KR102157997B1 - Polymer, composition for organic electroluminescent element, organic electroluminescent element, organic el display device, and organic el lighting - Google Patents

Abstract

A polymer having a repeating unit represented by the following formula (1). In the formula, 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 represents an integer of 4 or more. A plurality of the aromatic hydrocarbon groups and aromatic heterocyclic groups may be connected directly or through a linking group.
[Formula 1]

Description

Polymer, composition for organic electroluminescent device, organic electroluminescent device, organic EL display, and organic EL lighting {POLYMER, COMPOSITION FOR ORGANIC ELECTROLUMINESCENT ELEMENT, ORGANIC ELECTROLUMINESCENT ELEMENT, ORGANIC EL DISPLAY DEVICE, AND ORGANIC EL LIGHTING}

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 an organic EL display having the organic electroluminescent device, and It relates to organic EL lighting.

As a method of forming an organic layer in an organic electroluminescent device, a vacuum evaporation method and a wet film forming method are mentioned. The vacuum evaporation method has advantages in that it is easy to form a lamination, so that charge injection from the anode and/or the cathode is improved, and the light emitting layer of excitons is easily sealed. On the other hand, the wet film formation method does not require a vacuum process, is easy to achieve a large area, and uses a coating solution in which a plurality of materials having various functions are mixed, so that a layer containing a plurality of materials having various functions is used. There are advantages such as being able to form.

However, since the wet film formation method is difficult to laminate, the driving stability is inferior to that of the device by the vacuum evaporation method, and the present situation has not reached the practical level except for some.

Therefore, in order to perform lamination by a wet film forming method, a charge-transporting polymer having a crosslinkable group is desired, and its development is being carried out. For example, in Patent Documents 1 to 5, an organic electroluminescent device containing a polymer having a specific repeating unit and laminated by a wet film forming method is disclosed.

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

However, these devices described in Patent Documents 1 to 5 have problems of high driving voltage, low light emission luminance, and short driving life. Therefore, there has been a demand for improvement in charge injection transport capability and durability of the charge transport material.

Therefore, it is an object of the present invention to provide a polymer having high hole injection and transporting ability and high durability, and a composition for organic electroluminescent devices containing the polymer. Moreover, it is an object of the present invention to provide an organic electroluminescent device having high luminance and long drive life.

As a result of intensive examination, the inventors of the present invention found that the above problem was solved by using a polymer having a specific repeating unit, and the present invention was completed.

That is, the present invention relates to the following.

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

[Formula 1]

(In the formula, 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 represents an integer of 4 or more. The aromatic hydrocarbon group and the aromatic heterocyclic group are, Directly or through a connector, a plurality of pieces may be connected.)

[2]

The polymer according to [1], wherein at least one or more 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]

In [2] or [3], having two or more repeating units represented by the above formula (1), at least one repeating unit containing a crosslinkable group, and at least one repeating unit not containing a crosslinkable group Described polymer.

[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).

[Formula 2]

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

[7]

The polymer according to any one of [1] to [5], wherein Ar ³ is an aromatic hydrocarbon group or an aromatic heterocyclic group connected in plural through a linking group represented by the following formula (3).

[Formula 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, an aromatic hydrocarbon group, or an aromatic heterocyclic group. R ¹ , R ² When a plurality of s are present, they may be the same or different.)

[8]

The polymer according to any one of [1] to [7], wherein the weight average molecular weight (Mw) is 20,000 or more, and the dispersion degree (Mw/Mn) is 2.5 or less.

[9]

A composition for organic electroluminescent devices containing the polymer according to any one of [1] to [8].

[10]

An organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate,

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 [9].

[11]

The organic electroluminescent device according to [10], wherein the layer formed by the wet film formation method is at least one of a hole injection layer and a hole transport layer.

[12]

The organic electric field according to [10] or [11], comprising a hole injection layer, a hole transport layer, and a light-emitting layer between an anode and a cathode, wherein the hole injection layer, the hole transport layer, and the light-emitting layer are all formed by a wet film formation method. Light-emitting element.

[13]

An organic EL display device comprising the organic electroluminescent element according to any one of [10] to [12].

[14]

An organic EL illumination comprising the organic electroluminescent element according to any one of [10] to [12].

The polymer of the present invention has four or more consecutive p-phenylene groups between the nitrogen atom and the nitrogen atom having a non-shared electron pair, and since the HOMO is sufficiently broadly delocalized, it is excellent in hole transporting ability. If the p-phenylene group has a substituent, the dihedral angle of each p-phenylene period increases due to steric hindrance, and delocalization of the orbit is hindered, so that high hole transport capacity is not obtained, but p- Since the phenylene group does not have a substituent, the orbital is sufficiently delocalized and has a high hole transport ability.

In addition, since the polymer of the present invention has 4 or more p-phenylene groups between two nitrogen atoms, the interaction between nitrogen atoms is small and the ionization potential is increased compared to 3 or less p-phenylene groups, 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.

Further, the polymer of the present invention has four or more consecutive p-phenylene groups, and since LUMO is sufficiently broadly delocalized, it is excellent in durability against electrons and excitons. Of four or more consecutive p-phenylene groups, as LUMO is distributed in two or more consecutive p-phenylene groups located far from two nitrogen atoms, LUMO is relatively not distributed around nitrogen atoms weak to electrons or excitons. Because it is not, it is excellent in durability. If the p-phenylene group has a substituent, the dihedral angle of each p-phenylene period increases due to steric hindrance, and delocalization of the orbit is hindered, so high durability is not obtained, but p-phenylene in the polymer of the present invention Since the group does not have a substituent, the orbital is sufficiently delocalized and has high durability.

Further, the layer obtained by forming a wet film using the composition for an organic electroluminescent device containing the polymer of the present invention is flat without cracking or the like. According to the organic electroluminescent device in the present invention, the luminance is high and the driving life is long.

In addition, since the polymer of the present invention has excellent electrochemical stability, devices including a layer formed using the polymer include flat panel displays (for example, OA computers or wall-mounted televisions), on-vehicle display devices, It is considered to be applied to a mobile phone display or a light source utilizing the characteristics of a surface illuminant (for example, a light source for a photocopier, a backlight light source for a liquid crystal display or instrument), a display panel, a sign, etc., and its technical value is great.

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

The embodiments of the present invention will be described in detail below, but the description of the constitutional requirements described below is an example (representative example) of the embodiments of the present invention, and the present invention is specific to these contents as long as the gist of the present invention is not exceeded. It doesn't work.

In this specification, "mass%" and "weight%" have the same meaning.

The polymer of the present invention is a polymer having a repeating unit represented by the following formula (1).

[Formula 4]

(In the formula, 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 represents an integer of 4 or more. The aromatic hydrocarbon group and the aromatic heterocyclic group are, Directly or through a connector, a plurality of pieces may be connected.)

[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.

As an aromatic hydrocarbon group, 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, fluorine A monovalent group of a 6-membered ring or a 2 to 5 condensed ring, such as a lanthene ring and a fluorene ring, is mentioned.

As an aromatic heterocyclic group, for example, 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 p Roloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, Benzoimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, phenanthridine ring, perimidine ring, quinazoline ring And a monovalent group of a 5 or 6 membered ring or a monovalent group of a 2 to 4 condensed ring, such as a quinazolinone ring and an azulene ring.

From the viewpoint of excellent charge transport property and excellent durability, Ar ¹ and Ar ² are preferably aromatic hydrocarbon groups, and among them, monovalent groups of a benzene ring and a fluorene ring, that is, a phenyl group and a fluorenyl group, are more preferable, A fluorenyl group is more preferable, and a 2-fluorenyl group is particularly preferable.

The aromatic hydrocarbon group and the substituent which the aromatic heterocyclic group may have are not particularly limited as long as the properties of the polymer are not significantly reduced, but examples include a group selected from the following substituent group Z, and an alkyl group, An alkoxy group, an aromatic hydrocarbon group, and an aromatic heterocyclic group are preferable, and an alkyl group is more preferable.

[Substituent group Z]

For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group, etc. , A linear, branched, or cyclic alkyl group having usually 1 or more carbon atoms, usually 24 or less, preferably 12 or less;

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

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

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

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

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

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

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

An arylalkylamino group having usually 7 or more carbon atoms, and usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;

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

Halogen atoms, such as a fluorine atom and a chlorine atom;

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

An alkylthio group having usually 1 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methylthio group and an ethylthio group;

For example, an arylthio group having a carbon number of usually 4 or more, preferably 5 or more, and usually 36 or less, preferably 24 or less, such as a phenylthio group, a naphthylthio group, and a pyridylthio group;

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

For example, a siloxy group having a carbon number of usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less, such as a trimethylsiloxy group and a triphenylsiloxy group;

Cyano group;

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

An aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 36 or less, preferably 24 or less carbon atoms, such as thienyl group and pyridyl group.

Among these substituents, from the viewpoint of solubility, an alkyl group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms are preferable.

Further, each of the above substituents may further have a substituent, and examples thereof are selected from the groups exemplified in the above (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 aromatic hydrocarbon groups and aromatic heterocyclic groups may be bonded.

As an aromatic hydrocarbon group, 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, fluorine A monocyclic 6-membered ring or a divalent group of 2 to 5 condensed rings, such as a lanthene ring and a fluorene ring.

As an aromatic heterocyclic group, for example, 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 p Roloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, Benzoimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, phenanthridine ring, perimidine ring, quinazoline ring , 5- or 6-membered monocyclic or 2-4 condensed divalent groups such as a quinazolinone ring and an azulene ring.

From the viewpoint of excellent charge transport property and excellent durability, for Ar ³ , an aromatic hydrocarbon group is preferable, 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, and 1 A ,3-phenylene group, a 1,4-phenylene group, and a 2,7-fluorenylene group are more preferable.

The aromatic hydrocarbon group and the substituent that the aromatic heterocyclic group may have are not particularly limited as long as the properties of the polymer are not significantly reduced, but examples include a group selected from the above substituent group Z, and an alkyl group and an alkoxy A group, an aromatic hydrocarbon group, and an aromatic heterocyclic group are preferable, and an 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, it is preferable that 2 to 6 of these groups are connected from the viewpoint of excellent charge transport properties and excellent durability. One type may be sufficient as the aromatic hydrocarbon group and the aromatic heterocyclic group to be connected, and multiple types may be sufficient as it.

Ar ³ is a group in which 1 to 3 p-phenylene groups represented by the following formula (2) are bonded, in addition to charge transport properties and durability, it is particularly preferable from the viewpoint of excellent hole injection from the anode side.

[Formula 5]

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

Moreover, when Ar ³ is a group in which a plurality of the aromatic hydrocarbon groups and aromatic heterocyclic groups are bonded, they may be bonded through a linking group. In this case, 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 having 2 to 10 linking them are preferred. . Moreover, when two or more are connected, 1 type may be sufficient as a connector, and multiple types may be sufficient as it. 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, and an aromatic heterocyclic group which may have a substituent. The alkyl group, aromatic hydrocarbon group, or aromatic heterocyclic group is preferably the same group as the group described in the aforementioned substituent group Z. As a linking group, -CR ¹ R ² -and 2 to 6 connected -CR ¹ R ² -are particularly preferable, and -CR ¹ R ² -is more preferable from the viewpoint of durability.

Ar ³ is particularly preferably an aromatic hydrocarbon group and an aromatic heterocyclic group connected in plural through a linking group represented by the following formula (3) from the viewpoint of durability.

[Formula 6]

(In the formula, p represents an integer of 1 to 10. R ¹ and R ² each independently represent a hydrogen atom or an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group which may have a substituent. An alkyl group or an aromatic hydrocarbon group. Or the aromatic heterocyclic group is preferably the same group as the group described in the aforementioned substituent group Z. When a plurality of R ¹ and R ² are present, they may be the same or different.)

[for n]

n represents an integer of 4 or more. Since the hole transport ability is high and hole injection from the anode side is excellent, n is preferably 4. Since the hole transporting ability is high and hole injection into the light emitting layer is excellent, n is preferably 5.

[About the crosslinked penis]

It is preferable that the polymer of the present invention has a crosslinkable group as a substituent in at least one or more of Ar ¹ , Ar ² and Ar ³ . By having a crosslinkable group, a large difference in solubility in an organic solvent can be generated before and after a reaction (slightly solubilization reaction) that occurs by irradiation of heat and/or active energy rays. From the viewpoint of durability, it is more preferable to have a crosslinkable group as a substituent for Ar ³ .

The crosslinkable group refers to a group that reacts with a group constituting another molecule located in the vicinity of the crosslinkable group by irradiation of heat and/or an active energy ray to form a new chemical bond. In this case, the reactive group may have the same or different contributions as the crosslinkable group. As a crosslinkable group, the group shown to the following crosslinkable group group T is mentioned, for example.

〈Cross-linked seonggi group T〉

[Formula 7]

(In the formula, 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. Ar ⁷ may have an aromatic hydrocarbon group or a substituent which may have a substituent. It represents an aromatic heterocyclic group to become.)

As the alkyl group of R ¹ to R ⁵ , a linear or branched chain alkyl group having 6 or less carbon atoms is usually preferred, and for example, methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group And isobutyl group. More preferably, it is a methyl group or an ethyl group. When the number of carbon atoms of R ¹ to R ⁵ is 6 or less, the crosslinking reaction is not sterically inhibited, and insolubilization of the film tends to occur.

As the alkoxy group of R ⁴ and R ⁵ , a linear or branched chain alkoxy group having 6 or less carbon atoms is usually preferable, and for example, a methoxy group, an ethoxy group, an n-propoxy group, a 2-propoxy group, n-butoxy group and the like. More preferably, they are a methoxy group and an ethoxy group. When the number of carbon atoms of R ⁴ and R ⁵ is 6 or less, the crosslinking reaction is not sterically inhibited, and insolubilization of the film tends to occur.

In addition, examples of the aromatic hydrocarbon group which may have a substituent for Ar ⁷ include a monocyclic or 2 to 5 condensed ring having one free valency and a 6-membered ring such as a benzene ring and a naphthalene ring. In particular, a benzene ring having one free valency is preferred. Moreover, Ar ⁷ may also be a contribution 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.

Among these, a group which crosslinks by cation polymerization such as an epoxy group and an oxetane group, or a vinyl ether group is preferable because of its high reactivity and easy insolubilization by crosslinking. Among them, an oxetane group is more preferable from the viewpoint of being easy to control the rate of cation polymerization, and a vinyl ether group is preferable because hydroxyl groups that may cause deterioration of the device during cation polymerization are not easily produced.

Further, a group subjected to cyclization addition reaction, such as an arylvinylcarbonyl group such as a cinnamoyl group and a benzocyclobutene ring having one free valency, is preferable from the viewpoint of further improving the electrochemical stability of the device.

In addition, among the crosslinkable groups, a benzocyclobutene ring having one free valency is particularly preferred from the viewpoint that 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 directly bonded to a group other than an aromatic hydrocarbon group and/or an aromatic heterocyclic group, You may bond to these groups through an arbitrary divalent group. As an arbitrary divalent group, a group formed by connecting 1 to 30 groups selected from -O- group, -C(=O)- group, and (may have a substituent) -CH ₂ -group is preferable Do.

Since the crosslinkable group which the polymer of the present invention has is sufficiently insolubilized by crosslinking and other layers are easily formed thereon by a wet film forming method, many are preferable. On the other hand, it is preferable that there are few crosslinkable groups from the point that cracks do not easily occur in the formed layer, unreacted crosslinkable groups do not remain, and the organic electroluminescent device (organic EL device) tends to have a long life.

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

In addition, the number of crosslinkable groups that the polymer of the present invention has can be represented by the number per 1000 molecular weight of the polymer.

When the number of crosslinkable groups in the polymer of the present invention is expressed as the number per 1000 molecular weight of the polymer, per 1000 molecular weight, usually 3.0 or less, preferably 1.0 or less, more preferably 0.5 or less, even more preferably It is 0.2 or less, and is usually 0 or more, preferably 0.01 or more, more preferably 0.02 or more, even more preferably 0.05 or more.

When the number of crosslinkable groups is within the above range, cracks and the like are less likely to occur, and a flat film is easily obtained. Moreover, since the crosslinking density is appropriate, there are few unreacted crosslinkable groups remaining in the layer after the crosslinking reaction, and it is difficult to affect the life of the resulting device.

In addition, since the poor solubility in the organic solvent after the crosslinking reaction is sufficient, a multilayered structure by a wet film formation method is easily formed.

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

For example, in the case of the target polymer 1 synthesized in Synthesis Example 1 described later, in the target polymer 1, the molecular weight of the repeating unit excluding the terminal group is on average 1148.69, and the crosslinkable group is on average 0.1156 per repeating unit. It's a dog. When this is calculated by simple proportion, the number of crosslinkable groups per 1000 molecular weight is calculated as 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, still more preferably 200,000 or less, and usually 2,500 or more, preferably 5,000 or more, more preferably Preferably, it is 10,000 or more, more preferably 30,000 or more.

When the weight average molecular weight of the polymer exceeds the above upper limit, the solubility in the solvent is lowered, so that the film formation property may be impaired. Moreover, when the weight average molecular weight of a polymer is less than the said lower limit, since the glass transition temperature, melting point, and vaporization temperature of a polymer fall, heat resistance may fall.

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

In addition, the dispersion degree (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. In addition, since the smaller the value of the degree of dispersion is, the better the lower limit is 1. When the dispersion degree of the polymer is equal to or less than the above upper limit, purification is easy, and solubility in a solvent and charge transport ability are good.

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

[Specific example]

Specific examples of the polymer of the present invention are shown below, but the polymer of the present invention is not limited thereto. In addition, the number in the formula indicates the molar ratio of the repeating units.

In the case of a polymer containing a repeating unit having a crosslinkable group and a repeating unit not having a crosslinkable group in the formula (1), for example, the number in the formula is the molar ratio of the crosslinkable group. With respect to the repeating unit having, the repeating unit not having a crosslinkable group is usually 0 or more, preferably 1 or more, more preferably 2 or more, still more preferably 5 or more, and usually 100 or less, preferably 50 Below, it is 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, poor solubility in the organic solvent after the crosslinking reaction is not sufficient, and the multilayered structure in the wet film formation method tends to become difficult, and if it is too large, cracks and the like occur. There is a tendency that it is not easy to obtain a flat film.

These polymers may be any of a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer, and are not limited to the sequence of monomers.

[Formula 8]

[Formula 9]

<Production method of 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 prepared by combining CC bond formation reactions and CN bond formation reactions such as Suzuki reaction, Grignard reaction, Ullmann reaction, and Buchwald-Hartwig reaction. I can. However, since the portion of 4 or more consecutive p-phenylene groups, which is a characteristic of the polymer of the present invention, has a structure having insufficient solubility, after introducing a substituent to increase solubility in Ar ¹ and/or Ar ² , 4 or more It is desirable to conduct a study to construct a portion of a continuous p-phenylene group. By such a study, the purity of the monomer (repeating unit) increases, and a polymer having a desired degree of polymerization and molecular weight distribution becomes easy to be obtained.

Specifically, after reacting a highly soluble primary amine such as 9,9-dialkyl-2-aminofluorene with bromobenzene to obtain a secondary amine, the p-position of the amino group is changed to N-bromo. It is preferable to form intermediate 1 by bromination with succinimide or the like and further reacting with 4,4'-biphenyldiboronic acid, 4,4'-p-terphenyldiboronic acid or their ester derivatives. The polymer of the present invention is obtained by reacting Intermediate 1 with a dihalide.

By carrying out the reaction of bromide with 4,4'-biphenyldiboronic acid, 4,4'-p-terphenyldiboronic acid or their ester derivatives ^one by one, two Ar ¹ of Intermediate 1 can be made into different groups from each other. .

[Formula 10]

Further, by reacting a highly soluble primary amine such as 9,9-dialkyl-2-aminofluorene with 4,4'-dibromobiphenyl to obtain a monobromide having a secondary amine moiety, bis (Pinacolato) Converted to a boronic acid ester with diborone, etc. to obtain intermediate 2, and also, a highly soluble primary amine and 4,4'-dibromobiphenyl, 4,4'-dibromo-p- It is preferable to react a dihalide such as terphenyl to obtain intermediate 3, and to react intermediate 2 and intermediate 3 to form intermediate 4. The polymer of the present invention is obtained by reacting the intermediate 4 with a dihalide.

[Formula 11]

In addition, usually, the reaction step of the primary or secondary amine compound and the halide is carried out in the presence of a base such as potassium carbonate, tert-butoxy sodium, and triethylamine. In addition, it can also be carried out in the presence of a transition metal catalyst such as copper or palladium complex.

In addition, usually, the reaction step of the boron derivative and the halide is carried out in the presence of a base such as potassium carbonate, sodium tert-butoxy, and triethylamine. Moreover, it can also be implemented in the presence of a transition metal catalyst, such as copper or a palladium complex, as needed. In addition, in the reaction step with a boron derivative, for example, it can be carried out in the presence of a base such as potassium carbonate, potassium phosphate, tert-butoxy sodium, triethylamine, or a transition metal catalyst such as a palladium complex.

<Organic EL 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 a hole injection layer and a hole transport layer in an organic electroluminescent device, that is, a charge transport material.

When used as a charge transport material, one type of the polymer of the present invention may be contained, or two or more types may be contained in any combination and in any ratio.

When at least one of the hole injection layer and the hole transport layer of an organic electroluminescent device is formed by using the polymer of the present invention, the content of the polymer of the present invention in the hole injection layer and/or the hole transport layer is usually 1 to 100% by mass. , Preferably it is 5 to 100 mass%, More preferably, it is 10 to 100 mass%. Within the above range, charge transport properties of the hole injection layer and/or the hole transport layer are improved, the driving voltage is reduced, and the driving stability is improved, which is preferable.

When the polymer according to the present invention is not 100% by mass in the hole injection layer and/or the hole transport layer, as a component constituting the hole injection layer and/or the hole transport layer, a hole-transporting compound to be described later may be mentioned.

Further, since an organic electroluminescent device can be manufactured simply, the polymer of the present invention is preferably used for an organic layer formed by a wet film forming method.

[Composition for organic electroluminescent device]

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

{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.

Within the above range, defects are less likely to occur in the formed organic layer, and film thickness irregularities are less likely to occur, which is preferable.

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

{menstruum}

The composition for an organic electroluminescent device of the present invention usually contains a solvent. It is preferable that this solvent dissolve the polymer of this invention. Specifically, a solvent which dissolves the polymer of the present invention at room temperature is usually 0.05% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass or more 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 Aliphatic ethers such as glycol diethyl ether and propylene glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethyl, 2-methoxytoluene, Ether solvents such as aromatic ethers such as 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole; ethyl acetate, n-butyl acetate, ethyl lactate, and lactate n -Alphatic esters such as butyl; Ester solvents such as aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and n-butyl benzoate; organic solvents such as organic solvents, as described later An organic solvent used in a composition for forming a hole injection layer or a composition for forming a hole transport layer may be mentioned.

In addition, one type of solvent may be used, and 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, the surface tension at 20°C is usually less than 40 dyn/cm, preferably 36 dyn/cm or less, more preferably 33 A solvent of 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, it is preferable that the affinity between the solvent and the base is high. This is because the uniformity of the film quality greatly affects the uniformity and stability of light emission of the organic electroluminescent device. Accordingly, the composition for an organic electroluminescent device used in the wet film formation method is required to have a lower surface tension so that a more leveling property and a uniform coating film can be formed. Therefore, the use of a solvent having a low surface tension as described above is preferable because a uniform layer containing the polymer of the present invention can be formed, and further, a uniform crosslinked layer can be formed.

Specific examples of the low surface tension solvent include aromatic solvents such as toluene, xylene, mesitylene, and cyclohexylbenzene, ester solvents such as ethyl benzoate, ether solvents such as anisole, and trifluoromethoxy. Anisole, pentafluoromethoxybenzene, 3-(trifluoromethyl)anisole, ethyl (pentafluorobenzoate), etc. are mentioned.

On the other hand, as the solvent contained in the composition for an organic electroluminescent device of the present invention, the vapor pressure at 25°C is usually 10 mmHg or less, preferably 5 mmHg or less, and usually 0.1 mmHg or more. It is desirable. By using such a solvent, a composition for an organic electroluminescent device suitable for the process of manufacturing 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 aromatic solvents such as toluene, xylene and mesitylene described above, ether solvents, and ester solvents.

However, moisture may cause deterioration in the performance of the organic electroluminescent device, and among them, there is a possibility of promoting a decrease in luminance particularly during continuous driving. Therefore, in order to reduce the moisture remaining during wet film formation as much as possible, among the solvents, the solubility of water at 25°C is preferably 1% by mass or less, and more preferably 0.1% by mass or less.

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 more than the above lower limit, the flatness and uniformity of the formed layer can be improved.

<Electron-accepting compound>

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

As the electron accepting compound, a compound having an oxidizing power and an ability to accept one electron from the polymer of the present invention is preferable. Specifically, a compound 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.

As such an electron-accepting compound, for example, selected from the group consisting of a triarylboron compound, a metal halide, a Lewis acid, an organic acid, an onium salt, a salt of an arylamine and a metal halide, and a salt of an arylamine and a Lewis acid. One type or two or more types of compounds to be used.

Specifically, onium salts substituted with organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (International Publication No. 2005/089024 No.); Iron (III) chloride (Japanese Patent Laid-Open No. 11-251067), high-valent inorganic compounds such as ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; tris(pentafluorophenyl) borane Aromatic boron compounds, such as (Japanese Patent Application Laid-Open No. 2003-31365); fullerene derivatives, iodine, and the like.

Examples of such compounds include elements belonging to groups 15 to 17 of the long periodic table (hereinafter, in the case of a "periodic table" unless otherwise specified, the long periodic table is referred to.) , It is preferably an ionic compound having a structure in which at least one organic group is bonded with a carbon atom, and particularly, it is preferably a compound represented by the following formula (4).

[Formula 12]

In formula (4), R ⁶ represents an organic group bonded to A ₁ with a carbon atom, and R ⁷ represents an arbitrary substituent. R ⁶ and R ⁷ may be bonded to each other to form a ring.

As R ^{6, as long} as it is an organic group having a carbon atom in the bonding portion with A ₁ , the kind is not particularly limited unless it is contrary to the spirit of the present invention. The molecular weight of R ⁶ is a value including a substituent and is generally 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 the static charge. Among them, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferable because it delocalizes the static charge and is thermally stable.

Examples of the aromatic hydrocarbon group include a five-membered ring or a six-membered monocyclic ring or a two to five condensed ring having one free valency, and a group that delocalizes a static charge by the group phase. Specific examples thereof include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, which has one free valency, Acenaphthene ring, fluorene ring, etc. are mentioned.

Examples of the aromatic heterocyclic group include a 5-membered ring or a 6-membered monocyclic ring or a 2-4 condensed ring having one free valency, and a group that delocalizes a static charge by the phase of the group. Specific examples thereof include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, and an indole having one free valency. Ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisooxazole ring , Benzoisothiazole ring, benzoimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, phenanthridine ring, A perimidine ring, a quinazoline ring, a quinazolinone ring, an azulene ring, etc. are mentioned.

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

Examples of the alkenyl group include those having usually 2 or more, usually 12 or less, and preferably 6 or less carbon atoms. As a specific example, a vinyl group, an allyl group, 1-butenyl group, etc. are mentioned.

Examples of the alkynyl group include those having usually 2 or more, usually 12 or less, and preferably 6 or less carbon atoms. As a specific example, an ethynyl group, a propargyl group, etc. are mentioned.

R ⁷ is not particularly limited unless contrary to the spirit of the present invention. The molecular weight of R ⁷ is a value including a substituent, and is usually 1000 or less, and preferably 500 or less.

Examples of R ⁷ include an alkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, aromatic heterocyclic group, amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylcarbonyloxy group, alkyl thi Group, arylthio group, sulfonyl group, alkylsulfonyl group, arylsulfonyl group, cyano group, hydroxyl group, thiol group, silyl group, and the like.

Among them, as in R ⁶ , from the viewpoint of high electron acceptability, an organic group having a carbon atom in the bonding portion with A ₁ is preferable. Examples include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. desirable. In particular, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferable from the viewpoint of high electron acceptability and thermal stability.

Alkyl group of R ^7, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, aromatic heterocyclic group, there may be mentioned those described above for R ⁶ the same.

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 one or more alkyl groups having usually 1 or more carbon atoms, and usually 12 or less, and preferably 6 or less carbon atoms. As a specific example, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group, etc. are mentioned.

Examples of the arylamino group include an arylamino group having at least one aromatic hydrocarbon group or at least one aromatic heterocyclic group having usually 3 or more carbon atoms, preferably 4 or more, and usually 25 or less, preferably 15 or less. As a specific example, a phenylamino group, a diphenylamino group, a tolylamino group, a pyridylamino group, a thienylamino group, etc. are mentioned.

Examples of the acylamino group include an acylamino group having one or more acyl groups having usually 2 or more carbon atoms, and usually 25 or less, preferably 15 or less. As a specific example, an acetylamino group, a benzoylamino group, etc. are mentioned.

Examples of the alkoxy group include an alkoxy group having usually 1 or more carbon atoms, and usually 12 or less, and preferably 6 or less carbon atoms. As a specific example, a methoxy group, an ethoxy group, a butoxy group, etc. are mentioned.

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, and preferably 15 or less carbon atoms. As a specific example, a phenyloxy group, a naphthyloxy group, a pyridyloxy group, a thienyloxy group, etc. are mentioned.

Examples of the acyl group include an acyl group having usually 1 or more carbon atoms, and usually 25 or less, preferably 15 or less carbon atoms. As a specific example, a formyl group, an acetyl group, a benzoyl group, etc. are mentioned.

Examples of the alkoxycarbonyl group include an alkoxycarbonyl group having usually 2 or more carbon atoms, and usually 10 or less, and preferably 7 or less carbon atoms. As a specific example, a methoxycarbonyl group, an ethoxycarbonyl group, etc. are mentioned.

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 carbon atoms. As a specific example, a phenoxycarbonyl group, a pyridyloxycarbonyl group, etc. are mentioned.

Examples of the alkylcarbonyloxy group include an alkylcarbonyloxy group having usually 2 or more carbon atoms, and usually 10 or less, and preferably 7 or less carbon atoms. As a specific example, an acetoxy group, a trifluoroacetoxy group, etc. are mentioned.

Examples of the alkylthio group include an alkylthio group having usually 1 or more carbon atoms, and usually 12 or less, and preferably 6 or less carbon atoms. As a specific example, a methylthio group, an ethylthio group, etc. are mentioned.

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 carbon atoms. As a specific example, a phenylthio group, a naphthylthio group, a pyridylthio group, etc. are mentioned.

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

As a specific example of a sulfonyloxy group, a mesyloxy group, a tosyloxy group, etc. are mentioned.

As a specific example of a silyl group, a trimethylsilyl group, a triphenylsilyl group, etc. are mentioned.

The groups exemplified as R ⁶ and R ⁷ above may be further substituted with other substituents as long as they do not contradict the spirit of the present invention. The kind of the substituent is not particularly limited, but examples thereof include a halogen atom, a cyano group, a thiocyano group, a nitro group, etc. in addition to the groups exemplified as R ⁶ and R ⁷ respectively. Among them, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an aromatic hydrocarbon group, and an aromatic heterocyclic group are preferable from the viewpoint of not disturbing the heat resistance and electron acceptability of the ionic compound (electron-accepting compound).

In formula (4), A ₁ is preferably an element belonging to Group 17 of the periodic table, and from the viewpoint of electron acceptability and availability, an element before the 5th period of the periodic table (3rd to 5th periods) is preferable. Do. That is, as A ₁ , any of an iodine atom, a bromine atom, and a chlorine atom is preferable.

In particular, from the viewpoint of electron acceptability and stability of the compound, 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 which is an iodine atom is most preferable.

In Formula (4), Z ₁ ^n1- represents a counter anion. The kind of 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 the negative charge becomes delocalized, and the correspondingly, the static charge is delocalized and the electron accepting capacity increases. Therefore, the complex ion is more preferable than the monoatomic ion.

n ₁ is an arbitrary positive integer corresponding to the ionic value of the counter anion Z ₁ ^n1- . The value of n ₁ is not particularly limited, but it is preferably 1 or 2, and most preferably 1.

As a specific example of Z ₁ ^n1- , a hydroxide ion, a fluoride ion, a chloride ion, a bromide ion, an iodide ion, a cyanide ion, a nitrate ion, a nitrite ion, a sulfate ion, a sulfite ion, a perchlorate ion, a perbromate ion , Periodate ion, chlorate ion, chlorite ion, hypochlorite ion, phosphate ion, phosphorous acid ion, hypophosphorous acid ion, boric acid ion, isocyanate ion, hydrogen sulfide ion, tetrafluoroborate ion, hexafluorophosphate ion, Hexachloroantimony acid ions; Carboxylic acid ions such as acetate ions, trifluoroacetate ions and benzoic acid ions; sulfonic acid ions such as methanesulfonic acid ions and trifluoromethanesulfonic acid ions; methoxy ions, t-butoxy ions, etc. Alkoxy ions and the like, and tetrafluoroboronic acid ions and hexafluoroboronic acid ions are preferable.

In addition, since the counter anion Z ₁ ^n1- is the stability of the compound, the solubility in the solvent, and the large size, the negative charge becomes delocalized, and the accompanying electrostatic charge is delocalized, thereby increasing the electron accepting capacity. Complex ions represented by formula (5) are particularly preferred.

[Formula 13]

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

In 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 ring or a 6-membered monocyclic ring or a 2-4 condensed ring having one free valency as exemplified above for R ⁶ . Among them, from the viewpoint of stability and heat resistance of the compound, a benzene ring, naphthalene ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring having one free valency desirable.

The aromatic hydrocarbon group and the aromatic heterocyclic group exemplified as Ar ⁶ to Ar ⁹ may be further substituted with other substituents as long as they do not contradict the spirit of the present invention. The kind of the substituent is not particularly limited, and an arbitrary substituent is applicable, but it is preferably an electron withdrawing group.

When an electron withdrawing group preferable as a substituent which Ar ⁶ to Ar ⁹ may have, a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom; a cyano group; a thiocano group; a nitro group; an alkylsulfonyl group such as a mesyl group; Arylsulfonyl groups such as tosyl groups; 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, ethoxycarbonyl group, etc., An alkoxycarbonyl group having a carbon number of usually 2 or more, usually 10 or less, preferably 7 or less; A carbon number such as a phenoxycarbonyl group and a pyridyloxycarbonyl group, such as, usually 3 or more, preferably 4 or more, usually 25 or less, An aryloxycarbonyl group having an aromatic hydrocarbon group or an aromatic heterocyclic group of preferably 15 or less; an aminocarbonyl group; an aminosulfonyl group; a trifluoromethyl group, a pentafluoroethyl group, and the like, with carbon number of usually 1 or more, usually 10 or less, Preferably, a haloalkyl group in which a halogen atom such as a fluorine atom or a chlorine atom is substituted with 6 or less linear, branched or cyclic alkyl groups, and the like are exemplified.

Among them, it is more preferable that at least one group of Ar ⁶ to Ar ⁹ has 1 or 2 or more fluorine atoms or chlorine atoms as substituents. Particularly, it is most preferable that the hydrogen atoms of Ar ⁶ to Ar ⁹ are all substituted with fluorine atoms from the point of effectively delocalizing negative charges and having suitable sublimation properties. As a specific example of a perfluoroaryl group, a pentafluorophenyl group, a heptafluoro-2-naphthyl group, a tetrafluoro-4-pyridyl group, etc. are mentioned.

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

If it is within the above range, it is preferable in that the electrostatic charge and the negative charge are sufficiently delocalized, the electron accepting capacity is good, and it is difficult to obstruct charge transport.

Specific examples of the electron accepting compound suitable for the present invention are shown below, but the present invention is not limited thereto.

The composition for an organic electroluminescent device of the present invention may contain one type of electron-accepting compound as described above alone, or may contain two or more types in any combination and 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 mass% or more, preferably 0.001 mass% or more, Usually it is 20 mass% or less, Preferably it is 10 mass% or less. Further, the proportion 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, and usually 80 It is mass% or less, Preferably it is 60 mass% or less, More preferably, it is 40 mass% or less.

If the content of the electron-accepting compound in the composition for an organic electroluminescent device is more than the above lower limit, the electron acceptor from the polymer accepts electrons, and the formed organic layer is preferable because it reduces resistance, and if it is less than the above upper limit, the formed organic layer is defective. This is preferable because this does not occur easily, and film thickness unevenness does not easily occur.

<Cationic 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 consisting of a cation radical, which is a species removed by one electron from the hole transporting compound, and a counter anion are preferable. However, when the cation radical is derived from a hole-transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

As a cation radical, it is preferable that it is a chemical species which removed one electron from the compound mentioned above as a hole-transporting compound. As a hole-transporting compound, it is preferable that it is a chemical species removed by one electron from a compound preferable in terms of amorphousness, visible light transmittance, heat resistance, and solubility.

Here, the cation radical compound can be produced 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, thereby producing a cationic compound consisting of a cation radical of the hole-transporting compound and a counter anion. .

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 mass% or more, preferably 0.001 mass% or more. And usually 40 mass% or less, preferably 20 mass% or less. If the content of the cation radical compound is more than the above lower limit, it is preferable because the formed organic layer is reduced in resistance, and if it is less than the above upper limit, defects are less likely to occur in the formed organic layer, and film thickness unevenness is less likely to occur. desirable.

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

[Organic EL 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, the organic layer comprising the polymer of the present invention. It is characterized by including a layer formed by a wet film forming method using a composition for an organic electroluminescent device.

In the organic electroluminescent device of the present invention, the layer formed by the wet film formation method is preferably at least one of a hole injection layer and a hole transport layer, and in particular, the organic layer includes a hole injection layer, a hole transport layer and a light emitting layer, It is preferable that all of these hole injection layers, hole transport layers, and light emitting layers are layers formed by a wet film formation method.

In the present invention, the wet film forming method refers to 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. , A capillary coating method, an ink jet method, a nozzle printing method, a screen printing method, a gravure printing method, a method of forming a film by a wet method such as a flexo printing method, and drying the coated film to form a film. Say. 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 the organic electroluminescent device of the present invention and a general formation method thereof will be described with reference to FIG. 1.

1 is a schematic diagram of a cross-section 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, and 5 is 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.

{Board}

The substrate 1 serves as a support for an organic electroluminescent element, and generally, a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, or the like is used. Among these, a glass plate or a plate made of transparent synthetic resin such as polyester, polymethacrylate, polycarbonate and polysulfone is preferable. The substrate is preferably made of a material having a high gas barrier property because deterioration of the organic electroluminescent element due to outside air does not occur easily. For this reason, in particular, when a material having low gas barrier properties such as a synthetic resin substrate is used, it is preferable to increase gas barrier properties by forming a dense silicon oxide film or the like on at least one side of the substrate.

{anode}

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

Anode (2) Silver is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum; metal oxides such as indium and/or tin oxides; halogenated metals such as copper iodide; carbon black and poly(3- Methylthiophene), polypyrrole, polyaniline, and other conductive polymers.

The formation of the anode 2 is usually performed by a dry method such as a sputtering method and a vacuum evaporation method in many cases. In addition, in the case of 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., by dispersing in a suitable binder resin solution and coating it on the substrate. It can also be formed. In the case of a conductive polymer, a thin film may be directly formed on a substrate by electrolytic polymerization, or an anode may be formed by coating a conductive polymer on the substrate (Appl. Phys. Lett., Vol. 60, p. 2711, 1992). year).

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

The thickness of the anode 2 may be determined according to required transparency and material. When particularly high transparency is required, the thickness at which the transmittance of visible light becomes 60% or more is preferable, and the thickness becomes 80% or more. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably 500 nm or less. On the other hand, when transparency is unnecessary, the thickness of the anode 2 may be arbitrarily set according to the required strength or the like, and in this case, the anode 2 may have the same thickness as the substrate.

In the case of forming another layer on the surface of the anode 2, prior to the film formation, treatment such as ultraviolet/ozone, oxygen plasma, argon plasma, etc. is performed to remove impurities on the anode 2 and the ionization potential thereof. It is preferable to improve the hole injection property by adjusting.

{Hole injection layer}

The layer responsible for transporting holes from the anode 2 side to the light emitting layer 5 side is usually called a hole injection transport layer or a hole transport layer. And, when there are two or more layers responsible for transporting holes from the anode (2) side to the light emitting layer (5) side, the layer closer to the anode side is sometimes referred to as a hole injection layer (3). have. The hole injection layer 3 is preferably formed from the viewpoint of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5 side. When forming the hole injection layer 3, usually the hole injection layer 3 is formed on the anode 2.

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

The method of forming the hole injection layer may be a vacuum vapor deposition method or a wet film forming method. From the viewpoint of excellent film formation, it is preferable to form by a wet film formation method.

The hole injection layer 3 preferably contains a hole-transporting compound, more preferably a hole-transporting compound and an electron-accepting compound. Furthermore, it is preferable to contain a cation radical compound in a hole injection layer, and it is especially preferable to contain a cation radical compound and a hole transporting compound.

Hereinafter, a general method of forming a hole injection layer will be described, but 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. desirable.

<Hole-transporting compound>

The composition for forming a hole injection layer usually contains a hole transporting compound serving as the hole injection layer 3. In addition, in the case of a wet film forming method, usually, a solvent is also contained. It is preferable that the composition for forming a hole injection layer has high hole transport properties and can efficiently transport the injected holes. For this reason, it is preferable that the hole mobility is large and that impurities that become trapping do not readily occur during manufacture or use. Moreover, it is preferable that the stability is excellent, the ionization potential is small, and the transparency to visible light is high. Particularly, when the hole injection layer is in contact with the light emitting layer, it is preferable that light emission from the light emitting layer is not quenched, or by forming an exciplex with the light emitting layer so as not to lower the light emission efficiency.

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 the 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 a tertiary amine is linked with a fluorene group, hydra A zone compound, a silazane compound, a quinacridone compound, etc. are mentioned.

Among the exemplary compounds described above, 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 type of the aromatic tertiary amine compound is not particularly limited, but since it is easy to obtain uniform light emission due to the surface smoothing effect, a polymer compound having a weight average molecular weight of 1000 or more and 1000000 or less (a polymeric compound with repeating units) is used. It is preferable to use. Preferred examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (6).

[Formula 14]

(In formula (6), Ar ¹¹ and Ar ¹² each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Ar ¹³ to Ar ¹⁵ each independently have a substituent group. Represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent Y represents a linking group selected from the linking group group shown below In addition, among Ar ¹¹ to Ar ¹⁵ , two groups bonded to the same N atom You may combine with each other to form a ring.)

[Formula 15]

(In each of 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 a hydrogen atom or a substituent. Represents an arbitrary substituent.)

As the aromatic hydrocarbon group and the aromatic heterocyclic group of Ar ¹⁶ to Ar ²⁶ , a benzene ring, a naphthalene ring, a phenanthrene ring having one or two free valences in view of solubility, heat resistance, and hole injection and transport properties of the polymer compound, A thiophene ring and a pyridine ring are preferable, and a benzene ring and a naphthalene ring having one or two free valences are more preferable.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by formula (6) include those described in International Publication No. 2005/089024.

Since the hole injection layer 3 can improve the electrical conductivity of the hole injection layer by oxidation of the hole transporting compound, it is preferable to contain the electron-accepting compound or the cation radical compound described above.

Cationic radical compounds derived from polymer compounds such as PEDOT/PSS (Adv. Mater., 2000, vol. 12, p. 481) or emeraldine hydrochloride (J. Phys. Chem., 1990, vol. 94, p. 7716) , Also produced by oxidation polymerization (dehydrogenation polymerization).

The oxidation polymerization referred to herein is to oxidize a monomer chemically or electrochemically in an acidic solution using peroxo disulfate or the like. In the case of this oxidation polymerization (dehydrogenation polymerization), the monomer is oxidized to polymerize, and a cation radical removed by one electron from the repeating unit of the polymer is generated using an anion derived from an acidic solution as a counter anion.

<Formation of hole injection layer by wet film formation method>

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

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

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

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

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

As an aromatic hydrocarbon solvent, for example, toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, methylnaphthalene And the like. As an amide solvent, N,N-dimethylformamide, N,N-dimethylacetamide, etc. are mentioned, for example.

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

The formation of the hole injection layer 3 by a wet film formation method is usually performed after preparing a composition for forming a hole injection layer, and then this is a layer corresponding to the lower layer of the hole injection layer 3 (usually, the anode 2). ) Is formed on the coating film and dried.

As for the hole injection layer 3, after film formation, the coating film is usually dried by heating or drying under reduced pressure.

<Formation of hole injection layer by vacuum evaporation method>

In the case of forming the hole injection layer 3 by a vacuum evaporation method, usually, one type or two or more types of the constituent materials of the hole injection layer 3 (the aforementioned hole transporting compound, electron accepting compound, etc.) Put it in a crucible installed inside (when using two or more types of materials, usually put each in another crucible), evacuate the inside of the vacuum container to about 10 ^-4 Pa with a vacuum pump, and heat the crucible (2 types In the case of using the above materials, each crucible is usually evaporated while controlling the evaporation amount of the material in the crucible (in the case of using two or more types of materials, it is usually evaporated while controlling the evaporation amount independently. ), to form a hole injection layer on the anode on the substrate placed facing the crucible. In addition, when two or more types of materials are used, a mixture of them may be placed in a crucible, heated, and evaporated to form a hole injection layer.

The degree of vacuum at the time of deposition include, but are not limited to one that does not significantly inhibit the effects of the present invention, typically ^{0.1 × 10 -6 Torr (0.13 ×} 10 -4 ㎩) ^{above, 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 Å/second or more and 5.0 Å/second or less. The film formation temperature at the time of vapor deposition is not limited as long as it does not significantly impair the effect of the present invention, but is preferably performed at 10°C or higher and 50°C or lower.

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

{Hole transport layer}

The hole transport layer 4 is a layer that plays 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 it is preferable to form this layer 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, usually, the hole transport layer 4 is formed between the anode 2 and the light emitting layer 5. Moreover, when there is the hole injection layer 3 mentioned above, it is formed between the hole injection layer 3 and the light emitting layer 5.

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

The method of forming the hole transport layer 4 may be a vacuum evaporation method or a wet film forming method. From the viewpoint of excellent film formation, it is preferable to form by a wet film formation method.

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

The hole transport layer 4 usually contains a hole transport compound. As the hole-transporting compound contained in the hole-transporting layer 4, in particular, two or more tertiary amines represented by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl are used. Including aromatic diamine in which two or more condensed aromatic rings are substituted with nitrogen atoms (Japanese Laid-Open Patent Publication No. Hei 5-234681), 4,4',4''-tris(1-naphthylphenylamino)triphenylamine, etc. Aromatic amine compounds having a starburst structure (J. Lumin., Vol. 72-74, p. 985, 1997), an aromatic amine compound consisting of tetramers of triphenylamine (Chem. Commun., p. 2175, 1996), Spiro compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth.Metals, 91 vol., 209 pages, 1997), 4,4 Carbazole derivatives, such as'-N,N'-dicarbazole biphenyl, etc. are mentioned. Further, for example, polyvinylcarbazole, polyvinyltriphenylamine (Japanese Laid-Open Patent Publication No. Hei 7-53953), and polyarylene ether sulfone containing tetraphenylbenzidine (Polym. Adv. Tech., Vol. 7, 33) Page, 1996) and the like can also be preferably used.

<Formation of hole transport layer by wet film formation method>

In the case of forming the hole transport layer by the wet film forming method, in general, in the same manner as in the case of forming the hole injection layer described above by the wet film forming method, a composition for forming a hole transport layer is used instead of the composition for forming a hole injection layer. To form.

When forming the hole transport layer by the wet film forming method, the composition for forming the 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 in 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-injection layer.

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

<Formation of hole transport layer by vacuum evaporation method>

Also in the case of forming the hole transport layer by the vacuum evaporation method, it is usually the same as the case of forming the hole injection layer described above by the vacuum evaporation method, and is formed using a composition for forming a hole transport layer instead of the composition for forming a hole injection layer. I can. Film formation conditions, such as a degree of vacuum, a deposition rate, and a temperature during evaporation, may be formed under the same conditions as in the vacuum evaporation of the hole injection layer.

{Light emitting layer}

When an electric field is applied between a pair of electrodes, the light-emitting layer 5 is a layer that is excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9, and serves to emit light. The light emitting layer 5 is a layer formed between the anode 2 and the cathode 9, and the light emitting layer is formed between the hole injection layer and the cathode when there is a hole injection layer on the anode, and In the case where there is a hole transport layer, it is formed between the hole transport layer and the cathode.

The film thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effect of the present invention, but from the viewpoint that defects are less likely to occur in the film, the thicker one is preferable, and the thinner one is the lower driving voltage. It is preferable in that it is easy to do. For this reason, it is preferable that it is 3 nm or more, and it is more preferable that it is 5 nm or more, and on the other hand, it is usually preferably 200 nm or less, and more preferably 100 nm or less.

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

<Light-emitting material>

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

As a fluorescent light emitting material, the following materials are mentioned, for example.

As a fluorescent light-emitting material (blue fluorescent light-emitting material) that gives blue light emission, for example, naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis(2-phenylethenyl)benzene, and derivatives thereof, etc. Can be lifted.

As a fluorescent light emitting material (green fluorescent light emitting material) which gives green light emission, for example, a quinacridone derivative, a coumarin derivative, an aluminum complex such as Al(C ₉ H ₆ NO) _3, and the like can be mentioned.

As a fluorescent light emitting material (yellow fluorescent light emitting material) that gives yellow light emission, for example, rubrene, a perimidone derivative, and the like can be mentioned.

As a fluorescent light-emitting material (red fluorescent light-emitting material) that gives red light emission, for example, DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran) system Compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene, and the like.

Further, examples of the phosphorescent light emitting material include organometallic complexes containing a metal selected from Groups 7 to 11 of the long 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 can be 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 connected to a pyridine, pyrazole, phenanthroline, etc. is preferable. In particular, a phenylpyridine ligand , A phenylpyrazole ligand is preferred. Here, (hetero)aryl represents an aryl group or a heteroaryl group.

As a preferable phosphorescent material, specifically, for example, tris(2-phenylpyridine)iridium, tris(2-phenylpyridine)ruthenium, tris(2-phenylpyridine)palladium, bis(2-phenylpyridine)platinum, Phenylpyridine complexes such as tris(2-phenylpyridine)osmium and tris(2-phenylpyridine)rhenium, and porphyrin complexes such as octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethylpalladium porphyrin, octaphenylpalladium porphyrin, etc. have.

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

<Charge transporting material>

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

As the charge transport material, a compound conventionally used in the light emitting layer of an organic electroluminescent device can be used, and in particular, a compound used as a host material of the light emitting layer is preferable.

Specific examples of the charge transport material include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and compounds in which a tertiary amine is linked with a fluorene group. , Hydrazone-based compounds, silazane-based compounds, silanamine-based compounds, phosphamine-based compounds, and quinacridone-based compounds. Electron-transporting compounds such as a system compound, a carbazole compound, a pyridine compound, a phenanthroline compound, an oxadiazole compound, and a silol compound, and the like.

In addition, for example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl contains at least two tertiary amines, and at least two condensed aromatic rings are nitrogen atoms. Aromatic amine-based compounds having a starburst structure, such as substituted aromatic diamine (Japanese Laid-Open Patent Publication No. Hei 5-234681), 4,4',4''-tris(1-naphthylphenylamino)triphenylamine (J Lumin., Vol. 72-74, pages 985, 1997), aromatic amine compounds consisting of tetramers of triphenylamine (Chem. Commun., pages 2175, 1996), 2,2',7,7' -Fluorene-based compounds such as tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth.Metals, 91 vol., 209 pages, 1997), 4,4'-N,N'- Compounds exemplified as hole-transporting compounds in the hole-transporting layer, such as carbazole-based compounds such as dicarbazole biphenyl, can also be preferably used. In addition, in addition to this, 2-(4-biphenylyl)-5-(p-tertalbutylphenyl)-1,3,4-oxadiazole (tBu-PBD), 2,5-bis(1-naphthyl) )-1,3,4-oxadiazole (BND), and other oxadiazole compounds, 2,5-bis(6'-(2',2''-bipyridyl))-1,1-dimethyl- Silol compounds such as 3,4-diphenylsilol (PyPySPyPy), vasophenanthroline (BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, vasocupro Phosphorus) and the like phenanthroline compounds.

<Formation of light emitting layer by wet film formation method>

The method of forming the light emitting layer may be a vacuum evaporation method or a wet film formation method, but from the viewpoint of excellent film formation, a wet film formation method is preferable, and a spin coating method and an inkjet method are more preferable. In particular, when the composition for an organic electroluminescent device of the present invention is used to form a hole injection layer or a hole transport layer serving as a lower layer of the light emitting layer, lamination by a wet film formation method is easy, so it is preferable to employ a wet film formation method. . In the case of forming the light emitting layer by the wet film forming method, in general, in the same manner as in the case of forming the hole injection layer described above by the wet film forming method, instead of the composition for forming the hole injection layer, a material serving as the light emitting layer is soluble. It is formed using a composition for forming a light emitting layer prepared by mixing with a solvent (solvent for a light emitting layer).

As the solvent, for example, in addition to the ether solvent, ester solvent, aromatic hydrocarbon solvent, and amide solvent exemplified for the formation of the hole injection layer, an alkane solvent, a halogenated aromatic hydrocarbon solvent, an aliphatic alcohol solvent, And alicyclic alcohol solvents, aliphatic ketone solvents, and alicyclic ketone solvents. Specific examples of the solvent will be given below, but it is not limited thereto as long as the effect of the present invention is 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, Aromatic ether solvents such as anisole, phenethyl, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether; Aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylbiphenyl, 1 Aromatic hydrocarbon-based solvents such as ,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene; Amide-based solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; Alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; cyclo Alicyclic alcohol solvents such as hexanol and cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and fencon. Among these, an alkane solvent and an aromatic hydrocarbon solvent are particularly preferred.

{Hole blocking layer}

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

The hole blocking layer 6 serves to prevent holes moving from the anode 2 from reaching the cathode 9, and efficiently transports electrons injected from the cathode 9 in the direction of the light emitting layer 5 Has a role to play. As the physical properties required for the material constituting the hole blocking layer 6, the electron mobility is high and the hole mobility is low, the energy gap (the difference between HOMO and LUMO) is large, and the triplet level (T1) is Higher ones are mentioned.

As a material for the hole blocking layer satisfying such conditions, for example, bis(2-methyl-8-quinolinolato)(phenolato)aluminum, bis(2-methyl-8-quinolinolato) Mixed ligand complexes such as (triphenylsilanolato)aluminum, bis(2-methyl-8-quinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinoliato)aluminum dinuclear metal complex Metal complexes such as, and styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Application Laid-Open No. 11-242996), 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)- Triazole derivatives such as 1,2,4-triazole (Japanese Laid-Open Patent Publication No. Hei 7-41759), phenanthroline derivatives such as vasocuproin (Japanese Laid-Open Patent Publication No. Hei 10-79297), and the like. have. Further, a compound having at least one pyridine ring substituted at positions 2, 4 and 6 described in International Publication No. 2005/022962 is also preferable as a material for the hole blocking layer.

There is no limitation on the method of forming the hole blocking layer 6. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

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

{Electron transport layer}

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

Examples of the electron-transporting compound used in the electron-transporting layer include, for example, metal complexes such as 8-hydroxyquinoline aluminum complexes (Japanese Patent Application Laid-Open No. 59-194393), 10-hydroxybenzo [h ]Metal complex of quinoline, oxadiazole derivative, distyrylbiphenyl derivative, silol derivative, 3-hydroxyflavone metal complex, 5-hydroxyflavone metal complex, benzoxazole metal complex, benzothiazole metal complex, trisbenzimi Dazolylbenzene (U.S. Patent No.5645948), quinoxaline compound (Japanese Laid-Open Patent Publication No. Hei6-207169), phenanthroline derivatives (Japanese Laid-Open Patent Publication No. Hei 5-331459), 2-t-butyl-9, 10-N,N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, and the like.

The film 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 forming method or a vacuum vapor deposition method in the same manner as described above. Usually, a vacuum evaporation method is used.

{Electron injection layer}

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

In order to efficiently perform electron injection, the material for forming the electron injection layer 8 is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. The film thickness is usually preferably 0.1 nm or more and 5 nm or less.

In addition, alkali metals such as sodium, potassium, cesium, lithium, and rubidium are doped into organic electron transport materials typified by metal complexes such as nitrogen-containing heterocyclic compounds such as vasophenanthroline or aluminum complexes of 8-hydroxyquinoline. (Described in Japanese Unexamined Patent Publication No. Hei 10-270171, Japanese Unexamined Patent Publication No. 2002-100478, and Japanese Unexamined Patent Publication No. 2002-100482, etc.), because electron injection and transport properties are improved and excellent film quality can be achieved. desirable.

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

The electron injection layer 8 is formed by laminating on the light emitting layer 5 or the hole blocking layer 6 or electron transport layer 7 thereon by a wet film forming method or a vacuum vapor deposition method.

Details in the case of the wet film formation method are the same as in the case of the light emitting layer described above.

{cathode}

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

As the material for the cathode 9, it is possible to use the material used for the anode 2, but in order to efficiently inject electrons, it is preferable to use a metal having a low work function. For example, metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys thereof are used. As a specific example, an alloy electrode of low work function, such as a magnesium-silver alloy, a magnesium-indium alloy, and an aluminum-lithium alloy, etc. are mentioned, for example.

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

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

{Other floors}

The organic electroluminescent device of the present invention may have another layer as long as the effect of the present invention is not significantly impaired. That is, you may have the other arbitrary layer mentioned above between an anode and a cathode.

{Other device configuration}

The organic electroluminescent device of the present invention has a structure opposite to the above description, that is, a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, a hole transport layer, a hole injection layer, and an anode are stacked on the substrate in the order of It is also possible to do.

When the organic electroluminescent element of the present invention is applied to an organic electroluminescent device, it may be used as a single organic electroluminescent element, or a plurality of organic electroluminescent elements may be arranged in an array. You may use it in a configuration in which the cathode is arranged in an XY matrix.

[Organic EL display device]

The organic electroluminescent element display device (organic EL display device) of the present invention uses the organic electroluminescent element of the present invention described above. There is no particular limitation on the form or structure of the organic EL display device of the present invention, and it can be assembled according to a conventional method using the organic electroluminescent device of the present invention.

For example, by the method described in ``Organic EL Display'' (Oum Corporation, published on August 20, 2016, by Shizuo Tokito, Chihaya Adachi, Hideyuki Murata), the organic EL display device of the present invention is Can be formed.

[Organic EL lighting]

The organic electroluminescent element illumination (organic EL illumination) of the present invention uses the organic electroluminescent element of the present invention described above. There is no restriction|limiting in particular with respect to the form and structure of the organic EL illumination of this invention, It can assemble by a conventional method using the organic electroluminescent element of this invention.

Example

Hereinafter, the present invention will be described in more detail by showing examples. However, the present invention is not limited to the following examples, and the present invention can be carried out with arbitrary changes as long as it does not deviate from the gist.

<Synthesis of monomer>

[Formula 16]

Compound 1 (10.0 g, 28.61 mmol), bromobenzene (4.27 g, 27.18 mmol), tert-butoxy sodium (7.4 g, 77.25 mmol), and toluene (150 mL) were added, and the system was replaced with nitrogen. Then, it was heated to 60°C (solution A). To a 15 ml solution of tris(dibenzylideneacetone)dipalladium chloroform complex (0.089 g, 0.086 mmol) in toluene, 1,1′-bis(diphenylphosphino)ferrocene (0.19 g, 0.344 mmol) was added, and , Heated to 60°C (solution B). In a nitrogen stream, solution B was added to solution A, and heated to reflux for 3.0 hours. After standing to cool to room temperature, ethyl acetate (300 ml) and brine (100 ml) were added to the reaction solution, stirred, and separated, the aqueous layer was extracted with ethyl acetate (100 ml×2 times), the organic layers were combined, and sulfuric acid After drying over magnesium, it was concentrated. Further, by purifying by silica gel column chromatography (n-hexane/methylene chloride = 3/1), a pale yellow oily compound 2 (10.4 g) was obtained.

[Formula 17]

N,N-dimethylformamide (200 mL) and methylene chloride (200 mL) were added to compound 2 (10.4 g, 24.43 mmol), and cooled in an ice bath. A solution of N,N-dimethylformamide (50 ml) and methylene chloride (50 ml) of N-bromosuccinimide (4.35 g, 24.43 mmol) was added dropwise thereto, and the temperature was raised to room temperature over 3 hours while stirring. . Water was added to the reaction solution, and extraction was performed 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).

[Formula 18]

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 added to the flask, and the system was sufficiently nitrogen-substituted and heated to 80°C. Tetrakis (triphenylphosphine) palladium (1.8 g, 1.58 mmol) was added, followed by stirring 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, it purified again by column chromatography (developing solution: THF/acetonitrile = 1/2). Compound 4 (8.5 g, yield 52.6%) was obtained. The HPLC purity of compound 4 was 99.7 area%.

[Formula 19]

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

[Formula 20]

Under nitrogen stream, dimethyl sulfoxide (100 ml), 4-(3-iodophenyl)benzocyclobutene (5.00 g, 16.3 mmol), bis(pinacolato)diborone (5.39 g, 21.2 mmol), acetic acid Potassium (4.00 g, 40.8 mmol) was put into a flask, and it stirred at 60 degreeC 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 It heated and stirred at C for 8 hours. Toluene was added to the reaction solution, washed with water, magnesium sulfate was added, and stirred, followed by filtration. Activated clay was added to the filtrate, and after stirring, it was filtered. The filtrate was concentrated to obtain a colorless solid compound 6 (4.71 g, yield 94.2%).

[Formula 21]

Under 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), 2 M sodium carbonate An aqueous solution (50 ml) was added to the flask, followed by heating and stirring 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, stirred, filtered, and the filtrate was concentrated. It purified by silica gel column chromatography (developing solvent: n-hexane: toluene = 5:1), and obtained the colorless oil compound 7 (3.89 g, yield 71.9%).

[Formula 22]

Under a nitrogen stream, dimethyl sulfoxide (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) was added, the inside of the system was substituted with nitrogen, and the mixture was stirred at 60°C for 30 minutes. Subsequently, 0.32 g (0.387 mmol) of 1,1'-bis(diphenylphosphino)ferrocene palladium(II)dichloridedichloromethane adduct was added, followed by reaction at 83°C for 4 hours. The reaction solution was filtered under reduced pressure, water was added to the filtrate, and extraction was performed with toluene. Anhydrous magnesium sulfate and activated clay were added to the organic layer, stirred, and filtered under reduced pressure, and the filtrate was concentrated. The precipitated solid was suspended and washed with methanol to obtain a colorless solid compound 7 (amount 2.8 g, yield 75%).

[Formula 23]

Compound 3 (4.95 g, 9.95 mmol), Compound 7 (2.36 g, 4.97 mmol), potassium carbonate (5.53 g, 40.0 mmol), and toluene (60 mL), ethanol (20 mL), water (20 mL ) Was added, and the system was sufficiently replaced with nitrogen and heated to 60°C. Tetrakis (triphenylphosphine) palladium (0.29 g, 0.25 mmol) was added, followed by stirring 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>

[Formula 24]

Compound 4 (2.0 g, 1.997 mmol), compound 6 (0.095 g, 0.2296 mmol), tert-butoxy sodium (1.48 g, 15.38 mmol) and toluene (30 mL) were added, and the system was replaced with nitrogen. Then, it was heated to 60°C (solution A). To a toluene solution (5 ml) of tris(dibenzylideneacetone)dipalladium chloroform complex (0.042 g, 0.0399 mmol), [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.085) g, 0.3195 mmol) was added, and the mixture was heated to 60°C (solution B). In a nitrogen stream, solution B was added to solution A, and heated to reflux for 1.0 hour. Then, 4,4'-dibromobiphenyl (0.52 g, 1.667 mmol) was added. After heating and refluxing for 1.0 hour, 4,4'-dibromobiphenyl (0.025 g, 0.08 mmol) was further added. After 30 minutes, the reaction solution was allowed to stand to cool, and the reaction solution was dripped in 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 tert-butoxy sodium (0.74 g, 7.7 mmol) were added, and the system was converted into nitrogen. It was substituted and warmed to 60 degreeC (solution C). To a toluene solution (3 ml) of tris(dibenzylideneacetone)dipalladium chloroform complex (0.021 g, 0.0203 mmol), [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.043 g, 0.1598 mmol) was added, and the mixture was heated to 60°C (solution D). Solution D was added to solution C in nitrogen stream, and it heated and refluxed for 3 hours. Bromobenzene (0.35 g, 0.2229 mmol) was added to this reaction liquid. To a toluene solution (3 ml) of tris(dibenzylideneacetone)dipalladium chloroform complex (0.021 g, 0.0203 mmol), [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.043 g, 0.1598 mmol) was added, and the mixture was heated to 60°C (solution E). Solution E was added to the reaction solution in a nitrogen stream, followed by heating and refluxing for 3 hours. The reaction solution was allowed to stand to cool, and dropwise added to an ethanol/water (1500 ml/100 ml) solution to obtain an end-capped crude polymer.

This end-capped crude polymer was dissolved in toluene, reprecipitated with acetone, and the precipitated polymer was redissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ethanol containing ammonia. 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 (Mw/Mn) = 1.41

<Synthesis of Polymer 2>

[Formula 25]

Compound 8 (2.155 g, 2.00 mmol), compound 6 (0.095 g, 0.23 mmol), tert-butoxy sodium (1.48 g, 15.4 mmol), and toluene (35 mL) were added, and the system was replaced with nitrogen. Then, it was heated to 60°C (solution A). To a toluene solution (5 ml) of tris(dibenzylideneacetone)dipalladium chloroform complex (0.041 g, 0.041 mmol), [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.085 g, 0.32 mmol) was added, and the mixture was heated to 60°C (solution B). In a nitrogen stream, solution B was added to solution A, and heated to reflux for 1.0 hour. Then, 4,4'-dibromobiphenyl (0.493 g, 1.58 mmol) was added. After 1.0 hour, heating and refluxing, the reaction liquid was allowed to stand to cool, and the reaction liquid was dripped in 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 tert-butoxy sodium (0.74 g, 7.7 mmol) were added, and the system was nitrogen It was substituted and warmed to 60 degreeC (solution C). To a toluene solution (3 ml) of tris(dibenzylideneacetone)dipalladium chloroform complex (0.021 g, 0.0203 mmol), [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.043 g, 0.16 mmol) was added, and the mixture was heated to 60°C (solution D). Solution D was added to solution C in nitrogen stream, and it heated and refluxed for 3 hours. Bromobenzene (0.35 g, 0.223 mmol) was added to this reaction liquid. To a toluene solution (3 ml) of tris(dibenzylideneacetone)dipalladium chloroform complex (0.021 g, 0.0203 mmol), [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.043 g, 0.1598 mmol) was added, and the mixture was heated to 60°C (solution E). Solution E was added to the reaction solution in a nitrogen stream, followed by heating and refluxing for 3 hours. The reaction solution was allowed to stand to cool, and dropwise added to an ethanol/water (1500 ml/100 ml) solution to obtain an end-capped crude polymer.

This end-capped crude polymer was dissolved in toluene, reprecipitated with acetone, and the precipitated polymer was redissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ethanol containing ammonia. The polymer collected by filtration was purified by column chromatography to obtain a polymer 2 (1.2 g).

Weight average molecular weight (Mw) = 110000

Number average molecular weight (Mn) = 48200

Dispersion (Mw/Mn) = 2.28

<Synthesis of Polymer 3>

[Formula 26]

Compound 4 (9.0 g, 8.99 mmol), compound 9 (0.911 g, 1.36 mmol), and tert-butoxy sodium (6.66 g, 69.3 mmol) and toluene (187 mL) were added, and the system was sufficiently nitrogen It was substituted and warmed to 60 degreeC (solution A). To a 31 ml solution of tris(dibenzylideneacetone)dipalladium chloroform complex (0.186 g, 1.8 mmol) in toluene, [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.382 g, 1.4 mmol) was added, and it heated up to 60 degreeC (solution B). In nitrogen stream, solution B was added to solution A, and it heated and refluxed for 1.0 hour. Subsequently, 4,4′-dibromo-p-terphenyl (2.546 g, 6.56 mmol) was added. It was heated to reflux for 1.0 hour. The reaction solution was allowed to stand to cool, toluene (125 ml) was added, and the reaction solution was dripped in 1250 ml of ethanol to crystallize a crude polymer.

The obtained crude polymer was dissolved in 224 ml of toluene, and N,N-diphenylamine (0.573 g, 3.4 mmol) and tert-butoxy sodium (3.125 g, 32.5 mmol) were added, and the system was sufficiently nitrogen-substituted. Then, it was heated to 60°C (solution C). To a 12.5 ml solution of tris(dibenzylideneacetone)dipalladium chloroform complex (0.088 g, 0.1 mmol) in toluene, [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.18 g, 0.7 mmol) was added, and it heated up to 60 degreeC (solution D). In a nitrogen stream, solution D was added to solution C, followed by heating and reflux reaction for 3 hours. Bromobenzene (2.659 g, 16.9 mmol) was added to this reaction liquid. To a 12.5 ml solution of tris(dibenzylideneacetone)dipalladium chloroform complex (0.088 g, 0.1 mmol) in toluene, [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.18 g, 0.7 mmol) was added, and it heated up to 60 degreeC (solution E). In a nitrogen stream, solution E was added to the reaction solution, followed by heating and reflux reaction for 3 hours. The reaction solution was allowed to stand to cool, and dropped into an ethanol/water (1120 mL/108 mL) solution to obtain an end-capped crude polymer.

This end-capped crude polymer was dissolved in toluene, reprecipitated with acetone, and the precipitated polymer was redissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ethanol containing ammonia. 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 (Mw/Mn) = 1.30

<Synthesis of Polymer 4>

[Formula 27]

Compound 4 (5.0 g, 4.99 mmol), compound 6 (0.313 g, 0.756 mmol), tert-butoxy sodium (3.699 g, 38.5 mmol), and toluene (104 mL) were added, and the system was sufficiently nitrogen It was substituted and warmed to 60 degreeC (solution A). To a 17 ml solution of tris(dibenzylideneacetone)dipalladium chloroform complex (0.103 g, 0.1 mmol) in toluene, [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.212 g, 0.8 mmol) was added, and it heated up to 60 degreeC (solution B). In nitrogen stream, solution B was added to solution A, and it heated and refluxed for 1.0 hour. Then, compound 10 (2.053 g, 3.74 mmol) was added. It was heated to reflux for 1.0 hour.

N,N-diphenylamine (0.338 g, 2.0 mmol) was added, followed by heating and reflux reaction for 1 hour. Bromobenzene (1.568 g, 10 mmol) was added to this reaction liquid. It reacted with heating and reflux for 2 hours. The reaction solution was allowed to stand to cool, and dropped into an ethanol/water (342 ml/100 ml) solution to obtain an end-capped crude polymer.

This end-capped crude polymer was dissolved in toluene, reprecipitated with acetone, and the precipitated polymer was re-dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ethanol containing ammonia. 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 (Mw/Mn) = 1.30

<Manufacture of organic electroluminescent device>

(Example 1)

The organic electroluminescent device shown in FIG. 1 was manufactured.

On the glass substrate 1, an indium-tin oxide (ITO) transparent conductive film was deposited by sputtering film formation and patterned into 2 mm wide stripes using a conventional photolithography technique and hydrochloric acid etching, and a film thickness of 70 nm. The anode (2) of was formed. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, followed by drying with compressed air, and finally UV ozone cleaning. Implemented.

Next, holes containing the arylamine polymer represented by the following structural formula (P1), 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and ethyl benzoate represented by the structural formula (A1) A coating liquid for forming an injection layer was prepared. This coating liquid was formed on the anode 2 by spin coating under the following conditions to obtain a hole injection layer having a thickness of 31 nm.

[Formula 28]

<Coating liquid for forming a hole injection layer>

Solvent ethyl benzoate

Coating liquid concentration P1: 2.5% by weight

A1: 0.5% by weight

<Film formation conditions of the hole injection layer 3>

Spinner speed 3100 rpm

Spinner rotation time 30 seconds

Waiting for the spin court atmosphere

Heating condition 240 ℃ 1 hour in the air

Subsequently, a coating liquid for forming a hole transport layer containing polymer 1 (P2) having the structural formula shown below was prepared, and a film was formed on the hole injection layer 3 by spin coating and heated under the following conditions to obtain a film thickness. A 20 nm hole transport layer was formed.

[Chemical Formula 29]

<Coating liquid for forming a hole transport layer>

Solvent cyclohexylbenzene

Coating solution concentration 1.5% by weight

<Film formation conditions of the hole transport layer 4>

Spinner RPM 1950 rpm

Spinner rotation time 120 seconds

Spin coat atmosphere in nitrogen

Heating conditions in nitrogen 230 ℃ 1 hour

Next, a coating liquid for forming a light-emitting layer containing compounds (H1), (H2), and (D1) represented by the following structural formulas was prepared, film formation was performed by spin coating under the following conditions, and heated. A light emitting layer having a film thickness of 50 nm was formed on the hole transport layer 4.

[Formula 30]

<Coating liquid for forming a light-emitting layer>

Solvent cyclohexylbenzene

Coating liquid concentration H1: 1.2% by weight

H2: 3.6% by weight

D1: 0.48% by weight

<Film formation conditions of the light-emitting layer 5>

Spinner speed 2050 rpm

Spinner rotation time 120 seconds

Spin coat atmosphere in nitrogen

Heating condition 130 ℃ 10 minutes in nitrogen

Here, the substrate on which the light emitting layer was formed is transferred into a vacuum evaporation apparatus, and after evacuating until the degree of vacuum in the apparatus becomes 2.0 x 10 ^-4 Pa or less, an organic compound (E1) having a structure shown below is vacuum evaporated. As a result, the vapor deposition rate was controlled in the range of 0.9 to 1.0 Å/second, and the layer was laminated on the light emitting layer 5 to obtain a hole blocking layer 6 having a thickness of 10 nm.

[Formula 31]

Next, the organic compound (E2) having the structure shown below was controlled by a vacuum evaporation method in the range of 0.9 to 1.9 Å/sec, and laminated on the hole blocking layer 6 to form an electron transport layer having a thickness of 20 nm. (7) was obtained.

[Formula 32]

Here, the element which has been deposited to the electron transport layer 7 is transferred to another vacuum evaporation apparatus, and a 2 mm wide striped shadow mask is placed on the element so as to be orthogonal to the ITO stripe of the anode 2 as a cathode evaporation mask. It was brought into close contact and evacuated until the degree of vacuum in the apparatus became 3.1 x 10 ^-4 Pa or less.

As the electron injection layer 8, lithium fluoride (LiF) was first controlled at a vapor deposition rate of 0.1 Å/second using a molybdenum boat, and a film was formed on the electron transport layer 7 with a film thickness of 0.5 nm. Next, as the cathode 9, aluminum was similarly heated by a molybdenum boat, and the deposition rate was controlled in the range of 1.1 to 8.8 Å/sec, thereby forming an aluminum layer having a thickness of 80 nm. The substrate temperature during the vapor deposition of the above two layers was maintained at room temperature.

Subsequently, in order to prevent the device from deteriorating due to moisture in the air 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 Chemicals Co., Ltd.) was applied to the outer periphery of a 23 mm x 23 mm-sized glass plate with a width of about 1 mm, and a moisture getter sheet (Dynic Co., Ltd. Manufacturing) was installed. On this, the substrate on which the cathode formation was completed was bonded so that the vapor-deposited side faced the desiccant sheet. After that, ultraviolet light was irradiated only to the region to which the photocurable resin was applied, and the resin was cured.

In the manner described above, an organic electroluminescent device having a light emitting area portion having a size of 2 mm x 2 mm was obtained. Table 9 shows the characteristics of this device.

(Comparative Example 1)

A coating liquid for forming a hole transport layer containing (P3) represented by the structural formula shown below was prepared as the hole transport layer 4, and a film was formed on the hole injection layer 3 by spin coating and heated under the following conditions. An organic electroluminescent device was manufactured in the same manner as in Example 1, except that a hole transport layer having a film thickness of 19 nm was formed. Table 9 shows the characteristics of the obtained device.

[Formula 33]

<Coating liquid for forming a hole transport layer>

Solvent cyclohexylbenzene

Coating solution concentration 1.5% by weight

<Film formation conditions of the hole transport layer 4>

Spinner speed 1850 rpm

Spinner rotation time 120 seconds

Spin coat atmosphere in nitrogen

Heating conditions in nitrogen 230 ℃ 1 hour

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

(Example 2)

A coating solution for forming a hole transport layer containing polymer 2 (P4) represented by the structural formula shown below was prepared as the hole transport layer 4, and a film was formed on the hole injection layer 3 by spin coating under the following conditions, By heating, a hole transport layer having a thickness of 20 nm was formed.

[Formula 34]

<Coating liquid for forming a hole transport layer>

Solvent cyclohexylbenzene

Coating solution concentration 1.5% by weight

<Film formation conditions of the hole transport layer 4>

Spinner speed 3000 rpm

Spinner rotation time 120 seconds

Spin coat atmosphere in nitrogen

Heating conditions in nitrogen 230 ℃ 1 hour

A coating liquid for forming a light-emitting layer containing compounds (H3) and (D2), which is represented by the following structural formula, is prepared, a film is formed by spin coating under the following conditions, and then the film thickness is heated. A 41 nm light emitting layer was formed on the hole transport layer 4.

Other than that, an organic electroluminescent device was manufactured in the same manner as in Example 1. Table 10 shows the characteristics of the obtained device.

[Formula 35]

<Coating liquid for forming a light-emitting layer>

Solvent cyclohexylbenzene

Coating liquid concentration H3: 3.5% by weight

D2: 0.35% by weight

<Film formation conditions of the light-emitting layer 5>

Spinner speed 1850 rpm

Spinner rotation time 120 seconds

Spin coat atmosphere in nitrogen

Heating condition 130 ℃ 10 minutes in nitrogen

(Comparative Example 2)

Example 2 except that the hole transport layer 4 was formed by forming a film and heating the coating liquid for forming a hole transport layer 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 film thickness of 19 nm. In the same manner as, an organic electroluminescent device was manufactured. Table 10 shows the characteristics of the obtained device.

(Comparative Example 3)

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

[Formula 36]

<Coating liquid for forming a hole transport layer>

Solvent cyclohexylbenzene

Coating solution concentration 1.5% by weight

<Film formation conditions of the hole transport layer 4>

Spinner speed 1850 rpm

Spinner rotation time 120 seconds

Spin coat atmosphere in nitrogen

Heating conditions in nitrogen 230 ℃ 1 hour

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

<Measurement of hole mobility>

(Example 3)

Using the time of flight (TOF) method, the hole mobility of Polymer 3 (P6) was measured in the same manner as in the method described in JP 2014-51667 A.

[Formula 37]

First, on a glass substrate, an ITO transparent conductive film (ITO stripe) was deposited to a thickness of 70 nm, for a substrate (manufactured by Geomatech), ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic wave with ultrapure water After washing in the order of washing and washing with water with ultrapure water, after drying with compressed air, ultraviolet ozone washing was performed.

A solution obtained by dissolving (P6) at a concentration of 10% by mass was prepared in a solvent in which toluene and silicone oil (manufactured by Shin-Etsu Silicone Co., Ltd.: KF-96) were mixed, and a film was formed on the cleaned substrate by spin coating. . In addition, all film formation was performed in a nitrogen atmosphere. By the above, a film of the target polymer 1 having a film thickness of 2 µm was obtained. Next, the sample was conveyed to the vacuum chamber of the vacuum evaporation apparatus. As a cathode evaporation mask, a 2 mm wide striped shadow mask was placed in close contact with the element so as to be perpendicular 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 having a thickness of 80 nm on the sample. In addition, during the formation of the aluminum film, the degree of vacuum in the chamber was maintained at 2.0 × 10 ^-3 Pa or less, and at a deposition rate of 0.6 to 10.0 Å/sec.

With respect to the sample, an electric field strength was applied so that the ITO film was the anode and the aluminum electrode was the cathode, and "VSL-337ND-S (nitrogen laser)" by Spectra Physics Co. It used to measure the transient photocurrent. In addition, the light irradiation energy was irradiated from the ITO electrode side by adjusting the amount of light per pulse at 10 μJ with a reflective ND filter. The transient photocurrent waveform was measured using an oscilloscope ("TDS2022" manufactured by Techtronics), and the charge mobility was calculated from the bending point. This measurement was carried out in a state to which an electric field strength of 160 kV/cm was applied.

The calculation result of the hole mobility was expressed as a relative value (normalized hole mobility) when the calculation result of the hole mobility of the compound of the structural formula (P7) described later was "1.0". The results are shown in Table 11.

(Comparative Example 4)

Except having changed the compound of structural formula (P6) to the compound of structural formula (P7), it carried out similarly to Example 3, and measured (P7), and the calculated hole mobility was set to 1.0.

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 is clear to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application filed on October 4, 2013 (Japanese Patent Application Publication 2013-209111), and a Japanese patent application filed on January 28, 2014 (Japanese Patent Application Publication 2014-013358), Its content is incorporated herein by reference.

1: substrate
2: anode
3: hole injection layer
4: hole transport layer
5: light emitting layer
6: hole blocking layer
7: electron transport layer
8: electron injection layer
9: cathode

Claims (17)

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

(In the formula, 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 represents an integer of 4 or more. The aromatic hydrocarbon group and the aromatic heterocyclic group are, Directly or through a connector, a plurality of pieces may be connected.) The method of claim 1,
A polymer having a crosslinkable group as a substituent in at least one or more of Ar ¹ , Ar ² and Ar ³ . The method of claim 2,
A polymer in which the crosslinkable group is a group containing a benzocyclobutene ring. The method of claim 2,
A polymer having two or more repeating units represented by the above formula (1), at least one repeating unit containing a crosslinkable group, and at least one repeating unit not containing a crosslinkable group. The method of claim 1,
At least one of Ar ¹ and Ar ² is a 2-fluorenyl group which may have a substituent. The method of claim 1,
A polymer in which Ar ³ is a group represented by the following formula (2).

(In the formula, m represents the integer of 1-3.) The method of claim 1,
A polymer wherein Ar ³ is an aromatic hydrocarbon group or an aromatic heterocyclic group connected in plural through a linking group represented by the following formula (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, an aromatic hydrocarbon group, or an aromatic heterocyclic group. R ¹ , R ² When a plurality of s are present, they may be the same or different.) The method of claim 1,
A polymer having a weight average molecular weight (Mw) of 20,000 or more and a dispersion degree (Mw/Mn) of 2.5 or less. A composition for organic electroluminescent devices containing the polymer according to any one of claims 1 to 8. An organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate,
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 9. The method of claim 10,
The organic electroluminescent device, wherein the layer formed by the wet film formation method is at least one of a hole injection layer and a hole transport layer. The method of claim 10,
An organic electroluminescent device comprising a hole injection layer, a hole transport layer, and a light-emitting layer between an anode and a cathode, wherein the hole injection layer, the hole transport layer, and the light-emitting layer are all formed by a wet film formation method. An organic EL display device comprising the organic electroluminescent element according to claim 10. An organic EL illumination comprising the organic electroluminescent element according to claim 10. A method for manufacturing an organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate,
A method of manufacturing an organic electroluminescent device, comprising forming a layer contained in the organic layer by a wet film forming method using the composition for an organic electroluminescent device according to claim 9. The method of claim 15,
The method of manufacturing an organic electroluminescent device, wherein the layer formed by the wet film formation method is at least one of a hole injection layer and a hole transport layer. The method of claim 16,
A method for manufacturing an organic electroluminescent device, comprising a hole injection layer, a hole transport layer, and a light-emitting layer between an anode and a cathode, wherein the hole injection layer, the hole transport layer, and the light-emitting layer are all formed by a wet film formation method.

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