JP2007335696A - Organic electric field light-emitting element, method of manufacturing the same, and image display medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electric field light-emitting element which has sufficient luminance, whose light-emitting efficiency is high, whose life is long, and which is easily manufactured, and to provide a method of manufacturing the same, and an image display medium. <P>SOLUTION: An organic electric field light-emitting element comprises a pair of electrodes comprising a positive pole and a negative pole at least one of which is transparent or translucent, and one or a plurality of organic compound layers held between the pair of electrodes. In the element, at least one layer of the organic compound layers contains at least one kind of charge transportive polyester composed of a repeating unit comprising at least one kind selected from a structure shown by a general formula (I-1) as a partial structure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent element that emits light by converting electric energy into light, a method for manufacturing the same, and an image display medium. Specifically, the display element, electronic paper, a backlight, an illumination light source, an electrophotographic exposure apparatus, a sign, The present invention relates to an organic electroluminescent element that can be suitably used in a field such as a signboard, a manufacturing method thereof, and an image display medium.

  An electroluminescent element is a self-luminous all-solid-state element, has high visibility and is resistant to impact, and thus is widely expected to be applied. Currently, those using inorganic phosphors are the mainstream and widely used. However, since driving requires an AC voltage of 200 V or higher and 50 to 1000 Hz, the running cost is high and the luminance is insufficient. Has a problem. On the other hand, research on electroluminescent devices using organic compounds first started with a single crystal such as anthracene, but the film thickness was as thick as about 1 mm and a driving voltage of 100 V or more was required. For this reason, attempts have been made to reduce the thickness by vapor deposition (see, for example, Non-Patent Document 1).

  The light emission of these elements is such that electrons are injected from one of the electrodes and holes are injected from the other electrode, so that the light emitting material in the element is excited to a high energy level, and the excited illuminant becomes the base. This is a phenomenon in which excess energy for returning to the state is emitted as light. However, the driving voltage is still as high as 30 V, the density of electron / hole carriers in the film is low, and the photon generation probability due to carrier recombination is low, so that sufficient luminance cannot be obtained, leading to practical use. There wasn't.

However, in 1987, Tang et al., A functionally separated organic electric field in which a hole transporting organic low molecular weight compound and a fluorescent organic low molecular weight compound having an electron transporting ability were sequentially stacked on a transparent substrate by a vacuum deposition method. A light-emitting element having a high luminance of 1000 cd / m ² or more at a low voltage of about 10 V has been reported (for example, see Patent Document 1 or Non-Patent Document 2). Since then, research and development of organic electroluminescent elements has been conducted. It is active.

  These electroluminescent devices with a stacked structure are structures in which an organic light emitter and a charge transporting organic substance (charge transport material) are stacked on an electrode, and each hole and electron move through the charge transport material and recombine. Emits light. As the organic light emitter, an organic dye emitting fluorescence such as 8-quinolinol aluminum complex or coumarin compound is used. Examples of the charge transport material include diamino compounds such as N, N-di (m-tolyl) N, N′-diphenylbenzidine and 1,1-bis [N, N-di (p-tolyl) aminophenyl] cyclohexane, 4- (N, N-diphenyl) aminobenzaldehyde-N, N-diphenylhydrazone compound and the like.

Organic electroluminescent devices using these organic compounds have high emission characteristics, but have problems in thermal stability and storage stability during light emission. A layer formed of an organic material of an electroluminescent element is very thin, tens to hundreds of nanometers, and a voltage applied per unit thickness is very high, and is driven at a high current density of several mA / cm ^2. Therefore, a large amount of Joule heat is generated. For this reason, hole transporting low molecular weight compounds and fluorescent organic low molecular weight compounds formed in an amorphous glass state by vapor deposition gradually crystallize as the temperature rises and finally melt, resulting in a decrease in luminance and dielectric breakdown. Many phenomena were observed, and as a result, the lifetime of the device was reduced. This low thermal stability is believed to be due to the low glass transition temperature of the material. That is, many low molecular weight compounds have low melting points and high symmetry.

  Therefore, in order to solve the problems related to thermal stability, N, N-di (1-naphthyl) N, N′— introduced with an α-naphthyl group that improves the glass transition temperature and obtains a stable amorphous glass state. An organic electroluminescent device using diphenylbenzidine (for example, see Non-Patent Document 3) and starburst amine (for example, see Non-Patent Document 4) has been reported.

  However, since these materials alone have an energy barrier due to the ionization potential of the hole transport material, they do not satisfy the hole injection property from the anode or the hole injection property to the light emitting layer. Furthermore, in the two-layered element structure of the hole transport layer and the light emitting layer, an interdiffusion phenomenon occurs and the light emission efficiency is lowered. Also, during device fabrication, considerable heat is applied during fabrication processes such as vapor deposition, baking, annealing, wiring, and sealing, and thermal stability is ensured enough to withstand changes over time due to prolonged use. Therefore, improvement of the glass transition temperature in a further material is desired.

  On the other hand, research and development have also been conducted on electroluminescent devices using polymer materials instead of low molecular compounds, and conductive polymer devices such as poly (p-phenylene vinylene) (for example, Patent Document 2 or Non-Patent Document 5). Reference), a polymer device in which triphenylamine is introduced into the side chain of polyphosphazene (see, for example, Non-Patent Document 6), a device in which an electron transport material and a fluorescent dye are mixed in hole transporting polyvinyl carbazole (for example, Non-Patent Document 7) has been proposed.

  Although these have a relatively high glass transition point compared to low molecular weight compounds, poly (p-phenylene vinylene) is heat-treated after spin coating of a soluble precursor, so that defects occur in the main chain conjugated polymer. Easily reduces the light emission characteristics. Phosphazene has a problem that the ionization potential is high and the charge injection characteristic is lowered. Polyvinylcarbazole has a high glass transition point, but when trapped by impurities or when a low molecular weight compound is mixed into a polymer, the low molecular weight acts as a plasticizer, and the brightness and luminous efficiency are still low. It does not reach the laminated type field emission device using a compound.

In addition, as a manufacturing method, a coating method is desirable from the viewpoint of simplification of manufacturing, workability, large area, cost, and the like, and it has been reported that an element can be obtained by a casting method (for example, Non-Patent Document 8). And 9). However, since the charge transport material has poor solubility and compatibility with solvents and resins, it is easy to crystallize and has defects in production or characteristics.
JP 59-194393 A Japanese Patent Laid-Open No. 10-92576 Thin Solid Films, 94, 171 (1982) Appl. Phys. Lett. , 51, 913 (1987) IEICE technical report, OME95-54 (1995) Proceedings of the 40th Joint Conference on Applied Physics 30a-SZK-14 (1993) Nature, 357, 477 (1992) 42nd Polymer Symposium Proceedings 20J21 (1993) Proceedings of the 38th Joint Conference on Applied Physics 31p-G-12 (1991) Proceedings of the 50th Japan Society of Applied Physics, 29p-ZP-5 (1989) Proceedings of the 51st Japan Society of Applied Physics, 28a-PB-7 (1990)

  The present invention has been made in view of the above-described problems in the prior art, and an object thereof is to achieve the following objects. That is, an object of the present invention is to provide an organic electroluminescence device having a high light emission intensity, a high light emission efficiency, a long device life, and an easy production, and an image display medium.

As a result of intensive studies on charge transporting polymers to achieve the above-mentioned object, specific charge transporting polyesters are suitable for organic electroluminescence devices, in addition to charge injection characteristics, charge mobility, thin film forming ability, and light emission characteristics, It has been found that it has thermal stability and storage stability, and the present invention has been completed.
That is, the present invention
<1>
A pair of electrodes composed of an anode and a cathode, at least one of which is transparent or translucent, and one or a plurality of organic compound layers sandwiched between the pair of electrodes,
At least one of the organic compound layers contains at least one charge transporting polyester composed of a repeating unit containing at least one selected from the structure represented by the following general formula (I-1) as a partial structure. An organic electroluminescent element.

(In General Formula (I-1), R ₁ and R ₂ are each independently hydrogen, a substituted or unsubstituted monovalent linear hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted ring number. 3-10 monovalent cyclic hydrocarbon group, substituted or unsubstituted monovalent branched hydrocarbon group having 3 to 20 carbon atoms, substituted or unsubstituted monovalent straight chain having 1 to 20 carbon atoms Perfluoroalkyl group, substituted or unsubstituted monovalent cyclic perfluoroalkyl group having 3 to 10 rings, substituted or unsubstituted monovalent branched chain perfluoroalkyl group having 3 to 20 carbon atoms, substituted Or an unsubstituted monovalent phenyl group, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic rings, a substituted or unsubstituted monovalent condensed aromatic carbon having 2 to 10 aromatic rings Represents hydrogen or a substituted or unsubstituted monovalent aromatic heterocycle; One or more CH ₂ in the alkyl group O, CO, or replaced by NH. Also, one or more CF ₂ in the perfluorooctanol alkyl group _CH 2, O, CO, or replaced with NH T represents a divalent linear hydrocarbon group having 1 to 10 carbon atoms or a divalent branched hydrocarbon group having 2 to 10 carbon atoms, a is an integer of 1 to 4, and b is 0. Represents ~ 3)

<2>
The organic compound layer includes at least a light emitting layer and at least one layer of an electron transport layer and an electron injection layer, and at least one layer selected from the light emitting layer, the electron transport layer and the electron injection layer has the general formula The organic electroluminescence according to <1>, comprising at least one charge transporting polyester comprising a repeating unit containing at least one selected from the structure represented by (I-1) as a partial structure. element.

<3>
The organic compound layer includes at least a light emitting layer and at least one layer of a hole transport layer and a hole injection layer, and at least one layer selected from the light emitting layer, the hole transport layer and the hole injection layer is <1> characterized by containing at least one charge transporting polyester comprising a repeating unit containing at least one selected from the structure represented by the general formula (I-1) as a partial structure. Organic electroluminescent element.

<4>
The organic compound layer includes at least a light emitting layer, at least one layer of a hole transport layer and a hole injection layer, and at least one layer of an electron transport layer and an electron injection layer, and the light emitting layer and the hole transport layer , At least one layer selected from a hole injection layer, an electron transport layer, and an electron injection layer is composed of a repeating unit containing at least one selected from the structure represented by the general formula (I-1) as a partial structure The organic electroluminescent element according to <1>, which contains at least one kind of charge transporting polyester.

<5>
The organic compound layer is composed only of a light emitting layer having a charge transport function, and the light emitting layer having the charge transport function is a partial structure of at least one selected from the structure represented by the general formula (I-1) The organic electroluminescent element according to <1>, comprising at least one kind of charge transporting polyester comprising repeating units contained as

<6>
A charge transporting polyester comprising a repeating unit containing at least one selected from the structure represented by the general formula (I-1) as a partial structure is represented by the following general formula (II-1) or (II-2). <1> The organic electroluminescent device according to <1>, wherein the organic electroluminescent device is a charge transporting polyester.

(In the general formulas (II-1) and (II-2), A ₁ represents at least one selected from the structure represented by the general formula (I-1), and Y ₁ represents a divalent alcohol residue. Represents a group, Z ₁ represents a divalent carboxylic acid residue, m represents an integer of 1 to 5, R ₃ represents —O— (Y ₁ —O) m—H, or a group —O— ( Y ₁ —O) group represented by m—CO—Z ₁ —CO—OR ′ (provided that Y ₁ , Z ₁ and m have the same meaning as described above, R ′ represents a hydrogen atom, an alkyl group, Represents a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group), m represents an integer of 1 to 5, and p represents an integer of 5 to 5000.

<7>
An organic electroluminescent element according to <1> is arranged in at least one of a matrix and a segment shape.

<8>
<1> A method for producing an organic electroluminescent device according to <1>, wherein at least a coating step in which a coating solution prepared by dissolving the constituent components of the organic compound layer in a solvent is applied by an inkjet method. A method for producing an organic electroluminescent element, comprising:

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element which is large in luminescence intensity, has high luminous efficiency, has a long element lifetime, and is easy to manufacture, its manufacturing method, and an image display medium can be provided.

<Organic electroluminescent device and manufacturing method thereof>
The organic electroluminescence device of the present invention (hereinafter sometimes referred to as “organic EL device”) includes a pair of electrodes composed of an anode and a cathode, at least one of which is transparent or translucent, and a sandwiched between the pair of electrodes. One or more organic compound layers, and at least one of the organic compound layers includes at least one selected from the structure represented by the following general formula (I-1) as a partial structure. It contains the charge transport polyester which has these.

  The charge transporting polyester in the present invention has thermal stability and storage stability during light emission, in addition to charge injection characteristics, charge mobility, thin film forming ability, and light emission characteristics suitable for organic electroluminescent devices. Therefore, in the organic electroluminescent device of the present invention, since at least one of the organic compound layers contains the charge transporting polyester, the emission intensity is high, the emission efficiency is high, and the device lifetime is long.

  Further, by using the charge transporting polyester, it is possible to increase the area and to easily manufacture the polyester. In addition, since the charge transporting polyester is excellent in solubility and compatibility with solvents and resins, it is possible to realize higher manufacturability.

  Moreover, since the charge transporting polyester can impart both functions of hole transporting ability and electron transporting ability by appropriately selecting the structure described later, a hole transporting layer and a light emitting layer are used depending on the purpose. And any layer such as an electron transport layer. Further, since the charge transporting polyester in the present invention has good charge injection from ITO used as an electrode and high electrical conductivity, the organic electroluminescence device of the present invention can obtain desired characteristics.

  Hereinafter, in describing the present invention in detail, the charge transporting polyester in the present invention will be described in detail.

(Charge transporting polyester)
The said polyester has a repeating unit which contains at least 1 sort (s) selected from the structure shown by the following general formula (I-1) as a partial structure.

(In General Formula (I-1), R ₁ and R ₂ are each independently hydrogen, a substituted or unsubstituted monovalent linear hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted ring number. 3 to 20 monovalent cyclic hydrocarbon group, substituted or unsubstituted monovalent branched hydrocarbon group having 3 to 10 carbon atoms, substituted or unsubstituted monovalent straight chain having 1 to 20 carbon atoms Perfluoroalkyl group, substituted or unsubstituted monovalent cyclic perfluoroalkyl group having 3 to 10 rings, substituted or unsubstituted monovalent branched chain perfluoroalkyl group having 3 to 20 carbon atoms, substituted Or an unsubstituted monovalent phenyl group, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic rings, a substituted or unsubstituted monovalent condensed aromatic carbon having 2 to 10 aromatic rings Represents hydrogen or a substituted or unsubstituted monovalent aromatic heterocycle; One or more CH ₂ in the alkyl group O, CO, or replaced by NH. Also, one or more CF ₂ in the perfluorooctanol alkyl group _CH 2, O, CO, or replaced with NH T represents a divalent linear hydrocarbon group having 1 to 10 carbon atoms or a divalent branched hydrocarbon group having 2 to 10 carbon atoms, a is an integer of 1 to 4, and b is 0. Represents ~ 3)

In general formula (I-1), the number of carbon atoms constituting the linear hydrocarbon group selected as the structure representing R ₁ and R ₂ and the linear perfluoroalkyl group is 1 to 20, Preferably, it is 1-10, More preferably, it is 1-6.

In the general formula (I-1), the number of carbon atoms constituting the branched chain hydrocarbon group, and branched perfluorooctanol alkyl groups selected as structures representing R ₁ and R ₂ is a 3-20 However, Preferably it is 3-10, More preferably, it is 3-5.

In general formula (I-1), the number of carbon atoms constituting the cyclic hydrocarbon group selected as the structure representing R ₁ and R ₂ and the cyclic perfluoroalkyl group is 3 to 10, preferably 3 ~ 6.

In general formula (I-1), the number of aromatic rings constituting the polynuclear aromatic hydrocarbon and the condensed aromatic hydrocarbon selected as the structure representing R ₁ and R ₂ is ₂ to 10, but the condensed aromatic Among the group hydrocarbons, those of 1 to 5 are preferable.

  In the present invention, the polynuclear aromatic hydrocarbon, condensed aromatic hydrocarbon and aromatic heterocycle specifically mean a polycyclic aromatic as defined below.

  That is, the “polynuclear aromatic hydrocarbon” represents a hydrocarbon in which two or more aromatic rings composed of carbon and hydrogen are present, and the rings are bonded by a carbon-carbon bond. Specific examples include biphenyl and terphenyl.

  “Condensed aromatic hydrocarbon” means a hydrocarbon compound in which two or more aromatic rings composed of carbon and hydrogen are present, and these aromatic rings share a pair of adjacently bonded carbon atoms. Represents. Specific examples include naphthalene, anthracene, pyrene, phenanthrene, perylene, and fluorene.

  “Aromatic heterocycle” refers to an aromatic ring containing elements other than carbon and hydrogen. Both those in which the aromatic ring is substituted with a heterocyclic ring and those in which the heterocyclic ring is substituted with an aromatic ring are included. In the heterocyclic ring, the number of atoms (Nr) constituting the ring skeleton is preferably Nr = 5 and / or 6. Further, the type and number of atoms (heterogeneous atoms) other than carbon atoms constituting the ring skeleton are not particularly limited. For example, a sulfur atom, a nitrogen atom, an oxygen atom and the like are preferably used, and two types are included in the ring skeleton. The above and / or two or more different atoms may be contained. In particular, as a heterocyclic ring having a 5-membered ring structure, thiophene, pyrrole and furan, or a heterocyclic ring in which the 3- and 4-position carbons of the compound are replaced with nitrogen are preferably used. Pyridine is preferably used. Examples of the aromatic ring include polynuclear aromatic hydrocarbons and condensed aromatic hydrocarbons in addition to phenyl groups.

  These may be either all composed of a conjugated system or partly composed of a conjugated system, but all are composed of a conjugated system in terms of charge transportability and luminous efficiency. preferable.

In the general formula (I-1), examples of the substituent that can be substituted for each group selected as a structure representing R ₁ and R ₂ include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, and a substituted amino group. And halogen atoms. As said alkyl group, a C1-C10 thing is preferable, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group etc. are mentioned. As said alkoxyl group, a C1-C10 thing is preferable, for example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group etc. are mentioned. As said aryl group, a C6-C20 thing is preferable, for example, a phenyl group, a toluyl group etc. are mentioned, As said aralkyl group, a C7-C20 thing is preferable, for example, a benzyl group, a phenethyl, etc. Groups and the like. Examples of the substituent of the substituted amino group include an alkyl group, an aryl group, an aralkyl group and the like, and specific examples are as described above.

Among these, in order to further improve the solubility and compatibility with respect to a solvent or a resin, R ₁ and R ₂ preferably represent an alkyl group, an alkoxy group, an aryl group, or the like.

  In general formula (I-1), a represents an integer of 1 to 4, and preferably 2 to 3 from the viewpoint of electrical characteristics. Although b shows the integer of 0-3, 1-2 are preferable from the point which improves a glass transition temperature and implement | achieves higher thermal stability. In particular, a = 2 and b = 1 in order to improve the charge injection characteristics, charge mobility, thin film forming ability, light emission characteristics, thermal stability during light emission, and storage stability in a well-balanced manner. It is preferable that

  In general formula (I-1), T represents a C1-C6 bivalent linear hydrocarbon group or a C2-C10 bivalent branched hydrocarbon group, preferably carbon. The number is selected from a divalent linear hydrocarbon group having 2 to 6 carbon atoms and a divalent branched hydrocarbon group having 3 to 7 carbon atoms. Among these, more specifically, the divalent hydrocarbon groups shown below are particularly preferable.

Here, specific examples of the structure represented by the general formula (I-1) are shown below. Incidentally, in the table A ₁ in the general formula (I-1), shows the interposed at the two T.

  The charge transporting polyester having a repeating structure containing at least one selected from the structure represented by the general formula (I-1) as a partial structure is represented by the following general formulas (II-1) and (II-2). Are preferably used.

(In the general formulas (II-1) and (II-2), A ₁ represents at least one selected from the structure represented by the general formula (I-1), and Y ₁ represents a divalent alcohol residue. Represents a group, Z ₁ represents a divalent carboxylic acid residue, m represents an integer of 1 to 5, R ₃ represents —O— (Y ₁ —O) m—H, or a group —O— ( Y ₁ —O) group represented by m—CO—Z ₁ —CO—OR ′ (provided that Y ₁ , Z ₁ and m have the same meaning as described above, R ′ represents a hydrogen atom, an alkyl group, Represents a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group), and p represents an integer of 5 to 5,000.

In the general formulas (II-1) and (II-2), A ₁ represents at least one selected from the structure represented by the general formula (I-1), and the general formulas (II-1) and (II-1) The plurality of A ₁ present in the charge transporting polyester represented by II-2) may have the same structure or different structures.

In general formulas (II-1) and (II-2), examples of Y ₁ and Z ₁ include groups selected from the following formulas (1) to (6).

Here, in the formula, R ₄ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, or a halogen atom. (The specific examples are as described above, and the substituents capable of substituting each group are the same as the above-described substituents). c and d are each an integer of 1 to 10, e and g are each 0 or 1, f is an integer of 0 to 6, and V is selected from the following (7) to (17) Group.

Here, in the formula, h and i each represent an integer of 1 to 10. R ₄ has the same meaning as above.

Hereinafter, although the specific example of said polyester shown by general formula (II-1) and (II-2) is shown, this invention is not limited to these specific examples.
In the following table, the number of columns A ₁ monomer column corresponds to the structure number of specific examples of the structure represented by the general formula (I-1). In addition, those in which the column of Z ₁ is “−” show specific examples of the charge transporting polyester represented by the general formula (II-1), and the others are the charge transporting polyesters represented by the general formula (II-2). A specific example is shown. In addition, regarding each specific example of the charge transporting polyester given the compound number in the following table, for example, the specific example given the number 15 is referred to as “Exemplary Compound (15)”. The terminal group R ₃ is a group represented by —O— (Y ₁ —O) m—H or a group —O— (Y ₁ —O) m—CO—Z ₁ —CO—OR ′ ( Y ₁ , Z ₁ and m have the same meaning as described above, and R ′ represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group (specific examples) Is as described above, and the substituents capable of substituting each group are the same as those described above.

The charge transporting polyester preferably has a weight average molecular weight Mw in the range of 5,000 to 300,000. The glass transition point (Tg) of the charge transporting polyester is preferably 60 ° C. or higher.
The weight average molecular weight Mw can be measured by the following method. That is, the weight average molecular weight was prepared by preparing a 1.0 mass% THF solution of a charge transporting polyester, and using a differential refractive index detector (RI) and gel permeation chromatography (GPC), using a styrene polymer as a standard sample. Measured.
The glass transition point is determined by using a differential scanning calorimeter with α-Al ₂ O ₃ as a reference. The sample is heated to a rubber state, immersed in liquid nitrogen and rapidly cooled, and then the rate of temperature increase is 10 ° C./min. The temperature can be measured under conditions.

Hereinafter, a method for synthesizing the charge transporting polyester will be described.
The method for synthesizing the charge transporting polyester can be used in combination with known methods depending on the desired structure, and is not particularly limited, but as a specific example, it is represented by the general formula (I-1). The case where the charge transporting polyester comprising a repeating unit containing at least one selected from the structure as a partial structure is a polyester as represented by the general formula (II-1) or (II-2) is as follows: This will be described in detail.

  When the charge transporting polyester is a charge transporting polyester as represented by the general formula (II-1) or (II-2), the monomer represented by the following general formula (I-2) is, for example, And can be synthesized by polymerization by a known method described in the 4th edition, Experimental Chemistry Course Vol. 28 (Maruzen, 1992).

In General Formula (I-2), A ₁ represents at least one selected from the structure represented by General Formula (I-1), and A ′ represents a hydroxyl group, a halogen atom, or a group —O. represents -R _5, R ₅ is an alkyl group, a substituted or unsubstituted aryl group, or an aralkyl group.

  Specifically, the monomer represented by the general formula (I-2) can be synthesized as follows, for example.

First, a thiophene having a halogen compound at positions 3 and 4 is reacted with an alkyl halide (perfluoroalkyl halogen or alkylmagnesium bromide) (reference: J. Org. Chem., 62, 7128 (1997), J. Fluorine. Chem., 27, 291 (1985), Tetrahedron, 38, 3347 (1982)). Subsequently, the 2- and 3-positions are halogenated to obtain monohalogenthiophene and dihalogenthiophene (reference: Bull. Chem. Soc. Jpn., 64, 2566 (1991), Chem. Mater., 6, 401 (1994). )). Using these compounds, multimeric thiophenes were obtained (reference documents: J. Am. Chem. Soc., 117, 233 (1995), Chem. Mater., 6, 401 (1994)). Get the body. These and a catalyst such as acrylic acid ester and palladium complex can be obtained _{A 1} is reacted (reference:. J.Am.Chem.Soc, 121,2123 (1995) , 4th edition Jikken Kagaku Koza Vol. 25 396 (Maruzen, 1992)).

  In addition, the monomer represented by the general formula (I-2) can be obtained by reacting a halogenated carboalkoxyalkylbenzene with thiophene diboronic acid. In addition, the dihalogenated thiophene and methyl 3- [4, (4,4,5,5-tetramethyl- [1,3,2] dioxyborolane) -phenyl] propinate and 3- (4-dihydroxyborolylphenyl) The monomer represented by the general formula (I-2) can also be obtained by reacting with propionic acid (reference: J. Organometallic Chem., 657, 129 (2002). The obtained compound is subjected to silica gel column chromatography. The method for synthesizing the monomer represented by the general formula (I-2) is not limited thereto.

  Using the monomer represented by the general formula (I-2), the charge transporting polyester can be synthesized as follows.

When A ′ is a hydroxyl group, HO— (Y ₁ —O) _m —H (Y ₁ , m is synonymous with Y ₁ and m in formulas (II-1) and (II-2), The same applies to the dihydric alcohol represented by the formula (1)), and polymerization is carried out using an acid catalyst. As the acid catalyst, those used for usual esterification reaction such as sulfuric acid, toluenesulfonic acid, trifluoroacetic acid and the like can be used, and 1 / 10,000 to 1/10 parts by weight, preferably 1 part by weight of monomer. It is used in the range of 1/1000 to 1/50 parts by weight. In order to remove water generated during polymerization, it is preferable to use a solvent azeotropic with water, and toluene, chlorobenzene, 1-chloronaphthalene and the like are effective, and 1 to 100 parts by weight per 1 part by weight of the monomer. It is used in the range of parts by weight, preferably 2 to 50 parts by weight. The reaction temperature can be arbitrarily set, but it is preferable to carry out the reaction at the boiling point of the solvent in order to remove water generated during the polymerization.

  When the solvent is not used after completion of the reaction, it is dissolved in a soluble solvent. When a solvent is used, the reaction solution is dropped as it is in a poor solvent in which alcohols such as methanol and ethanol and polymers such as acetone are difficult to dissolve, to precipitate the polyester, and after separating the polyester, Wash thoroughly with organic solvent and dry. Further, if necessary, the reprecipitation treatment in which the polyester is precipitated by dissolving in an appropriate organic solvent and dropping in a poor solvent may be repeated. The reprecipitation treatment is preferably carried out with efficient stirring with a mechanical stirrer or the like. The solvent for dissolving the polyester during the reprecipitation treatment is used in the range of 1 to 100 parts by weight, preferably 2 to 50 parts by weight, with respect to 1 part by weight of the polyester. The poor solvent is used in an amount of 1 to 1,000 parts by weight, preferably 10 to 500 parts by weight, based on 1 part by weight of the polyester.

When A ′ is —O—R _5, an excessive amount of a dihydric alcohol represented by HO— (Y ₁ —O) _m —H is added to the monomer, and then an inorganic acid such as sulfuric acid or phosphoric acid, a titanium alkoxide, or the like. It can be synthesized by transesterification by heating using acetate or carbonate such as calcium and cobalt, oxide of zinc or lead as a catalyst. The dihydric alcohol is used in the range of 2 to 100 equivalents, preferably 3 to 50 equivalents, with respect to 1 equivalent of the monomer. The catalyst is used in the range of 1 / 10,000 to 1 part by weight, preferably 1 / 1,000 to 1/2 part by weight, based on 1 part by weight of the monomer. The reaction is carried out at a reaction temperature of 200 to 300 ° C. After completion of transesterification from the group —O—R ₅ to the group —O— (Y ₁ —O) _m —H, HO— (Y ₁ —O) _m —. In order to promote polymerization due to elimination of H, the reaction is preferably performed under reduced pressure. Also, HO- (Y ₁ -O) _m —H is removed azeotropically under normal pressure using a high boiling point solvent such as 1-chloronaphthalene that can be azeotroped with HO— (Y ₁ —O) _m —H. Can also be reacted.

In addition, a charge transporting polyester can be synthesized as follows. In each of the above cases, a compound represented by the following general formula (I-3) was formed by adding an excess of dihydric alcohols and reacting, and then the compound was represented by the above general formula (I-2). It can be used in place of a monomer and reacted with a divalent carboxylic acid or a divalent carboxylic acid halide in the same manner as described above (when A ′ is —O—R ₅ ), thereby obtaining a polyester. Can do.

However, in General Formula (I-3), A ₁ represents at least one selected from the structure represented by General Formula (I-1), Y ₁ represents a divalent alcohol residue, m Represents an integer of 1 to 5.

  Further, any molecule may be introduced into the terminal of the charge transporting polyester. In that case, the following method is mentioned. That is, when A ′ of the monomer represented by the general formula (I-2) is a hydroxyl group, a monocarboxylic acid as a terminal-introducing compound is copolymerized, or the compound after the polymerization reaction of the polymer is charged and reacted. Can be introduced.

When A ′ is halogen, the monoacid chloride of the terminally introduced compound can be copolymerized, or after the polymerization reaction of the polymer, the monoacid chloride of the terminally introduced compound can be charged and reacted for introduction. When A ′ is —O—R ₅ , the monoester of the terminally introduced compound can be copolymerized, or after the polymerization reaction of the polymer, the monoester of the terminally introduced compound can be charged and reacted for introduction.

Next, the structure of the organic electroluminescent element of the present invention will be described in detail.
The organic electroluminescent element of the present invention comprises a pair of electrodes, at least one of which is transparent or translucent, and one or a plurality of organic compound layers sandwiched between the electrodes, and is formed on at least one layer of the organic compound layers. The layer structure is not particularly limited as long as it contains at least one kind of charge transporting polyester as described above.

  In the organic electroluminescent element of the present invention, when there is one organic compound layer, the organic compound layer means a light emitting layer having charge transporting ability, and the light emitting layer contains the charge transporting polyester. On the other hand, in the case where there are a plurality of organic compound layers (that is, in the case of a function separation type in which each layer has a different function), at least one of the layers is a light emitting layer, Also good. In this case, the following (1) to (3) can be given as specific examples of the layer structure composed of the light emitting layer or the light emitting layer having the charge transporting capability and other layers.

(1) A layer configuration including a light emitting layer and at least one of an electron transport layer and an electron injection layer.
(2) A layer configuration including at least one of a hole transport layer and a hole injection layer, a light emitting layer, and at least one layer of an electron transport layer and an electron injection layer.
(3) A layer structure formed of at least one of a hole transport layer and a hole injection layer and a light emitting layer.

  The layers other than the light-emitting layer and the light-emitting layer having the charge transport ability of the layer structures (1) to (3) have a function as a charge transport layer or a charge injection layer.

  In any of the layer configurations (1) to (3), it is sufficient that the charge transporting polyester is contained in any one layer.

  In the organic electroluminescent device of the present invention, the light-emitting layer, the hole transport layer, the hole injection layer, the electron transport layer, and the electron injection layer are formed of a charge transport compound other than the charge transport polyester (hole transport material, An electron transport material) may be further included. Details of such a charge transporting compound will be described later.

Hereinafter, although it demonstrates in detail, referring drawings, this invention is not necessarily limited to these.
1 to 4 are schematic cross-sectional views for explaining the layer structure of the organic electroluminescent element of the present invention. In the case of FIGS. 1, 2, and 3, the case where there are a plurality of organic compound layers is shown. FIG. 4 shows an example in which the number of organic compound layers is one. In FIG. 1 to FIG. 4, components having similar functions are described with the same reference numerals.

  The organic electroluminescent element shown in FIG. 1 is obtained by sequentially laminating a transparent electrode 2, a light emitting layer 4, at least one layer 5 of an electron transport layer and an electron injection layer, and a back electrode 7 on a transparent insulator substrate 1, This corresponds to the layer structure (1). However, when the layer denoted by reference numeral 5 is composed of an electron transport layer and an electron injection layer, the electron transport layer, the electron injection layer, and the back electrode 7 are laminated in this order on the back electrode 7 side of the light emitting layer 4. .

  The organic electroluminescent device shown in FIG. 2 has a transparent electrode 2, at least one layer 3 of a hole transport layer and a hole injection layer, at least one layer of a light emitting layer 4, an electron transport layer and an electron injection layer on a transparent insulator substrate 1. The first layer 5 and the back electrode 7 are sequentially laminated and correspond to the layer configuration (2). However, when the layer denoted by reference numeral 3 is composed of a hole transport layer and a hole injection layer, the hole injection layer, the hole transport layer, and the light emitting layer 4 are provided on the back electrode 7 side of the transparent electrode 2. Laminated sequentially. When the layer denoted by reference numeral 5 is composed of an electron transport layer and an electron injection layer, the electron transport layer, the electron injection layer, and the back electrode 7 are laminated in this order on the back electrode 7 side of the light emitting layer 4. .

  The organic electroluminescent element shown in FIG. 3 is obtained by sequentially laminating a transparent electrode 2, at least one layer 3 of a hole transport layer and a hole injection layer, a light emitting layer 4 and a back electrode 7 on a transparent insulator substrate 1. This corresponds to the layer structure (3). However, when the layer indicated by reference numeral 3 is composed of a hole transport layer and a hole injection layer, the hole injection layer, the hole transport layer, and the light emitting layer 4 are provided on the back electrode 7 side of the transparent electrode 2. They are stacked in this order.

The organic electroluminescent element shown in FIG. 4 is obtained by sequentially laminating a transparent electrode 2, a light emitting layer 6 having a charge transporting capability, and a back electrode 7 on a transparent insulator substrate 1.
When the top emission structure or the cathode / anode is made to be a transmission type using a transparent electrode, it is also possible to have a structure in which the layer structure of FIGS.

Each will be described in detail below.
In the case of the layer configuration of the organic electroluminescent element shown in FIGS. 1 to 4, the transparent insulator substrate 1 is preferably transparent in order to extract emitted light, and glass, plastic film or the like is used. The term “transparent” means that the light transmittance in the visible region is 10% or more, and the transmittance is preferably 75% or more. The transparent electrode 2 is transparent in order to extract emitted light in the same manner as the transparent insulator substrate, and has a high work function for injecting holes, and preferably has a work function of 4 eV or more.
As specific examples, oxide films such as indium tin oxide (ITO), tin oxide (NESA), indium oxide, zinc oxide, indium zinc oxide, and gold, platinum, palladium, or the like deposited or sputtered are used. The sheet resistance of the electrode is desirably as low as possible, preferably several hundred Ω / □ or less, and more preferably 100 Ω / □ or less. Further, like the transparent insulator substrate, it is preferable that the light transmittance in the visible region is 10% or more, and the transmittance is 75% or more.

  Further, for the purpose of improving the durability of the organic electroluminescent device or improving the luminous efficiency, hole transport other than the charge transporting polyester for adjusting the hole mobility with respect to the charge transporting polyester used in the present invention. The material may be formed by mixing and dispersing the material in the range of 0.1 mass% to 50 mass%. Examples of such hole transporting materials include tetraphenylenediamine derivatives, triphenylamine derivatives, carbazole derivatives, stilbene derivatives, aryl hydrazone derivatives, and porphyrin compounds, but they have good compatibility with charge transporting polyesters. , Tetraphenylenediamine derivatives and triphenylamine derivatives are preferred.

Similarly, when adjusting the electron mobility, the electron transport material may be mixed and dispersed in the range of 0.1% by mass to 50% by mass with respect to the charge transporting polyester. Such electron transport materials include oxadiazole derivatives, nitro-substituted fluorenone derivatives, diphenoquinone derivatives, thiopyran dioxide oxide derivatives, silole derivatives, chelate-type organometallic complexes, polynuclear or condensed aromatic ring compounds, perylene derivatives, triazole derivatives, full Examples include olenylidene methane derivatives.
Further, when both the hole mobility and the electron mobility need to be adjusted, both the hole transport material and the electron transport material may be mixed together in the charge transporting polyester.

  Furthermore, an appropriate resin (polymer) or an additive may be added to improve film formability and prevent pinholes. Specific resins include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, cellulose resin, urethane resin, epoxy resin, polystyrene resin, polyvinyl acetate resin, styrene butadiene copolymer, vinylidene chloride-acrylonitrile. Copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, silicone resins, poly-N-vinyl carbazole resins, polysilane resins, polythiophenes, polypyrrole, and other conductive resins can be used. Moreover, as an additive, a well-known antioxidant, a ultraviolet absorber, a plasticizer, etc. can be used.

In order to improve the charge injection property, a hole injection layer and / or an electron injection layer may be used. As the hole injection material, a phenylenediamine derivative, a phthalocyanine derivative, an indanthrene derivative, a polyalkylene diester, An oxythiophene derivative or the like is used. These may be mixed with a Lewis acid, a sulfonic acid, or the like. As the electron injection material, metals such as Li, Ca, and Sr, metal fluorides such as LiF and MgF ₂ , and metal oxides such as MgO, Al ₂ O ₃ , and LiO are used.

  Further, when the charge transporting polyester is used for a function other than the light emitting function, a light emitting compound is used as a light emitting material. As the light-emitting material, a compound that exhibits high emission quantum efficiency in a solid state is used. The light-emitting material may be either a low molecular compound or a high molecular compound. Preferred examples of organic low molecular compounds include chelate-type organometallic complexes, polynuclear or condensed aromatic ring compounds, perylene derivatives, coumarin derivatives, and styrylarylene derivatives. In the case where a silole derivative, an oxazole derivative, an oxathiazole derivative, an oxadiazole derivative or the like is a polymer, a polyparaphenylene derivative, a polyparaphenylene vinylene derivative, a polythiophene derivative, a polyacetylene derivative, or the like is used. As preferable specific examples, the following light emitting materials (IV-1) to (IV-17) are used, but are not limited thereto. In the light emitting materials (IV-13) to (IV-17), V represents the functional group shown above, and n and j represent 1 or an integer of 2 or more.

  Further, for the purpose of improving the durability of the device or improving the light emission efficiency, the light emitting material or the charge transporting polyester may be doped with a dye compound different from the light emitting material as a guest material. The doping ratio of the dye compound is about 0.001% to 40% by mass, preferably about 0.001% to 10% by mass. As the dye compound used for such doping, an organic compound that has good compatibility with the light emitting material and the charge transporting polyester and does not prevent the formation of a good thin film of the light emitting layer is used, preferably a coumarin derivative, DCM derivatives, quinacridone derivatives, rubrene derivatives, porphyrin derivatives, metal complex compounds such as Ir, Eu, and Pt are used. Preferable specific examples include the following dye compounds (V-1) to (V-6), but are not limited thereto.

In the case of the layer configuration of the organic electroluminescent device shown in FIGS. 1 to 4, the back electrode 7 is made of a metal, metal oxide, metal fluoride, etc., which can be vacuum-deposited and has a low work function for performing electron injection. Is done. Examples of the metal include magnesium, aluminum, gold, silver, indium, lithium, calcium, and alloys thereof. Examples of the metal oxide include lithium oxide, magnesium oxide, aluminum oxide, indium tin oxide, tin oxide, indium oxide, zinc oxide, and indium zinc oxide. Examples of the metal fluoride include lithium fluoride, magnesium fluoride, strontium fluoride, calcium fluoride, and aluminum fluoride. Further, a protective layer may be provided on the back electrode 7 in order to prevent deterioration of the organic electroluminescent element due to moisture or oxygen.
Specific examples of the protective layer material include metals such as In, Sn, Pb, Au, Cu, Ag, and Al, metal oxides such as MgO, SiO ₂ , and TiO ₂ , polyethylene resins, polyurea resins, and polyimide resins. A vacuum deposition method, a sputtering method, a plasma polymerization method, a CVD method, and a coating method can be applied to the formation of the protective layer including a resin.

  The organic electroluminescent elements shown in FIGS. 1 to 4 are manufactured by sequentially forming individual layers on the transparent electrode 2 according to the layer structure of each organic electroluminescent element. In addition, at least one layer 3 of the hole transport layer and the hole injection layer, a light emitting layer 4, at least one layer 5 of the electron transport layer and the electron injection layer, or a light emitting layer 6 having a charge transporting capability is composed of the above materials. It is formed by spin coating method, cast method, dipping method, ink jet method or the like on the transparent electrode by using a vacuum deposition method or by dissolving or dispersing in an appropriate organic solvent and using the obtained coating solution. Of these, only a necessary amount of layer forming material can be applied to the desired pixel position, and there are few materials that are wasted, which is also friendly to the global environment, and high-definition patterning. It is preferable to use the inkjet method because it is possible to make a large panel, and the degree of freedom of printing is large. Specifically, as a method for manufacturing an organic electroluminescent element, It is particularly preferable to have a coating process in which a coating solution in which the constituent components of the organic compound layer are dissolved in a solvent is coated by an inkjet method.

In the case of using the inkjet method, the organic compound layer coating liquid is used instead of the ink, and the droplet-shaped organic compound layer coating liquid is ejected from the nozzle of the droplet ejection head, thereby obtaining a desired position on the substrate. In addition, an organic compound layer having a desired film thickness and shape can be formed.
In addition, as a droplet discharge head, the same basic configuration and principle as those of a recording head used in an ink jet printer can be used. That is, by applying an external stimulus such as pressure or heat to the organic compound layer coating liquid, a method of discharging the organic compound layer coating liquid from a nozzle in a droplet form (piezo ink jet method using a piezoelectric element, heat A thermal ink jet method using a boiling phenomenon) can be used.

  However, in the production of the organic electroluminescent device of the present invention, the external stimulus is more preferably pressure than heat. When the external stimulus is heat, the inkjet printing process involves the formation (solidification) of a coating film by discharging the organic compound layer coating liquid from the nozzle and volatilizing the solvent of the organic compound layer coating liquid that has landed on the substrate. In this case, since the viscosity of the coating solution for organic compound layer is largely changed by heat, it may be difficult to control the leveling property and patterning accuracy. In addition to this, charge transporting polyethers that are inferior in heat resistance cannot be used, and material options may be narrowed.

  Moreover, as an apparatus used for manufacturing the organic electroluminescent element of the present invention using the inkjet method, in addition to the above-described liquid droplet ejection head, for example, an organic electroluminescent element is formed as necessary. A fixing or conveying means for the substrate or the like, or a droplet discharge head scanning means for scanning the droplet discharge head with respect to the substrate plane direction may be provided.

The composition and properties of the organic compound layer coating solution are not particularly limited, but the viscosity of the organic compound layer coating solution is preferably within a range of 0.01 to 1000 cps at 25 ° C. , Preferably in the range of 1-100 cps.
When the viscosity is less than 0.01 cps, the coating solution for the organic compound layer that has landed on the substrate is likely to spread in the plane direction of the substrate, and it becomes difficult to control the film thickness or the patterning accuracy deteriorates. There is. Moreover, when the viscosity exceeds 1000 cps, the viscosity of the organic compound layer coating solution is too high, and it may be liable to cause ejection failure.

  The viscosity of the coating solution for the organic compound layer is controlled by controlling the content of the charge transporting polyester, other additive components added as necessary, the molecular weight of the charge transporting polyester, and the like. Can be adjusted to the value.

The film thicknesses of at least one layer 3 of the hole transport layer and the hole injection layer, the light emitting layer 4, at least one layer 5 of the electron transport layer and the electron injection layer, and the light emitting layer 6 having a charge transporting ability are each 10 μm or less. In particular, the range of 0.001 to 5 μm is preferable. The dispersion state of each of the above materials (the non-conjugated polymer, the light emitting material, etc.) may be a molecular dispersion state or a fine particle state such as a microcrystal. In the case of a film forming method using a coating solution, it is necessary to select a dispersion solvent in consideration of the dispersibility and solubility of each material in order to obtain a molecular dispersion state. In order to disperse into fine particles, a ball mill, a sand mill, a paint shaker, an attritor, a homogenizer, an ultrasonic method, or the like can be used.
In the case of the organic electroluminescent device shown in FIGS. 1 and 2, the back electrode 7 is formed on at least one layer 5 of the electron transport layer and the electron injection layer by vacuum deposition, sputtering, or the like. The organic electroluminescent element of the invention is obtained. In the case of the organic electroluminescent element shown in FIG. 3, the back electrode 7 is provided on the light emitting layer 4 and in the case of the organic electroluminescent element shown in FIG. The organic electroluminescent element of the present invention can be obtained by forming by a vacuum deposition method, a sputtering method or the like.

The organic electroluminescent element of the present invention can emit light by applying a direct current voltage of 1 to 200 mA / cm ² at a current density of, for example, 4 to 20 V between a pair of electrodes.

<Image display medium>
The image display medium of the present invention is characterized in that the organic electroluminescent elements of the present invention are arranged in at least one of a matrix shape and a segment shape. In the present invention, when the organic electroluminescent elements are arranged in a matrix, only the electrodes may be arranged in a matrix, or both the electrodes and the organic compound layer may be arranged in a matrix. . In the present invention, when organic electroluminescent elements are arranged in segments, only the electrodes may be arranged in segments, or both electrodes and organic compound layers may be arranged in segments. Also good.
A matrix-like or segment-like organic compound layer can be easily formed by using the ink jet method described above.
A conventionally known device can be used as a driving device and a driving method for the matrix organic electroluminescent device and the segment organic electroluminescent device.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention.

-Synthesis of charge transporting polyester-
(Synthesis Example 1)
In a mixed solution of 2,5-dibromothiophene (1 mol), 3- [4, (4,4,5,5-tetramethyl- [1,3,2] dioxyborolane) -phenyl] propinate (2 mol) and 30 ml of tetrahydrofuran. Under a nitrogen atmosphere, tetrakis (triphenylphosphine) palladium (5%) and 10 ml of 2N sodium carbonate were added and refluxed. After completion of the reaction, the mixture was poured into toluene, washed with 1N hydrochloric acid and pure water, added with magnesium sulfate and dried. After the solvent was distilled off, the resulting crude product was purified by column chromatography and recrystallization to obtain monomer compound [48] (0.4 mol). 1.2 g of this monomer compound [48] was placed in a 50 ml three-necked eggplant flask, and the heating reaction was continued at 210 ° C. for 8 hours under a reduced pressure of 4.8 Pa. Thereafter, the mixture was cooled to room temperature, dissolved in 50 ml of monochlorobenzene by heating, insoluble matters were filtered through a 0.5 μm PTFE filter, and the filtrate was dropped into 500 ml of stirring methanol to precipitate a polymer. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 0.6 g of a polymer [Exemplary Compound 20].

(Synthesis Example 2)
Of 2,5′-dibromobithiophene (0.5 mol) and methyl acrylate (0.62 mol), triethylamine (1 mol), palladium acetate (0.005 mol), tri (o-tolyl) phosphine (0.01 mol) The mixed solution was heated at 100 ° C. under a nitrogen atmosphere. After completion of the reaction, the mixture was poured into toluene, washed with pure water, added with magnesium sulfate and dried. After the solvent was distilled off, palladium carbon (10%) was added to a toluene / methanol mixed solution and stirred in an atmosphere under hydrogen. Then, after filtering through celite and distilling off the solvent, the obtained crude product was purified by column chromatography and recrystallization to obtain a monomer compound [30] (0.3 mol). 1.0 g of this monomer compound [30] was placed in a 50 ml three-necked eggplant flask, and the heating reaction was continued at 210 ° C. for 8 hours under a reduced pressure of 4.8 Pa. Thereafter, the mixture was cooled to room temperature, dissolved in 50 ml of monochlorobenzene by heating, insoluble matters were filtered through a 0.5 μm PTFE filter, and the filtrate was dropped into 500 ml of stirring methanol to precipitate a polymer. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 0.5 g of a polymer [Exemplary Compound 13].

(Synthesis Example 3)
2,5-dibromo-3,4-dimethylthiophene (1 mol) and 3- [4, (4,4,5,5-tetramethyl- [1,3,2] dioxyborolane) -phenyl] propinate (2 mol), Tetrakis (triphenylphosphine) palladium (5%) and 10 ml of 2N sodium carbonate were added to a mixed solution of 30 ml of tetrahydrofuran under a nitrogen atmosphere and refluxed. After completion of the reaction, the mixture was poured into toluene, washed with 1N hydrochloric acid and pure water, added with magnesium sulfate and dried. After the solvent was distilled off, the resulting crude product was purified by column chromatography and recrystallization to obtain monomer compound [56] (0.4 mol). 1.0 g of this monomer compound [56] was placed in a 50 ml three-necked eggplant flask, and the heating reaction was continued at 210 ° C. for 8 hours under a reduced pressure of 4.8 Pa. Thereafter, the mixture was cooled to room temperature, dissolved in 50 ml of monochlorobenzene by heating, insoluble matters were filtered through a 0.5 μm PTFE filter, and the filtrate was dropped into 500 ml of stirring methanol to precipitate a polymer. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 0.6 g of a polymer [Exemplary Compound 24].

(Synthesis Example 4)
Tetrakis (triphenylphosphine) palladium (5%) and 2N carbonic acid in a mixed solution of 2,5′-bithiophenediboronic acid (1 mol), 4-iodophenylpropionic acid methyl ester (2 mol) and tetrahydrofuran 30 ml under nitrogen atmosphere 10 ml of sodium was added and refluxed. After completion of the reaction, the mixture was poured into toluene, washed with 1N hydrochloric acid and pure water, added with magnesium sulfate and dried. After the solvent was distilled off, the resulting crude product was purified by column chromatography and recrystallization to obtain monomer compound [68] (0.4 mol). 1.0 g of this monomer compound [68] was placed in a 50 ml three-necked eggplant flask, and the heating reaction was continued at 210 ° C. for 8 hours under a reduced pressure of 4.8 Pa. Thereafter, the mixture was cooled to room temperature, dissolved in 50 ml of monochlorobenzene by heating, insoluble matters were filtered through a 0.5 μm PTFE filter, and the filtrate was dropped into 500 ml of stirring methanol to precipitate a polymer. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 0.6 g of a polymer [Exemplary Compound 31].

(Synthesis Example 5)
5,5 "-Dibromo-3 ', 4'-dibutyl-4,4" -diperfluorobutyl- [2,2'; 5 ', 2 "] terthiophene (1 mol) and methyl 4-iodophenylpropionate Tetrakis (triphenylphosphine) palladium (5%) and 10 ml of 2N sodium carbonate were added to a mixed solution of ester (2 mol) and tetrahydrofuran in 1000 ml under a nitrogen atmosphere, and the mixture was refluxed. After the solvent was distilled off, the resulting crude product was purified by column chromatography and recrystallization to obtain monomer compound [99] (0.4 mol). Compound [99] (1.0 g) is placed in a 50 ml three-necked eggplant flask and heated at 230 ° C. for 8 hours under a reduced pressure of 4.8 Pa. Thereafter, the reaction was continued, and the mixture was cooled to room temperature, dissolved in 50 ml of monochlorobenzene by heating, insoluble matters were filtered through a 0.5 μm PTFE filter, and the filtrate was dropped into 500 ml of stirring methanol to give a polymer. The polymer obtained was filtered, washed thoroughly with methanol, and then dried to obtain 0.6 g of the polymer [Exemplary Compound 41].

(Synthesis Example 6)
2,5′-bithiophene diboronic acid (1 mol), 4′-iodo-4-biphenylphenylpropionic acid methyl ester (2 mol) and 30 ml of tetrahydrofuran in a mixed solution of tetrakis (triphenylphosphine) palladium (5 %) And 10 ml of 2N sodium carbonate and refluxed. After completion of the reaction, the mixture was poured into toluene, washed with 1N hydrochloric acid and pure water, added with magnesium sulfate and dried. After the solvent was distilled off, the resulting crude product was purified by column chromatography and recrystallization to obtain monomer compound [117] (0.4 mol). 1.0 g of this monomer compound [117] was placed in a 50 ml three-necked eggplant flask and the heating reaction was continued at 210 ° C. for 8 hours under a reduced pressure of 4.8 Pa. Thereafter, the mixture was cooled to room temperature, dissolved in 50 ml of monochlorobenzene by heating, insoluble matters were filtered through a 0.5 μm PTFE filter, and the filtrate was dropped into 500 ml of stirring methanol to precipitate a polymer. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 0.5 g of a polymer [Exemplary Compound 51].

-Fabrication of organic electroluminescence device-
Example 1
ITO (manufactured by Sanyo Vacuum Co., Ltd.) formed on the transparent insulating substrate was patterned by photolithography using a strip-shaped photomask and further etched to form a strip-shaped ITO electrode (width 2 mm). Next, the ITO glass substrate was washed with neutral detergent, pure water, acetone (for electronics industry, manufactured by Kanto Chemical) and isopropanol (for electronics industry, manufactured by Kanto Chemical) for 5 minutes each, and then spinned. It was dried with a coater. A charge transporting polyester [Exemplary Compound (20)] is prepared as a hole transporting layer on the substrate in a 5% by weight monochlorobenzene solution, filtered through a 0.1 μm PTFE filter, and then dried to a thickness of 0. A thin film of 050 μm was formed. The said exemplary compound (IV-1) was vapor-deposited as a luminescent material, and the 0.055-micrometer-thick luminescent layer was formed. Subsequently, using a metallic mask provided with a strip-shaped hole, this mask is finally installed, and a Mg-Ag alloy is vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm by ITO. It formed so that it might cross | intersect an electrode. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

(Example 2)
In the same manner as in Example 1, an ITO glass substrate etched and washed in the same manner as in Example 1 was charged with 1 part by weight of charge transporting polyester [Exemplary Compound (13)], 4 parts by weight of poly (N-vinylcarbazole), and the Exemplified Compound (IV -1) was prepared as a 10 wt% dichloroethane solution and filtered through a 0.1 µm PTFE filter. Using this solution, a thin film having a thickness of about 0.15 μm was formed by a spin coater method on a glass substrate on which a 2 mm wide strip-shaped ITO electrode was formed by etching as a light emitting layer having charge transporting ability. After sufficiently drying, a Mg—Ag alloy was vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

(Example 3)
A thin film having a thickness of 0.050 μm was formed on the ITO glass substrate etched and washed in the same manner as in Example 1 using a charge transporting polyester [Exemplary Compound (24)] as a hole transporting layer in the same manner as in Example 1. The exemplary compound (IV-1) and the exemplary compound (V-1) were formed as a light emitting layer with a thickness of 0.065 μm, and the electron transport layer was formed as the exemplary compound (IV-9) with a thickness of 0.030 μm. Subsequently, a Mg—Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

Example 4
A thin film having a thickness of 0.050 μm is formed on the ITO glass substrate etched and washed in the same manner as in Example 1 using a charge transporting polyester [Exemplary Compound (31)] as a hole transporting layer in the same manner as in Example 1. did. The exemplified compound (IV-17) and the exemplified compound (V-5) were formed as a light emitting layer by a spin coater method with a thickness of 0.065 μm. After sufficiently drying, a back electrode having a width of 2 mm and a total thickness of 0.23 μm was formed so as to intersect the ITO electrode by vapor-depositing Ca to a thickness of 0.08 μm and Al to a thickness of 0.15 μm. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

(Example 5)
An organic electroluminescent device was produced in the same manner as in Example 1 except that the exemplified compound (41) was used instead of the exemplified compound (20) used in Example 1.

(Example 6)
A 1.5 part by weight dichloroethane solution of charge transporting polyester [Exemplary Compound (51)] was prepared on an ITO glass substrate etched and washed in the same manner as in Example 1, and filtered through a 0.1 μm PTFE filter. Using this solution, a thin film having a thickness of about 0.05 μm was formed as a hole transport layer by a inkjet method on a glass substrate on which a 2 mm wide strip ITO electrode was formed by etching. A light emitting layer having a thickness of 0.050 μm was formed by the inkjet method using the exemplified compound (IV-14) as a light emitting material. After sufficiently drying, a back electrode having a width of 2 mm and a total thickness of 0.23 μm was formed so as to intersect the ITO electrode by vapor-depositing Ca to a thickness of 0.08 μm and Al to a thickness of 0.15 μm. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

(Comparative Example 1)
A device was produced in the same manner as in Example 1 except that the compound represented by the following structural formula (VI-1) was used instead of the exemplified compound (20) used in Example 1 above.

(Comparative Example 2)
2 parts by weight of the following compound (VI-2) as a charge transporting polymer, 0.1 part by weight of the exemplified compound (VI-1) as a light emitting material, and 1 part by weight of the compound (IV-9) as an electron transporting material After mixing, a 10 wt% dichloroethane solution was prepared and filtered through a 0.1 μm PTFE filter. Using this solution, a light emitting layer having a thickness of 0.15 μm and having a charge transporting capability was formed on a glass substrate formed by etching a 2 mm wide strip-shaped ITO electrode by dipping. After sufficiently drying, a Mg—Ag alloy was vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the formed organic EL element was 0.04 cm ² .

The organic EL device produced as described above was sealed with glass with an adhesive in dry nitrogen, and the measurement was performed with the ITO electrode side as plus and the Mg-Ag back electrode as minus.
The light emission characteristics were compared based on the driving current density when the initial luminance was 400 cd / m ² in the direct current driving method (DC driving). In addition, the evaluation of the light emission lifetime is based on the drive time when the luminance (initial luminance L ₀ : 400 cd / m ² ) of the element of Comparative Example 1 becomes luminance L / initial luminance L ₀ = 0.5 at room temperature. _0.0 , and the relative time when the brightness was set to ₀ , and the voltage increase (= voltage / initial driving voltage) when the luminance of the element became luminance L / initial luminance L ₀ = 0.5 were evaluated. The results are shown in Table 17.

In addition, the organic electroluminescence device produced as described above was measured for light emission by applying a DC voltage of 5 V in vacuum (1.33 × 10 ⁻¹ Pa) with the ITO electrode side plus and the back electrode side minus. The maximum luminance and the emission color at this time were evaluated. The results are shown in Table 17.

It is the schematic block diagram which showed an example of the laminated constitution of the organic electroluminescent element of this invention. It is the schematic block diagram which showed another example of the layer structure of the organic electroluminescent element of this invention. It is the schematic block diagram which showed another example of the layer structure of the organic electroluminescent element of this invention. It is the schematic block diagram which showed another example of the layer structure of the organic electroluminescent element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent insulator board | substrate 2 Transparent electrode 3 At least 1 layer of a hole transport layer and a hole injection layer 4 Light emitting layer 5 At least 1 layer of an electron transport layer and an electron injection layer 6 Light emitting layer 7 which has charge transport ability 7 Back electrode

Claims (8)

A pair of electrodes composed of an anode and a cathode, at least one of which is transparent or translucent, and one or a plurality of organic compound layers sandwiched between the pair of electrodes,
At least one of the organic compound layers contains at least one charge transporting polyester composed of a repeating unit containing at least one selected from the structure represented by the following general formula (I-1) as a partial structure. An organic electroluminescent element.

(In General Formula (I-1), R ₁ and R ₂ are each independently hydrogen, a substituted or unsubstituted monovalent linear hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted ring number. 3-10 monovalent cyclic hydrocarbon group, substituted or unsubstituted monovalent branched hydrocarbon group having 3 to 20 carbon atoms, substituted or unsubstituted monovalent straight chain having 1 to 20 carbon atoms Perfluoroalkyl group, substituted or unsubstituted monovalent cyclic perfluoroalkyl group having 3 to 10 rings, substituted or unsubstituted monovalent branched chain perfluoroalkyl group having 3 to 20 carbon atoms, substituted Or an unsubstituted monovalent phenyl group, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic rings, a substituted or unsubstituted monovalent condensed aromatic carbon having 2 to 10 aromatic rings Represents hydrogen or a substituted or unsubstituted monovalent aromatic heterocycle; One or more CH ₂ in the alkyl group O, CO, or replaced by NH. Also, one or more CF ₂ in the perfluorooctanol alkyl group _CH 2, O, CO, or replaced with NH T represents a divalent linear hydrocarbon group having 1 to 10 carbon atoms or a divalent branched hydrocarbon group having 2 to 10 carbon atoms, a is an integer of 1 to 4, and b is 0. Represents ~ 3)   The organic compound layer includes at least a light emitting layer and at least one layer of an electron transport layer and an electron injection layer, and at least one layer selected from the light emitting layer, the electron transport layer and the electron injection layer has the general formula 2. The organic electroluminescence according to claim 1, comprising at least one charge transporting polyester comprising a repeating unit containing at least one selected from the structure represented by (I-1) as a partial structure. element.   The organic compound layer includes at least a light emitting layer and at least one layer of a hole transport layer and a hole injection layer, and at least one layer selected from the light emitting layer, the hole transport layer and the hole injection layer is 2. The composition according to claim 1, comprising at least one charge transporting polyester comprising a repeating unit containing at least one selected from the structure represented by the general formula (I-1) as a partial structure. Organic electroluminescent element.   The organic compound layer includes at least a light emitting layer, at least one layer of a hole transport layer and a hole injection layer, and at least one layer of an electron transport layer and an electron injection layer, and the light emitting layer and the hole transport layer , At least one layer selected from a hole injection layer, an electron transport layer, and an electron injection layer is composed of a repeating unit containing at least one selected from the structure represented by the general formula (I-1) as a partial structure The organic electroluminescent element according to claim 1, comprising at least one kind of charge transporting polyester.   The organic compound layer is composed only of a light emitting layer having a charge transport function, and the light emitting layer having the charge transport function is a partial structure of at least one selected from the structure represented by the general formula (I-1) The organic electroluminescent device according to claim 1, comprising at least one kind of charge-transporting polyester composed of repeating units. A charge transporting polyester comprising a repeating unit containing at least one selected from the structure represented by the general formula (I-1) as a partial structure is represented by the following general formula (II-1) or (II-2). The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is a charge transporting polyester.

(In the general formulas (II-1) and (II-2), A ₁ represents at least one selected from the structure represented by the general formula (I-1), and Y ₁ represents a divalent alcohol residue. Represents a group, Z ₁ represents a divalent carboxylic acid residue, m represents an integer of 1 to 5, R ₃ represents —O— (Y ₁ —O) m—H, or a group —O— ( Y ₁ —O) group represented by m—CO—Z ₁ —CO—OR ′ (provided that Y ₁ , Z ₁ and m have the same meaning as described above, R ′ represents a hydrogen atom, an alkyl group, Represents a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group), and p represents an integer of 5 to 5,000.   2. An image display medium comprising the organic electroluminescence device according to claim 1 arranged in at least one of a matrix and a segment shape.   A method for producing an organic electroluminescent device according to claim 1, wherein a coating solution in which a constituent component of the organic compound layer is dissolved in a solvent is applied by an inkjet method. A method for producing an organic electroluminescent element, comprising:

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