JP2013229370A - Color change inhibitor, ink composition containing said color change inhibitor, organic thin film formed using said ink composition, organic electronic element, organic electroluminescence element, display element, lighting system, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a color change inhibitor which prevents color change of an ink composition containing a charge-transporting compound and an electron-accepting compound; an ink composition with suppressed color change; an organic thin film formed using the ink composition; an organic electronic element; and an organic electroluminescence element.SOLUTION: A color change inhibitor prevents color change of an ink composition containing one or more charge-transporting compounds and electron-accepting compounds, and contains a compound having a group 15 or 16 element. The ink composition contains the one or more charge-transporting compounds and electron-accepting compounds, and contains the color change inhibitor containing the compound having the group 15 or 16 element.

Description

  The present invention relates to a color change inhibitor, an ink composition containing the color change inhibitor, an organic thin film formed using the ink composition, an organic electronics element, an organic electroluminescence element (hereinafter also referred to as an organic EL element). A display device, a lighting device, and a display device.

Organic electronics elements are elements that perform electrical operations using organic substances, and are expected to exhibit features such as energy saving, low cost, and flexibility, and are attracting attention as a technology that can replace conventional inorganic semiconductors based on silicon. ing.
An organic EL element, an organic photoelectric conversion element, an organic transistor etc. are mentioned as an example of an organic electronics element.

  Among organic electronics elements, organic EL elements are attracting attention as applications for large-area solid-state light sources as an alternative to incandescent lamps and gas-filled lamps, for example. It is also attracting attention as the most powerful self-luminous display that can replace the liquid crystal display (LCD) in the flat panel display (FPD) field, and its commercialization is progressing.

  Organic EL elements are roughly classified into two types, low molecular organic EL elements and polymer organic EL elements, depending on the materials and film forming methods used. High-molecular organic EL elements are composed of high-molecular materials, and can be used for simple film formation such as printing and ink-jet compared to low-molecular organic EL elements that require vacuum-based film formation. Therefore, it is an indispensable element for future large-screen organic EL displays.

  In recent years, for the purpose of lowering the driving voltage of organic EL devices and improving light emission efficiency and lifetime, an electron-accepting compound is mixed with a charge-transporting compound to form a radical cation compound composed of a charge-transporting compound, and charge transporting Attempts have been made to improve performance.

  For example, Patent Document 1 discloses that tris (4-bromophenylaminium hexachloroantimonate) (TBPAH) is mixed as an electron-accepting compound with a hole-transporting polymer compound. It is disclosed that an organic electroluminescence device capable of being driven at a low voltage can be obtained.

Patent Document 2 discloses that iron (III) chloride (FeCl ₃ ) is mixed with a hole transporting compound as an electron accepting compound by a vacuum deposition method.
Further, in Patent Document 3, tris (pentafluorophenyl) borane (PPB) as an electron-accepting compound is mixed with a hole-transporting polymer compound by a wet film forming method to form holes. Forming an injection layer is disclosed.
Furthermore, Patent Document 4 discloses a composition comprising an ionic compound and a charge transporting compound as the charge transport film composition.

  Thus, it is considered important to generate a compound composed of a radical cation and a counter anion of a charge transporting compound, which is generated when an electron accepting compound is mixed with the charge transporting compound.

  On the other hand, as described in Patent Document 4, when a compound comprising a radical cation and a counter anion is produced, an absorption spectrum different from that of the original charge transporting compound and electron accepting compound is exhibited.

Japanese Patent No. 3748491 Japanese Patent Laid-Open No. 11-251067 Japanese Patent No. 4023204 JP 2006-233162 A

  In order to produce an organic EL device with a large area and low cost, it is necessary to use a wet process, and an ink composition for a charge transport film suitable for this wet process is required.

  In the charge transport film ink composition, the charge transport compound for forming the charge transport film and other compounds are uniformly dissolved in order to reduce the quality variation due to the difference in the coating process and the coating lot. In addition, it is important that no precipitates, no precipitates, no color change of the ink appearance occur.

  However, as described above, in an ink composition containing a charge transporting compound and an electron accepting compound, it is considered that the color on the appearance of the ink changes due to the formation of a radical cation compound, making quality control difficult. There existed a subject that the organic EL element characteristic varied.

  In view of the above problems, the present invention provides a color change preventing agent for preventing color change of an ink composition containing a charge transporting compound and an electron accepting compound, an ink composition in which color change over time is suppressed, An object of the present invention is to provide an organic thin film, an organic electronics element, an organic electroluminescence element, a display element, a lighting device, and a display device formed using an ink composition.

As a result of intensive studies, the present inventors have found a color change inhibitor that prevents color change of an ink composition containing a charge transporting compound and an electron accepting compound, and an ink composition containing the color change inhibitor and The organic electronics material has little color change in the ink composition which is important for quality control, and the organic thin film formed using the ink composition and / or the organic electronics material can suppress variations in organic EL element characteristics. The headline and the present invention have been completed.
That is, the present invention is characterized by the following items (1) to (12).

(1) A color change preventing agent for preventing color change of an ink composition comprising at least one charge transporting compound and an electron accepting compound,
A color change inhibitor comprising a compound having a Group 15 element or a Group 16 element.

(2) An ink composition comprising at least one charge transporting compound and an electron accepting compound,
An ink composition comprising a color change inhibitor containing a compound having a Group 15 element or a Group 16 element.

(3) An organic thin film formed using the ink composition according to (2).

(4) An organic electronic device including the organic thin film according to (3).

(5) An organic electroluminescent device comprising the organic thin film according to (3).

(6) The organic electroluminescent element according to (5), wherein the organic thin film is a hole injection layer.

(7) The organic electroluminescent element according to (5) or (6), wherein the organic thin film is a hole transport layer.

(8) The organic electroluminescent element according to any one of (5) to (7), wherein a flexible substrate is used.

(9) The organic electroluminescent element according to any one of (5) to (8), wherein a resin film substrate is used.

(10) A display device comprising the organic electroluminescent device according to any one of (5) to (9).

(11) A lighting device comprising the organic electroluminescent element according to any one of (5) to (9).

(12) A display device comprising the illumination device according to (11) and a liquid crystal element as display means.

According to the present invention, a color change inhibitor for preventing color change of an ink composition containing a charge transporting compound and an electron accepting compound, an ink composition in which color change with time is suppressed, and the ink composition An organic thin film, an organic electronics element, an organic electroluminescence element, a display element, a lighting device, and a display device that are formed using the above can be provided.
By using the ink composition of the present invention, a thin film can be formed stably and easily. Moreover, the organic electronics element including the organic thin film formed from the ink composition can reduce variation in characteristics. Therefore, it is possible to provide an organic electronics material and an ink composition that are extremely useful for improving the productivity of organic electronics elements, particularly polymer type organic EL elements.

It is a schematic diagram which shows an example of an organic EL element.

The color change preventing agent of the present invention is a color change preventing agent for preventing a color change of an ink composition comprising at least one charge transporting compound and an electron accepting compound, and is a Group 15 element or Group 16 It is characterized by containing a compound having an element.
The ink composition of the present invention is an ink composition containing at least one charge transporting compound and an electron accepting compound, and prevents color change containing a compound having a Group 15 element or a Group 16 element. It is characterized by containing an agent.
First, the color change inhibitor of the present invention will be described.

[Color change inhibitor]
The color change preventive agent of the present invention exhibits a color change triggered by time, external stimuli such as heat and light, or melting, decomposition, dissolution in a solvent, mixing and / or their combined environment. It includes a compound (hereinafter referred to as “color change prevention compound”) that prevents and suppresses color change such as the resulting compound, a mixture thereof, and an ink composition.

  Here, “color change” in the present invention will be described. In the present invention, the color change means that the color changes before and after the above-described opportunity. The cause of the color change is not particularly limited, and examples thereof include those caused by the formation / decomposition of a compound, a change in structure, and the like.

  In the present invention, the form of the color change preventing compound is not particularly limited as long as the effect of preventing and suppressing the color change is obtained, and includes a solvent that dissolves and / or disperses the color change preventing compound. Or a mixture thereof.

  In the present invention, the color change preventing compound has an element belonging to Group 15 or Group 16 on the periodic table from the viewpoint of enhancing the effect of preventing color change, and nitrogen, phosphorus from the viewpoint of availability. More preferably, any element of oxygen, oxygen, and sulfur may be included, and a plurality of any of these elements may be included.

  Examples of the compound having nitrogen include aromatic amine compounds, aliphatic amine compounds, amide compounds, imide compounds, nitro compounds, heterocyclic compounds, ammonium, aminium, pyridinium and other salt compounds, preferably aliphatic amines. Compounds, amide compounds, imide compounds, and heterocyclic compounds. More specifically, dialkylamine (such as dibutylamine), trialkylamine (dicyclohexylmethylamine, N, N-dimethyl-N-tetradecylamine, N-methyldioctylamine, tris (2-ethylhexyl) amine, triisoamyl Amine, N, N-dimethyl-N-octadecylamine, N, N-didecyl-N-methylamine, etc.), trialkanolamine (such as triethanolamine), tribenzylamine, N, N-dimethylformamide, N, N -Diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, aniline, alkylaniline (such as 4-octylaniline), N, N-dialkylaniline, N, N-dibenzylaniline, N, N-dialkyl -N-benzylamine (N- Til-N-methylbenzylamine, etc.), N-alkyl-N, N-dibenzylamine, N, N-dialkyl-N-arylamine, N-alkyl-N, N-diarylamine, N-alkyl-N- Aryl-N-benzylamine, N, N-diaryl-N-benzylamine, N, N-dibenzyl-N-arylamine, piperidine, pyridine, pyrazine, pyrimidine, piperazine, pyridazine, pyrrole, imidazole, nitrobenzene, ethylenediamine, propylene Diamine, tetramethylenediamine, pentamethylenediamine, N, N-dialkylethylenediamine, N, N, N ′, N′-tetraalkylethylenediamine, N, N-dialkylpropylenediamine, N, N, N ′, N′-tetra Alkylpropylenediamine, N, , N ′, N′-tetramethyl-1,6-diaminohexane, N, N, N ′, N′-tetramethylnaphthalenediamine, hexamethylenediamine, cyclohexanediamine, diethylenetriamine, tridodecylamine, triethylenetetramine, tetra Examples thereof include ethylenepentamine, tetraalkylammonium iodide (such as tetraethylammonium iodide), trialkoxyamine (such as tris {(2-methoxyethoxy) ethyl} amine), and anisidine, among others, dissolution in the ink composition. From the viewpoint of properties, trialkylamine, N, N-dialkylformamide, N, N-dialkylacetamide, N-alkyl-N-aryl-N-benzylamine, N, N-dialkyl-N-arylamine, N-alkyl -N, N-dia Reelamine, aniline and alkylenediamine are preferred.

  Examples of compounds having phosphorus include phosphine compounds, phosphine oxide compounds, phosphonic acid ester compounds, phosphonium salt compounds, phosphonic acid compounds, etc., preferably phosphine compounds, phosphine oxide compounds, phosphonic acid compounds, phosphonic acid esters. A compound. More specifically, dimethylphosphinic acid, phenylphosphinic acid, phenylphosphonic acid, arylphosphine (such as o-tolylphosphine), triarylphosphine, trialkylphosphine, triarylphosphine oxide, trialkylphosphine oxide, triarylphosphine sulfide , Tetraarylphosphonium chloride, tetraalkylphosphonium bromide (such as tetraoctylphosphonium bromide), tetraarylphosphonium bromide, tetraarylphosphonium iodide, phosphonic acid dimethyl, phosphonic acid diethyl, methylphosphonic acid dimethyl, trimethyl phosphate, etc. Triarylphosphine, trialkylphosphine, triarylphosphine from the viewpoint of easy availability and solubility N'okishido, trialkyl phosphine oxide.

  Examples of compounds having oxygen include aliphatic alcohol compounds, aromatic alcohol compounds, phenol compounds, aliphatic ether compounds, aromatic ether compounds, aliphatic ketone compounds, aromatic ketone compounds, aliphatic ester compounds, aromatic esters. Compounds, aliphatic carboxylic acid compounds, aromatic carboxylic acid compounds, oxonium chlorides, etc., preferably aliphatic alcohol compounds, aromatic alcohol compounds, phenol compounds, aliphatic ether compounds, aromatic ester compounds, fats Group ester compounds. More specifically, methanol, ethanol, propanol, butanol, hexanol, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, diethylene glycol, Diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, 18-crown-6, dibenzo-18-crown-6, 3-methyl-3-oxetanemethanol, benzyl alcohol, phenol, cresol, catechol, resorcinol, Anisole, Fene Dimethyl ether, diethyl ether, diphenyl ether, dimethoxybenzene, tetramethoxymethane, cyclohexanol, methyl benzoate, ethyl benzoate, methyl formate, ethyl formate, methyl acetate, ethyl acetate, isopentyl acetate, pentyl acetate, butyl acetate, acetic acid Examples include octyl, methyl propionate, methyl butyrate, ethyl butyrate, and methyl salicylate. Among them, cyclohexanol, benzyl alcohol, phenol, cresol, glycol from the viewpoint of easy availability and solubility in the ink composition Compounds, glycol monoester compounds, and glycol diester compounds are preferred.

  Examples of compounds having sulfur include aliphatic sulfonic acid compounds, aromatic sulfonic acid compounds, aliphatic sulfonic acid ester compounds, aromatic sulfonic acid ester compounds, thiophene compounds, sulfenic acid compounds, sulfone compounds, sulfide compounds, and sulfoxide compounds. , Aliphatic thiol compounds, aromatic thiol compounds, sulfonium salt compounds, and the like, preferably aliphatic thiol compounds, aromatic thiol compounds, thiophene compounds, sulfoxide compounds, sulfide compounds, and sulfone compounds. More specifically, methanethiol, ethanethiol, propanethiol, butanethiol, pentanethiol, hexanethiol, cyclopentanethiol, ethanedithiol, pentanedithiol, hexanedithiol, cyclohexanethiol, thiophenol, thiocresol, thioanisidine, thioanisole , Thiophenetol, naphthalenethiol, benzenedithiol, thiophene, bithiophene, terthiophene, dimethyl sulfoxide, diphenyl sulfoxide, methylphenyl sulfoxide, dimethyl sulfide, diethyl sulfide, ethyl methyl sulfide, dimethylene sulfide, cyclopropyl phenyl sulfide, trimethylene sulfide , Ethyl phenyl sulfide, diphenyl sulfide, dimethyl sulfate , Ethyl methyl sulfone, diethyl sulfone, diphenyl sulfone, ethyl phenyl sulfone, etc. Among them, ethanethiol, ethanedithiol, cyclohexanethiol, thiol from the viewpoint of easy availability and solubility in the ink composition Phenol, thioanisole, thiophene, dimethyl sulfide, diphenyl sulfide, dimethyl sulfone, diphenyl sulfone, dimethyl sulfoxide, and diphenyl sulfoxide are preferred.

  The solvent when the color change inhibitor includes a solvent is not particularly limited, but is water, alcohol such as methanol, ethanol, isopropyl alcohol, and cyclohexanol, alkane such as pentane, hexane, and octane, cyclic alkane such as cyclohexane, Aromatic solvents such as benzene, toluene, xylene, mesitylene, tetralin, diphenylmethane, aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate, 1,2-dimethoxybenzene, 1, Aromatics such as 3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole Aliphatic esters such as ether, ethyl acetate, n-butyl acetate, ethyl lactate, n-butyl lactate, aroma such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate Amide solvents such as aromatic esters, N, N-dimethylformamide, N, N-dimethylacetamide, halogen solvents such as chloroform, methylene chloride, chlorobenzene, o-dichlorobenzene, ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, etc. From the viewpoint of solubility, aromatic solvents, aliphatic esters, aromatic esters, aliphatic ethers, aromatic ethers, and halogen solvents can be preferably used.

  The color change inhibitor of the present invention is particularly preferably used in an ink composition because it can provide a uniform effect over the entire range where prevention of color change is expected.

[Ink composition]
The ink composition of the present invention contains the above color change inhibitor. The solvent used in the ink composition of the present invention is not particularly limited, and examples thereof include the same solvents as the color change inhibitor.

  The proportion of the color change inhibitor in the ink composition is usually preferably 0.01% by mass to 50% by mass, more preferably 0.01% by mass to 40% by mass, and more preferably 0.01% by mass to 30% by mass. % Or less is most preferable. If the amount is less than 0.01% by mass, the effect of preventing color change may not be sufficiently obtained. If the amount is more than 50% by mass, the color change inhibitor cannot be dissolved in the ink and a uniform ink composition is prepared. There is a risk that it will not be possible.

  Since the ink composition of the present invention can be used for forming a charge transport film, it contains a charge transport compound.

[Charge transporting compound]
Here, the “charge transporting compound” in the present invention will be described in detail. In the present invention, the charge transporting compound may be a commercially available compound or a compound synthesized by a method known to those skilled in the art, and is not particularly limited. Moreover, it is sufficient that it contains an atomic group having a hole or electron transport capability, and is not particularly limited, but is preferably an amine having an aromatic ring (aromatic amine), carbazole, or a thiophene compound. It is preferable to have a partial structure represented by the general formulas (1) to (58).

(Wherein, -R ¹ each E is ^{independently, -OR 2, -SR 3, -OCOR} 4, -COOR 5, -SiR 6 R 7 R 8, halogen or the formula, (59) - (61) (Wherein R ^{1 to} R ¹¹ represent a hydrogen atom, a linear, cyclic or branched alkyl group having 1 to 22 carbon atoms, or an aryl group or heteroaryl group having 2 to 30 carbon atoms; a and b and c represents an integer greater than or equal to 1. Here, the aryl group is an atomic group obtained by removing one hydrogen atom from an aromatic hydrocarbon, which may have a substituent. An atomic group obtained by removing one hydrogen atom from an aromatic compound having a hetero atom, which may have a substituent.), Or represented by the following substituent group (A) to substituent group (N) Ar represents carbon independently. Represents an arylene group of 2 to 30 or a heteroarylene group, which is an atomic group obtained by removing two hydrogen atoms from an aromatic hydrocarbon, and may have a substituent, for example, phenylene, biphenyl -Diyl, terphenyl-diyl, naphthalene-diyl, anthracene-diyl, tetracene-diyl, fluorene-diyl, phenanthrene-diyl, etc. A heteroarylene group is an aromatic compound having two hetero atoms. And may have a substituent, such as pyridine-diyl, pyrazine-diyl, quinoline-diyl, isoquinoline-diyl, acridine-diyl, phenanthroline-diyl, furan-diyl, pyrrole-diyl. Thiophene-diyl, oxazole-diyl, oxadia Zol-diyl, thiadiazole-diyl, triazole-diyl, benzoxazole-diyl, benzooxadiazole-diyl, benzothiadiazole-diyl, benzotriazole-diyl, benzothiophene-diyl, etc. X and Z are each independently. There are no particular restrictions on the divalent linking group, but a group in which one hydrogen atom is further removed from a group having one or more hydrogen atoms in the R or a group exemplified by the linking group group (A) described later X is an integer of 0 to 2. Y is the trivalent linking group, and the R is a group obtained by removing two hydrogen atoms from a group having two or more hydrogen atoms.

Substituent group (A)

Substituent group (B)

Substituent group (C)

Substituent group (D)

Substituent group (E)

Substituent group (F)

Substituent group (G)

Substituent group (H)

Substituent group (I)

Substituent group (J)

Substituent group (K)

Substituent group (L)

Substituent group (M)

Substituent group (N)

Linking group (A)

  In addition, the charge transporting compound is preferably a polymer or an oligomer because of its high solubility in a solvent and easy preparation of an ink composition. From the viewpoint of excellent charge transporting property, the following general formula (1a) It is more preferable that it is a polymeric aromatic amine, carbazole, or thiophene compound represented by-(84a).

  When the charge transporting compound is a polymer or an oligomer, the number average molecular weight is preferably 1,000 or more and 1,000,000 or less from the viewpoint of solubility in a solvent and film formability. More preferably, it is 2,000 or more and 900,000 or less, and further preferably 3,000 or more and 800,000 or less. If it is less than 1,000, the compound is easily crystallized, resulting in poor film-forming properties. On the other hand, if it exceeds 1,000,000, the solubility in a solvent is lowered, and it becomes difficult to prepare a coating solution or a coating ink.

  The charge transporting compound preferably has one or more “polymerizable substituents” in order to change the solubility. Here, the “polymerizable substituent” means a substituent capable of forming a bond between two or more molecules by causing a polymerization reaction, and details thereof will be described below.

  Examples of the polymerizable substituent include a group having a carbon-carbon multiple bond (for example, vinyl group, acetylene group, butenyl group, acrylic group, acrylate group, acrylamide group, methacryl group, methacrylate group, methacrylamide group, arene group). , Allyl group, vinyl ether group, vinylamino group, furyl group, pyrrole group, thiophene group, silole group, etc.), a group having a small ring (for example, cyclopropyl group, cyclobutyl group, epoxy group, oxetane group) , Diketene groups, episulfide groups, etc.), lactone groups, lactam groups, or groups containing siloxane derivatives. In addition to the above groups, combinations of groups capable of forming an ester bond or an amide bond can also be used. For example, a combination of an ester group and an amino group, an ester group and a hydroxyl group, or the like. As the polymerizable substituent, an oxetane group, an epoxy group, a vinyl group, a vinyl ether group, an acrylate group, and a methacrylate group are particularly preferable from the viewpoint of reactivity, and an oxetane group is most preferable. From the viewpoint of increasing the degree of freedom of the polymerizable substituent and facilitating the occurrence of a curing reaction, it is more preferable that the polymerizable substituent in the charge transporting compound is connected by an alkyl chain having 1 to 8 carbon atoms. From the viewpoint of increasing the affinity with a hydrophilic electrode such as ITO, the alkyl chain is more preferably a hydrophilic group such as ethylene glycol or diethylene glycol. Further, from the viewpoint of facilitating the preparation of the corresponding compound, it may have an ether bond at the terminal part of the alkyl chain, that is, the connecting part with the polymerizable substituent and the connecting part with the charge transporting compound. More specifically, it is specifically represented by the substituent groups (A) to (C).

  Further, the polymer or oligomer in the present invention is represented by the following structural formula group (O) as the above arylene group and heteroarylene group in addition to the above repeating unit for the purpose of adjusting the solubility, heat resistance, and electrical characteristics. It may be a copolymer having a structure as a copolymer repeating unit. In this case, the copolymer may be a random, block or graft copolymer, or may be a polymer having an intermediate structure thereof, for example, a random copolymer having a block property. In addition, the polymer or oligomer used in the present invention may have branching in the main chain and may have three or more terminals.

Structural formula group (O)

  The ink composition of the present invention contains an electron-accepting compound in order to improve the charge transporting property of the charge transporting compound.

<Electron-accepting compound>
Here, the “electron-accepting compound” in the present invention will be described in detail. In the present invention, the electron-accepting compound may be a commercially available compound or a compound synthesized by a method known to those skilled in the art, and is not particularly limited.
Specifically, both inorganic substances and organic substances can be used, and examples thereof include the compounds described in Patent Documents 1 to 4, among which compounds having a perfluoroaryl group or a perfluoroalkyl group are preferable. .

  In the present invention, the conditions for using the electron-accepting compound may be 0.1 to 50% by mass of the electron-accepting compound based on the mass of the charge transporting compound.

  The ink composition of the present invention may contain a polymerization initiator in order to change the solubility of the charge transporting compound. The polymerization initiator may be a commercially available product or may be synthesized by a method known to those skilled in the art, and is not particularly limited. The conditions for using the polymerization initiator are as follows: after forming a thin film using 0.1 to 50% by weight of the polymerization initiator based on the mass of the compound having a polymerizable substituent, in vacuum, in the air or in a nitrogen atmosphere You can heat with. The heating temperature and time are not particularly limited as long as the polymerization reaction can be sufficiently advanced. However, the temperature is preferably 300 ° C. or less, more preferably 200 ° C. or less, more preferably, since various substrates can be applied. Is 150 ° C. or lower. From the viewpoint of increasing productivity, the time is preferably 2 hours or less, more preferably 1 hour or less, and even more preferably 30 minutes or less.

  In addition to the above components, the ink composition of the present invention includes other additives such as polymerization inhibitors, stabilizers, thickeners, gelling agents, flame retardants, antioxidants, reducing agents, oxidizing agents, reducing agents. , Surface modifiers, emulsifiers, antifoaming agents, dispersants, surfactants and the like may be included.

<Organic thin film>
The organic thin film of the present invention is formed from the ink composition of the present invention described above. The organic thin film of the present invention can produce an organic thin film having uniform characteristics due to the effect of the color change inhibitor of the present invention, and when applied to an organic EL element, variations in element characteristics such as light emission efficiency and light emission lifetime. Can be suppressed.

<Organic electronics devices, organic electroluminescence devices>
The organic electronic device of the present invention is characterized by including at least one organic thin film of the present invention described above.
Similarly, the organic electroluminescent element (organic EL element) of the present invention is characterized by including at least one organic thin film of the present invention described above.
All of the elements include the organic thin film of the present invention as the organic thin film, and have little variation in characteristics.
The EL element of the present invention will be described in detail below.

[Organic EL device]
The organic electronic device of the present invention is characterized by including an organic thin film obtained from the ink composition of the present invention described above. The organic EL device of the present invention is not particularly limited as long as it includes a light emitting layer, a polymerized layer, an anode, a cathode, and a substrate. Other elements such as a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer are used. It may have a layer. Moreover, it is preferable to apply the organic thin film of this invention to a positive hole injection layer or a positive hole transport layer.
Hereinafter, each layer will be described in detail.

[Light emitting layer]
The material used for the light emitting layer may be a low molecular compound, a polymer or an oligomer, and a dendrimer or the like can also be used. Low molecular weight compounds that utilize fluorescence include perylene, coumarin, rubrene, quinacridone, dye dyes for dye laser (eg, rhodamine, DCM1, etc.), aluminum complexes (eg, Tris (8-hydroxyquinolinato) aluminum (III) (Alq ₃ )), Stilbene, and derivatives thereof. Polymers or oligomers that utilize fluorescence include polyfluorene, polyphenylene, polyphenylene vinylene (PPV), polyvinyl carbazole (PVK), fluorene-benzothiadiazole copolymer, fluorene-triphenylamine copolymer, and derivatives thereof. And a mixture can be suitably used.

  On the other hand, in recent years, phosphorescent organic EL devices have been actively developed in order to increase the efficiency of organic EL devices. In the phosphorescent organic EL element, not only singlet state energy but also triplet state energy can be used, and the internal quantum yield can be increased to 100% in principle. In a phosphorescent organic EL device, phosphorescence is extracted by doping a host material with a metal complex phosphorescent material containing a heavy metal such as platinum or iridium as a phosphorescent dopant (MABaldo et al., Nature, vol. 395). , p. 151 (1998), MABaldo et al., Applied Physics Letters, vol. 75, p. 4 (1999), MABaldo et al., Nature, vol. 403, p. 750 (2000)). .

Also in the organic EL device of the present invention, it is preferable to use a phosphorescent material for the light emitting layer from the viewpoint of high efficiency. As the phosphorescent material, a metal complex containing a central metal such as Ir or Pt can be preferably used. Specifically, as an Ir complex, for example, FIr (pic) that emits blue light [iridium (III) bis [(4,6-difluorophenyl) -pyridinate-N, C ² ] picolinate], green light is emitted. Ir (ppy) ₃ [Factris (2-phenylpyridine) iridium] (see MABaldo et al., Nature, vol. 403, p. 750 (2000)) or Adachi et al. , Appl. Phys. Lett. 78no. (Btp) ₂ Ir (acac) {bis [2- (2′-benzo [4,5-α] thienyl) pyridinate-N, C3] iridium (acetyl-acetonate) )}, Ir (piq) ₃ [Tris (1-phenylisoquinoline) iridium] and the like.

Examples of the Pt complex include 2,3,7,8,12,13,17, 18-octaethyl-21H, 23H-forminplatinum (PtOEP) that emits red light.
The phosphorescent material can be a small molecule or a dendrite species, such as an iridium nucleus dendrimer. Moreover, these derivatives can also be used conveniently.

Further, in the case where a phosphorescent material is included in the light emitting layer, it is preferable that a host material is included in addition to the phosphorescent material.
The host material may be a low molecular compound or a high molecular compound, and a dendrimer or the like can also be used.

  Examples of the low molecular weight compound include CBP (4,4′-Bis (Carbazol-9-yl) -biphenyl), mCP (1,3-bis (9-carbazolyl) benzene), CDBP (4,4′-Bis). (Carbazol-9-yl) -2,2′-dimethylbiphenyl) and the like, for example, polyvinyl carbazole, polyphenylene, polyfluorene, etc. can be used as the polymer compound, and derivatives thereof can also be used.

The light emitting layer may be formed by a vapor deposition method or a coating method.
When forming by the apply | coating method, an organic EL element can be manufactured cheaply and it is more preferable. In order to form a light emitting layer by a coating method, a solution containing a phosphorescent material and, if necessary, a host material is used, for example, an ink jet method, a casting method, a dipping method, a relief printing, an intaglio printing, an offset printing, a flat printing, a relief printing. It can be carried out by applying on a desired substrate by a known method such as a printing method such as reverse offset printing, screen printing or gravure printing, or spin coating method.

[cathode]
The cathode material is preferably a metal or metal alloy such as Li, Ca, Mg, Al, In, Cs, Ba, Mg / Ag, LiF, and CsF.

[anode]
As the anode, a metal (for example, Au) or other material having metal conductivity, for example, an oxide (for example, ITO: indium oxide / tin oxide), a conductive polymer (for example, a polythiophene-polystyrene sulfonic acid mixture (for example, PEDOT: PSS)) can also be used.

[Electron transport layer, electron injection layer]
Examples of the electron transport layer and the electron injection layer include phenanthroline derivatives (for example, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)), bipyridine derivatives, nitro-substituted fluorene derivatives, diphenylquinone. Derivatives, thiopyrandioxide derivatives, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives (2- (4-Biphenylyl) -5 -(4-tert-butylphenyl-1,3,4-oxadiazole) (PBD)), aluminum complexes (for example, Tris (8-hydroxyquinolinato) aluminum (III) (Alq ₃ )) and the like. Furthermore, in the oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can be used.

[substrate]
As the substrate that can be used in the organic EL device of the present invention, the kind of glass, plastic and the like is not particularly limited, and is not particularly limited as long as it is transparent, but glass, quartz, light transmissive A resin film or the like is preferably used. When a resin film is used, flexibility can be imparted to the organic EL element (that is, a flexible substrate), which is particularly preferable.

  Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose triacetate. Examples thereof include films made of (TAC), cellulose acetate propionate (CAP) and the like.

  Moreover, when using a resin film, in order to suppress permeation | transmission of water vapor | steam, oxygen, etc., you may coat and use inorganic substances, such as a silicon oxide and silicon nitride, on a resin film.

[Luminescent color]
The emission color in the organic EL device of the present invention is not particularly limited, but the white light-emitting device is preferable because it can be used for various lighting devices such as home lighting, interior lighting, clocks, and liquid crystal backlights.

  As a method of forming a white light emitting element, since it is currently difficult to show white light emission with a single material, a plurality of light emitting colors can be simultaneously emitted and mixed using a plurality of light emitting materials. White luminescence is obtained. A combination of a plurality of emission colors is not particularly limited. However, a combination of three emission maximum wavelengths of blue, green, and red, a complementary color relationship such as blue and yellow, yellow green and orange is used. The thing containing two light emission maximum wavelengths is mentioned. The emission color can be controlled by adjusting the type and amount of the phosphorescent material.

<Display element, lighting device, display device>
The display element of the present invention is characterized by including the above-described organic EL element of the present invention.
For example, a color display element can be obtained by using the organic EL element of the present invention as an element corresponding to each pixel of red, green, and blue (RGB).
Image formation includes a simple matrix type in which individual organic EL elements arranged in a panel are directly driven by electrodes arranged in a matrix, and an active matrix type in which thin film transistors are arranged and driven in each element. The former is simple in structure but has a limit on the number of vertical pixels and is used for displaying characters. The latter is used for high-quality displays because the drive voltage is low and the current is small, and a bright high-definition image is obtained.

  The illumination device of the present invention is characterized by including the organic EL element of the present invention described above. Furthermore, the display device of the present invention is characterized by including a lighting device and a liquid crystal element as a display means. The illumination device of the present invention described above may be used as a backlight (white light source), and a display device using a liquid crystal element as a display unit, that is, a liquid crystal display device may be used. This configuration is a configuration in which only the backlight is replaced with the illumination device of the present invention in a known liquid crystal display device, and a known technique can be diverted to the liquid crystal element portion.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

<Preparation of Pd catalyst>
In a glove box under a nitrogen atmosphere, tris (dibenzylideneacetone) dipalladium (73.2 mg, 80 μmol) was weighed into a sample tube at room temperature, anisole (15 ml) was added, and the mixture was stirred for 30 minutes. Similarly, tris (t-butyl) phosphine (129.6 mg, 640 μmol) was weighed in a sample tube, anisole (5 ml) was added, and the mixture was stirred for 5 minutes. These solutions were mixed and stirred at room temperature for 30 minutes to obtain a catalyst.

<Synthesis of charge transporting compound>
The following monomer 1 (4.0 mmol), the following monomer 2 (5.0 mmol), the following monomer 3 (2.0 mmol) and anisole (20 ml) were added to a three-necked round bottom flask, and a further prepared Pd catalyst solution (7.5 ml) ) Was added. After stirring for 30 minutes, 10% tetraethylammonium hydroxide aqueous solution (20 ml) was added. All solvents were used after degassing with nitrogen bubble for more than 30 minutes. This mixture was heated to reflux for 2 hours. All the operations so far were performed under a nitrogen stream.

  After completion of the reaction, the organic layer was washed with water, and the organic layer was poured into methanol-water (9: 1). The resulting precipitate was suction filtered and washed with methanol-water (9: 1). The resulting precipitate was dissolved in toluene and reprecipitated from methanol. The obtained precipitate was suction filtered, dissolved in toluene, triphenylphosphine, polymer-bound on styrene-divine benzene copolymer (200 mg from 100 mg of polymer, polymer), and stirred overnight. After completion of the stirring, triphenylphosphine, polymer-bound on styrene-divinylbenzene copolymer and insoluble matter were removed by filtration, and the filtrate was concentrated by a rotary evaporator. The residue was dissolved in toluene and then reprecipitated from methanol-acetone (8: 3). The resulting precipitate was filtered by suction and washed with methanol-acetone (8: 3). The resulting precipitate was vacuum-dried to obtain polymer 1. The molecular weight was measured by GPC (polystyrene conversion) using THF as an eluent. The number average molecular weight of the obtained polymer 1 was 7,800, and the weight average molecular weight was 31,000.

<Preparation of ink composition containing color change inhibitor>
[Example 1]
Polymer 1 (150 mg), electron-accepting compound 1 (15 mg), toluene (8.0 mL), and triamylamine (100 μL) obtained above were stirred for 5 hours to prepare an ink composition. A light red ink composition was obtained.

[Example 2]
An ink composition was prepared in the same manner except that triamylamine of Example 1 was replaced with dicyclohexylmethylamine (100 μL). A light red ink composition was obtained.

[Example 3]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with cyclohexanol (100 μL). A light red ink composition was obtained.

[Example 4]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with triethanolamine (100 μL). A light red ink composition was obtained.

[Example 5]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with N, N-dimethylformamide (100 μL). A light red ink composition was obtained.

[Example 6]
An ink composition was prepared in the same manner except that triamylamine of Example 1 was replaced with diethylene glycol monoethyl ether (100 μL). A light red ink composition was obtained.

[Example 7]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with benzyl alcohol (100 μL). A light red ink composition was obtained.

[Example 8]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with N-ethyl-N-methylbenzylamine (100 μL). A light red ink composition was obtained.

[Example 9]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with N, N, N ′, N′-tetramethylnaphthalenediamine (100 mg). A light red ink composition was obtained.

[Example 10]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with 1-ethylpiperidine (100 μL). A light red ink composition was obtained.

[Example 11]
An ink composition was prepared in the same manner except that triamylamine of Example 1 was replaced with tetraoctylphosphonium bromide (100 mg). A light red ink composition was obtained.

[Example 12]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with tetraethylammonium iodide (100 mg). A light red ink composition was obtained.

[Example 13]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with N, N-dimethyl-N-tetradecylamine (100 μL). A light red ink composition was obtained.

[Example 14]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with N-methyldioctylamine (100 μL). A light red ink composition was obtained.

[Example 15]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with tris (2-ethylhexyl) amine (100 μL). A light red ink composition was obtained.

[Example 16]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with tris {(2-methoxyethoxy) ethyl} amine (100 μL). A light red ink composition was obtained.

[Example 17]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with triisoamylamine (100 μL). A light red ink composition was obtained.

[Example 18]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with N, N-dimethyl-N-octadecylamine (100 μL). A light red ink composition was obtained.

[Example 19]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with N, N, N ′, N′-tetramethyl-1,6-diaminohexane (100 μL). A light red ink composition was obtained.

[Example 20]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with 1,2-cyclohexanediamine (100 μL). A light red ink composition was obtained.

[Example 21]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with tridodecylamine (100 μL). A light red ink composition was obtained.

[Example 22]
An ink composition was prepared in the same manner except that triamylamine of Example 1 was replaced with dibutylamine (100 μL). A light red ink composition was obtained.

[Example 23]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with N, N-didecyl-N-methylamine (100 μL). A light red ink composition was obtained.

[Example 24]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was replaced with a saturated toluene solution (100 μL) of dibenzo-18-crown-6. A light red ink composition was obtained.

[Example 25]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with 18-crown-6 (100 mg). A light red ink composition was obtained.

[Example 26]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with o-tolylphosphine (100 mg). A light red ink composition was obtained.

[Example 27]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with 4-octylaniline (100 μL). A light red ink composition was obtained.

[Example 28]
An ink composition was prepared in the same manner except that trimethylamine in Example 1 was replaced with 3-methyl-3-oxetanemethanol (100 μL). A light red ink composition was obtained.

[Example 29]
An ink composition was prepared in the same manner except that triamylamine of Example 1 was replaced with p-anisidine (100 mg). A light red ink composition was obtained.

[Comparative Example 1]
An ink composition was prepared in the same manner except that the triamylamine of Example 1 was not included. A light red ink composition was obtained.

[Comparative Example 2]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with o-xylene (100 μL). A light red ink composition was obtained.

[Comparative Example 3]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with chlorobenzene (100 μL). A light red ink composition was obtained.

[Comparative Example 3]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with mesitylene (100 μL). A light red ink composition was obtained.

[Comparative Example 4]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with 1-phenylhexane (100 μL). A light red ink composition was obtained.

[Comparative Example 5]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with fluorene (100 mg). A light red ink composition was obtained.

[Comparative Example 6]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with tetralin (100 μL). A light red ink composition was obtained.

[Comparative Example 7]
An ink composition was prepared in the same manner except that triamylamine in Example 1 was replaced with diphenylmethane (100 μL). A light red ink composition was obtained.

<Color change test 1>
The ink compositions obtained in Examples 1 to 29 and Comparative Examples 1 to 7 were transferred to a sample tube and sealed. The sample tube was immersed in a hot water bath in a constant temperature bath under light shielding and stored at 50 ° C. for 200 hours.
<Color change test 2>
The ink compositions obtained in Examples 1 to 29 and Comparative Examples 1 to 7 were transferred to a sample tube and sealed. The sample tube was stored at normal temperature for 200 hours under normal light.
The results of the above color change tests 1 and 2 are shown in Table 1.

  From the results in Table 1, it can be seen that the color change of the ink composition containing the color change inhibitor in the present invention is suppressed during storage at high temperature or storage in the presence of light.

<Production of organic EL element>
[Example 30]
After spin-coating the ink composition obtained in Example 1 at 3000 min ⁻¹ on a glass substrate on which ITO was patterned to a width of 1.6 mm, it was cured by heating at 180 ° C. for 10 minutes on a hot plate, A hole injection layer (40 nm) was formed.

Next, in nitrogen, CDBP (15 mg), FIr (pic) (0.9 mg), Ir (ppy) 3 (0.9 mg), (btp) 2Ir (acac) (1.2 mg), dichlorobenzene (0. 5 mL) was spin-coated at 3000 rpm and then dried at 80 ° C. for 5 minutes to form a light emitting layer (40 nm). Further, transferred into a vacuum deposition _{machine, BAlq (10nm), Alq 3} (30nm), LiF ( film thickness 0.5 nm), deposited in this order Al (thickness 100 nm), white organic EL device and to sealing treatment Five lighting devices were produced.

[Example 31]
Five white organic EL elements and lighting devices were produced in the same manner except that the ink composition obtained in Example 1 in Example 30 was replaced with the ink composition that had passed 200 hours in the color change test 1 in Example 1. did.

[Comparative Example 8]
Five white organic EL elements and lighting devices were produced in the same manner except that the ink composition obtained in Example 1 in Example 30 was replaced with the ink composition obtained in Comparative Example 1.

[Comparative Example 9]
Five white organic EL elements and lighting devices were produced in the same manner except that the ink composition obtained in Example 1 in Example 30 was replaced with the ink composition that had passed 200 hours in Color Change Test 1 of Comparative Example 1. .

A voltage was applied to the organic EL elements and lighting devices obtained in Examples 30 and 31 and Comparative Examples 8 and 9, and the light emission start voltage and the light emission lifetime corresponding to the initial luminance of 1000 cd / m ² were the maximum value and the minimum value, respectively. The results for the values and Δ (maximum value−minimum value) are shown in Table 2.

  From Table 2, the organic EL element including the organic thin film formed using the ink composition of the present invention and the white lighting device have a Δ value which is a variation in the light emission start voltage and the light emission lifetime, and the organic EL element It can be seen that productivity and yield can be improved.

DESCRIPTION OF SYMBOLS 1 Light emitting layer 2 Anode 3 Hole injection layer 4 Cathode 5 Electron injection layer 6 Hole transport layer 7 Electron transport layer 8 Substrate

Claims (12)

A color change preventing agent for preventing color change of an ink composition comprising at least one charge transporting compound and an electron accepting compound,
A color change inhibitor comprising a compound having a Group 15 element or a Group 16 element. An ink composition comprising at least one charge transporting compound and an electron accepting compound,
An ink composition comprising a color change inhibitor containing a compound having a Group 15 element or a Group 16 element.   An organic thin film formed using the ink composition according to claim 2.   An organic electronic device comprising the organic thin film according to claim 3.   The organic electroluminescent element containing the organic thin film of Claim 3.   The organic electroluminescent element according to claim 5, wherein the organic thin film is a hole injection layer.   The organic electroluminescent element according to claim 5 or 6, wherein the organic thin film is a hole transport layer.   The organic electroluminescent element of any one of Claims 5-7 using a flexible substrate.   The organic electroluminescent element according to any one of claims 5 to 8, wherein a resin film substrate is used.   The display element provided with the organic electroluminescent element of any one of Claims 5-9.   The illuminating device provided with the organic electroluminescent element of any one of Claims 5-9.   The display apparatus provided with the illuminating device of Claim 11, and a liquid crystal element as a display means.

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