution (3 ml) of tris (dibenzylideneacetone) dipalladium chloroform complex (0.021 g, 0.0203 mmol). , 0.1598 mmol) and heated to 60 ° C. (Solution D). The solution D was added to the solution C in a nitrogen stream, and the mixture was heated under reflux for 3 hours. Bromobenzene (0.35 g, 0.2229 mmol) was added to the reaction. [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.043 g) was added to a toluene solution (3 ml) of tris (dibenzylideneacetone) dipalladium chloroform complex (0.021 g, 0.0203 mmol). , 0.1598 mmol) and heated to 60 ° C. (Solution E). The solution E was added to the reaction solution in a nitrogen stream, and the mixture was heated under reflux for 3 hours. The reaction solution was allowed to cool and dropped into a solution of ethanol / water (1500 ml / 100 ml) to obtain an end-capped crude polymer.
The end-capped crude polymer was dissolved in toluene and reprecipitated with acetone. The precipitated polymer was redissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The polymer collected by filtration was purified by column chromatography to obtain a polymer 1 (1.0 g).
Weight average molecular weight (Mw) = 47100
Number average molecular weight (Mn) = 33400
Dispersion degree (Mw / Mn) = 1.41

<Synthesis of Polymer 2>

Compound 8 (2.155 g, 2.00 mmol), compound 6 (0.095 g, 0.23 mmol), sodium tert-butoxide (1.48 g, 15.4 mmol) and toluene (35 ml) were charged, and the system was purged with nitrogen. Replace and warm to 60 ° C. (Solution A). [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.085 g) was added to a toluene solution (5 ml) of tris (dibenzylideneacetone) dipalladium chloroform complex (0.041 g, 0.041 mmol). , 0.32 mmol) and warmed to 60 ° C. (Solution B). Solution B was added to Solution A in a nitrogen stream, and the mixture was heated under reflux for 1.0 hour. Subsequently, 4,4′-dibromobiphenyl (0.493 g, 1.58 mmol) was added. After heating under reflux for 1.0 hour, the reaction solution was allowed to cool, and the reaction solution was dropped into 500 ml of ethanol to crystallize a crude polymer.
The obtained crude polymer was dissolved in toluene (150 ml), N, N-diphenylamine (0.068 g, 0.040 mmol) and sodium tert-butoxy (0.74 g, 7.7 mmol) were charged, and the system was purged with nitrogen. Then, the mixture was heated to 60 ° C. (solution C). [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.043 g) was added to a toluene solution (3 ml) of tris (dibenzylideneacetone) dipalladium chloroform complex (0.021 g, 0.0203 mmol). , 0.16 mmol) and warmed to 60 ° C. (Solution D). The solution D was added to the solution C in a nitrogen stream, and the mixture was heated under reflux for 3 hours. Bromobenzene (0.35 g, 0.223 mmol) was added to the reaction. [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.043 g) was added to a toluene solution (3 ml) of tris (dibenzylideneacetone) dipalladium chloroform complex (0.021 g, 0.0203 mmol). , 0.1598 mmol) and heated to 60 ° C. (Solution E). The solution E was added to the reaction solution in a nitrogen stream, and the mixture was heated under reflux for 3 hours. The reaction solution was allowed to cool and dropped into a solution of ethanol / water (1500 ml / 100 ml) to obtain an end-capped crude polymer.
The end-capped crude polymer was dissolved in toluene and reprecipitated with acetone. The precipitated polymer was redissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The polymer collected by filtration was purified by column chromatography to obtain a polymer 2 (1.2 g).
Weight average molecular weight (Mw) = 110,000
Number average molecular weight (Mn) = 48200
Dispersion degree (Mw / Mn) = 2.28

<Synthesis of Polymer 3>

Compound 4 (9.0 g, 8.99 mmol), compound 9 (0.911 g, 1.36 mmol), sodium tert-butoxide (6.66 g, 69.3 mmol), and toluene (187 ml) were charged, and the system was sufficiently charged. The solution was heated to 60 ° C. (solution A). To a solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.186 g, 1.8 mmol) in 31 ml of toluene, [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.382 g, 1 .4 mmol) and heated to 60 ° C. (solution B). Solution B was added to solution A in a nitrogen stream, and the mixture was heated and refluxed for 1.0 hour. Subsequently, 4,4 "-dibromo-p-terphenyl (2.546 g, 6.56 mmol) was added. The mixture was heated under reflux for 1.0 hour. The reaction solution was allowed to cool, and toluene (125 ml) was added. The reaction solution was dropped into 1250 ml of ethanol to crystallize a crude polymer.
The obtained crude polymer was dissolved in 224 ml of toluene, N, N-diphenylamine (0.573 g, 3.4 mmol) and sodium tert-butoxy (3.125 g, 32.5 mmol) were charged, and the inside of the system was sufficiently purged with nitrogen. Then, the mixture was heated to 60 ° C. (solution C). [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.18 g) was added to a solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.088 g, 0.1 mmol) in 12.5 ml of toluene. , 0.7 mmol) and heated to 60 ° C. (solution D). Solution D was added to Solution C in a nitrogen stream, and the mixture was heated under reflux for 3 hours. Bromobenzene (2.659 g, 16.9 mmol) was added to the reaction. [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.18 g) was added to a solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.088 g, 0.1 mmol) in 12.5 ml of toluene. , 0.7 mmol) and warmed to 60 ° C. (Solution E). The solution E was added to the reaction solution in a nitrogen stream, and the mixture was heated and refluxed for 3 hours. The reaction solution was allowed to cool and dropped into a solution of ethanol / water (1120 ml / 108 ml) to obtain an end-capped crude polymer.
The end-capped crude polymer was dissolved in toluene and reprecipitated with acetone. The precipitated polymer was redissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The polymer collected by filtration was purified by column chromatography to obtain a polymer 3 (4.3 g).
Weight average molecular weight (Mw) = 35900
Number average molecular weight (Mn) = 27600
Dispersion degree (Mw / Mn) = 1.30

<Synthesis of Polymer 4>

Compound 4 (5.0 g, 4.99 mmol), compound 6 (0.313 g, 0.756 mmol), sodium tert-butoxide (3.699 g, 38.5 mmol), and toluene (104 ml) were charged, and the system was sufficiently charged. The solution was heated to 60 ° C. (solution A). To a solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.103 g, 0.1 mmol) in 17 ml of toluene, [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (0.212 g, 0 .8 mmol) and heated to 60 ° C. (Solution B). Solution B was added to solution A in a nitrogen stream, and the mixture was heated and refluxed for 1.0 hour. Subsequently, compound 10 (2.053 g, 3.74 mmol) was added. The mixture was heated under reflux for 1.0 hour.
N, N-diphenylamine (0.338 g, 2.0 mmol) was heated and refluxed for 1 hour. Bromobenzene (1.568 g, 10 mmol) was added to the reaction. The mixture was heated and refluxed for 2 hours. The reaction solution was allowed to cool and dropped into a solution of ethanol / water (342 ml / 100 ml) to obtain an end-capped crude polymer.
The crude end-capped polymer was dissolved in toluene, reprecipitated with acetone, and the precipitated polymer was redissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The polymer collected by filtration was purified by column chromatography to obtain a polymer 4 (2.1 g).
Weight average molecular weight (Mw) = 38800
Number average molecular weight (Mn) = 29800
Dispersion degree (Mw / Mn) = 1.30

<Preparation of organic electroluminescent device>
(Example 1)
The organic electroluminescent device shown in FIG. 1 was manufactured.
A transparent conductive film of indium tin oxide (ITO) deposited on a glass substrate 1 by sputtering is patterned into 2 mm-wide stripes using normal photolithography and hydrochloric acid etching to form a 70-nm thick film. An anode 2 was formed. The patterned ITO substrate is washed in the order of ultrasonic cleaning with an aqueous solution of a surfactant, water with ultrapure water, ultrasonic cleaning with ultrapure water, and water with ultrapure water, followed by drying with compressed air and finally ultraviolet light. Ozone cleaning was performed.
Next, a hole injection containing an arylamine polymer represented by the following structural formula (P1), 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate represented by the structural formula (A1), and ethyl benzoate A coating solution for forming a layer was prepared. This coating solution was spin-coated on the anode 2 under the following conditions to obtain a hole injection layer having a thickness of 31 nm.

<Coating liquid for forming hole injection layer>
Solvent Ethyl benzoate Coating solution concentration P1: 2.5% by weight
A1: 0.5% by weight
<Deposition conditions of hole injection layer 3>
Spinner rotation speed 3100rpm
Spinner rotation time 30 seconds Spin coat atmosphere Atmospheric heating condition Atmospheric temperature 240 ° C. 1 hour Subsequently, a coating liquid for forming a hole transport layer containing polymer 1 (P2) having the following structural formula was prepared. Under the conditions, a film was formed by spin coating on the hole injection layer 3 and heated to form a hole transport layer having a thickness of 20 nm.

<Coating solution for forming hole transport layer>
Solvent Cyclohexylbenzene Coating solution concentration 1.5% by weight
<Deposition conditions of hole transport layer 4>
Spinner rotation speed 1950rpm
Spinner rotation time 120 seconds Spin coating atmosphere Heating condition in nitrogen 230 ° C for 1 hour in nitrogen Next, a coating solution for forming a light emitting layer containing compounds (H1), (H2) and (D1) represented by the following structural formula Was prepared, and a film was formed by spin coating under the following conditions, and a 50 nm-thick light emitting layer was formed on the hole transport layer 4 by heating.

<Coating solution for forming light emitting layer>
Solvent Cyclohexylbenzene Coating solution concentration H1: 1.2% by weight
H2: 3.6% by weight
D1: 0.48% by weight
<Deposition condition of light emitting layer 5>
Spinner rotation speed 2050rpm
Spinner rotation time 120 seconds Spin coat atmosphere Nitrogen heating condition Nitrogen 130 ° C 10 minutes

Here, the substrate on which the layers up to the light-emitting layer were formed was transferred into a vacuum evaporation apparatus, and evacuated until the degree of vacuum in the apparatus became 2.0 × 10 ⁻⁴ Pa or less. ) Was deposited on the light emitting layer 5 by controlling the deposition rate in the range of 0.9 to 1.0 ° / sec by a vacuum deposition method to obtain a 10 nm-thick hole blocking layer 6.

  Next, an organic compound (E2) having the structure shown below is deposited on the hole blocking layer 6 by controlling the deposition rate in the range of 0.9 to 1.9 ° / sec by a vacuum deposition method. An electron transport layer 7 having a thickness of 20 nm was obtained.

Here, the element on which the electron transport layer 7 was deposited was transferred to another vacuum deposition apparatus, and a 2 mm-wide stripe-shaped shadow mask was used as a cathode deposition mask so that the element was perpendicular to the ITO stripe of the anode 2. And evacuated until the degree of vacuum in the apparatus became 3.1 × 10 ⁻⁴ Pa or less.
As the electron injection layer 8, lithium fluoride (LiF) was first formed on the electron transport layer 7 with a thickness of 0.5 nm by using a molybdenum boat at a deposition rate of 0.1 ° / sec. Next, aluminum was similarly heated as a cathode 9 by a molybdenum boat, and an aluminum layer having a film thickness of 80 nm was formed by controlling the deposition rate within the range of 1.1 to 8.8 ° / sec. The substrate temperature during the deposition of the above two layers was kept at room temperature.
Subsequently, in order to prevent the element from being deteriorated by atmospheric moisture or the like during storage, a sealing treatment 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.) is applied to the outer periphery of a glass plate of 23 mm × 23 mm with a width of about 1 mm, and a moisture getter sheet (Dynic Co., Ltd.) is applied to the center. Company-made). On this, the substrate on which the cathode formation was completed was bonded so that the vapor-deposited surface faced the desiccant sheet. After that, only the region where the photocurable resin was applied was irradiated with ultraviolet light to cure the resin.
As described above, an organic electroluminescent device having a light emitting area of 2 mm × 2 mm was obtained. Table 1 shows the characteristics of this device.

(Comparative Example 1)
The hole transport layer 4 is prepared by preparing a coating solution for forming a hole transport layer containing (P3) represented by the following structural formula and spin-coating the hole transport layer 4 on the hole injection layer 3 under the following conditions. An organic electroluminescent device was produced in the same manner as in Example 1, except that a hole transport layer having a thickness of 19 nm was formed by heating. Table 9 shows the characteristics of the obtained device.

<Coating solution for forming hole transport layer>
Solvent Cyclohexylbenzene Coating solution concentration 1.5% by weight
<Deposition conditions of hole transport layer 4>
Spinner rotation speed 1850rpm
Spinner rotation time 120 seconds Spin coat atmosphere Heating conditions in nitrogen 230 ° C for 1 hour in nitrogen

  As is clear from Table 9, the voltage of the organic electroluminescent device using the polymer of the present invention is low.

(Example 2)
The hole transport layer 4 is prepared by preparing a coating solution for forming a hole transport layer containing a polymer 2 (P4) represented by the following structural formula, and spin-coating the hole transport layer 3 on the hole injection layer 3 under the following conditions. The film was formed and heated to form a hole transport layer having a thickness of 20 nm.

<Coating solution for forming hole transport layer>
Solvent Cyclohexylbenzene Coating solution concentration 1.5% by weight
<Deposition conditions of hole transport layer 4>
Spinner rotation speed 3000rpm
Spinner rotation time 120 seconds Spin coating atmosphere Heating condition in nitrogen 230 ° C. for 1 hour in nitrogen A light emitting layer 5 was prepared by preparing a coating solution for forming a light emitting layer containing compounds (H3) and (D2) represented by the following structural formula. A film was formed by spin coating under the following conditions, and a light emitting layer having a thickness of 41 nm was formed on the hole transport layer 4 by heating.
Otherwise, an organic electroluminescent device was manufactured in the same manner as in Example 1. Table 10 shows the characteristics of the obtained device.

<Coating solution for forming light emitting layer>
Solvent Cyclohexylbenzene Coating solution concentration H3: 3.5% by weight
D2: 0.35% by weight
<Deposition condition of light emitting layer 5>
Spinner rotation speed 1850rpm
Spinner rotation time 120 seconds Spin coat atmosphere Nitrogen heating condition Nitrogen 130 ° C 10 minutes

(Comparative Example 2)
The hole transport layer 4 was formed by coating and heating a hole transport layer forming coating solution containing the compound of the structural formula (P3) in the same manner as in Comparative Example 1 to form a hole transport layer having a thickness of 19 nm. In the same manner as in Example 2, an organic electroluminescent device was produced. Table 10 shows the characteristics of the obtained device.

(Comparative Example 3)
The hole transport layer 4 is prepared by preparing a coating solution for forming a hole transport layer containing (P5) represented by the following structural formula and spin-coating the hole transport layer 4 on the hole injection layer 3 under the following conditions. An organic electroluminescent device was produced in the same manner as in Example 2, except that a hole transport layer having a thickness of 20 nm was formed by heating. Table 10 shows the characteristics of the obtained device.

<Coating solution for forming hole transport layer>
Solvent Cyclohexylbenzene Coating solution concentration 1.5% by weight
<Deposition conditions of hole transport layer 4>
Spinner rotation speed 1850rpm
Spinner rotation time 120 seconds Spin coat atmosphere Heating conditions in nitrogen 230 ° C for 1 hour in nitrogen

  As is clear from Table 10, the organic electroluminescent device using the polymer of the present invention has low voltage and high efficiency.

<Measurement of hole mobility>
(Example 3)
Using the Time of Flight (TOF) method, the hole mobility of the polymer 3 (P6) was measured in the same manner as in the method described in JP-A-2014-51667.

First, a substrate (manufactured by Geomatec) having an ITO transparent conductive film (ITO stripe) deposited to a thickness of 70 nm on a glass substrate was subjected to ultrasonic cleaning with a surfactant aqueous solution, water cleaning with ultrapure water, and ultrapure water. After cleaning in the order of ultrasonic cleaning with water and water cleaning with ultrapure water, the substrate was dried with compressed air and then subjected to ultraviolet ozone cleaning.
A solution was prepared by dissolving (P6) at a concentration of 10% by mass in a solvent in which toluene and silicone oil (KF-96 manufactured by Shin-Etsu Silicone Co., Ltd.) were mixed, and this solution was spin-coated on the washed substrate. A film was formed. The film formation was all performed in a nitrogen atmosphere. Thus, a film of the target polymer 1 having a thickness of 2 μm was obtained. Next, the sample was transferred to the vacuum chamber of the vacuum evaporation apparatus. A stripe-shaped shadow mask having a width of 2 mm as a mask for cathode deposition was placed in close contact with the element so as to be orthogonal to the ITO stripe. Thereafter, the inside of the apparatus was evacuated until the degree of vacuum became 8.0 × 10 ⁻⁴ Pa or less, and then aluminum was heated using a molybdenum boat to form an electrode with a thickness of 80 nm on the sample. During the aluminum film formation, the degree of vacuum in the chamber was kept at 2.0 × 10 ⁻³ Pa or less, and the deposition rate was kept at 0.6 to 10.0 ° / sec.
With respect to this sample, "VSL-337ND-S (nitrogen laser)" (excitation wavelength: 337 nm, pulse width <4 ns) manufactured by Spectra Physics Co., Ltd. with an electric field strength applied such that the ITO film functions as an anode and the aluminum electrode functions as a cathode. ) Was used to measure the transient photocurrent. The light irradiation energy was adjusted to 10 μJ by a reflection type ND filter to adjust the amount of light per pulse, and irradiated from the ITO electrode side. The transient photocurrent waveform was measured using an oscilloscope (“TDS2022” manufactured by Tektronix), and the charge mobility was calculated from the inflection point. This measurement was performed with an electric field strength of 160 kV / cm applied.
The calculation result of the hole mobility was represented by a relative value (normalized hole mobility) when the calculation result of the hole mobility of the compound represented by Structural Formula (P7) described below was “1.0”. . Table 11 shows the results.

(Comparative Example 4)
(P7) was measured in the same manner as in Example 3 except that the compound of the structural formula (P6) was changed to the compound of the structural formula (P7), and the calculated hole mobility was set to 1.0. And

  As is clear from Table 11, the polymer of the present invention has a large hole mobility.

  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 October 4, 2013 (Japanese Patent Application No. 2013-209111) and a Japanese patent application filed on January 28, 2014 (Japanese Patent Application No. 2014-013358). Here incorporated by reference.

1. Substrate 2. Anode 3. 3. hole injection layer 4. Hole transport layer Light emitting layer 6. 6. hole blocking layer Electron transport layer8. 8. electron injection layer cathode

Claims (15)

A polymer having a repeating unit represented by the following formula (1).

(In the formula, Ar ¹ and Ar ² are each independently a monovalent aromatic hydrocarbon group of a 6-membered monocyclic or 2 to 5 condensed ring which may have a substituent, or a substituent A 5- or 6-membered monocyclic or 2-4 condensed monovalent aromatic heterocyclic group which may have
Ar ³ is a monocyclic 6-membered ring or a divalent aromatic hydrocarbon group having 2 to 5 condensed rings which may have a substituent, or a 5- or 6-membered ring which may have a substituent Represents a monocyclic or 2 to 4 condensed ring divalent aromatic heterocyclic group,
At least one of Ar ¹ , Ar ² and Ar ³ has a crosslinkable group as a substituent,
n represents an integer of 4 or more.
A plurality of the aromatic hydrocarbon groups and the aromatic heterocyclic groups may be linked directly or via a linking group. )   The polymer according to claim 1, wherein the crosslinkable group is a group containing a benzocyclobutene ring. Ar ³ is a group represented by the following formula (2), or an aromatic hydrocarbon group or an aromatic heterocyclic group linked to one another via a linking group represented by the following formula (3): Item 3. The polymer according to item 1 or 2.

(In the formula, m represents an integer of 1 to 3.)

(In the formula, p represents an integer of 1 to 10. R ¹ and R ² each independently represent a hydrogen atom or an optionally substituted alkyl group, aromatic hydrocarbon group, or aromatic group. Represents a group heterocyclic group. When a plurality of R ¹ and R ² are present, they may be the same or different.) A polymer having a repeating unit represented by the following formula (1).

(In the formula, Ar ¹ and Ar ² are each independently a monovalent aromatic hydrocarbon group of a 6-membered monocyclic or 2 to 5 condensed ring which may have a substituent, or a substituent A 5- or 6-membered monocyclic or 2-4 condensed monovalent aromatic heterocyclic group which may have
Ar ³ represents a group represented by the following formula (2), or an aromatic hydrocarbon group or an aromatic heterocyclic group connected to a plurality of groups via a linking group represented by the following formula (3);
n represents an integer of 4 or more.
A plurality of the aromatic hydrocarbon groups and the aromatic heterocyclic groups may be linked directly or via a linking group. )

(In the formula, m represents an integer of 1 to 3.)

(In the formula, p represents an integer of 1 to 10. R ¹ and R ² each independently represent a hydrogen atom or an optionally substituted alkyl group, aromatic hydrocarbon group, or aromatic group. Represents a group heterocyclic group. When a plurality of R ¹ and R ² are present, they may be the same or different.)   5. The composition according to claim 4, wherein the polymer has two or more kinds of repeating units represented by the formula (1), at least one kind of the repeating units contains a crosslinkable group, and at least one kind of the repeating units contains no crosslinkable group. The polymer according to the above.   The polymer according to claim 5, wherein the crosslinkable group is a group containing a benzocyclobutene ring. Ar ¹ and Ar ² are each independently a monovalent 6-membered monocyclic or 2- to 5-condensed monovalent aromatic hydrocarbon group which may have a substituent. The polymer according to any one of the above. Ar ^1, Ar ² are each independently have a phenyl group or a substituted group may have a substituent is also good fluorenyl group, according to any one of claims 1 to 7 Polymer.   The polymer according to any one of claims 1 to 8, wherein the polymer has a weight average molecular weight (Mw) of 20,000 or more and a dispersity (Mw / Mn) of 2.5 or less.   A composition for an organic electroluminescent device, comprising the polymer according to claim 1. On a substrate, an anode, a cathode, and an organic electroluminescent device having an organic layer between the anode and the cathode,
An organic electroluminescent device, wherein the organic layer includes a layer formed by a wet film forming method using the composition for an organic electroluminescent device according to claim 10.   The organic electroluminescent device according to claim 11, 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 hole injection layer, a hole transport layer and a light emitting layer are included between the anode and the cathode, wherein the hole injection layer, the hole transport layer and the light emitting layer are all formed by a wet film formation method. Item 13. The organic electroluminescent device according to item 11 or 12.   An organic EL display device comprising the organic electroluminescent device according to claim 11.   An organic EL lighting device comprising the organic electroluminescent device according to claim 11.

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