JP5759670B2 - Organic light emitting device - Google Patents

Description

  The present invention relates to an organic light emitting device that emits light by applying a voltage to one or more organic compound layers including a light emitting layer and includes a charge transporting polymer in the light emitting layer.

In recent years, materials having high luminous efficiency and durability have been actively developed in order to expand the applications of organic light emitting devices. However, in order to develop organic light-emitting elements for display and lighting applications, it is essential to develop materials that have higher luminous efficiency and maintain stable driving of the elements. Among them, a phosphorescent material that emits light from a triplet excited state generated by the combination of holes and electrons is expected as a material that can greatly improve the light emission efficiency of an organic light emitting device. (Non-Patent Document 1)
An organic light emitting element generally has a configuration including one or more organic layers sandwiched between a pair of electrodes. When a polymer compound or a mixture of a polymer compound and a non-polymer compound is used as a material for forming these layers, it is possible to easily form a film by applying a solution in which the polymer compound is dissolved, and the device can have a large area and can be mass-produced. Become. As such a polymer compound, a charge transporting polymer having a charge transporting structure in its side chain is known, and as disclosed in Patent Documents 1 and 2, triarylamine derivatives have high hole mobility. Therefore, it is preferable as a side chain structure of the charge transporting polymer.

  However, if the charge-transporting polymer has both a hole-transporting triarylamine structure and an electron-transporting structure in the side chain, when the polymer is photoexcited, in addition to the light emission of the triarylamine structure and the electron-transporting structure alone A lower energy emission is observed. This emission energy is often lower than the excitation energy of the phosphor dispersed in the charge transporting polymer, causing the emission from the phosphor to decrease, especially in the case of phosphorescent emitters with high excitation energy. The luminous efficiency of the device is greatly reduced.

JP-A-7-53953 JP-A-8-269133

Applied Physics Letters 75, 4-6, 1999

  The present invention provides a charge transporting polymer that contains a triarylamine structure and an electron transporting structure in the same molecule at the same time, and suppresses light emission at a lower energy than light emission derived from each structure, and It is an object to increase the light emission efficiency of an organic light emitting device using the above.

  As a result of intensive studies to solve the above problems, the present inventors use a charge transporting polymer having a specific structure as a side chain in addition to a triarylamine structure and an electron transporting structure as a material for the light emitting layer. As a result, it was found that the luminous efficiency of the organic light emitting device was improved, and the present invention was completed.

That is, the present invention relates to the following [1] to [4].
[1] An organic light emitting device having a pair of electrodes and one or more organic compound layers including a light emitting layer and emitting light by applying a voltage between the pair of electrodes, wherein the light emitting layer transports holes. The charge transporting polymer comprises a repeating unit represented by the following formulas (1) to (3), and is represented by the formula (1). When the number of repeating units is x, the number of repeating units represented by formula (2) is y, and the number of repeating units represented by formula (3) is z, x, y and z are 1 or more. , Z is 4 times or more and 200 times or less of the sum of x and y, The organic light emitting element characterized by the above-mentioned.

上記式（１）中、Ａｒ^１およびＡｒ^２はそれぞれ独立に、フェニル基、またはジアリールアミノフェニル基を表し、該フェニル基、またはジアリールアミノフェニル基は、アルキル基及びアルコキシ基から選ばれる置換基を有してもよい。

In the above formula (1), Ar ¹ and Ar ² are each independently a phenyl group, or represents a diarylamino phenyl group, the phenyl group, or diaryl amino phenyl group, selected from alkyl and alkoxy groups which may have a substituent that is not good.

上記式（２）中、Ａはトリアリールボラン誘導体を表す。

In the above formula (2), A represents a triarylborane derivative .

[2] The organic light-emitting element according to [1], wherein the light-emitting layer includes a phosphorescent compound .

  The organic light emitting device of the present invention includes a charge transporting polymer that can be formed into a film by coating in the light emitting layer, and has a high light emitting efficiency by suppressing a decrease in the light emitting efficiency of the light emitter due to the charge transporting polymer.

Next, the present invention will be specifically described.
The organic light-emitting device of the present invention is characterized in that the light-emitting layer comprises a repeating unit represented by the above formulas (1) to (3) and contains a copolymer having a charge transporting property and a light-emitting compound. The copolymer is preferably 30 to 99% by weight, more preferably 60 to 99% by weight of the components constituting the light emitting layer.

The repeating unit represented by the above formula (1) is a repeating unit containing a triarylamine structure. Ar ¹ and Ar ² each independently represent a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, or a diarylaminophenyl group, which may have a substituent such as an alkyl group or an alkoxy group.

  Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, an amyl group, a hexyl group, an octyl group, and a decyl group.

  Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a t-butoxy group, a hexyloxy group, a 2-ethylhexyloxy group, and a decyloxy group.

Ar ¹ and Ar ² further have a diarylamino group or a diarylaminophenyl group as a substituent, so that the repeating unit represented by the formula (1) has two triarylamine structures in one repeating unit. A structure including the above may be formed.

R ¹ in the above formula (1) represents an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group. , Isobutyl group, t-butyl group, amyl group, hexyl group, octyl group, decyl group and the like. Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group. Group, t-butoxy group, hexyloxy group, 2-ethylhexyloxy group, decyloxy group and the like.

  Specific examples of the repeating unit represented by the above formula (1) are shown below.

上記式（２）で表される繰り返し単位におけるＡは電子輸送性を有する基を表す。電子輸送性を有する基としては、例えば、ヘテロ芳香族化合物誘導体やトリアリールボラン誘導体を挙げることができ、これらは上記式（Ａ−１）〜（Ａ−８）で表される構造であることが好ましい。

A in the repeating unit represented by the above formula (2) represents a group having an electron transporting property. Examples of the group having an electron transporting property include heteroaromatic compound derivatives and triarylborane derivatives, and these are structures represented by the above formulas (A-1) to (A-8). Is preferred.

In formulas (A-1) to (A-8), R ¹¹ , R ¹⁶ , R ¹⁷ and R ^{19 to} R ²² are each independently a fluorine atom, a cyano group, an alkyl group, an aryl group, an alkoxy group or a silyl group. Represents. Here, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, an amyl group, a hexyl group, an octyl group, and a decyl group. Examples of the group include phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group, biphenyl group, terphenyl group and pyridyl group, pyrazyl group, quinolyl group, isoquinolyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, oxazolyl group. Groups, oxadiazolyl groups, toazolyl groups, benzoxazolyl groups, benzthiazolyl groups, thienyl groups, furyl groups, tetrazole groups, carbazolyl groups, carbazolylphenyl groups and the like heteroaryl groups. Examples of alkoxy groups include Methoxy group, ethoxy group, propoxy group, Examples include a propoxy group, a butoxy group, an isobutoxy group, a t-butoxy group, a hexyloxy group, a 2-ethylhexyloxy group, a decyloxy group. Examples of the silyl group include a trimethylsilyl group, a triethylsilyl group, and a t-butyldimethylsilyl group. Group, trimethoxysilyl group and the like. Among these substituents, an alkyl group, an aryl group, and an alkoxy group are preferable, and a methyl group, a t-butyl group, a phenyl group, a tolyl group, a biphenyl group, a carbazolyl group, and a carbazolylphenyl group are more preferable.

In the above formulas (A-1) to (A-8), Ar ^{11 to} Ar ¹⁹ and Ar ²¹ each represent an aryl group. For example, phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group, biphenyl group, ter Examples thereof include a phenyl group, a carbazolyl group, a carbazolylphenyl group, and the like, preferably a phenyl group, a tolyl group, a xylyl group, a biphenyl group, a carbazolyl group, and a carbazolylphenyl group. These groups may be further substituted with an aryl group.

  Specific examples of the compounds represented by the above formulas (A-1) to (A-8) are shown below.

上記式（３）で表される繰り返し単位におけるＲ²は炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、置換基を有してもよいフェニル基、置換基を有してもよいビフェニル基または置換基を有してもよいターフェニル基を表し、該アルキル基としては例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔ−ブチル基、アミル基、ヘキシル基、オクチル基、デシル基などが挙げられ、該アルコキシ基としては、例えば、メトキシ基、エトキシ基、プロポキシ基、イソプロポキシ基、ブトキシ基、イソブトキシ基、ｔ−ブトキシ基、ヘキシルオキシ基、２−エチルヘキシルオキシ基、デシルオキシ基などが挙げられる。上記フェニル基、ビフェニル基およびターフェニル基は置換基としてアルキル基やアルコキシ基を有していてもよい。

R ² in the repeating unit represented by the above formula (3) has an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an optionally substituted phenyl group, and a substituent. Represents an optionally substituted biphenyl group or an optionally substituted terphenyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, and an amyl group. Group, hexyl group, octyl group, decyl group and the like. Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, t-butoxy group, hexyloxy group. , 2-ethylhexyloxy group, decyloxy group and the like. The phenyl group, biphenyl group and terphenyl group may have an alkyl group or an alkoxy group as a substituent.

  The repeating unit represented by the above formula (3) has a larger band gap than the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2). Low energy emission can be suppressed.

  In the copolymer of the present invention, the number of repeating units represented by the above formula (1) is x, the number of repeating units represented by the above formula (2) is y, and the above formula (3). When the number of repeating units is z, x, y and z are 1 or more, and z is 2 or more times the sum of x and y. If z is smaller than twice the sum of x and y, the light emission efficiency of the organic light emitting device does not increase because the effect of suppressing the low energy emission is small. z is more than twice the sum of x and y, and the larger it is, the higher the effect of suppressing the above-mentioned low energy emission is, and it is more preferably 4 times or more of the sum of x and y, more preferably 6 times or more. More preferably, when it exceeds 200 times, the charge transport properties of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) are deteriorated. preferable.

The ratio of x and y in the copolymer, that is, the optimum value of x / y is determined by the charge transporting ability, concentration, etc. of each repeating unit, but is preferably preferably in the range of 0.05 to 20, respectively. More preferably, it is in the range of 0.25-4. The ratio of each repeating unit in such a copolymer is estimated by ¹³ C-NMR measurement.

  The copolymer is represented by the repeating unit represented by the above formula (1) having a different structure, the repeating unit represented by the above formula (2) having a different structure, and / or the above formula (3) having a different structure. Repeating units may be included. In this case, the above x, y, and z are defined as the total number of repeating units represented by the formulas (1), (2), and (3), respectively.

  The weight average molecular weight of the copolymer is usually 1,000 to 2,000,000, and preferably 5,000 to 1,000,000. When the weight average molecular weight is in this range, the polymer compound is soluble in an organic solvent, and a uniform thin film can be obtained. Here, the weight average molecular weight is a value measured at 40 ° C. using tetrahydrofuran as a solvent by gel permeation chromatography (GPC).

  The copolymer can be produced by radical polymerization, cation polymerization or anion polymerization of a composition containing a vinyl group monomer corresponding to each repeating unit in a predetermined ratio. From the viewpoint of easy production, it is preferable to produce by radical polymerization. The copolymer is preferably a random copolymer.

  As an example of the configuration of the organic light-emitting device according to the present invention, a configuration in which a hole transport layer, a light-emitting layer, and an electron transport layer are laminated in this order between an anode and a cathode provided on a transparent substrate can be given. In the configuration of another organic light emitting device, for example, either 1) a hole transport layer / light emitting layer or 2) a light emitting layer / electron transport layer may be provided between the anode and the cathode of the organic light emitting device. 3) a layer containing a hole transport material, a light emitting material, an electron transport material, 4) a layer containing a hole transport material, a light emitting material, 5) a layer containing a light emitting material, an electron transport material, 6) Any one of the layers may be provided. Further, two or more light emitting layers may be stacked. The organic layer may be formed inside pores (cavities) provided in the electrode surface on the substrate.

  Each of the above layers may be formed by mixing a polymer material as a binder. Examples of the polymer material include polymethyl methacrylate, polycarbonate, polyester, polysulfone, and polyphenylene oxide.

  The light-emitting layer preferably contains a light-emitting compound, and the light-emitting compound is preferably a phosphorescent compound. Examples of the phosphorescent compound include an iridium complex having a ligand such as aryl pyridine and carbene, a platinum complex, and an osmium complex. More specific examples of the iridium complex include the following compounds (E1-1) to (E1-39).

上記発光層は、上記共重合体１００重量部に対して、上記発光性化合物を、好ましくは１〜５０重量部、より好ましくは５〜２０重量部の量で含むことが望ましい。また、上記発光性化合物は、上記式（１）で表される共重合体の側鎖構造として含まれていてもよい。

The light emitting layer preferably contains the light emitting compound in an amount of 1 to 50 parts by weight, more preferably 5 to 20 parts by weight, with respect to 100 parts by weight of the copolymer. Moreover, the said luminescent compound may be contained as a side chain structure of the copolymer represented by the said Formula (1).

  The hole transport material and the electron transport material used for each of the above layers may be formed independently, or may be formed by mixing materials having different functions. Also in the light emitting layer in the organic light emitting device according to the present invention, in addition to the copolymer according to the present invention and the phosphorescent compound, other known hole transport materials and / or for the purpose of supplementing the carrier transport property. An electron transport material may be included. Such a transport material may be a low molecular compound or a high molecular compound, and is preferably 5 to 95 parts by weight, more preferably 20 to 80 parts by weight based on 100 parts by weight of the copolymer. Included in parts by weight.

  The method for forming the light emitting layer is not particularly limited, and for example, the light emitting layer can be formed as follows. First, a solution in which the copolymer, the light-emitting compound and, if necessary, a charge transporting compound are dissolved is prepared. The solvent used for the preparation of the solution is not particularly limited. For example, a chlorine solvent such as chloroform, methylene chloride, dichloroethane, an ether solvent such as tetrahydrofuran and anisole, an aromatic hydrocarbon solvent such as toluene and xylene, Ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate are used. Next, the solution thus prepared is subjected to spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and screen printing. The film is formed on the substrate by a wet film forming method such as a flexographic printing method, an offset printing method, or an ink jet printing method. For example, in the case of a spin coating method or a dip coating method, the solution contains a mixture of the copolymer, the light-emitting compound, and the charge transporting compound in an amount of 0.5 to 0.5. It is preferably included in an amount of 5% by weight.

  As the substrate of the organic light emitting device of the present invention, an insulating substrate transparent to the emission wavelength of the light emitting material is preferably used. Specifically, in addition to glass, transparent materials such as PET (polyethylene terephthalate) and polycarbonate are used. Plastic or the like is used.

  A hole injection layer may be provided between the anode and the light emitting layer in order to relax the injection barrier in hole injection. In order to form the hole injection layer, a known material such as copper phthalocyanine, a mixture of polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS), fluorocarbon, silicon dioxide or the like is used.

  An insulating layer having a thickness of 0.1 to 10 nm is provided between the cathode and the electron transport layer or between the cathode and the organic compound layer laminated adjacent to the cathode in order to improve electron injection efficiency. It may be done. In order to form the insulating layer, known materials such as lithium fluoride, sodium fluoride, magnesium fluoride, magnesium oxide, and alumina are used.

  As a hole transport material for forming the hole transport layer or a hole transport material mixed in the light emitting layer, for example, TPD (N, N′-dimethyl-N, N ′-(3-methylphenyl)- 1,1′-biphenyl-4,4′diamine); α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl); m-MTDATA (4,4 ′, Low molecular weight triphenylamine derivatives such as 4 ″ -tris (3-methylphenylphenylamino) triphenylamine), low molecular weight such as 4,4′-dicarbazolylbiphenyl, 1,3-dicarbazolylbiphenyl And carbazole derivatives. The above hole transport materials may be used singly or in combination of two or more, or different hole transport materials may be laminated and used. Since the thickness of the hole transport layer depends on the conductivity of the hole transport layer and the like, it cannot be unconditionally limited, but is preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm, and particularly preferably 10 nm to 500 nm. Is desirable.

  Examples of the electron transport material for forming the electron transport layer or the electron transport material mixed in the light emitting layer include quinolinol derivative metal complexes such as Alq3 (aluminum trisquinolinolate), oxadiazole derivatives, triazole derivatives, imidazole. Examples include known compounds such as derivatives, triazine derivatives, and triarylborane derivatives. The electron transport materials may be used singly or in combination of two or more, or different electron transport materials may be laminated and used. The thickness of the electron transport layer depends on the conductivity of the electron transport layer and cannot be generally limited, but is preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm, and particularly preferably 10 nm to 500 nm. .

  In addition, a hole blocking layer is provided adjacent to the cathode side of the light emitting layer for the purpose of preventing holes from passing through the light emitting layer and efficiently recombining holes and electrons in the light emitting layer. May be. In order to form the hole blocking layer, a known material such as a triazole derivative, an oxadiazole derivative, or a phenanthroline derivative is used.

  Examples of film formation methods for the light-emitting layer, the hole transport layer, and the electron transport layer include dry coating methods such as resistance heating evaporation, electron beam evaporation, and sputtering, as well as spin coating, casting, and microgravure. Wet film forming methods such as coating methods, gravure coating methods, bar coating methods, roll coating methods, wire bar coating methods, dip coating methods, spray coating methods, screen printing methods, flexographic printing methods, offset printing methods, and inkjet printing methods ( Application method) can be used. The layer containing the compound of the present invention has an advantage that it can be formed by a coating method capable of suppressing the manufacturing cost of the organic light emitting device.

  As an anode material used for the organic light emitting device of the present invention, for example, a known transparent conductive material such as ITO (indium tin oxide), tin oxide, zinc oxide, polythiophene, polypyrrole, polyaniline or the like is preferably used. It is done. The surface resistance of the electrode formed of the transparent conductive material is preferably 1 to 50Ω / □ (ohm / square). The thickness of the anode is preferably 50 to 300 nm.

  Examples of the cathode material used in the organic EL device of the present invention include alkali metals such as Li, Na, K, and Cs; alkaline earth metals such as Mg, Ca, and Ba; Al; MgAg alloys; Al such as AlLi and AlCa A known cathode material such as an alloy of alkali metal or alkaline earth metal is preferably used. The thickness of the cathode is preferably 10 nm to 1 μm, more preferably 50 to 500 nm. When a highly active metal such as an alkali metal or alkaline earth metal is used, the thickness of the cathode is preferably 0.1 to 100 nm, more preferably 0.5 to 50 nm. In this case, a metal layer that is stable to the atmosphere is laminated on the cathode for the purpose of protecting the cathode metal. Examples of the metal forming the metal layer include Al, Ag, Au, Pt, Cu, Ni, and Cr. The thickness of the metal layer is preferably 10 nm to 1 μm, more preferably 50 to 500 nm.

  In addition, as a method for forming the anode material, for example, an electron beam evaporation method, a sputtering method, a chemical reaction method, a coating method, or the like is used. As a method for forming the cathode material, for example, a resistance heating evaporation method, An electron beam evaporation method, a sputtering method, an ion plating method, or the like is used.

  The organic light-emitting element of the present invention is suitably used in an image display device as a matrix-type or segment-type pixel by a known method. The organic EL element is also suitably used as a surface light source without forming pixels.

  Specifically, the organic light-emitting device of the present invention is suitably used for displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, reading light sources, signs, signboards, interiors, optical communications, and the like.

Next, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited by these.
( Reference Synthesis Example 1)
A reference copolymer (1-1) was synthesized by copolymerizing the following compounds (M-1), (M-2) and (M-3). Compounds (M-1) and (M-2) were synthesized according to the method described in JP-A-2005-200508, and (M-3) was distilled from Tokyo Chemical Industry Co., Ltd. under reduced pressure. Using.

密閉容器に化合物（Ｍ−１）２００ｍｇ（０．３３ｍｍｏｌ）、化合物（Ｍ−２）２００ｍｇ（０．３４ｍｍｏｌ）および化合物（Ｍ−３）１４０ｍｇ（１．３４ｍｍｏｌ）を入れ、脱水トルエン（５．０ｍＬ）を加えた。次いで、Ｖ−６０１（和光純薬工業（株）製）のトルエン溶液（０．１Ｍ、０．１０ｍＬ）を加え、凍結脱気操作を５回繰り返した。真空のまま密閉し、６０℃で６０時間撹拌した。反応後、反応液をアセトン２００ｍＬ中に滴下し、沈殿を得た。さらにトルエン−アセトンでの再沈殿精製を２回繰り返した後、５０℃で一晩真空乾燥して、参考共重合体（１−１）を得た。参考共重合体（１−１）の重量平均分子量（Ｍｗ）は３４５００、分子量分布指数（Ｍｗ／Ｍｎ）は２．０５であった。¹³Ｃ−ＮＭＲ測定の結果から見積もった参考共重合体（１−１）におけるｘ／ｙの値は１．００であり、ｚ／（ｘ＋ｙ）は２．１３であった。

Compound (M-1) 200 mg (0.33 mmol), compound (M-2) 200 mg (0.34 mmol) and compound (M-3) 140 mg (1.34 mmol) were placed in a sealed container, and dehydrated toluene (5.0 mL). ) Was added. Next, a toluene solution (0.1 M, 0.10 mL) of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the freeze degassing operation was repeated 5 times. It sealed in vacuum and stirred at 60 ° C. for 60 hours. After the reaction, the reaction solution was dropped into 200 mL of acetone to obtain a precipitate. Further, reprecipitation purification with toluene-acetone was repeated twice, followed by vacuum drying at 50 ° C. overnight to obtain a reference copolymer (1-1). The weight average molecular weight (Mw) of the reference copolymer (1-1) was 34500, and the molecular weight distribution index (Mw / Mn) was 2.05. The value of x / y in the reference copolymer (1-1) estimated from the result of ¹³ C-NMR measurement was 1.00, and z / (x + y) was 2.13.

(Synthesis Example 2)
The amounts of compound (M-1), compound (M-2) and compound (M-3) used for the polymerization were 150 mg (0.25 mmol), 150 mg (0.26 mmol) and 210 mg (2.02 mmol), respectively. The copolymerization was conducted in the same manner as in Reference Synthesis Example 1 to obtain a copolymer (1-2). The weight average molecular weight (Mw) of the copolymer (1-2) was 29600, and the molecular weight distribution index (Mw / Mn) was 2.18. The value of x / y in the copolymer (1-2) estimated from the result of ¹³ C-NMR measurement was 1.00, and z / (x + y) was 4.05.

(Comparative Synthesis Example 1)
The amounts of compound (M-1), compound (M-2) and compound (M-3) used for the polymerization were 200 mg (0.33 mmol), 200 mg (0.34 mmol) and 70 mg (0.67 mmol), respectively. Otherwise, polymerization was carried out in the same manner as in Reference Synthesis Example 1 to obtain a comparative copolymer (C1-1). The weight average molecular weight (Mw) of the comparative copolymer (C1-1) was 36600, and the molecular weight distribution index (Mw / Mn) was 2.15. The value of x / y in the comparative copolymer (C1-1) estimated from the result of ¹³ C-NMR measurement was 1.00, and z / (x + y) was 1.00.

(Comparative Synthesis Example 2)
The amount of the compound (M-1), compound (M-2) and compound (M-3) used for the polymerization was 200 mg (0.33 mmol), 200 mg (0.34 mmol) and 0 mg (0 mmol), respectively. Were polymerized in the same manner as in Reference Synthesis Example 1 to obtain a comparative copolymer (C1-2). The weight average molecular weight (Mw) of the comparative copolymer (C1-2) was 35100, and the molecular weight distribution index (Mw / Mn) was 2.07. The value of x / y in the comparative copolymer (C1-2) estimated from the result of ¹³ C-NMR measurement was 0.92, and z / (x + y) was 0.

[ Reference Example 1]
A substrate with ITO (manufactured by Nippon Electric Co., Ltd.) was used. This was a substrate in which two ITO (indium tin oxide) electrodes (anodes) having a width of 4 mm were formed in one stripe on one surface of a 25 mm square glass substrate.

First, on the substrate with ITO, N, N′-di (1-naphthyl) -N, N′-diphenyl-4,4′-diaminobiphenyl (manufactured by Sigma-Aldrich, sublimation purified product, purity 99%) A hole transport layer was formed to a thickness of about 50 nm at a rate of 0.2 nm / sec by resistance heating vapor deposition under a reduced pressure of 8.5 × 10 ⁻⁵ Pa. Next, a mixture of 82 mg of the reference copolymer (1-1) and 8 mg of the phosphorescent emitter (E1-4) was dissolved in 2910 mg of toluene (special grade, manufactured by Wako Pure Chemical Industries, Ltd.). The solution was filtered through a 2 μm filter to prepare a coating solution. Next, the coating solution was coated on the hole transport layer by a spin coating method under the conditions of a rotation speed of 3000 rpm and a coating time of 30 seconds. After the application, it was dried at room temperature (25 ° C.) for 30 minutes to form a light emitting layer. The film thickness of the obtained light emitting layer was about 50 nm.

Next, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (manufactured by Sigma-Aldrich, sublimation purified product, purity 99.99%) and Alq3 (manufactured by Tokyo Chemical Industry Co., Ltd.) are formed on the light emitting layer. , Sublimation refined product, purity 98%) under reduced pressure of 8.5 × 10 ⁻⁵ Pa by resistance heating vapor deposition method to a film thickness of 20 nm and 30 nm respectively at a rate of 0.2 nm / sec. An electron transport layer was formed. Next, barium and aluminum were co-evaporated at a weight ratio of 1:10 under a reduced pressure of 8.5 × 10 ⁻⁵ Pa, and a cathode having a width of 3 mm was striped in a shape of 2 so as to be orthogonal to the extending direction of the anode. The book was formed. The film thickness of the obtained cathode was about 50 nm.

  Finally, in an argon atmosphere, lead wires (wirings) were attached to the anode and the cathode to produce four organic light emitting elements having a length of 4 mm and a width of 3 mm. A voltage was applied to the organic EL element to emit light using a programmable DC voltage / current source (TR6143, manufactured by Advantest Corporation).

The light emitting external quantum efficiency of the produced organic light emitting device was 8.6%.
[Example 2]
An organic light emitting device was produced in the same manner as in Reference Example 1 except that the copolymer (1-2) was used instead of the reference copolymer (1-1). The light-emitting external quantum efficiency of the produced organic light-emitting device was 9.9%.

[Comparative Example 1]
An organic light emitting device was produced in the same manner as in Reference Example 1 except that the copolymer (C1-1) was used instead of the reference copolymer (1-1). The produced organic light emitting device had a light emission external quantum efficiency of 6.5%.

[Comparative Example 2]
An organic light emitting device was produced in the same manner as in Reference Example 1 except that the copolymer (C1-2) was used instead of the reference copolymer (1-1). The produced organic light emitting device had a light emission external quantum efficiency of 5.5%.

  Specifically, the organic light-emitting device of the present invention is suitably used for displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, reading light sources, signs, signboards, interiors, optical communications, and the like.

Claims (2)

An organic light emitting device having a pair of electrodes and one or more organic compound layers including a light emitting layer and emitting light by applying a voltage between the pair of electrodes, wherein the light emitting layer has a hole transport property and an electron. A charge transporting polymer having a transporting property and a light-emitting compound, wherein the charge transporting polymer is composed of repeating units represented by the following formulas (1) to (3), and the repeating unit represented by the formula (1): When the number is x, the number of repeating units represented by formula (2) is y, and the number of repeating units represented by formula (3) is z, x, y and z are 1 or more, and z is An organic light emitting device characterized by being 4 to 200 times the sum of x and y.

In the above formula (1), Ar ¹ and Ar ² are each independently a phenyl group, or represents a diarylamino phenyl group, the phenyl group, or diaryl amino phenyl group, selected from alkyl and alkoxy groups which may have a substituent that is not good.

In the above formula (2), A represents a triarylborane derivative .

The organic light emitting device according to claim 1, wherein the light emitting layer contains a phosphorescent compound .