JP5326417B2 - Charge transport film and organic electroluminescence device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-life organic electroluminescent element equipped with a charge transport film including a crosslinkable polymer. <P>SOLUTION: The organic electroluminescent element is equipped with the charge transport film containing the crosslinkable polymer, wherein the crosslinkable polymer has a relative permittivity of &ge;3.3 and &le;6.3 measured using an element for measurement at 25&deg;C, a measurement frequency of 100 Hz and measurement AC voltage of 250 mV. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a charge transport film containing a crosslinkable polymer, and more particularly to a charge transport film used as a hole transport film of an organic electroluminescence device, and an organic electroluminescence device using the same.

Since the announcement of the stacked organic electroluminescent device using the vacuum evaporation method by Kodak Company, the development of organic EL displays has been actively carried out and is now in practical use.
In such a stacked organic electroluminescent device, a plurality of organic layers (such as a light emitting layer, a hole injection layer, a hole transport layer, and an electron transport layer) are stacked between an anode and a cathode. In many cases, these organic layers are formed by vacuum-depositing organic layer materials such as low molecular weight dyes. However, it is difficult to obtain a thin film that is homogeneous and free of defects by the vacuum deposition method, and it takes a long time to form several organic layers.

  On the other hand, a technique for forming a plurality of organic layers of a stacked organic electroluminescent element by a wet film forming method has been reported. For example, Patent Document 1 describes an organic electroluminescent device having a charge transport film and a light emitting layer containing a crosslinkable polymer obtained by applying a composition containing a compound having a crosslinking group and crosslinking with light or heat. Has been. When a charge transport film containing a crosslinkable polymer is used, another layer can be easily formed on the charge transport film by a wet film formation method.

Japanese Unexamined Patent Publication No. 7-114987

However, in the organic electroluminescent element having a charge transport film containing the conventional crosslinkable polymer described in Patent Document 1, a sufficient lifetime has not been obtained.
An object of the present invention is to provide an organic electroluminescent device having a long lifetime in an organic electroluminescent device having a charge transport film containing a crosslinkable polymer.

  As a result of intensive studies by the present inventors, it has been found that the above problem can be solved by setting the range of the relative permittivity of the charge transport film, which is considered to be better as it is higher, to a certain range. Reached.

  That is, the present invention is a charge transport film containing a crosslinkable polymer, and the crosslinkable polymer has a relative dielectric constant measured using the following measurement element at 25 ° C., a measurement frequency of 100 Hz, and a measurement AC voltage of 250 mV. Is in the charge transport film, characterized in that it is not less than 3.3 and not more than 6.3.

[Measuring element]
A hole transporting polymer having a repeating structure represented by the following formula (P1) (weight average molecular weight: 10,000 to 50,000, weight average molecular weight / A film of an ethyl benzoate solution containing 2.0% by weight of a number average molecular weight: 1 or more and 3 or less) and 0.8% by weight of 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, A measurement anode provided with a 30 nm thick layer formed by baking at 230 ° C. for 3 hours in the atmosphere, and a sample layer made of the crosslinkable polymer and having a thickness of 100 nm to 200 nm formed on the measurement anode; A measuring element comprising a measuring cathode made of Al and having a thickness of 80 nm formed on the sample layer.

  At this time, it is preferable that the current mutation point measured by the measuring element is 1050 kV / cm or more.

Another subject matter of the present invention lies in an organic electroluminescent device comprising an anode, a cathode, and the charge transport film of the present invention provided between the anode and the cathode. ).
At this time, the charge transport film is preferably a hole transport layer.

  Another subject matter of the present invention lies in an organic EL display characterized by using the above-mentioned organic electroluminescent element (claim 5).

  Another gist of the present invention resides in a compound having a cross-linking group, characterized in that it forms a cross-linkable polymer contained in the charge transport film of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the charge transport film | membrane which can implement | achieve a long life organic electroluminescent element, and a long life organic electroluminescent element can be provided.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention. .

[1. Charge transport film]
The charge transport film refers to a film having a property of transporting charges such as holes and electrons when applied from the outside or generated inside the film. The charge transport film of the present invention is formed using a predetermined charge transport film composition and contains at least a crosslinkable polymer.

[1-1. Crosslinkable polymer]
The crosslinkable polymer according to the present invention refers to a polymer obtained by crosslinking a compound having a crosslinking group. That is, it refers to a polymer in which at least one monomer, oligomer and / or polymer having a crosslinking group is linked by the crosslinking group. The compound having a crosslinking group may be any of a monomer, an oligomer, and a polymer.

  Examples of the crosslinking group include: a group derived from a cyclic ether such as oxetane or epoxy; a vinyl group optionally having a substituent such as a vinyl group or a trifluorovinyl group; a styryl group, an acryloyl group, a methacryloyl group, or cinnamoyl. A group having an unsaturated double bond such as a group; a group derived from a benzocyclobutene ring, and the like. In addition, the compound which has a crosslinking group may have said crosslinking group only by 1 type, and may have 2 or more types by arbitrary combinations and ratios.

The compound having a crosslinking group is usually a charge transporting compound. The number of crosslinking groups in the compound having a crosslinking group is not particularly limited, but is preferably less than 2.0, preferably 0.8 or less, more preferably 0.5 or less per unit charge transport unit. This is to keep the relative dielectric constant of the crosslinkable polymer within a suitable range. Moreover, when the number of crosslinking groups is too large, reactive active species are generated, which may adversely affect other materials.
Here, when the compound having a crosslinkable group is a monomer, the unit charge transport unit is a monomer itself and indicates a skeleton (main skeleton) excluding the crosslinkable group. When the compound having a crosslinking group is an oligomer or polymer, in the case of repeating a structure in which conjugation is broken organically, the repeated structure is defined as a unit charge transport unit. In the case of a structure in which conjugation is widely connected, a minimum repeating structure exhibiting charge transporting property or a monomer structure is shown. Examples of the unit charge transport unit include naphthalene, anthracene, phenanthrene, tetracene, chrysene, pyrene, perylene, fluorene, triphenylene, carbazole, triarylamine, tetraarylbenzidine, 1,4-bis (diarylamino) benzene, and the like. It is done.

When the compound having a crosslinking group is a polymer (when it is a compound having a molecular weight distribution), its weight average molecular weight is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less. Also, it is usually 1,000 or more, preferably 2,500 or more, more preferably 5,000 or more.
The weight average molecular weight here is determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the elution time is shorter for higher molecular weight components and the elution time is longer for lower molecular weight components, but using the calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the elution time of the sample is changed to the molecular weight. The weight average molecular weight is calculated by conversion.

  When the compound having a crosslinking group is a monomer (when it is a compound specified by a single molecular weight), its molecular weight is usually 5000 or less, preferably 2500 or less, preferably 300 or more, more preferably 500 or more. It is.

Furthermore, it is preferable to use a hole transporting compound as the compound having a crosslinking group. Examples of hole transporting compounds include nitrogen-containing aromatic compound derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives, phthalocyanine derivatives, porphyrin derivatives; triphenylamine derivatives Arylamine derivatives such as: silole derivatives; oligothiophene derivatives, condensed polycyclic aromatic derivatives, metal complexes and the like. Among them, nitrogen-containing aromatic derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives; arylamine derivatives such as triphenylamine derivatives, silole derivatives, condensed polycyclic aromatic derivatives And metal complexes are preferable, and arylamine derivatives such as triphenylamine derivatives are particularly preferable.
Here, the term “derivative” does not exclude a compound to which the term is attached. For example, a “triphenylamine derivative” refers to both triphenylamine and a compound derived from triphenylamine. Shall be included.

（上記式中、Ａｒ¹及びＡｒ²は、それぞれ独立して、置換基を有していてもよい芳香族炭化水素基または置換基を有していてもよい芳香族複素環基を表す。） The arylamine derivative is preferably a compound having a repeating unit represented by the following formula (A). In particular, a polymer having a repeating unit of the following formula (A) is preferable. In this case, Ar ¹ and Ar ² may be different from each other in each repeating unit.

(In the above formula, Ar ¹ and Ar ² each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.)

  Examples of the aromatic hydrocarbon group which may have a substituent include, for example, a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, and acenaphthene. And groups derived from a 6-membered monocyclic ring or a 2-5 condensed ring, such as a ring, a fluoranthene ring, and a fluorene ring.

  Examples of the aromatic heterocyclic group which may have a substituent include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, and a carbazole ring. , Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine Ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. Or it includes groups derived from 2-4 fused rings.

From the viewpoint of solubility and heat resistance, Ar ¹ and Ar ² are each independently selected from the group consisting of a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, triphenylene ring, pyrene ring, thiophene ring, pyridine ring, and fluorene ring. A group derived from a selected ring or a group formed by linking two or more benzene rings (for example, a biphenyl group or a terphenyl group) is preferable.

  Among these, a group derived from a benzene ring (phenyl group), a group formed by connecting two benzene rings (biphenyl group), and a group derived from a fluorene ring (fluorenyl group) are preferable.

In particular, in the compound having a repeating unit represented by the formula (A), when Ar ^{2 in} the side chain is a single ring such as a phenyl group, the number of cross-linking groups is 0.3 or less per unit charge transport unit. Preferably, 0.2 or less is more preferable.

Ar ¹ and Ar ² preferably have the above-described crosslinking group as a substituent. When it has a crosslinking group as a substituent, the crosslinking group may be bonded to Ar ¹ or Ar ² via a linking group such as an alkylene group.
The substituent that Ar ¹ and Ar ² may have is not particularly limited, and examples thereof include one or more selected from the following substituent group Z.

[Substituent group Z]
An alkyl group having preferably 1 or more, preferably 24 or less, more preferably 12 or less, such as a methyl group or an ethyl group;
An alkenyl group having preferably 2 or more, preferably 24 or less, more preferably 12 or less, such as a vinyl group;
An alkynyl group having preferably 2 or more, preferably 24 or less, more preferably 12 or less, such as an ethynyl group;
An alkoxy group having preferably 1 or more, preferably 24 or less, more preferably 12 or less, such as a methoxy group or an ethoxy group;
An aryloxy group having preferably 4 or more, more preferably 5 or more, preferably 36 or less, more preferably 24 or less carbon atoms, such as a phenoxy group, a naphthoxy group, or a pyridyloxy group;
An alkoxycarbonyl group having preferably 2 or more, preferably 24 or less, more preferably 12 or less, such as a methoxycarbonyl group or an ethoxycarbonyl group;
A dialkylamino group having preferably 2 or more, preferably 24 or less, more preferably 12 or less, such as a dimethylamino group or a diethylamino group;
A diarylamino group having preferably 10 or more, more preferably 12 or more, and preferably 36 or less, more preferably 24 or less, such as a diphenylamino group, a ditolylamino group, or an N-carbazolyl group;
An arylalkylamino group having preferably 6 or more, more preferably 7 or more, preferably 36 or less, more preferably 24 or less carbon atoms, such as a phenylmethylamino group;
An acyl group having preferably 2 or more, preferably 24 or less, more preferably 12 or less, such as an acetyl group or a benzoyl group;
Halogen atoms such as fluorine atoms and chlorine atoms;
A haloalkyl group having preferably 1 or more, preferably 12 or less, more preferably 6 or less, such as a trifluoromethyl group;
An alkylthio group having preferably 1 or more, preferably 24 or less, more preferably 12 or less, such as a methylthio group or an ethylthio group;
An arylthio group having preferably 4 or more, more preferably 5 or more, preferably 36 or less, more preferably 24 or less carbon atoms, such as a phenylthio group, a naphthylthio group, a pyridylthio group;
A silyl group having 2 or more carbon atoms, more preferably 3 or more, preferably 36 or less, more preferably 24 or less, such as a trimethylsilyl group or a triphenylsilyl group;
A siloxy group having preferably 2 or more, more preferably 3 or more, and preferably 36 or less, more preferably 24 or less, such as a trimethylsiloxy group or a triphenylsiloxy group;
A cyano group;
An aromatic hydrocarbon ring group having preferably 6 or more, preferably 36 or less, more preferably 24 or less, such as a phenyl group or a naphthyl group;
An aromatic heterocyclic group having preferably 3 or more, more preferably 4 or more, preferably 36 or less, more preferably 24 or less, such as a thienyl group or a pyridyl group.
Each of the above substituents may further have a substituent, and examples thereof include the groups exemplified in the substituent group Z.

The molecular weight of the substituents of Ar ¹ and Ar ² is preferably 500 or less, and more preferably 250 or less, including further substituted groups.
From the viewpoint of solubility, the substituents that Ar ¹ and Ar ² may have are each independently preferably an alkyl group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms.

Preferable examples of the compound having a crosslinking group include the following.

  Moreover, in the charge transport film, only one type of crosslinkable polymer may be contained, or two or more types may be contained in any combination and ratio. In that case, the dielectric constant of at least one crosslinkable polymer of two or more is preferably 3.3 or more and 6.3 or less, and the dielectric constant of all the crosslinkable polymers contained in the charge transport film is 3. It is particularly preferably 3 or more and 6.3 or less.

[Physical properties of crosslinkable polymer]
[Relative permittivity]
The crosslinkable polymer according to the present invention has a relative dielectric constant of 3.3 or more and 6.3 or less measured at room temperature of 25 ° C., a measurement frequency of 100 Hz, and a measurement AC voltage of 250 mV using the following measurement element. , Preferably 4.0 or less. When the relative dielectric constant falls within the above range, the lifetime of the organic electroluminescence device using the charge transport film of the present invention can be extended.

As a measuring element, a hole transporting polymer (weight average) having a repeating structure represented by the following formula (P1) on an ITO layer made of ITO (that is, indium tin oxide) having a thickness of 100 nm to 200 nm. Molecular weight: 10,000 or more and 50,000 or less, weight average molecular weight / number average molecular weight: 1 or more and 3 or less) 2.0% by weight, and 4-isopropyl-4′-methyldiphenyliodonium tetrakis represented by the following formula (A1) A measuring anode comprising a 30 nm thick layer formed by forming a film of an ethyl benzoate solution containing 0.8% by weight of (pentafluorophenyl) borate and baking at 230 ° C. for 3 hours in the atmosphere, and the measuring anode A sample layer made of a crosslinkable polymer according to the present invention having a thickness of 100 nm to 200 nm and an Al layer formed on the sample layer. And a cathode having a thickness of 80 nm for measurement.

A specific measurement method may be performed as follows. In addition, in FIG. 1, the layer structure of the element for a measurement is shown typically.
As shown in FIG. 1, an indium tin oxide (ITO) transparent conductive film deposited on a glass substrate 1 to a thickness of 100 nm or more and 200 nm or less (for example, a sputtered film manufactured by Sanyo Vacuum Co., Ltd.). A dimension of 250 mm × 375 mm) is prepared. Then, the ITO layer 2 is formed by patterning into stripes having a width of 2 mm using a normal photolithography technique and hydrochloric acid etching. The substrate having the ITO layer thus patterned is cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, and then with compressed air. Dry and finally perform UV ozone cleaning.

Next, a hole transporting polymer having a repeating structure represented by the above formula (P1) (weight average molecular weight 10,000 to 50,000, weight average molecular weight / number average molecular weight: 1 to 3) 2.0 weight % And 4-benzoyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate 0.8% by weight represented by the above formula (A1) is prepared. And this ethyl benzoate solution is formed into a film by the spin coat method on the film-forming conditions shown in following Table 1, and the polymer layer 3 with a film thickness of 30 nm is formed. Thereby, the measurement anode 4 is constituted by the ITO layer 2 and the polymer layer 3.

  Thereafter, the sample layer 5 is formed on the measurement anode 4 using a compound having a crosslinkable group that forms the crosslinkable polymer according to the present invention. For the sample layer 5, a coating solution is prepared by dissolving or dispersing the compound having a crosslinking group in a solvent, and this is formed on the measurement anode 4 by spin coating. The solvent can be appropriately selected according to the compound having a crosslinking group, and examples thereof include those exemplified as the solvent contained in the composition for a charge transport film described in detail below. The spin coating conditions are preferably a spinner rotation speed of 150 to 1500 rpm, a spinner rotation time of 30 seconds, and a nitrogen atmosphere. After film formation, the solvent is removed by heating. Moreover, the crosslinking reaction of the compound having a crosslinking group is caused by heating simultaneously with or separately from this heating, or the crosslinking reaction is caused by irradiating electromagnetic energy such as light simultaneously with or separately from the heating. Thereby, a sample layer made of a crosslinkable polymer is obtained. The film thickness of the sample layer after the heating or after the irradiation is made to be 100 nm or more and 200 nm or less.

The element in which the sample layer 5 is formed is carried, for example, into a multi-chamber type vacuum deposition apparatus connected to a glove box without being exposed to the atmosphere, and the apparatus is roughly evacuated by an oil rotary pump or the like, and then the vacuum inside the apparatus The air is exhausted using a cryopump or the like until the degree becomes 9.9 × 10 ⁻⁴ Pa or less. Next, it is conveyed to a metal vapor deposition chamber in a vacuum, and a 2 mm wide stripe shadow mask is brought into close contact with the element so as to be orthogonal to the stripe of the ITO layer 2 as a cathode vapor deposition mask. Install in. And it exhausts until the vacuum degree in an apparatus becomes 9.9 * 10 <^-4> Pa or less. Thereafter, aluminum is heated by a molybdenum boat, and an aluminum layer having a thickness of 80 nm is formed by controlling the deposition rate at 0.2 to 16.0 Å / sec and the degree of vacuum from 2.0 to 250 × 10 ⁻⁵ Pa. Is the measurement cathode 6. In addition, the substrate temperature at the time of vapor deposition of the measurement cathode 6 is kept at room temperature. As described above, a measurement element used for measuring the relative dielectric constant of the crosslinkable polymer according to the present invention is obtained as a sample having an element area of 2 mm × 2 mm.

The relative permittivity may be measured using the measurement element thus obtained as it is. However, if it takes time from the preparation of the measurement element to the measurement of the relative permittivity, the measurement element is in storage. In order to prevent deterioration due to moisture or the like in the atmosphere, it is preferable to perform a sealing treatment by the method described below.
The produced measuring element is carried into a nitrogen glove box without being exposed to the atmosphere. On the other hand, in a nitrogen glove box, a photocurable resin (for example, 30Y-437 manufactured by ThreeBond Co., Ltd.) with a width of about 1 mm is applied to the outer periphery of a 23 mm × 23 mm glass plate, and a moisture getter sheet is applied to the center. (For example, Dynic Co., Ltd.) is installed. On this, the measuring element is bonded so that the measuring cathode faces the desiccant sheet. After that, only the region where the photocurable resin is applied is irradiated with ultraviolet light to cure the photocurable resin.

（関係式（１）において、Ｃは計測された静電容量を表わし、ｄはサンプル層の膜厚を表わし、Ｓは面積（パターニングされたＩＴＯ層２とアルミニウム（測定用陰極６）とが交差してできる面の面積）を表わし、ε_ｒは比誘電率を表わし、ε_０は真空中の誘電率を表わす。） A voltage having a measurement frequency of 100 Hz and a measurement AC voltage of 250 mV is applied to the electrodes 4 and 6 of the measurement element obtained as described above at a room temperature of 25 ° C., and the capacitance of the measurement element is measured. At this time, the measurement speed per one time is set to 480 milliseconds, a parallel equivalent circuit is selected as the equivalent circuit, and, for example, the measurement is performed for 30 minutes by a method of obtaining one point measurement value per second, and then the average is obtained. The value is the capacitance of the crosslinkable polymer that forms the sample layer 5. Then, the relative dielectric constant is measured by calculating the relative dielectric constant from the measured capacitance according to the following relational expression (1).

(In relational expression (1), C represents the measured capacitance, d represents the thickness of the sample layer, and S represents the area (the patterned ITO layer 2 and aluminum (measurement cathode 6) intersect). Ε _r represents the relative dielectric constant, and ε ₀ represents the dielectric constant in vacuum.)

  For the measurement of the capacitance, a ZM2353 type LCR meter manufactured by NF Circuit Design Block Co., Ltd. can be used, and a 2335AL type test fixture (a Kelvin clip capable of connecting four terminals with two clips) can be used. Any device can be used as long as it can perform the same measurement. At the time of measurement, the electrode may be taken out from the ITO layer 2 of the produced measurement element using a contact probe and measured by sandwiching it with the above-mentioned clip.

Here, the reason why the above measuring method is used in measuring the relative dielectric constant of the crosslinkable polymer according to the present invention is as follows.
The charge transport film of the present invention is often used by being laminated with another organic layer at the time of use. For example, when the charge transport film of the present invention is used as a component of an organic electroluminescence device, it is usually used by being laminated with an organic layer such as a hole injection layer. When the relative dielectric constant is measured when the organic layer is laminated as described above, the measured relative dielectric constant does not necessarily match the relative dielectric constant of the crosslinkable polymer alone. Therefore, when measuring the relative dielectric constant of a crosslinkable polymer that exhibits the effects specific to the present invention, it is appropriate to measure the relative dielectric constant in a state where it is laminated with a predetermined organic layer. Therefore, in the present invention, the measurement anode 4 is obtained by laminating a predetermined polymer layer 3 on the ITO layer 2.

In the case of a device such as a direct current drive, the relative permittivity is mainly affected by the following three types of polarization if the response is ignored.
(1) Electron polarization (mainly changes following changes in the electric field of the electron cloud: molecular polarizability)
(2) Deformation polarization (the position of the nucleus changes following the change of the electric field: molecular vibration)
(3) Orientation polarization (produced by a change in orientation caused by the permanent dipole of the molecule: molecular rotation)

  Therefore, asymmetry of the position of the charge transport unit itself constituting the crosslinkable polymer and the group replacing it [mainly affects (3)], introduction of heteroatoms having lone pairs into the crosslinkable polymer [mainly ( 1)], design of substituents and molecules having a high degree of freedom in the crosslinkable polymer [mainly affects (2)], molecular structure in which the charge transport unit is easily oriented when a compound having a crosslinking group is applied, The specific permittivity of the crosslinkable polymer according to the present invention can be increased by devising the selection of the solvent [mainly affecting (1)].

Furthermore, adjustment of the number of crosslinking groups per charge transport unit of the compound having a crosslinking group is also closely related to the dielectric constant. Therefore, depending on the type of the cross-linking group, as described above, the relative dielectric constant of the present invention can be achieved by setting the number of cross-linking groups per charge transport unit to less than 2.0.
In addition, by controlling the conjugation length and steric hindrance of the crosslinkable polymer so that the polymer has appropriate planarity, the relative dielectric constant can be increased. Thus, a crosslinkable polymer having the range of relative dielectric constant of the present invention can be obtained by designing and selecting a crosslinkable polymer, that is, a compound having a crosslinkable group.

  In addition, the adjustment of the position and type of the group that substitutes for the main chain of the crosslinkable polymer also affects the spread of the electron cloud that tends to affect the dielectric constant, so that the dielectric constant is within the range of the present invention. It is effective for. For example, in an amine compound such as a triarylamine derivative, when a crosslinking group is introduced, if it is introduced at the meta position with reference to the amine, it tends to fall within the target relative dielectric constant range.

  The present invention also relates to a compound having a crosslinkable group that forms a crosslinkable polymer satisfying the above dielectric constant. The compound having such a crosslinkable group is the same as that described in detail as the compound having a crosslinkable group contained in the charge transport film composition, and after forming the crosslinkable polymer, the relative dielectric constant is It satisfies.

[Current mutation point]
In the crosslinkable polymer according to the present invention, the current mutation point measured by the above-mentioned measuring element is preferably 1050 kV / cm or more, usually 2500 kV / cm or less, more preferably 2000 kV / cm or less. If the current mutation point is too low, the charge transport film of the present invention may be easily destroyed by the charge and deteriorate, and if the current mutation point is too high, insulation may be generated, and the charge transport property may be lowered. is there.

  The current variation point is the first maximum value of the current density value detected with respect to the voltage used to apply holes or electrons alone, or both when the sample is injected with holes or electrons. Or the value obtained by converting the absolute value of the voltage value at the point where the current value suddenly increases or decreases into kV units and dividing by the film thickness (cm) of the sample. However, in the case of a minute noise associated with the application of charge that occurs at a low potential or a phenomenon in which fluctuation occurs, it is not regarded as a current mutation point.

The method for measuring the current mutation point of the crosslinkable polymer according to the present invention is as follows.
As a sample, a measurement element similar to that used in the relative dielectric constant measurement method is prepared. In addition, it is preferable to use a 2400 type source meter manufactured by Keithley for the generation of the voltage used for applying the electric charge and the detection of the current value associated therewith, but an equivalent device may be used. Then, the electrode on the output side of the source meter is connected to the electrode into which the charge of the measuring element is to be injected, and the value of the current when the voltage is changed is read. The voltage is increased by 0.1V every 2 seconds. By continuing to increase the voltage, the current value clearly shows a behavior of decreasing or suddenly increasing at a certain voltage, so the absolute value of the voltage value at that time is converted into kV units and divided by the film thickness (cm). To obtain the current mutation point.

The current mutation point is in a state where the phenomenon that the crosslinkable polymer cannot withstand the amount of charge when the charge flows through the crosslinkable polymer and the property as the crosslinkable polymer is destroyed is more dominant. It is a point. Therefore, preventing the self-decomposition of the generated radical ion species is one method for increasing the current mutation point. For example, in the case of a crosslinkable polymer that generates radical cation species, hydrogen or carbonyl group is not bonded to the triarylmethyl position and / or benzyl position in the molecular structure of the crosslinkable polymer. , It is possible to prevent generation of stable radicals or ionic species due to its own decay in the charge transport unit, and to increase the current mutation point. This is because stable radicals may be generated by releasing protons when hydrogen is bonded, and stable cation species (trityl cation, etc.) are generated by bond cleavage when carbonyl groups are bonded. Therefore, it corresponds to cutting relatively easily. This is presumed from the fact that pk-H1 and pk-H3 have smaller current mutation points than pk-H2 (removal of benzylic hydrogen) when referring to the examples described later.
Further, increasing the glass transition point Tg of the crosslinkable polymer itself is considered as one method for increasing the current mutation point. This is because when crystallization occurs, the current rises rapidly at that temperature and may lose its properties as a crosslinkable polymer.

[1-2. Charge transport film thickness]
The size of the charge transport film of the present invention is not limited, but the film thickness is usually 100 nm or more, preferably 110 nm or more, more preferably 120 nm or more, and usually 200 nm or less, preferably 180 nm or less, more preferably 150 nm or less. If the film thickness is too thin, the characteristics of the electrode may affect the charge transport film, and if it is too thick, the film quality may deteriorate.

[1-3. Method for producing charge transport film]
Although there is no restriction | limiting in the manufacturing method of the charge transport film | membrane of this invention, Usually, the compound (monomer, oligomer, and / or polymer which has a crosslinking group) which has a crosslinking group which forms a crosslinkable polymer, and as needed A composition containing other components to be used (hereinafter referred to as “charge transport film composition” as appropriate) was prepared, and after the charge transport film composition was formed, the compound having a crosslinking group was crosslinked. A charge transport membrane is produced by forming a crosslinkable polymer. In addition, the charge transport film composition usually contains an appropriate solvent so as to dissolve or disperse the compound having a crosslinking group and other components.

  The compound having a crosslinking group to be contained in the charge transport film composition is as described above. Moreover, only 1 type may be used for the compound which has these crosslinking groups, and the other component, respectively, and 2 or more types may be used together by arbitrary combinations and a ratio.

  In the charge transport film composition, the content of the compound having a crosslinking group is usually 0.1% by weight or more, preferably 0.5% by weight or more, usually 50% by weight or less, preferably 20% by weight or less. When two or more compounds having a crosslinking group are used in combination, the total amount is within the above range.

  The solvent to be contained in the charge transport film composition is not particularly limited, but a solvent that dissolves the above-described compound having a crosslinking group and other components is preferable. Specifically, the solvent dissolves the solute contained in the charge transport film composition of the present invention, usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more. Use what you want.

Examples of suitable solvents include aromatic solvents such as toluene, xylene, methicylene, and cyclohexylbenzene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene, and o-dichlorobenzene; ethylene glycol dimethyl ether, ethylene glycol diethyl Ethers, aliphatic ethers such as propylene glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4- Ether solvents such as aromatic ethers such as methoxytoluene, 2,3-dimethylanisole and 2,4-dimethylanisole; aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; phenyl acetate Propionate phenyl, benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and organic solvent of the ester solvents such as aromatic esters such as benzoic acid n- butyl.
In addition, only 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

  The concentration of the solvent contained in the charge transport film composition is not particularly limited, but is usually 10% by weight or more, preferably 50% by weight or more, more preferably 80% by weight or more, and usually 99.999% by weight or less. , Preferably 99.99% by weight or less, more preferably 99.9% by weight or less. If the solvent is too little or too much, the film quality tends to deteriorate.

Furthermore, the composition for charge transport films may contain components other than the compound having a crosslinking group. Examples include additives for accelerating the crosslinking reaction, coatability improvers such as leveling agents and antifoaming agents, electron accepting compounds, binder resins, compounds having charge transportability other than compounds having a crosslinking group, etc. Is mentioned. Therefore, these components may be contained in the charge transport film as components other than the crosslinkable polymer.
Additives for promoting the crosslinking reaction are used to reduce the solubility of the charge transport film. By accelerating the crosslinking reaction, the solubility of the charge transport film in the solvent is lowered, and another layer can be formed on the charge transport film by coating.

  Examples of additives that promote the crosslinking reaction include polymerization initiators and polymerization accelerators such as alkylphenone compounds, acylphosphine oxide compounds, metallocene compounds, oxime ester compounds, azo compounds, onium salts; condensed polycyclic hydrocarbons, And photosensitizers such as porphyrin compounds and diaryl ketone compounds.

  Moreover, as a compound which has charge transportability, any of a monomer, an oligomer, and a polymer may be sufficient. When the example is given, the hole transportable compound, electron transport compound, etc. which are normally used with an organic electroluminescent element will be mentioned.

  Examples of the film forming method for the charge transport film composition include wet film forming methods such as a spin coating method, a spray method, an ink jet method, and a screen method. Moreover, since the composition for charge transport films usually contains a solvent, the solvent is removed by drying as necessary after film formation. The drying conditions are arbitrary, and drying can be performed by heat drying, reduced pressure drying, or the like.

  After the film formation, the crosslinking reaction proceeds by irradiation with electromagnetic energy such as light and / or heating. If necessary, the solvent may be removed by drying. As a result, the compound having a crosslinking group in the formed film is crosslinked to form a crosslinkable polymer, whereby the film can be obtained as the charge transport film of the present invention. Since the resulting charge transport film has a lower solubility in a solvent due to cross-linking, it can be further formed thereon by a wet film formation method or the like.

When the crosslinking reaction proceeds by irradiation with electromagnetic energy such as light, there is no limitation on the irradiation apparatus for electromagnetic energy irradiation. For example, when light irradiation is used, ultra-high pressure mercury lamp, high-pressure mercury lamp, halogen lamp, infrared lamp, and other ultraviolet / visible / infrared light sources; mask aligners incorporating the above-mentioned light sources, conveyor-type light irradiation devices Etc. can be used. For electromagnetic energy irradiation other than light, for example, a device that irradiates a microwave generated by a magnetron; a microwave oven or the like can be used.
The electromagnetic energy irradiation time is preferably set to conditions necessary for reducing the solubility of the charge transport film, but is usually 0.1 seconds or longer, preferably 10 hours or shorter.

  On the other hand, when the crosslinking reaction proceeds by heating, the heating temperature is not limited, but is usually 80 ° C. or higher and usually 400 ° C. or lower. Moreover, there is no restriction | limiting also in the pressure at the time of a heating, Normal pressure may be sufficient and pressure reduction may be sufficient. The heating time is usually 1 minute or more and usually 24 hours or less. Although it does not specifically limit as a heating means, For example, what is necessary is just to heat on a hotplate or to heat in an oven. As a specific example, conditions such as heating on a hot plate at a temperature of 120 ° C. or higher for 1 minute or longer can be used.

  In addition, said heating and electromagnetic energy irradiation may perform only any one, and may perform it combining 2 or more operation arbitrarily. Moreover, when performing in combination, the order which implements them is not specifically limited.

  The above cross-linking reaction is performed in an atmosphere having a low water content in order to reduce the water content of the charge transport film of the present invention obtained after cross-linking and / or the amount of water adsorbed on the surface of the charge transport film. It is preferable to carry out in an atmosphere that does not contain moisture. Further, from the viewpoint of preventing unintended oxidation or the like from proceeding, it is preferable to perform the crosslinking reaction in an inert atmosphere, for example, in a nitrogen gas atmosphere.

[2. Organic electroluminescent device]
The organic electroluminescent element of the present invention comprises an anode, a cathode, and the charge transport film of the present invention provided between the anode and the cathode. Hereinafter, the organic electroluminescent element of the present invention will be described in detail with reference to an embodiment.

  FIG. 2A is a cross-sectional view schematically showing a layer configuration of an organic electroluminescent element according to an embodiment of the present invention. The organic electroluminescent element 10 shown in FIG. 2A is formed by laminating an anode 12, a hole injection layer 13, a charge transport film 14, a light emitting layer 15, an electron injection layer 16 and a cathode 17 in this order on a substrate 11. It is composed by doing.

[2-1. substrate]
The substrate 11 serves as a support for the organic electroluminescent element 10.
Although the material of the board | substrate 11 is not restrict | limited, As an example, quartz, glass, a metal, a plastic etc. are mentioned. Any one of these materials may be used, or two or more of these materials may be used in any combination and ratio.

Although the shape of the board | substrate 11 is not restrict | limited, As an example, the shape etc. which combined a board, a sheet | seat, a film, foil, etc. or these 2 or more types are mentioned.
Among them, the substrate 11 is preferably a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone, or the like.

  In addition, when using a synthetic resin as a material of the board | substrate 11, it is desirable to pay attention to gas barrier property. If the gas barrier property of the substrate 11 is too low, the organic electroluminescent element 1 may be deteriorated by the outside air that has passed through the substrate 11. Therefore, it is preferable to take a technique such as providing a dense silicone oxide film or the like on at least one surface of the substrate 11 made of synthetic resin to ensure gas barrier properties.

  The thickness of the substrate 11 is not limited, but is usually in the range of 1 μm or more, preferably 50 μm or more, and usually 50 mm or less, preferably 3 mm or less. If the substrate 11 is too thin, the mechanical strength may be low, and if it is too thick, the weight of the element may increase excessively.

  In addition, although the board | substrate 11 is good also as a structure which consists of a single layer, it is good also as a structure by which the several layer was laminated | stacked. In the latter case, the plurality of layers may be layers made of the same material, but may be layers made of different materials.

[2-2. anode]
An anode 12 is formed on the substrate 11.
The anode 12 plays a role of hole injection into the layer (the hole injection layer 13 or the charge transport film 14) on the light emitting layer 15 side.

The material of the anode 12 is arbitrary as long as it is a conductive material. Examples thereof include metals such as aluminum, gold, silver, nickel, palladium, and platinum, and metal oxides such as oxides of indium and / or tin. Products, metal halides such as copper iodide, carbon black, or conductive polymers such as poly (3-methylthiophene), polypyrrole, and polyaniline.
Any one of these materials for the anode 12 may be used, or two or more may be used in any combination and ratio.

  Although the method for forming the anode 12 is not limited, a sputtering method, a vacuum evaporation method, or the like is usually used. Also, when using materials such as metal fine particles such as silver, metal halide fine particles such as copper iodide, carbon material fine particles such as carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc. The anode 12 can also be formed by dispersing these materials in a suitable binder resin solution and applying the solution on the substrate 11.

  Further, when a conductive polymer is used as a material, the anode 12 is formed by a method such as forming a thin film directly on the substrate 11 by electrolytic polymerization or applying a conductive polymer on the substrate 11. (See Applied Physics Letters, 1992, Vol. 60, pp. 2711).

The thickness of the anode 12 varies depending on the transparency required for the anode 12.
When the anode 12 is required to be transparent, the visible light transmittance of the anode 12 is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode 12 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. If the anode 12 is too thin, the electrical resistance may increase, and if it is too thick, the transparency may decrease.

  On the other hand, when the anode 12 may be opaque, for example, when the anode 12 also serves as the substrate 11, the thickness of the anode 12 is usually 1 μm or more, preferably 50 μm or more, and usually 50 mm or less, preferably 30 mm. The following ranges are desirable. If the anode 12 is too thin, the mechanical strength may be low, and if it is too thick, the weight of the organic electroluminescent element may be excessively increased.

The anode 12 may have a single layer configuration, but may have a configuration in which a plurality of layers are stacked. In the latter case, the plurality of layers may be layers made of the same material, but may be layers made of different materials.
Furthermore, the anode 12 may be formed integrally with the substrate 11 described above, and the anode 12 may also serve as the substrate 11.

  After the anode 12 is formed, the surface of the anode 12 is subjected to ultraviolet (UV) treatment, ozone for the purpose of removing impurities adhering to the anode 12 and adjusting the ionization potential to improve the hole injection property. It is preferable to perform processing such as processing, plasma processing (for example, oxygen plasma processing, argon plasma processing, etc.).

[2-3. Hole injection layer]
A hole injection layer 13 is formed on the anode 12.
The hole injection layer 13 is a layer that transports holes from the anode 12 to the charge transport film 14.
The hole injection layer 13 preferably includes a hole transporting compound, and more preferably includes a hole transporting compound and an electron accepting compound. Further, the hole injection layer 13 preferably contains a cation radical compound, and particularly preferably contains a cation radical compound and a hole transporting compound.
Furthermore, the hole injection layer 13 may contain a binder resin and a coating property improving agent as necessary. The binder resin is preferably one that hardly acts as a charge trap.

[Hole transporting compound]
As the hole transporting compound, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferable. However, when used in the wet film forming method, it is preferable that the solubility in the solvent used in the wet film forming method is high.

  Examples of the hole transporting compound include aromatic amine compounds, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, and the like. Of these, aromatic amine compounds are preferred from the viewpoints of amorphousness and visible light transmittance.

  The type of the aromatic amine compound is not particularly limited, and may be a low molecular compound or a high molecular compound. From the viewpoint of the surface smoothing effect, the high molecular compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less. (Polymerized hydrocarbon compound in which repeating units are continuous) is preferred.

  Of the aromatic amine compounds, an aromatic tertiary amine compound is particularly preferable. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.

（上記式（ｉ）中、Ａｒ^ａ１、Ａｒ^ａ２は各々独立して、置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表わす。Ａｒ^ａ３〜Ａｒ^ａ５は、各々独立して、置換基を有していてもよい２価の芳香族炭化水素基、または置換基を有していてもよい２価の芳香族複素環基を表わす。Ｚ^ａは、下記の連結基群の中から選ばれる連結基を表わす。また、Ａｒ^ａ１〜Ａｒ^ａ５のうち、同一のＮ原子に結合する二つの基は互いに結合して環を形成してもよい。）

（上記各式中、Ａｒ^ａ６〜Ａｒ^ａ１６は、各々独立して、置換基を有していてもよい芳香族炭化水素環、または置換基を有していてもよい芳香族複素環由来の１価または２価の基を表わす。Ｒ^ａ１およびＲ^ａ２は、各々独立して、水素原子または任意の置換基を表わす。） Preferable examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (i).

(In the above formula (i), Ar ^a1 and Ar ^a2 each independently represent an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ^{a3 to} Ar ^a5 each independently represents a divalent aromatic hydrocarbon group which may have a substituent, or a divalent aromatic heterocyclic group which may have a substituent. Z ^a represents ^a linking group selected from the following group of linking groups, and two groups bonded to the same N atom among Ar ^{a1 to} Ar ^a5 are bonded to each other to form a ring. You may do it.)

(In the above formulas, Ar ^{a6 to} Ar ^a16 are each independently an aromatic hydrocarbon ring which may have a substituent or an aromatic heterocyclic ring which may have a substituent. R ^a1 and R ^a2 each independently represents a hydrogen atom or an arbitrary substituent.

As Ar ^{a1 to} Ar ^a16 , any monovalent or divalent group derived from any aromatic hydrocarbon ring or aromatic heterocyclic ring is applicable. These groups may be the same or different from each other. Further, these groups may further have an arbitrary substituent. The molecular weight of the substituent is usually 400 or less, and preferably 250 or less.

Ar ^a1 and Ar ^a2 are preferably monovalent groups derived from a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, or a pyridine ring from the viewpoints of solubility, heat resistance, and hole injection / transport properties of the polymer compound. More preferred are a phenyl group and a naphthyl group.

Ar ^{a3 to} Ar ^a5 are preferably divalent groups derived from a benzene ring, a naphthalene ring, an anthracene ring, or a phenanthrene ring from the viewpoint of heat resistance and hole injection / transport properties including redox potential. A group, a biphenylene group, and a naphthylene group are more preferable.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the general formula (i) include compounds described in International Publication No. 2005/089024 pamphlet.
In addition, the hole transportable compound may contain only 1 type in such a compound, and may contain 2 or more types.
When two or more hole transporting compounds are contained, the combination thereof is arbitrary, but one or more aromatic tertiary amine polymer compounds and one or two other hole transporting compounds are used. It is preferable to use the above together.

[Electron-accepting compound]
As the electron-accepting compound, a compound having an oxidizing power and an ability to accept one electron from the above-described hole-transporting compound is preferable. Specifically, a compound with an electron affinity of 4 eV or more is preferable, and a compound with a compound of 5 eV or more is more preferable.

  Examples of the electron-accepting compound include onium salts substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, iron (III) chloride (Japanese Patent Laid-Open No. 11-251067). Publication), high valence inorganic compounds such as ammonium peroxodisulfate, cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365), fullerene derivatives, iodine Etc.

  Of the above-mentioned compounds, an onium salt substituted with an organic group, a high-valence inorganic compound, and the like are preferable because they have strong oxidizing power. In addition, an onium salt substituted with an organic group, a cyano compound, an aromatic boron compound, or the like is preferable because it is soluble in various solvents and can be applied to wet film formation.

なお、電子受容性化合物は１種類のみを用いてもよく、また２種類以上を任意の組み合わせ、及び比率で用いてもよい。 Specific examples of onium salts, cyano compounds and aromatic boron compounds substituted with an organic group suitable as an electron-accepting compound include those described in International Publication No. 2005/089024, and the preferred examples thereof are also the same. is there. Examples thereof include compounds represented by the following structural formulas, but are not limited thereto.

In addition, only one type of electron-accepting compound may be used, or two or more types may be used in any combination and ratio.

[Cation radical compound]
As the cation radical compound, an ionic compound composed of a cation radical which is a chemical species obtained by removing one electron from a hole transporting compound and a counter anion is preferable. However, when the cation radical is derived from a hole transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

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

  Here, the cation radical compound can be generated by mixing the hole transporting compound and the electron accepting compound. That is, by mixing the hole transporting compound and the electron accepting compound, electron transfer occurs from the hole transporting compound to the electron accepting compound, and the cation radical and the counter anion of the hole transporting compound A cation ion compound consisting of

  In addition, cationic radicals derived from polymer compounds such as PEDOT / PSS (Adv. Mater., 2000, 12, 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, 94, 7716). The compound is also produced by oxidative polymerization (dehydrogenation polymerization).

The oxidative polymerization referred to here is a method in which a monomer is chemically or electrochemically oxidized using peroxodisulfate or the like in an acidic solution. In the case of this oxidative polymerization (dehydrogenation polymerization), the monomer is polymerized by oxidation, and a cation radical that is removed from the polymer repeating unit by using an anion derived from an acidic solution as a counter anion is removed. Generate.
In addition, a cation radical compound may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

[Method for producing hole injection layer 13]
The hole injection layer 13 can be formed by any method as long as the effects of the present invention are not significantly impaired. For example, the hole injection layer 13 is formed on the anode 12 by a wet film formation method or a vacuum evaporation method.

  In the case of layer formation by a wet film formation method, one or more predetermined amounts of each of the above-described materials (hole transporting compound, electron accepting compound, cation radical compound) act as a charge trap if necessary. First, a coating solution is prepared by dissolving it in a solvent together with a difficult binder resin and coating property improver. Next, the hole injection layer 13 can be formed by applying on the anode by a wet film formation method such as spin coating, spray coating, dip coating, die coating, flexographic printing, screen printing, and ink jet method, and drying.

As the solvent used for the layer formation by the wet film forming method, any solvent can be used as long as it can dissolve the above-mentioned materials (hole transporting compound, electron accepting compound, cation radical compound). Is not particularly limited. In addition, the material used for the hole injection layer (a hole transporting compound, an electron accepting compound, a cation radical compound) does not contain a deactivating substance or a substance that generates a deactivating substance that may deactivate the material. Is preferred.
Specific examples of preferred solvents include ether solvents or ester solvents. In addition, only 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

  The concentration of the solvent in the coating solution is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and usually 99.999% by weight or less, preferably 99.99% by weight or less. More preferably, it is 99.9% by weight or less. In addition, when using 2 or more types of solvents in mixture, the total of these solvents should just satisfy this range.

In the case of layer formation by vacuum deposition, first, one or more of the above-mentioned materials (hole transporting compound, electron accepting compound, cation radical compound) are placed in a crucible placed in a vacuum vessel. Put in each crucible when using two or more materials, and then evacuate the inside of the vacuum vessel to about 10 ⁻⁴ Pa with a suitable vacuum pump. After that, the crucible is heated (each crucible is heated when two or more materials are used), and the amount of evaporation is controlled and evaporated (when two or more materials are used, the amount of evaporation is controlled independently). Evaporation) and a hole injection layer can be formed on the anode of the substrate placed facing the crucible. In addition, when using 2 or more types of materials, they can also be put into a crucible, can be heated and evaporated, and can be used for hole injection layer formation.

  The thickness of the hole injection layer 13 formed as described above is usually in the range of 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. If the hole injection layer 13 is too thin, the hole injection property may be insufficient. Moreover, when it is too thick, resistance may become high.

  The hole injection layer 13 may be composed of a single layer, or may be composed of a plurality of layers. In the latter case, the plurality of layers may be layers made of the same material or layers made of different materials.

[2-4. Charge transport film]
The charge transport film 14 is formed by [1. It is a layer having the structure described in the section “Charge transport film”. In the present embodiment, the charge transport film 14 functions as a hole transport film (hole transport layer) that transports holes from the anode 12 or the hole injection layer 13 to the light emitting layer 15.

[2-5. Light emitting layer]
A light emitting layer 15 is formed on the charge transport film 14.
The light-emitting layer 15 is configured to regenerate holes injected from the anode 12 through the hole injection layer 13 and the charge transport film 14 and electrons injected from the cathode 17 through the electron injection layer 16 between the electrodes to which an electric field is applied. It is a layer that is excited by bonding and becomes the main light emitting source.

  The light emitting layer 15 contains at least a material having a light emitting property (light emitting material), and preferably a material having a hole transporting property (hole transporting compound) or a material having an electron transporting property. (Electron transporting compound).

As the luminescent material, it is preferable to use a low molecular weight material because it is preferable to form the luminescent layer 15 by a wet film formation method.
Moreover, when manufacturing the organic electroluminescent element of this invention, it is preferable to use at least a fluorescent light-emitting material as a light-emitting material. However, a phosphorescent material may be used in combination. For example, in the case of a light-emitting display device including the organic electroluminescent element of the present invention, a fluorescent light-emitting material and a phosphorescent light-emitting material may be used separately for each emission color. A phosphorescent material may be mixed and used.
For the purpose of improving the solubility in a solvent, the symmetry and rigidity of the molecules of the luminescent material can be reduced, or lipophilic substituents such as alkyl groups can be introduced.

  Examples of the fluorescent material that gives blue light emission include perylene, pyrene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof. Examples of the green fluorescent material include quinacridone derivatives and coumarin derivatives. Examples of the yellow fluorescent material include rubrene and perimidone derivatives. Examples of the red fluorescent material include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothiones. Xanthene and the like.

  Examples of phosphorescent materials include long-period periodic tables (hereinafter referred to as long-period periodic tables when referred to as “periodic tables” unless otherwise specified). And phosphorescent organometallic complexes containing a metal selected from:

  Preferred examples of the metal selected from Groups 7 to 11 of the periodic table contained in the phosphorescent organometallic complex include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. Preferred examples of these organometallic complexes include compounds represented by the following formula (I) or formula (II).

ML _(q−j) L ′ _j (I)
(In the formula (I), M represents a metal, q represents a valence of the metal, L and L ′ represent a bidentate ligand, and j represents a number of 0, 1 or 2. )

（式（ＩＩ）中、Ｍ^１は金属を表わし、Ｔは炭素原子又は窒素原子を表わす。Ｒ^１〜Ｒ^４は、それぞれ独立に置換基を表わす。但し、Ｔが窒素原子の場合は、Ｒ^３及びＲ^４は無い。）

(In formula (II), M ¹ represents a metal and T represents a carbon atom or a nitrogen atom. R ^{1 to} R ⁴ each independently represents a substituent. However, when T is a nitrogen atom, R 1 ³ and R ⁴ are not available.)

Hereinafter, the compound represented by formula (I) will be described first.
In formula (I), M represents an arbitrary metal, and specific examples of preferable ones include the metals described above as metals selected from Groups 7 to 11 of the periodic table.

（上記Ｌの部分構造において、環Ａ１は、置換基を有していてもよい、芳香族炭化水素基又は芳香族複素環基を表わす。） In formula (I), bidentate ligand L represents a ligand having the following partial structure.

(In the partial structure of L, ring A1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent.)

  Examples of the aromatic hydrocarbon group include a 5- or 6-membered monocyclic ring or a 2-5 condensed ring. Specific examples include monovalent groups derived from a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring, etc. Is mentioned.

  Examples of the aromatic heterocyclic group include a 5- or 6-membered monocyclic ring or a 2-4 condensed ring. Specific examples include furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, monovalent group derived from an azulene ring, and the like.

  In the partial structure of L, ring A2 represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.

  Examples of the nitrogen-containing aromatic heterocyclic group include groups derived from a 5- or 6-membered monocyclic ring or a 2-4 condensed ring. Specific examples include pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, furopyrrole ring, thienofuran ring, benzoisoxazole ring. , Benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone Examples thereof include a monovalent group derived from a ring.

  Examples of the substituent that each of ring A1 and ring A2 may have include a halogen atom, an alkyl group, an alkenyl group, an alkoxycarbonyl group, an alkoxy group, an aryloxy group, a dialkylamino group, a diarylamino group, and a carbazolyl group. Acyl group; haloalkyl group; cyano group; aromatic hydrocarbon group and the like.

  In formula (I), bidentate ligand L ′ represents a ligand having the following partial structure. In the following formulae, “Ph” represents a phenyl group.

Among these, as L ′, the following ligands are preferable from the viewpoint of the stability of the complex.

  More preferable examples of the compound represented by the formula (I) include compounds represented by the following formulas (Ia), (Ib), and (Ic).

（式（Ｉａ）中、Ｍ^２は、Ｍと同様の金属を表わし、ｗは、上記金属の価数を表わし、環Ａ１は、置換基を有していてもよい芳香族炭化水素基を表わし、環Ａ２は、置換基を有していてもよい含窒素芳香族複素環基を表わす。）

(In formula (Ia), M ² represents the same metal as M, w represents the valence of the metal, and ring A1 represents an aromatic hydrocarbon group which may have a substituent. Ring A2 represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.

（式（Ｉｂ）中、Ｍ^３は、Ｍと同様の金属を表わし、ｗは、上記金属の価数を表わし、環Ａ１は、置換基を有していてもよい芳香族炭化水素基又は芳香族複素環基を表わし、環Ａ２は、置換基を有していてもよい含窒素芳香族複素環基を表わす。）

(In formula (Ib), M ³ represents the same metal as M, w represents the valence of the metal, and ring A1 represents an aromatic hydrocarbon group or aromatic group which may have a substituent. Represents a heterocyclic group, and ring A2 represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.

（式（Ｉｃ）中、Ｍ^４は、Ｍと同様の金属を表わし、ｗは、上記金属の価数を表わし、ｊは、０、１又は２を表わし、環Ａ１及び環Ａ１′は、それぞれ独立に、置換基を有していてもよい芳香族炭化水素基又は芳香族複素環基を表わし、環Ａ２及び環Ａ２′は、それぞれ独立に、置換基を有していてもよい含窒素芳香族複素環基を表わす。）

(In formula (Ic), M ⁴ represents the same metal as M, w represents the valence of the metal, j represents 0, 1 or 2, and ring A1 and ring A1 ′ each represent Independently represents an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group, and ring A2 and ring A2 ′ are each independently a nitrogen-containing aromatic optionally having a substituent. Represents a heterocyclic group.)

  In the above formulas (Ia) to (Ic), preferable examples of the ring A1 and the ring A1 ′ include phenyl group, biphenyl group, naphthyl group, anthryl group, thienyl group, furyl group, benzothienyl group, benzofuryl group, pyridyl group. Quinolyl group, isoquinolyl group, carbazolyl group and the like.

  In the above formulas (Ia) to (Ic), preferred examples of the ring A2 and the ring A2 ′ include pyridyl group, pyrimidyl group, pyrazyl group, triazyl group, benzothiazole group, benzoxazole group, benzimidazole group, quinolyl group, An isoquinolyl group, a quinoxalyl group, a phenanthridyl group, and the like can be given.

  The substituents that the compounds represented by the above formulas (Ia) to (Ic) may have include a halogen atom, an alkyl group, an alkenyl group, an alkoxycarbonyl group, an alkoxy group, an aryloxy group, a dialkylamino group, and a diaryl. An amino group; a carbazolyl group; an acyl group; a haloalkyl group; a cyano group;

  These substituents may be connected to each other to form a ring. As a specific example, a substituent of the ring A1 and a substituent of the ring A2 are bonded, or a substituent of the ring A1 ′ and a substituent of the ring A2 ′ are bonded. A condensed ring may be formed. Examples of such a condensed ring include a 7,8-benzoquinoline group.

  Among these, as a substituent for ring A1, ring A1 ′, ring A2 and ring A2 ′, an alkyl group, alkoxy group, aromatic hydrocarbon group, cyano group, halogen atom, haloalkyl group, diarylamino group, carbazolyl are more preferable. Groups.

In addition, preferable examples of M ^{2 to} M ⁴ in the formulas (Ia) to (Ic) include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, or gold.

  Specific examples of the organometallic complexes represented by the above formulas (I) and (Ia) to (Ic) are shown below, but are not limited to the following compounds.

  Among the organometallic complexes represented by the above formula (I), in particular, as the ligand L and / or L ′, a 2-arylpyridine-based ligand, that is, 2-arylpyridine, and an arbitrary substituent is bonded thereto. And compounds having an arbitrary group condensed thereto are preferable.

  The compounds described in International Patent Publication No. 2005/019373 pamphlet can also be used as the light emitting material.

Next, the compound represented by formula (II) will be described.
In formula (II), M ¹ represents a metal. Specific examples include the metals described above as the metal selected from Groups 7 to 11 of the periodic table. Among these, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold is preferable, and divalent metals such as platinum and palladium are particularly preferable.

In formula (II), R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, Represents an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group;

Further, when T is a carbon atom, R ³ and R ⁴ each independently represent a substituent represented by the same examples as R ¹ and R ² . Further, when T is a nitrogen atom, R ³ and R ⁴ are absent.

R ^{1 to} R ⁴ may further have a substituent. When it has a substituent, there is no restriction | limiting in particular in the kind, Arbitrary groups can be made into a substituent.
Further, any two or more groups of R ^{1 to} R ⁴ may be connected to each other to form a ring.

  Specific examples (T-1, T-10 to T-15) of the organometallic complex represented by the formula (II) are shown below, but are not limited to the following examples. In the following chemical formulae, Me represents a methyl group, and Et represents an ethyl group.

  The molecular weight of the compound used as the light emitting material is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, preferably 200 or more, more preferably 300 or more, still more preferably. The range is 400 or more. If the molecular weight is too low, the heat resistance may be significantly reduced, gas may be generated, the film quality may be deteriorated when the film is formed, or the morphology of the organic electroluminescent device may be changed due to migration or the like. There is a case. If the molecular weight is too high, it may be difficult to purify the organic compound, or it may take time to dissolve in the solvent.

  In addition, the light emitting layer 15 may contain only any 1 type among the various light-emitting materials demonstrated above, and may contain 2 or more types by arbitrary combinations and ratios.

Examples of the low molecular weight hole transporting compound include various compounds exemplified as the hole transporting compound of the hole injection layer 13, and 4,4′-bis [N- (1-naphthyl). -N-phenylamino] biphenyl, which includes two or more tertiary amines and two or more condensed aromatic rings substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), 4, Aromatic amine compounds having a starburst structure such as 4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine (Journal of Luminescence, 1997, Vol. 72-74, pp. 985), triphenylamine An aromatic amine compound consisting of a tetramer of (Chemical Communications, 1996, pp. 2175), 2, 2 ′, 7, 7 Examples include spiro compounds such as' -tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synthetic Metals, 1997, Vol. 91, pp. 209).
In addition, the positive hole transport compound may contain only any 1 type, and may contain 2 or more types by arbitrary combinations and ratios.

Examples of low molecular weight electron transport compounds include 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (BND) and 2,5-bis (6 ′-(2 ′). , 2 "-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), bathophenanthroline (BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ( BCP, bathocuproine), 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 4,4′-bis (9-carbazole) ) -Biphenyl (CBP) and the like.
In addition, the electron transport compound may contain only any 1 type, and may contain 2 or more types by arbitrary combinations and ratios.

  These hole transporting compounds and electron transporting compounds are preferably used as host materials in the light-emitting layer, but specifically, the following compounds can be used as host materials.

  Examples of the method for forming the light emitting layer 15 include a wet film forming method and a vacuum evaporation method. However, a low molecular weight can be obtained because a thin film that is homogeneous and free from defects can be easily obtained and the time required for forming the light emitting layer 15 is short. It is preferable to form the light emitting layer 15 by a wet film forming method using a system material.

  When the light emitting layer 15 is formed by a wet film forming method, the above-described material is dissolved in an appropriate solvent to prepare a light emitting layer forming composition, which is applied and formed on the hole injection layer 13. And drying to remove the solvent.

  The method of film formation is not limited, but depending on the components of the composition for forming the light emitting layer and the properties of the charge transport film and the hole injection layer 13 as a base, a coating method such as a spin coating method and a spray method, an inkjet method, etc. A printing method such as a printing method or a screen method can be arbitrarily selected and used.

In the case where film formation is performed by a wet film formation method, a drying process or the like is performed after film formation.
The method for the drying treatment is not particularly limited, and examples include natural drying, heat drying, and reduced pressure drying. Moreover, you may implement combining heat drying and reduced pressure drying.

In the case of performing heat drying, examples of the method include hot plate, oven, infrared irradiation, radio wave irradiation and the like.
When heat drying is performed, the heating temperature is usually room temperature or higher, preferably 50 ° C. or higher, and usually 300 ° C. or lower, preferably 260 ° C. or lower. In addition, the temperature at the time of heat drying may be constant, but may vary.

When drying under reduced pressure, the pressure during drying is usually normal pressure or lower, preferably 10 kPa or lower, more preferably 1 kPa or lower.
The drying treatment time is usually 1 second or longer, preferably 10 seconds or longer, more preferably 30 seconds or longer, and usually 100 hours or shorter, preferably 24 hours or shorter, more preferably 3 hours or shorter.

  The thickness of the light emitting layer 15 is not limited, but is usually in the range of 5 nm or more, preferably 20 nm or more, and usually 1000 nm or less, preferably 100 nm or less. If the light emitting layer 15 is too thin, the light emission efficiency may be reduced and the life may be shortened. If the light emitting layer 15 is too thick, the voltage of the device may be increased.

  The light emitting layer 15 may have a single layer structure, or may have a structure in which a plurality of layers are stacked. In the latter case, the plurality of layers may be layers made of the same material, but may be layers made of different materials.

[2-6. Electron injection layer]
An electron injection layer 16 is formed on the light emitting layer 15.
The electron injection layer 16 serves to efficiently inject electrons injected from the cathode 17 into the light emitting layer 15.

In order to perform electron injection efficiently, the material for forming the electron injection layer 16 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.
In this case, the thickness of the electron injection layer 16 is usually in the range of 0.1 nm or more, preferably 0.5 nm or more, and usually 5 nm or less, preferably 2 nm or less.

  Further, for example, nitrogen-containing heterocyclic compounds such as bathophenanthroline; organic electron transport materials represented by metal complexes such as aluminum complexes of 8-hydroxyquinoline are doped with alkali metals such as sodium, potassium, cesium, lithium and rubidium (Described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, etc.) makes it possible to improve electron injection / transport properties and achieve excellent film quality. Therefore, it is preferable.

  In this case, the thickness of the electron injection layer 16 is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

  Any one of these materials for the electron injection layer 16 may be used, or two or more may be used in any combination and ratio.

  The electron injection layer 16 is formed by laminating on the light emitting layer 15 by a wet film formation method or a vacuum deposition method.

The details of the wet film forming method are the same as in the case of the light emitting layer 15 described above.
On the other hand, in the case of the vacuum deposition method, a deposition source is put into a crucible or a metal boat installed in a vacuum vessel, and the inside of the vacuum vessel is evacuated to about 10 ⁻⁴ Pa with an appropriate vacuum pump, and then the crucible or metal The boat is heated and evaporated to form an electron injection layer 16 on the light emitting layer 15 on the substrate 11 placed facing the crucible or metal boat.

  The alkali metal is deposited as the electron injection layer 16 by using an alkali metal dispenser in which nichrome is filled with an alkali metal chromate and a reducing agent. By heating the dispenser in a vacuum container, the alkali metal chromate is reduced and the alkali metal is evaporated.

In the case of co-evaporating the organic electron transport material and the alkali metal, the organic electron transport material is put in a crucible installed in a vacuum vessel, and the inside of the vacuum vessel is evacuated to about 10 ⁻⁴ Pa with a suitable vacuum pump. Each crucible and dispenser are simultaneously heated and evaporated to form an electron injection layer 16 on the substrate placed facing the crucible and dispenser.
At this time, normally, the co-evaporation is uniformly performed in the film thickness direction of the electron injection layer 16, but there may be a concentration distribution in the film thickness direction.

  Note that the electron injection layer 16 may be composed of a single layer, or may be composed of a plurality of layers. In the latter case, the plurality of layers may be layers made of the same material, but may be layers made of different materials.

[2-6. cathode]
A cathode 17 is formed on the electron injection layer 16.
The cathode 17 plays a role of injecting electrons into a layer on the light emitting layer 15 side (such as the electron injection layer 16 or the light emitting layer 15).

As a material of the cathode 17, the material used for the anode 12 can be used. However, a metal having a low work function is preferable for efficient electron injection. Examples of the metal having a low work function include tin, magnesium, indium, calcium, aluminum, silver, or an alloy thereof. Examples of the alloy include a magnesium-silver alloy, a magnesium-indium alloy, and an aluminum-lithium alloy.
Any one of these cathode 17 materials may be used, or two or more may be used in any combination and ratio.

The thickness of the cathode 17 is not limited, but is usually the same as that of the anode 12.
The cathode 17 may be composed of a single layer, but may be composed of a plurality of layers. In the latter case, the plurality of layers may be layers made of the same material, but may be layers made of different materials.

[2-7. Hole blocking layer]
In the configuration of the organic electroluminescent element 10 shown in FIG. 2A, it is possible to provide a hole blocking layer 18 between the light emitting layer 15 and the electron injection layer 16. Hereinafter, this embodiment will be described below.

  FIG. 2B is a cross-sectional view schematically showing a layer configuration of an organic electroluminescent element 10 ′ according to still another embodiment of the present invention. An organic electroluminescent device 10 ′ shown in FIG. 2B has an anode 12, a hole injection layer 13, a charge transport film 14, a light emitting layer 15, a hole blocking layer 18, an electron injection layer 16, and a substrate 11 on a substrate 11. The cathode 17 is configured by stacking in this order.

  2B, components of the organic electroluminescent element 10 ′ indicated by the same reference numerals as those in FIG. 2A, that is, the substrate 11, the anode 12, the hole injection layer 13, the charge transport film 14, The details of the configuration, formation method, and the like of the light emitting layer 15, the electron injection layer 16, and the cathode 17 are the same as those in the case of the organic electroluminescent element 1 in FIG.

  The hole blocking layer 18 is stacked on the light emitting layer 15 so as to be in contact with the interface on the cathode 17 side of the light emitting layer 15, but prevents holes moving from the anode 12 from reaching the cathode 17. It is formed of a compound having a role and a role of efficiently transporting electrons injected from the cathode 17 in the direction of the light emitting layer 15 (this is referred to as a “hole blocking material”).

  The physical properties required for the material constituting the hole blocking layer 18 (hole blocking material) include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet. It can be mentioned that the term level (T1) is high.

  As a hole blocking material satisfying these conditions, mixed arrangements of bis (2-methyl-8-quinolinolato), (phenolato) aluminum, bis (2-methyl-8-quinolinolato), (triphenylsilanolato) aluminum, etc. Ligand complexes, metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, styryl compounds such as distyrylbiphenyl derivatives ( JP-A-11-242996), triazole derivatives such as 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7-41759) And phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297). Furthermore, a compound having at least one pyridine ring substituted at the 2,4,6-positions described in International Publication No. 2005-022962 is also preferable as the hole blocking material.

Specific examples of the hole blocking material include compounds having the following structures.

  Any one of these hole blocking materials may be used, or two or more of them may be used in any combination and ratio.

  The hole blocking layer 18 can also be formed by a wet film formation method, as with the light emitting layer 15, but is usually formed by a vacuum evaporation method. Details of the procedure of the vacuum deposition method are the same as those of the electron injection layer 16 described above.

  The thickness of the hole blocking layer 18 is not limited, but is usually 0.5 nm or more, preferably 1 nm or more, and usually 100 nm or less, preferably 50 nm or less. If the hole blocking layer 18 is too thin, the light emission efficiency may be reduced due to insufficient hole blocking capability, and if the hole blocking layer 18 is too thick, the voltage of the device may increase.

  The hole blocking layer 18 may be composed of a single layer, or may be composed of a plurality of layers stacked. In the latter case, the plurality of layers may be layers made of the same material, but may be layers made of different materials.

[2-8. Electron transport layer]
In the configuration of the organic electroluminescent element 10 shown in FIG. 2A, an electron transport layer 19 can be provided between the light emitting layer 15 and the electron injection layer 16. Hereinafter, this embodiment will be described below.

  FIG. 2C is a cross-sectional view schematically showing a layer structure of an organic electroluminescent element 10 ″ according to still another embodiment of the present invention. The organic electroluminescent element 10 ″ shown in FIG. The anode 12, the hole injection layer 13, the charge transport film 14, the light emitting layer 15, the electron transport layer 19, the electron injection layer 16, and the cathode 17 are laminated on the substrate 11 in this order.

  2C, the constituent elements of the organic electroluminescent element 10 ″ indicated by the same reference numerals as in FIG. 2A, that is, the substrate 11, the anode 12, the hole injection layer 13, the charge transport film 14, The details of the configuration, formation method, and the like of the light emitting layer 15, the electron injection layer 16, and the cathode 17 are the same as those of the organic electroluminescent element 10 in FIG.

  The electron transport layer 19 is provided for the purpose of further improving the light emission efficiency of the device, and efficiently transports electrons injected from the cathode 17 toward the light emitting layer 15 between electrodes to which an electric field is applied. Formed from a compound that can.

  As the electron transporting compound used for the electron transport layer 19, usually, the electron injection efficiency from the cathode 17 or the electron injection layer 16 is high, and the injected electrons having high electron mobility are efficiently transported. A compound that can be used (that is, an electron transport material) is used.

  Examples of electron transport materials include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives, distyrylbiphenyl. Derivatives, silole derivatives, 3- or 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds (JP-A-6-207169) Phenanthroline derivatives (Japanese Patent Laid-Open No. 5-33159), 2-t-butyl-9,10-N, N′-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type Examples include zinc selenide.

  In addition, these electron transport materials may be used alone or in combination of two or more in any combination and ratio.

  There is no restriction | limiting in the formation method of the electron carrying layer 19. FIG. The electron transport layer 19 can be formed using a wet film formation method, as with the light emitting layer 15, but is usually formed by a vacuum deposition method. The details of the procedure of the vacuum deposition method are the same as those of the electron injection layer 16.

  The film thickness of the electron transport layer 19 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[2-9. Others]
As mentioned above, although the detail of the manufacturing method of this invention was demonstrated taking the case of manufacturing the organic electroluminescent element 10, 10 ', 10''shown to Fig.2 (a)-(c) as an example, Details are not limited by the above description.

  For example, the configuration of the organic electroluminescent device manufactured by the manufacturing method of the present invention is not limited to the configuration of the organic electroluminescent devices 10, 10 ′, 10 ″ shown in FIGS. A configuration obtained by arbitrarily changing the configuration of the organic electroluminescent elements 10, 10 ′, 10 ″ may be used.

  As an example of the change, two or more of the hole blocking layer 18 shown in FIG. 2B and the electron transport layer 19 shown in FIG. 2C are used for the organic electroluminescent element 10 shown in FIG. The structure which combined and provided the layer is mentioned.

  In addition, as another example of the change, in the layer configuration of the organic electroluminescent elements 10, 10 ′, 10 ″ shown in FIGS. 2A to 2C, a configuration in which the stacking order is changed, or one or two or more The structure etc. which added or abbreviate | omitted the layer are mentioned.

  As an example of the configuration in which the stacking order is different, in the layer configuration of the organic electroluminescent elements 10, 10 ′, 10 ″ shown in FIGS. A configuration in which the elements 10, 10 ′, and 10 ″ are stacked in the reverse order may be used.

  As an example of a configuration in which another layer is added, for the purpose of further improving the efficiency of hole injection and improving the adhesion of the entire organic layer to the anode 12, For the purpose of protecting the cathode made of a low work function metal with a configuration in which an anode buffer layer is provided between them, a metal layer (for example, aluminum, silver, The structure etc. which provided the layer which consists of copper, nickel, chromium, gold | metal | money, platinum, etc. are mentioned.

  Furthermore, organic electroluminescent elements 10, 10 ′, and 10 ″ can be configured by sequentially laminating components other than the above-described substrate 11 between two substrates, at least one of which has transparency. It is.

In addition, among the above-described various organic electroluminescent elements 10, 10 ′, 10 ″, a structure in which a plurality of units (light emitting units) composed of layers other than the substrate 2 are stacked (a plurality of light emitting units are stacked) In this case, for example, vanadium pentoxide is used instead of the interface layer between the steps (between the light emitting units) (in the case where the anode is ITO and the cathode is Al). When a charge generation layer (Carrier Generation Layer: CGL) made of (V ₂ O ₅ ) or the like is provided, a barrier between stages is reduced, which is more preferable from the viewpoint of light emission efficiency and driving voltage.

In addition, the organic electroluminescent elements 10, 10 ′, 10 ″ having the above-described various layer configurations may be configured as a single organic electroluminescent element 10, 10 ′, 10 ″. 10, 10 ′, 10 ″ may be arranged in an array. Examples of such a structure include a structure in which the anode 12 and the cathode 17 are arranged in an XY matrix. A plurality of organic electroluminescent elements 10, 10 ′, 10 ″ arranged in an array may share one or more layers, for example, the substrate 11.
Such an organic electroluminescent element is used as a flat panel display or a light source provided in a light emitting device.

[3. Organic EL display]
The organic electroluminescent element of the present invention can be used for an organic EL display. The organic electroluminescent device obtained by the present invention is described in, for example, “Organic EL Display” (Ohm, August 20, 2004, written by Shizushi Tokito, Chiba Adachi, and Hideyuki Murata). An organic EL display can be formed by the method.

[4. Advantages of the present invention]
The organic electroluminescent device provided with the charge transport film of the present invention has a longer lifetime than the conventional organic electroluminescent device.
In addition, since the charge transport film of the present invention usually has a high charge transport capability and is excellent in voltage resistance and current resistance, an organic electroluminescent device produced using the same usually has high durability.

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

[Synthesis Example 1: Synthesis of Target 1]

  In a nitrogen stream, reagent 1 [N- (4-biphenyl) -N- (4-methoxy) amine] (5.78 g), reagent 2 [4-iodo-4′-methoxybiphenyl] (7.16 g), copper (1.87 g), potassium carbonate (5.80 g), and tetraglyme (15 ml) were stirred at 200 ° C. for 10 hours. After allowing to cool, chloroform (200 ml) was added and stirred, and then insoluble matters were filtered off, and the filtrate was concentrated. The obtained solid was suspended and washed with ethanol to obtain Target 1 (7.10 g).

[Synthesis Example 2: Synthesis of Target 2]

The target product 1 (6.86 g) and dichloromethane (100 ml) were cooled to 0 ° C. in a nitrogen stream, and a 1M methylene chloride solution of boron tribromide (35 ml) was added dropwise. The mixture was warmed to room temperature and stirred for 2 hours. After adding sodium bicarbonate water, the mixture was extracted with ethyl acetate, the organic layer was concentrated, and purified by silica gel column chromatography (hexane / ethyl acetate = 1/1) to obtain the desired product 2 (3.68 g). By EI-MS (m / z = 429 (M ⁺ )), it was confirmed that the product was the target product 2.

[Synthesis Example 3: Synthesis of Target 3 (h1)]

In a nitrogen stream, potassium hydroxide (3.25 g) and dimethyl sulfoxide (100 ml) were stirred at room temperature for 15 minutes, target product 2 (5.00 g) was added, and the mixture was stirred at room temperature for 15 minutes. Bromobutoxymethyl) -3-methyloxetane (6.90 g) was added and stirred at room temperature for 8 hours. After adding methylene chloride (200 ml) and water (200 ml) and stirring, the organic layer was dried over magnesium sulfate, concentrated and purified by silica gel chromatography (hexane / ethyl acetate mixture) to obtain the target compound 3 (4.2 g) was obtained. It was confirmed by DEI-MS (m / z = 741 (M ⁺ )) that the product was the target product 3.

[Synthesis Example 4: Synthesis of Object 4]

  To a four-necked flask equipped with a DC stirrer, dropping funnel, and condenser, a mixed solution of 50% by weight aqueous sodium hydroxide (300 g) and hexane (250 mL) was added, and tetra n-butylammonium bromide (TBABr) (4. 98 g, 15.5 mmol) was added. After cooling the mixture to 5 ° C., a mixture of methyl oxetane methanol (31 g) and 1,4-dibromobutane (200 g) was added dropwise with vigorous stirring. After completion of dropping, the mixture was stirred for 15 minutes at room temperature, further stirred for 15 minutes under reflux, and stirred for 15 minutes while being allowed to cool to room temperature. The organic layer is separated, the organic layer is washed with water and dried over magnesium sulfate, the solvent is removed under reduced pressure, and 3- (4-bromobutoxymethyl) -3- is obtained by distillation under reduced pressure (0.42 mmHg, 72 ° C.). Methyl oxetane (52.2 g) was obtained.

  In a nitrogen stream, pulverized potassium hydroxide (8.98 g) was added to dimethyl sulfoxide (50 ml), then m-bromophenol (6.92 g) was added, stirred for 30 minutes, and then 3- (4-bromobutoxymethyl). -3-Methyloxetane (12.33 g) was added and stirred at room temperature for 6 hours. The precipitate was collected by filtration, extracted with methylene chloride, the oil layer was concentrated, and purified by silica gel chromatography (hexane / methylene chloride mixed solution) to obtain the desired product 4 (11.4 g).

[Synthesis Example 5: Synthesis of target product 5 (h2)]

To a solution of N, N′-bis (4-biphenyl) amine (4.69 g), target product 4 (4.00 g), tert-butoxy sodium (1.63 g), and toluene (90 ml) in a nitrogen stream, Prepared by stirring tris (dibenzylideneacetone) dipalladium (0) chloroform complex (0.063 g), tri-tert-butylphosphine (0.098 g), and toluene (10 ml) at 60 ° C. for 15 minutes in a nitrogen atmosphere. The solution was added and stirred at 85 ° C. for 4 hours. After allowing to cool, toluene and activated clay are added, and the mixture is stirred at room temperature for 15 minutes. Insoluble matters are filtered off, the filtrate is concentrated, purified by silica gel column chromatography (methylene chloride solvent), and treated with activated clay. To obtain the intended product 5 (2.61 g).
The glass transition temperature of this product was 14 ° C., the melting point was not observed, and the weight loss starting temperature under a nitrogen stream was 404 ° C.
In addition, it was confirmed by DEI-MS (m / z = 569 (M ⁺ )) that the product was the target product 5.

[Synthesis Example 6: Synthesis of target product 6]

  To a solution of 3,4'-diaminodiphenyl ether (2.74 g), target compound 4 (9.00 g), tert-butoxy sodium (3.69 g), and toluene (50 ml) in a nitrogen stream, tris (dibenzylideneacetone ) A solution prepared by stirring dipalladium (0) chloroform complex (0.071 g), bis (triphenylphosphino) ferrocene (0.152 g), and toluene (5 ml) at 60 ° C. for 15 minutes in a nitrogen atmosphere. In addition, the mixture was stirred at 85 ° C. for 2 hours. After allowing to cool, toluene and activated clay were added, and the mixture was stirred for 15 minutes. The insoluble material was filtered off, the filtrate was concentrated, and purified by silica gel chromatography (ethyl acetate / methylene chloride mixed solution) to obtain the target compound 6 (6 .52 g) was obtained.

[Synthesis Example 7: Synthesis of object 7]

  In a nitrogen stream, 1-bromohexane (28.1 ml) and 3-bromophenol (36.3 g) were sequentially added to a mixed solution of potassium hydroxide (49.4 g) and dimethyl sulfoxide (220 ml) at room temperature. Stir for hours. A solution obtained by adding 350 ml of water to the reaction solution was extracted with methylene chloride (450 ml), and the extract was washed twice with brine, dried over anhydrous magnesium sulfate, and concentrated. This was purified by silica gel column chromatography (hexane) to give the intended product 7 (44.3 g) as a colorless liquid.

[Synthesis Example 8: Synthesis of Target Product 8]

  In a nitrogen stream, tris (dibenzylideneacetone) dipalladium (0) chloroform complex (0.673 g), bis (triphenylphosphino) ferrocene (0.708 g), and toluene (455 ml) were stirred at room temperature for 10 minutes. 3,4'-diaminodiphenyl ether (13.02 g), target product 7 (33.10 g), and tert-butoxy sodium (14.99 g) were sequentially added to the solution obtained in the above, Stir for hours. After standing to cool, 1 liter of ethyl acetate and 500 ml of brine were added and shaken. The organic layer was dried over anhydrous magnesium sulfate and concentrated. From silica gel column chromatography (hexane / methylene chloride mixture) and methylene chloride / methanol. To obtain white crystals (21.44 g) of the target product 8.

[Synthesis Example 9: Synthesis of target product 9 (H4)]

  In a nitrogen stream, target product 6 (0.840 g), target product 8 (6.00 g), 4,4′-dibromobutphenyl (3.76 g), tert-butoxy sodium (3.26 g), and toluene (60 ml) ), Tris (dibenzylideneacetone) dipalladium (0) chloroform complex (0.125 g), tri-tert-butylphosphine (0.196 g), and toluene (5 ml) at 60 ° C. under a nitrogen atmosphere. The solution prepared by stirring for 15 minutes was added and stirred for 2 hours under reflux with heating. Subsequently, bromobenzene (0.190 g) and toluene (25 ml) were added, and the mixture was stirred for 1 hour with heating under reflux. Subsequently, diphenylamine (0.410 g) was added, and the mixture was stirred for 1.5 hours with heating under reflux. After allowing to cool, toluene and activated clay were added and stirred for 15 minutes. The insoluble material was filtered off, the filtrate was concentrated, methylene chloride was added, and reprecipitation was carried out in methanol. After the precipitate was collected by filtration, activated clay was added to the solution dissolved in toluene, and the mixture was stirred for 15 minutes. The insoluble matter was filtered off, the filtrate was concentrated, methylene chloride was added, and the mixture was reprecipitated in methanol. The precipitate was collected by filtration and dried under reduced pressure to give the intended product 9 (2.74 g). The polymer compound had a weight average molecular weight (Mw) of 158,000 and a number average molecular weight (Mn) of 31,000.

（式（Ｉ）及び式（Ｉ’）において、Ｒは任意の置換基を表わす。） In general, the monomer for obtaining the repeating unit represented by the following formula (I) has an asymmetric structure. Therefore, when a polymer compound is usually synthesized from the monomer, the repeating unit represented by the formula (I) is used. Then, a polymer compound having a repeating unit represented by the following formula (I ′) is obtained. The target product 9 also corresponds to such a polymer compound, but only the structural formula corresponding to the formula (I) is shown here.

(In formula (I) and formula (I ′), R represents an optional substituent.)

[Synthesis Example 10: Synthesis of target product 10 (H6)]
(Compound 1)

  2-Nitrofluorene (25.0 g), 1-bromohexane (58.61 g), tetrabutylammonium bromide (TBAB) (7.63 g), dimethyl sulfoxide (DMSO) (220 ml) and aqueous sodium hydroxide solution (17M) 35 ml was slowly added dropwise and reacted at room temperature for 3 hours. Ethyl acetate (200 ml) and water (100 ml) were added and stirred, and the layers were separated. The aqueous layer was extracted with ethyl acetate (100 ml × 2 times), and the organic layers were combined, dried over magnesium sulfate, and concentrated. Furthermore, the compound 1 (44.0g) was obtained by refine | purifying with silica gel column chromatography (n-hexane / ethyl acetate liquid mixture).

(Monomer 1)

  10% Pd / C (8.6 g) was added to Compound 1 (44.0 g), tetrahydrofuran (THF) (120 ml) and ethanol (EtOH) (120 ml), and the temperature was raised to 50 ° C., followed by hydrazine monohydrate. (58.0 g) was slowly added dropwise and reacted at 50 ° C. for 3 hours. After allowing to cool, the reaction mixture was filtered through celite, the filtrate was concentrated, and the precipitated crystals were washed with methanol. Monomer 1 (34.9 g) was obtained by filtration under reduced pressure and drying.

(Compound 2)

In a nitrogen stream, 3-bromostyrene (5.0 g), 3-nitrophenylboronic acid (5.5 g), toluene: ethanol (Toluene / EtOH) (80 ml: 40 ml), 20 ml of aqueous sodium carbonate (2M), The mixture was stirred at 30 ° C. for 30 minutes, tetrakis (triphenylphosphine) palladium (0) (Pd (PPh ₃ ) ₄ ) was added, and the mixture was refluxed for 6 hours. After allowing to cool to room temperature, methylene chloride (100 ml) and water (100 ml) were added to the reaction mixture, and the mixture was stirred and separated. The aqueous layer was extracted with methylene chloride (100 ml × 2 times), and the organic layers were combined. After drying with magnesium, it was concentrated. Furthermore, the compound 2 (5.5g) was obtained by refine | purifying with silica gel column chromatography (n-hexane / methylene chloride liquid mixture).

(Compound 3)

  In a nitrogen stream, compound 2 (2.8 g), 4-bromocyclobutene (3.64 g), N, N-dimethylformamide (76 ml), potassium carbonate (2.73 g), tetrabutylammonium bromide (TBAB) ( 2.67 g) is stirred at 60 ° C. for 30 minutes, and bis [μ-chloro [5-chloro-2-[(4-chlorophenyl) (hydroxyimino) methyl] phenyl] palladium] (Pd cat./ DMF) (24.1 mg) was added, and the mixture was stirred at 130 ° C. for 7.5 hours. After allowing to cool to room temperature, ethyl acetate and water were added to the reaction mixture, and the mixture was stirred and separated. The organic layer was dried over magnesium sulfate and concentrated. Furthermore, the compound 3 (1.7g) was obtained by refine | purifying with silica gel column chromatography (n-hexane / ethyl acetate mixed liquid).

(Monomer 2)

  In a nitrogen stream, Compound 3 (1.6 g), acetic acid (AcOH) (30 ml), ethanol (30 ml), hydrochloric acid (1N, 1 ml), water (4 ml) and reduced iron (5.5 g) were refluxed for 1.5 hours. did. The reaction mixture was filtered at room temperature, ethyl acetate (30 ml) and water (30 ml) were added, and the mixture was stirred and neutralized with a saturated aqueous solution of sodium hydrogen carbonate. The mixture was separated, the aqueous layer was extracted with ethyl acetate, and the organic layer was sulfated. After drying with magnesium, it was concentrated. Furthermore, the monomer 2 (1.3g) was obtained by refine | purifying with silica gel column chromatography (n-hexane / ethyl acetate liquid mixture).

(Compound 4)

Potassium fluoride (23.01 g) was charged into the reaction vessel, and heating and drying and nitrogen substitution were repeated under reduced pressure to create a nitrogen atmosphere in the system. 3-Nitrophenylboronic acid (6.68 g), 4-bromo-benzocyclobutene (7.32 g) and dehydrated tetrahydrofuran (50 ml) were charged and stirred. Thereto was added tris (dibenzylideneacetone) dipalladium chloroform complex (Pd ₂ (dba) ₃ ) (0.21 g), and the inside of the system was sufficiently substituted with nitrogen, and tri-t-butylphosphine (0 .47 g) was added, and the mixture was stirred for 1 hour after the addition. After completion of the reaction, water was added to the reaction solution and extracted with ethyl acetate. The obtained organic layer was washed with water twice, added with sodium sulfate, dehydrated and dried, and concentrated. The crude product was purified by silica gel column chromatography (hexane / ethyl acetate) to obtain Compound 4 (8.21 g).

化合物５（８．１１ｇ）、テトラヒドロフラン３６ｍｌ、エタノール３６ｍｌ、１０％Ｐｄ／Ｃ（１．１５ｇ）を仕込み、７０℃で加熱撹拌した。そこへヒドラジン一水和物（１０．８１ｇ）をゆっくり滴下した。２時間反応後、放冷し、反応液をセライトでろ過して濾液を濃縮した。この濾液に酢酸エチルを加え、水で洗浄し、有機層を濃縮した。得られた粗生成物をカラムクロマトグラフィー（ヘキサン／酢酸エチル）にて精製することにより、モノマー３（４．９０ｇ）を得た。

Compound 5 (8.11 g), tetrahydrofuran 36 ml, ethanol 36 ml, 10% Pd / C (1.15 g) were charged, and the mixture was heated and stirred at 70 ° C. Hydrazine monohydrate (10.81 g) was slowly added dropwise thereto. After reacting for 2 hours, the mixture was allowed to cool, the reaction mixture was filtered through celite, and the filtrate was concentrated. Ethyl acetate was added to the filtrate, washed with water, and the organic layer was concentrated. The obtained crude product was purified by column chromatography (hexane / ethyl acetate) to obtain monomer 3 (4.90 g).

(Compound 5)

  In a nitrogen stream, dichlorobis (acetonitrile) palladium (II) (212 mg), copper iodide (104 mg), and dioxane (75 mL) were stirred. Tri-t-butylphosphine (331 mg) was added to this solution and stirred at room temperature for 15 minutes. To this solution, di-i-propylamine (3.31 g), 4-bromobenzocyclobutene (5.00 g) and 1,7-octadiyne (20.3 g) were added and stirred at room temperature for 9 hours. The obtained reaction mixture was distilled under a reduced pressure of 400 Pa at a bath temperature of 60 ° C., the light boiling portion was distilled off, saturated brine (50 mL), 1N hydrochloric acid (5 mL) were added, and ethyl acetate (3 × 30 mL) was added. Extraction and the organic layer were washed with saturated brine (2 × 30 mL). When the ethyl acetate layer was concentrated, a crude product (7.7 g) was obtained. The crude product was purified by silica gel column chromatography (solvent: n-hexane / ethyl acetate mixed solvent) to obtain 2.78 g of compound 5 as a colorless oil.

(Compound 6)

  In a nitrogen stream, m-iodinated nitrobenzene (3.64 g), potassium carbonate (5.06 g), copper iodide (111 mg), triphenylphosphine (307 mg), 5% Pd / C (623 mg), methoxyethane / water = 1/1 mixed solvent (95 mL) was stirred at room temperature for 1 hour. A solution prepared by dissolving compound 5 (2.77 g) in dimethoxyethane (2 mL) was added to this solution, and the mixture was reacted by heating in a 70 ° C. bath (internal temperature 63 ° C.) for 7 hours. The obtained reaction mixture was filtered through celite, concentrated with an evaporator, 25 mL of 1N hydrochloric acid was added, and the mixture was extracted with ethyl acetate (3 × 30 mL). The resulting ethyl acetate layer was washed with saturated brine (3 × 20 mL). ). The crude product obtained by concentrating the organic layer was recrystallized from a mixed solvent of ethyl acetate-n-hexane to obtain 2.50 g of compound 6 as very pale yellow needles.

(Monomer 4)

  Compound 6 (2.31 g) was dissolved in tetrahydrofuran (15 mL) and ethanol (15 mL). Raney nickel (1.07 g) (manufactured by Nikko Rica Co., Ltd., R-200) was added to the solution as a hydrogenation catalyst, and the mixture was replaced with hydrogen three times. The reaction solution was filtered through celite and concentrated with an evaporator to obtain 2.8 g of a crude product. The crude product was purified by silica gel column chromatography (solvent: n-hexane / ethyl acetate mixed solvent) to obtain 1.72 g of monomer 4 as white needle crystals.

(Monomer 5)

  In a nitrogen stream, Compound 2 (2.5 g), acetic acid (60 ml), ethanol (60 ml), hydrochloric acid (1N, 2 ml), water (8 ml) and reduced iron (12.4 g) were refluxed for 1 hour. The reaction mixture was filtered at room temperature, ethyl acetate (100 ml) and water (100 ml) were added, and the mixture was stirred and neutralized with a saturated aqueous solution of sodium hydrogen carbonate, separated, and the aqueous layer was extracted with ethyl acetate (twice with 100 ml). The organic layers were combined, dried over magnesium sulfate, and concentrated. Furthermore, the monomer 5 (2.1g) was obtained by refine | purifying with silica gel column chromatography (n-hexane / ethyl acetate liquid mixture).

(Synthesis of H6)

  As the primary amine, monomer 4, monomer 1, and monomer 5 were used in a molar ratio of monomer 4: monomer 1: monomer 5 = 0.8274: 0.0863: 0.863, and dibromide was 9,10-bis ( Polymerization was performed using 4-bromophenyl) anthracene to synthesize polymer 1 (H6).

  Monomer 4 (0.1087 g), Monomer 1 (1.185 g), Monomer 5 (0.069 g), 9,10-bis (4-bromophenyl) anthracene (1.000 g), and sodium tert-butoxy (1. 26 g and toluene (10 ml) were charged, the inside of the system was sufficiently purged with nitrogen, and the mixture was heated to 50 ° C. (solution A).

  Tri-t-butylphosphine (0.066 g) was added to a toluene 2 ml solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.042 g) and heated to 50 ° C. (solution B).

  In a nitrogen stream, solution B was added to solution A and heated to 90 ° C. for 1.5 hours to react. Subsequently, 9,10-bis (4-bromophenyl) anthracene (0.940 g) was additionally added. After heating and refluxing for 1 hour, the reaction solution was allowed to cool, and the reaction solution was dropped into ethanol to crystallize crude polymer 1.

  The obtained crude polymer 1 was dissolved in 150 ml of toluene, bromobenzene (0.52 g) and tert-butoxy sodium (0.63 g) were charged, the inside of the system was sufficiently replaced with nitrogen, and the mixture was heated to 50 ° C. ( Solution C).

  Tri-t-butylphosphine (0.033 g) was added to a toluene 2 ml solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.021 g) and heated to 50 ° C. (solution D).

  In a nitrogen stream, solution D was added to solution C, and heated to reflux for 3 hours. To this reaction solution, N, N-diphenylamine (1.63 g) was added, the solution D prepared again was added, and the mixture was further heated and refluxed for 4 hours. The reaction solution was allowed to cool and dropped into ethanol to obtain an end-capped crude polymer 1.

  This end-capped crude polymer 1 was dissolved in toluene, reprecipitated in acetone, and the precipitated polymer was separated by filtration. The obtained polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The polymer collected by filtration was purified twice by column chromatography to obtain purified polymer 1 (H6) (1.63 g).

  The obtained polymer 1 had a weight average molecular weight (Mw) of 330000 and a dispersity (Mw / Mn) of 9.2.

[Synthesis Example 11: Synthesis of target product 11 (H7)]

  As the primary amine, the above-mentioned monomer 3 and monomer 1 were used in a molar ratio of monomer 3: monomer 1 = 0.8298: 0.1702, and dibromide was 9,10-bis (4-bromophenyl) anthracene. Polymer 2 (H7) was synthesized in the same manner as Polymer 1 (H6) except that the polymerization reaction was performed using

  The obtained polymer 2 (H7) had a weight average molecular weight (Mw) of 68,000 and a dispersity (Mw / Mn) of 2.5.

[Synthesis Example 12: Synthesis of target product 12 (H8)]

  As the primary amine, the above-mentioned monomer 3, monomer 1, and aniline were used in a molar ratio of monomer 3: monomer 1: aniline = 0.134: 0.665: 0.201, and dibromide was 4,4 ' Polymer 3 (H8) was polymer 1 except that -dibromobiphenyl and 2,7-dibromo-9,9'-spirobi [fluorene] were used in a molar ratio of 0.5: 0.5 to conduct the polymerization reaction. Synthesized in the same manner as (H6).

  The obtained polymer 3 (H8) had a weight average molecular weight (Mw) of 23,000 and a dispersity (Mw / Mn) of 1.4.

[Synthesis Example 13: Synthesis of target product 13 (H9)]

  As the primary amine, the above-mentioned monomer 3, aniline was used in a molar ratio of monomer 3: aniline = 0.9442: 0.0558, and as dibromide, 4,4 "-dibromo-2 ', 5'-di Polymer 4 (H9) was synthesized in the same manner as Polymer 1 (H6) except that a polymerization reaction was performed using -n-octyl-p-terphenyl.

  The obtained polymer 4 (H9) had a weight average molecular weight (Mw) of 72,000 and a dispersity (Mw / Mn) of 2.0.

[Synthesis Example 14: Synthesis of target product 14 (H10)]

  As the primary amine, the above-mentioned monomer 2, monomer 1, and aniline were used in a molar ratio of monomer 2: monomer 1: aniline = 0.101: 0.505: 0.394, and dibromide was 4,4 ′. Polymer 5 (H10) was synthesized in the same manner as Polymer 1 (H6) except that a polymerization reaction was performed using dibromobiphenyl.

  The obtained polymer 5 (H10) had a weight average molecular weight (Mw) of 26000 and a dispersity (Mw / Mn) of 1.7.

一級アミンとして、上述のモノマー３、アニリンを、モノマー３：アニリン＝０．２２４：０．７７６のモル比で用いた点、ジブロマイドとして、１，３−ビス（７−ブロモ−９，９−ジヘキシルフルオレン−２−イル）ベンゼンを用いて重合反応を行った点を除いて、ポリマー５（Ｈ１１）をポリマー１（Ｈ６）と同様にして合成した。
得られたポリマー５（Ｈ１１）の重量平均分子量（Ｍｗ）は７７０００、分散度（Ｍｗ／Ｍｎ）は２．２であった。 [Synthesis Example 15: Synthesis of Target 15 (H11)]

As the primary amine, the above-mentioned monomer 3, aniline was used in a molar ratio of monomer 3: aniline = 0.224: 0.776, and as dibromide, 1,3-bis (7-bromo-9,9- Polymer 5 (H11) was synthesized in the same manner as Polymer 1 (H6) except that a polymerization reaction was performed using dihexylfluoren-2-yl) benzene.
The obtained polymer 5 (H11) had a weight average molecular weight (Mw) of 77000 and a dispersity (Mw / Mn) of 2.2.

[Preparation of measuring element]
As shown in FIG. 1, an indium tin oxide (ITO) transparent conductive film deposited on a glass substrate 1 to a thickness of 120 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film product) The ITO layer 2 was formed by patterning into stripes having a width of 2 mm using a photolithographic technique and hydrochloric acid etching. This ITO substrate is cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultra pure water, ultrasonic cleaning with ultra pure water, and water cleaning with ultra pure water, followed by drying with compressed air, and finally UV ozone cleaning. Went.

Next, 2.0% by weight of a hole transporting polymer having a repeating structure represented by the following formula (P1) (weight average molecular weight: 26500, number average molecular weight: 12000) and 4- (4) represented by the following formula (A1) An ethyl benzoate solution containing 0.8% by weight of isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate was prepared. This ethyl benzoate solution was deposited by spin coating under the deposition conditions shown in Table 2 to form a polymer layer 3 having a thickness of 30 nm, and the measurement anode 4 from the ITO layer 2 and the polymer layer 3 Formed.

  Also, as shown in Table 2, the material of the sample layer 5 was dissolved in a solvent to prepare a coating solution (charge transport film composition), and this was placed on the measurement anode 4 and the spinner rotation time: 30 Second, spin coating atmosphere: spin coating was performed under conditions in nitrogen, baking was performed, and the sample layer 5 was formed.

The compounds used as the material for the sample layer are as follows. In H1, H2, and H3, the ratio between h1 and h2 represents a weight ratio. Me represents a methyl group.

The element in which the sample layer 5 is formed is carried into a multi-chamber type vacuum deposition apparatus connected to a glove box without being exposed to the atmosphere. After the apparatus is roughly evacuated by an oil rotary pump or the like, the degree of vacuum in the apparatus is increased. It exhausted using the cryopump etc. until it became 9.9 * 10 <^-4> Pa or less. Next, it is transported in vacuum to an adjacent metal deposition chamber, and a 2 mm wide striped shadow mask is brought into close contact with the element so as to be orthogonal to the stripe of the ITO layer 2 as a mask for cathode deposition. It installed in the vapor deposition apparatus and exhausted until the vacuum degree in the apparatus became 9.9x10 <^-4> Pa or less. Thereafter, aluminum is heated by a molybdenum boat, and an aluminum layer having a thickness of 80 nm is formed by controlling the deposition rate from 0.6 to 16.0 liters / second and the degree of vacuum from 2.0 to 250 × 10 ⁻⁵ Pa. Was used as the measurement cathode 6. In addition, the substrate temperature at the time of vapor deposition of the above measurement cathode 6 was kept at room temperature.

  Subsequently, in order to prevent the measuring element from being deteriorated by moisture in the atmosphere during storage, a sealing treatment was performed by the method described below. In a nitrogen glove box connected to a vacuum vapor deposition device, a photocurable resin (30Y-437 manufactured by ThreeBond Co., Ltd.) with a width of about 1 mm is applied to the outer peripheral portion of a 23 mm × 23 mm size glass plate, and the central portion is applied. A moisture getter sheet (manufactured by Dynic Co., Ltd.) was installed. On this, the element which completed formation of the cathode 6 for a measurement was bonded together so that the vapor-deposited surface might oppose a desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened. As described above, a measuring element having an element area of 2 mm × 2 mm was produced.

[Measurement of relative permittivity]
The capacitance of the measuring element was measured, and the relative dielectric constant was calculated from the basic relational expression (1) between the capacitance and the dielectric constant. For the measurement of capacitance, a ZM2353 type LCR meter manufactured by NF Circuit Design Block Co., Ltd. was used, and a 2335AL type test fixture (Kelvin clip capable of connecting four terminals with two clips) was used. At the time of measurement, an electrode was taken out from the ITO layer 2 of the produced measuring element using a contact probe, and measured by sandwiching it with the aforementioned clip. The measurement conditions are a room temperature of 25 ° C., a measurement frequency of 100 Hz, a measurement voltage of 250 mV, a measurement speed of 480 milliseconds, a parallel equivalent circuit is selected as the equivalent circuit, and one point per second. After measuring for 30 minutes by the method of obtaining the measured value, the average value was taken as the capacitance of the sample.
The measured dielectric constants are shown in Tables 4 and 6.

[Measurement of current mutation point]
A Keithley 2400 type source meter was used for generation of a voltage used for charge application and detection of a current value associated therewith.
The electrode on the output side of the source meter was connected to the pole where the charge of the measuring element described above was to be injected, and the current value when the voltage was changed was read. The voltage was increased by 0.1V in 2 seconds. By continuing to increase the voltage, the current value clearly decreased or suddenly increased at a certain voltage. Therefore, the absolute value of the voltage value at that time was converted into kV units, and the film thickness (cm) The current mutation point was determined by dividing.
Table 4 and Table 6 show the measured current mutation points.

[Production of element for driving test]
When an actual organic electroluminescence device corresponding to the sample whose relative dielectric constant was measured was produced as follows. As shown in FIG. 3, a normal photolithography technique and hydrochloric acid etching are performed on a glass substrate 11 having an ITO transparent conductive film deposited to a thickness of 120 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film). The ITO layer 12 was formed by patterning into a stripe having a width of 2 mm. This ITO substrate was cleaned in the order of ultrasonic cleaning with a surfactant aqueous solution, ultrapure water cleaning, ultrapure ultrasonic cleaning, and ultrapure water cleaning, followed by drying with compressed air, and finally UV ozone cleaning. .

  Next, 2.0 wt% of a hole transporting polymer having a repeating structure represented by the formula (P1) and 0.8 wt% of 4-isopropyl-4′-methyl represented by the formula (A1) An ethyl benzoate solution containing diphenyliodonium tetrakis (pentafluorophenyl) borate was prepared. This ethyl benzoate solution was deposited by spin coating under the deposition conditions shown in Table 1 to obtain a hole injection layer 13 having a thickness of 30 nm.

  Thereafter, as a composition for a charge transport film, a coating solution was prepared by dissolving or dispersing each of the above-mentioned compounds H1 to H5 and pk-H1 to pk-H3 having a crosslinking group in a solvent shown in Table 3 below. A charge transport film made of a cross-linked polymer is formed on the hole injection layer 13 by spin coating (spinner rotation speed: 1500 rpm, spinner rotation time: 30 seconds, spin coating atmosphere: in nitrogen), and is subjected to cross-linking treatment. Hole transport layer) 14 was formed. Table 3 below shows the materials, film forming conditions, and film thickness after the crosslinking treatment in each example and comparative example.

  The rinsing treatment in Example 3 using H4 as the compound having a crosslinking group was performed by spin-out using xylene under the same spin coater conditions as in the film formation after the charge transport film was formed.

Next, using the organic compounds (C1), (C2), and (C3) represented by the following structural formula, a composition for forming a light emitting layer was prepared under the following conditions. The composition was formed by spin coating on a charge transport film under the following conditions, and dried to form a light-emitting layer 15 having a thickness of 40 nm.

<Composition for light emitting layer formation>
Solvent Xylene Coating solution concentration C1: 1.0% by weight
C2: 1.0% by weight
C3: 0.1% by weight
<Deposition conditions of the light emitting layer 15>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coating atmosphere In nitrogen Bake conditions In vacuum 130 ° C 1 hour

Next, the substrate on which the hole injection layer 13, the charge transport film 14 and the light emitting layer 15 are wet-formed is carried into the multi-chamber vacuum deposition apparatus connected to the glove box without being exposed to the atmosphere, and is rotated by an oil rotary pump. After roughly evacuating the apparatus, the apparatus was evacuated using a cryopump until the degree of vacuum in the apparatus was 5.3 × 10 ⁻⁵ Pa or less, and a compound represented by the following structural formula (C4) was vacuum deposited. Thus, a hole blocking layer 18 was obtained. The degree of vacuum during deposition is 3.1 to 4.8 × 10 ⁻⁵ Pa, the deposition rate is controlled in the range of 0.6 to 1.1 Å / sec, and a film with a thickness of 5 nm is stacked on the light emitting layer 15. Thus, a hole blocking layer 18 was formed.

Next, tris (8-hydroxyquinolinate) aluminum was heated and evaporated to form an electron transport layer 19. The degree of vacuum during deposition is 2.9 to 4.9 × 10 ⁻⁵ Pa, the deposition rate is controlled in the range of 0.7 to 1.3 Å / sec, and a film with a thickness of 30 nm is formed on the hole blocking layer 19. To form an electron transport layer 19.

Here, the element on which the electron transport layer 19 has been vapor-deposited is transported in vacuum from the organic layer vapor deposition chamber on which the electron transport layer 19 has been vapor-deposited to the metal vapor deposition chamber, and a 2 mm wide stripe is used as a mask for cathode vapor deposition. A thin shadow mask is placed in close contact with the element so as to be orthogonal to the ITO stripe of the anode 2 and placed in another vacuum deposition apparatus, and the degree of vacuum in the apparatus is 8.7 × in the same manner as in the organic layer deposition. It exhausted until it became below 10 <^-5> Pa.

As the electron injection layer 16, first, lithium fluoride (LiF) was controlled at a deposition rate of 0.07 to 0.15 liters / second and a degree of vacuum of 4.7 to 10.0 × 10 ⁻⁵ Pa using a molybdenum boat. The film was formed on the electron transport layer 19 with a film thickness of 0.5 nm. Next, aluminum is similarly heated as a cathode 17 by a molybdenum boat, and the film thickness is 80 nm by controlling the deposition rate from 0.6 to 16.0 Å / sec and the degree of vacuum from 2.0 to 13.0 × 10 ⁻⁵ Pa. The cathode 17 was formed. The substrate temperature at the time of vapor deposition of the above two-layer cathode was kept at room temperature.

Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, a sealing process was performed by the method described below.
In a nitrogen glove box connected to a vacuum vapor deposition device, a photocurable resin (30Y-437 manufactured by ThreeBond Co., Ltd.) with a width of about 1 mm is applied to the outer peripheral portion of a 23 mm × 23 mm size glass plate, and the central portion is applied. A moisture getter sheet (manufactured by Dynic Co., Ltd.) was installed. On top of this, the substrate on which the cathode 17 had been formed was bonded so that the deposited surface faced the desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened.
As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained.

[Measurement of luminance half-life]
The luminance half-life was measured using a driving test element. The results are shown in Table 4. FIG. 4 is a correlation diagram showing the relationship between the luminance half-life under the condition of 2500 cd / m ² and the relative dielectric constant of the crosslinkable polymer. FIG. 4 shows the relationship between the luminance half-life under the condition of 2500 cd / m ² and the crosslinking in the compound having a crosslinking group. FIG. 5 shows a correlation diagram showing the relationship with the number of groups, and FIG. 6 shows a graph showing the relationship between the luminance half-life and the current mutation point of the crosslinkable polymer (under the condition of 2500 cd / m ² ). In FIG. 4, the broken line represents the range of the relative dielectric constant of 3.3 to 6.3. In FIG. 5, a broken line represents a line having 2 cross-linking groups. Further, the broken line in FIG. 6 represents a line having a current variation point of 1050 kV / cm.
Moreover, the measuring method of a brightness | luminance half-life and how to count the number of crosslinking groups are as follows.

-Luminance half-life measurement method The luminance half-life measurement method (hereinafter referred to as drive test) is shown below. First, the current value was measured when the target device emitted light at 2500 cd / m ² . Next, a current was passed through the target element while maintaining the current value measured previously. The luminance of the element at that time was continuously observed, and the time until the initial luminance, that is, 2500 cd / m ² halved was measured, and this was defined as the luminance half life. The temperature condition was room temperature.
<Drive conditions>
Temperature Room temperature Drive method DC drive (DC drive)
Initial luminance 2,500 cd / m ²

-How to count the number of cross-linking groups Here, the number of cross-linking groups means the number of cross-linking groups per unit transport unit. When the calculation method is shown again, when the compound having a crosslinkable group forming the crosslinkable polymer is one kind of monomer, the number of the crosslinkable groups substituted by the monomer corresponds to that. Moreover, when the compound which has a crosslinking group which forms a crosslinkable polymer mixes several types of monomer bodies, it calculates simply from the number of the substituents substituted by each monomer, and the molar ratio mixed. For example, in the case of H1, since h1 has two substituents and h2 has one substituent, and the molar ratio thereof is 30 to 70, one mole of the mixture contains a bridging group derived from h1. Is 0.6 mol and h2 cross-linking group is 0.7 mol, so the number of cross-linking groups per unit charge transport unit is (0.6 + 0.7) /1=1.3. . Furthermore, when the compound having a crosslinking group is an oligomer / monomer system, the number of the crosslinking groups is the number of crosslinking groups with respect to the main skeleton having a charge transporting ability to form a crosslinkable polymer. For example, in the case of H4, the main skeleton having the charge transporting ability is benzidine. Therefore, when 100 repeating structures connected by ether bonds are connected, there are 20 crosslinking groups. The number is 0.2.

[Fabrication of driving test element using blue fluorescent material]
As another example for producing an actual light emitting element corresponding to a sample whose relative dielectric constant is measured, there is a driving test element using a blue fluorescent light emitting material (hereinafter referred to as “blue fluorescent driving test element”). )created. As shown in FIG. 3, a normal photolithography technique and hydrochloric acid etching are performed on a glass substrate 11 in which an ITO transparent conductive film is deposited to a thickness of 150 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film). The ITO layer 12 was formed by patterning into a stripe having a width of 2 mm. This ITO substrate was cleaned in the order of ultrasonic cleaning with a surfactant aqueous solution, ultrapure water cleaning, ultrapure ultrasonic cleaning, and ultrapure water cleaning, followed by drying with compressed air, and finally UV ozone cleaning. .

  Next, 2.0 wt% of a hole transporting polymer having a repeating structure represented by the formula (P1) and 0.8 wt% of 4-isopropyl-4′-methyl represented by the formula (A1) An ethyl benzoate solution containing diphenyliodonium tetrakis (pentafluorophenyl) borate was prepared. This ethyl benzoate solution was deposited by spin coating under the deposition conditions shown in Table 1 to obtain a hole injection layer 13 having a thickness of 30 nm.

Then, the coating liquid which melt | dissolved or disperse | distributed the compound H6-H11 which has the above-mentioned crosslinking group in the solvent shown in following Table 5 as a charge transport film composition was prepared, and this was spin-coated on the positive hole injection layer 13 The film was formed at (spinner rotation speed: 1500 rpm, spinner rotation time: 30 seconds, spin coat atmosphere: in nitrogen), and a charge transport film (hole transport layer) 14 made of a crosslinked polymer was formed by performing a crosslinking treatment. . Table 5 below shows the materials, film forming conditions, and film thickness after the crosslinking treatment in each example and comparative example.

Next, using the organic compounds (C5) and (C6) represented by the following structural formula, a composition for forming a light emitting layer was prepared under the following conditions. The composition was formed by spin coating on a charge transport film under the following conditions, and dried to form a light-emitting layer 15 having a thickness of 40 nm.

<Composition for light emitting layer formation>
Solvent Toluene Coating solution concentration C5: 0.75 wt%
C6: 0.075% by weight
<Deposition conditions of the light emitting layer 15>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coating atmosphere In nitrogen Bake conditions In vacuum 130 ° C 1 hour

Next, the substrate on which the hole injection layer 13, the charge transport film 14 and the light emitting layer 15 are coated is carried into the multi-chamber vacuum deposition apparatus connected to the glove box without being exposed to the atmosphere, and is rotated by an oil rotary pump. After roughly evacuating the apparatus, the apparatus was evacuated using a cryopump until the degree of vacuum in the apparatus was 3 × 10 ⁻⁴ Pa or less, and bis (2-methyl-8-quinolinolato) (paraphenylphenolate) aluminum Were stacked by a vacuum deposition method to obtain a hole blocking layer 18. The degree of vacuum during vapor deposition is 3 × 10 ⁻⁴ Pa or less, the vapor deposition rate is controlled in the range of 0.8 to 1.2 liters / second, and a 10 nm thick film is stacked on the light emitting layer 15 to block holes. Layer 18 was formed.

Next, tris (8-hydroxyquinolinate) aluminum was heated and evaporated to form an electron transport layer 19. The degree of vacuum during deposition is 2.9 to 4.9 × 10 ⁻⁵ Pa, the deposition rate is controlled in the range of 0.7 to 1.3 Å / sec, and a film with a thickness of 30 nm is formed on the hole blocking layer 19. To form an electron transport layer 19.

Here, the element on which the electron transport layer 19 has been vapor-deposited is transported in vacuum from the organic layer vapor deposition chamber on which the electron transport layer 19 has been vapor-deposited to the metal vapor deposition chamber, and a 2 mm wide stripe is used as a mask for cathode vapor deposition. A thin shadow mask is placed in close contact with the element so as to be orthogonal to the ITO stripe of the anode 2 and placed in another vacuum deposition apparatus, and the degree of vacuum in the apparatus is 8.7 × in the same manner as in the organic layer deposition. It exhausted until it became below 10 <^-5> Pa.

As the electron injection layer 16, first, lithium fluoride (LiF) was controlled at a deposition rate of 0.07 to 0.15 liters / second and a degree of vacuum of 4.7 to 10.0 × 10 ⁻⁵ Pa using a molybdenum boat. The film was formed on the electron transport layer 19 with a film thickness of 0.5 nm. Next, aluminum is similarly heated as a cathode 17 by a molybdenum boat, and the film thickness is 80 nm by controlling the deposition rate from 0.6 to 16.0 Å / sec and the degree of vacuum from 2.0 to 13.0 × 10 ⁻⁵ Pa. The cathode 17 was formed. The substrate temperature at the time of vapor deposition of the above two-layer cathode was kept at room temperature.

Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, a sealing process was performed by the method described below.
In a nitrogen glove box connected to a vacuum vapor deposition device, a photocurable resin (30Y-437 manufactured by ThreeBond Co., Ltd.) with a width of about 1 mm is applied to the outer peripheral portion of a 23 mm × 23 mm size glass plate, and the central portion is applied. A moisture getter sheet (manufactured by Dynic Co., Ltd.) was installed. On top of this, the substrate on which the cathode 17 had been formed was bonded so that the deposited surface faced the desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened.
As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained.

[Measurement of drive life]
The driving life was measured using a blue fluorescent driving test element. The results are shown in Table 6. In addition, FIG. 7 shows a correlation diagram showing the relationship between the relative ratio (hereinafter referred to as the relative life) of the luminance reduced to 80% when the H6 standard is 1000 cd / m ² and the relative dielectric constant of the crosslinkable polymer. FIG. 8 is a graph showing the relationship between the relative lifetime under the condition of 1000 cd / m ² and the current mutation point of the crosslinkable polymer. In FIG. 7, the broken line represents the range of the relative dielectric constant of 3.3 to 6.3. Furthermore, the broken line in FIG. 8 represents a line having a current variation point of 1050 kV / cm.
Moreover, the measuring method of a brightness | luminance 80% reduction lifetime is as follows.

• Driving life measurement method The driving life measurement method (hereinafter referred to as drive test) is shown below. First, the current value was measured when the target device emitted light at 1000 cd / m ² . Next, a current was passed through the target element while maintaining the current value measured previously. The luminance of the element at that time was continuously observed, and the initial luminance, that is, the time until 1000 cd / m ² was reduced by 80% was measured, and this was defined as the driving life. The temperature condition was room temperature.
<Drive conditions>
Temperature Room temperature Drive method DC drive (DC drive)
Initial luminance 1000 cd / m ²

  The present invention can be used for, for example, an organic electroluminescent element, an electrophotographic photosensitive member, a photoelectric conversion element, an organic solar battery, an organic rectifying element, and the like, and particularly suitable for an organic electroluminescent element.

It is sectional drawing which shows typically the layer structure of the element for a measurement. (A)-(c) is sectional drawing which shows typically the layer structure of the organic electroluminescent element which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the layer structure of the element for a drive test, and the element for a blue fluorescence drive test. It is a graph showing the relationship between the brightness | luminance half life measured by the Example and comparative example of this invention, and the dielectric constant of a crosslinkable polymer. It is a graph showing the relationship between the brightness | luminance half-life measured in the Example and comparative example of this invention, and the number of the crosslinking groups in the compound which has a crosslinking group. It is a graph showing the relationship between the brightness | luminance half life measured by the Example and comparative example of this invention, and the current variation point of a crosslinkable polymer. Relationship between relative ratio (hereinafter referred to as relative life) of luminance reduced to 80% when H6 is used as a criterion in 1000 cd / m ² condition measured in Examples and Comparative Examples of the present invention, and relative dielectric constant of crosslinkable polymer FIG. A broken line represents a range of a relative dielectric constant of 3.3 to 6.3. It is a graph showing the relationship between the relative lifetime in 1000 cd / m < ² > conditions measured by the Example and comparative example of this invention, and the current mutation point of a crosslinkable polymer. A broken line represents a line having a current mutation point of 1050 kV / cm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 ITO layer 3 Polymer layer 4 Measurement anode 5 Sample layer 6 Measurement cathode 10, 10 ', 10 "Organic electroluminescent element 11 Substrate (glass substrate)
12 Anode (ITO layer)
DESCRIPTION OF SYMBOLS 13 Hole injection layer 14 Charge transport film | membrane 15 Light emitting layer 16 Electron injection layer 17 Cathode 18 Hole blocking layer 19 Electron transport layer

Claims (6)

A charge transport film containing a crosslinkable polymer, wherein the crosslinkable polymer has a relative dielectric constant of 3.3 or more and 6 measured at 25 ° C., a measurement frequency of 100 Hz, and a measurement AC voltage of 250 mV using the following measurement element. A charge transporting film characterized by being 3 or less.
[Measuring element]
A hole transporting polymer having a repeating structure represented by the following formula (P1) (weight average molecular weight: 10,000 to 50,000, weight average molecular weight / A film of an ethyl benzoate solution containing 2.0% by weight of a number average molecular weight: 1 or more and 3 or less) and 0.8% by weight of 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, An anode for measurement provided with a layer having a thickness of 30 nm obtained by baking at 230 ° C. for 3 hours in the atmosphere;

A sample layer having a thickness of 100 nm or more and 200 nm or less formed of the crosslinkable polymer formed on the measurement anode;
A measuring element provided with a measuring cathode made of Al and having a thickness of 80 nm formed on the sample layer. The charge transport film according to claim 1, wherein the current mutation point measured by the measuring element is 1050 kV / cm or more. An organic electroluminescent device comprising: an anode; a cathode; and the charge transport film according to claim 1 or 2 provided between the anode and the cathode. 4. The organic electroluminescent device according to claim 3, wherein the charge transport film is a hole transport layer. An organic EL display using the organic electroluminescent element according to claim 3. A compound having a crosslinking group, which forms a crosslinkable polymer contained in the charge transport film according to claim 1 or 2.

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