JP2012235064A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element in which infiltration of moisture into a hole injection layer is prevented.SOLUTION: The organic electroluminescent element 1 has a light-emitting part 40 including at least a hole injection layer 41 and a luminous layer 43 between a pair of electrodes (positive electrode 20, negative electrode 30). The hole injection layer 41 consists of a conductive coating film formed of a conductive paint. The conductive paint contains a π-conjugated conductive polymer, polyanion, a fluorine-containing epoxy compound where at least some hydrogen atoms of an epoxy compound is replaced by a fluorine atom, and a solvent. When the total of mass of the π-conjugated conductive polymer and the polyanion is 1, the mass ratio of the fluorine-containing epoxy compound is 0.5-3.0.

Description

  The present invention relates to an organic electroluminescence element having a light emitting portion provided with a hole injection layer and a light emitting layer between a pair of electrodes.

In recent years, organic electroluminescence displays including organic electroluminescence elements have been commercialized as thin displays following plasma displays and liquid crystal displays.
An organic electroluminescence element is a spontaneous light-emitting element using a principle that a fluorescent material emits light by recombination energy of holes injected from an anode and electrons injected from a cathode. Specifically, the organic electroluminescence element is provided with a light-emitting portion composed of a laminate of a light-emitting layer and a thin film layer for functionally operating the light-emitting layer between a pair of electrodes. As the thin film layer, a hole injection layer for injecting holes from the anode, a hole transport layer for transporting holes to the light emitting layer, and the like are used.

As the hole injection layer of the organic electroluminescence element, a thin film containing a π-conjugated conductive polymer is sometimes used because it can be formed by a coating method (Patent Documents 1 and 2). Here, the hole injection layer has a HOMO level between the highest occupied orbital (HOMO) level of the hole transport layer and the work function of the anode, and serves as a hole injection barrier from the anode to the light emitting layer. Play the role of lowering. When a π-conjugated conductive polymer is used for the hole injection layer, it can be said that it is suitable as a hole injection layer if it has a conductivity with a surface resistivity of 10 ⁴ to 10 ⁸ Ω / □. It has been broken.
In order to improve the performance of the organic electroluminescence device, a conductive polymer containing poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (hereinafter referred to as “PEDOT / PSS”) is used as a hole injection layer. It is known to use a combination of fluorine-containing polymer acids. For example, Patent Document 3 discloses that the use of an aqueous dispersion polythiophene obtained by oxidative polymerization of thiophene in the presence of perfluoroethylenesulfonic acid for the hole injection layer improves the luminous efficiency and lifetime of the organic electroluminescence device. Has been.
Patent Document 4 discloses that the lifetime of the organic electroluminescence element is improved by using a material in which Nafion (registered trademark) is mixed with PEDOT / PSS for the hole injection layer.

However, since many conductive polymers represented by PEDOT / PSS are water-soluble, a coating film of the order of several tens of nanometers, such as a hole injection layer, absorbs moisture in the atmosphere and improves initial performance. It may not be maintained. Further, when moisture is absorbed, the ionic substance in the coating film can be easily moved, so that a power storage effect occurs, which may cause a leakage current and adversely affect the light emission characteristics.
As a method for removing moisture after coating with high efficiency and obtaining a stable coating film, drying at a glass transition point or higher (Patent Document 5) and freeze-drying (Patent Document 6) are disclosed. It was difficult to prevent the intrusion of water after becoming.

European Patent Application No. 1227529 JP 2005-108828 A JP-T-2006-500463 Japanese Patent Laying-Open No. 2005-226072 JP 2004-55283 A JP 2004-55279 A

  An object of this invention is to provide the organic electroluminescent element by which the penetration | invasion of the water | moisture content to the positive hole injection layer was prevented.

  The organic electroluminescence device of the present invention is an organic electroluminescence device having a light emitting portion having at least a hole injection layer and a light emitting layer between a pair of electrodes, wherein the hole injection layer is formed from a conductive paint. The conductive paint comprises a π-conjugated conductive polymer, a polyanion, a fluorine-containing epoxy compound in which at least some of the hydrogen atoms of the epoxy compound are substituted with fluorine atoms, and a solvent, and π The mass ratio of the fluorine-containing epoxy compound when the total mass of the conjugated conductive polymer and the polyanion is 1 is 0.5 to 3.0.

  In the organic electroluminescence device of the present invention, moisture permeation into the hole injection layer is prevented. Therefore, the moisture resistance is high and the initial performance is easy to maintain. Furthermore, since it is not easily affected by moisture in the atmosphere and the performance does not deteriorate even when left for a long period of time, the degree of freedom in manufacturing the organic electroluminescence element is increased.

It is sectional drawing which shows one Embodiment of the organic electroluminescent element of this invention.

An embodiment of the organic electroluminescence element (hereinafter referred to as “OEL element”) of the present invention will be described.
FIG. 1 shows a cross-sectional view of the OEL element of this embodiment. The OEL element 1 of the present embodiment includes a base material 10, an anode 20 and a cathode 30 provided on one side of the base material 10, and a light emitting unit 40 provided therebetween.

<Light emitting part>
The light emitting unit 40 is composed of a laminate of a hole injection layer 41, a hole transport layer 42, a light emitting layer 43, and an electron transport layer 44. Further, the hole injection layer 41, the hole transport layer 42, the light emitting layer 43, and the electron transport layer 44 are arranged in this order from the anode 20 side toward the cathode 30 side.

(Hole injection layer)
The hole injection layer 41 is made of a conductive coating film formed from a conductive paint.
The conductive paint includes a π-conjugated conductive polymer, a polyanion, a fluorine-containing epoxy compound, and a solvent.

[Π-conjugated conductive polymer]
The π-conjugated conductive polymer is not particularly limited as long as the main chain is an organic polymer composed of a π-conjugated system. For example, polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, Examples thereof include polyanilines, polyacenes, polythiophene vinylenes, and copolymers thereof. From the viewpoint of stability in air, polypyrroles, polythiophenes and polyanilines are preferred. Polythiophenes are more preferable in terms of compatibility with polar solvents and transparency.

  Specific examples of the π-conjugated conductive polymer include polypyrrole, poly (N-methylpyrrole), poly (3-methylpyrrole), poly (3-ethylpyrrole), poly (3-n-propylpyrrole), poly (3-butylpyrrole), poly (3-octylpyrrole), poly (3-decylpyrrole), poly (3-dodecylpyrrole), poly (3,4-dimethylpyrrole), poly (3,4-dibutylpyrrole) , Poly (3-carboxypyrrole), poly (3-methyl-4-carboxypyrrole), poly (3-methyl-4-carboxyethylpyrrole), poly (3-methyl-4-carboxybutylpyrrole), poly (3 -Hydroxypyrrole), poly (3-methoxypyrrole), poly (3-ethoxypyrrole), poly (3-butoxypyrrole), poly (3-methyl) -4-hexyloxypyrrole), poly (thiophene), poly (3-methylthiophene), poly (3-ethylthiophene), poly (3-propylthiophene), poly (3-butylthiophene), poly (3-hexyl) Thiophene), poly (3-heptylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), poly (3-octadecylthiophene), poly (3-bromothiophene) , Poly (3-chlorothiophene), poly (3-iodothiophene), poly (3-cyanothiophene), poly (3-phenylthiophene), poly (3,4-dimethylthiophene), poly (3,4-dibutyl) Thiophene), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3 -Ethoxythiophene), poly (3-butoxythiophene), poly (3-hexyloxythiophene), poly (3-heptyloxythiophene), poly (3-octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxythiophene), poly (3-octadecyloxythiophene), poly (3-methyl-4-methoxythiophene), poly (3,4-ethylenedioxythiophene), poly (3-methyl-4-ethoxy) Thiophene), poly (3-carboxythiophene), poly (3-methyl-4-carboxythiophene), poly (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxybutylthiophene), polyaniline , Poly (2-methylaniline), poly (3-isobutyla) Phosphorus), poly (2-aniline sulfonic acid), poly (3-aniline sulfonic acid), and the like.

Even if the π-conjugated conductive polymer remains unsubstituted, sufficient conductivity can be obtained. However, in order to further increase the conductivity, an alkyl group, a carboxy group, a sulfo group, an alkoxy group, a hydroxy group, etc. It is preferable to introduce a functional group into the π-conjugated conductive polymer.
Among the π-conjugated conductive polymers, poly (3,4-ethylenedioxythiophene) is preferable because of its excellent conductivity, transparency, and heat resistance.

[Polyanion]
Examples of the polyanion include a substituted or unsubstituted polyalkylene, a substituted or unsubstituted polyalkenylene, a substituted or unsubstituted polyimide, a substituted or unsubstituted polyamide, and a substituted or unsubstituted polyester having an anionic group. Examples thereof include a polymer composed only of a structural unit, and a polymer composed of a structural unit having an anionic group and a structural unit not having an anionic group.
Note that the polyanion also functions as a dopant for the π-conjugated conductive polymer.

A polyalkylene is a polymer whose main chain is composed of repeating methylenes. Polyalkenylene is a polymer composed of structural units containing one unsaturated double bond (vinyl group) in the main chain.
As polyimide, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, 2,2 ′-[4,4′-di (dicarboxyphenyloxy) phenyl] propane dianhydride And polyimides from acid anhydrides such as oxydiamine, paraphenylenediamine, metaphenylenediamine, benzophenonediamine and the like.
Examples of the polyamide include polyamide 6, polyamide 6,6, polyamide 6,10 and the like.
Examples of the polyester include polyethylene terephthalate and polybutylene terephthalate.

  When the polyanion has a substituent, examples of the substituent include an alkyl group, a hydroxy group, an amino group, a carboxy group, a cyano group, a phenyl group, a phenol group, an ester group, and an alkoxy group. In view of solubility in a solvent, heat resistance and the like, an alkyl group, a hydroxy group, a phenol group, and an ester group are preferable.

Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, and cycloalkyl groups such as cyclopropyl, cyclopentyl, and cyclohexyl. It is done.
Examples of the hydroxy group include a hydroxy group bonded directly or via another functional group to the main chain of the polyanion. Examples of the other functional group include an alkyl group having 1 to 7 carbon atoms and an alkyl group having 2 to 7 carbon atoms. An alkenyl group, an amide group, an imide group, etc. are mentioned. Hydroxy groups are substituted at the ends or in these functional groups.
Examples of the amino group include an amino group bonded to the main chain of the polyanion directly or via another functional group. Examples of the other functional group include an alkyl group having 1 to 7 carbon atoms and an alkyl group having 2 to 7 carbon atoms. An alkenyl group, an amide group, an imide group, etc. are mentioned. The amino group is substituted at the end or in these functional groups.
Examples of the phenol group include a phenol group bonded directly or via another functional group to the main chain of the polyanion. Examples of the other functional group include an alkyl group having 1 to 7 carbon atoms and an alkyl group having 2 to 7 carbon atoms. An alkenyl group, an amide group, an imide group, etc. are mentioned. The phenol group is substituted at the end or in these functional groups.

Examples of the polyalkylene having a substituent include polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyvinyl alcohol, polyvinylphenol, poly (3,3,3-trifluoropropylene), polyacrylonitrile, polyacrylate, polystyrene and the like. it can.
Specific examples of polyalkenylene include propenylene, 1-methylpropenylene, 1-butylpropenylene, 1-decylpropenylene, 1-cyanopropenylene, 1-phenylpropenylene, 1-hydroxypropenylene, 1-butenylene, 1-methyl-1-butenylene, 1-ethyl-1-butenylene, 1-octyl-1-butenylene, 1-pentadecyl-1-butenylene, 2-methyl-1-butenylene, 2-ethyl-1-butenylene, 2- Butyl-1-butenylene, 2-hexyl-1-butenylene, 2-octyl-1-butenylene, 2-decyl-1-butenylene, 2-dodecyl-1-butenylene, 2-phenyl-1-butenylene, 2-butenylene, 1-methyl-2-butenylene, 1-ethyl-2-butenylene, 1-octyl-2-butenylene 1-pentadecyl-2-butenylene, 2-methyl-2-butenylene, 2-ethyl-2-butenylene, 2-butyl-2-butenylene, 2-hexyl-2-butenylene, 2-octyl-2-butenylene, 2- Decyl-2-butenylene, 2-dodecyl-2-butenylene, 2-phenyl-2-butenylene, 2-propylenephenyl-2-butenylene, 3-methyl-2-butenylene, 3-ethyl-2-butenylene, 3-butyl 2-butenylene, 3-hexyl-2-butenylene, 3-octyl-2-butenylene, 3-decyl-2-butenylene, 3-dodecyl-2-butenylene, 3-phenyl-2-butenylene, 3-propylenephenyl- 2-butenylene, 2-pentenylene, 4-propyl-2-pentenylene, 4-propyl-2-pentenylene, 4- Tyl-2-pentenylene, 4-hexyl-2-pentenylene, 4-cyano-2-pentenylene, 3-methyl-2-pentenylene, 4-ethyl-2-pentenylene, 3-phenyl-2-pentenylene, 4-hydroxy- Examples thereof include polymers containing one or more structural units selected from 2-pentenylene, hexenylene and the like.

Examples of the anion group of the _{^{polyanion, -O-SO 3 - X +}} , -SO 3 - X +, -COO - X + (. X + is the hydrogen ion in each of the formulas, represents an alkali metal ion), and the like. That is, the polyanion is a polymer acid containing a sulfo group and / or a carboxy group. Among these, from the viewpoint of doping effects on the π-conjugated conductive _{^{polymer, -SO 3 - X +, -COO}} - X + are preferable.
Moreover, it is preferable that this anion group is arrange | positioned in the principal chain of a polyanion adjacently or at fixed intervals.

  Among the polyanions, polyisoprene sulfonic acid, a copolymer containing polyisoprene sulfonic acid, a polysulfoethyl methacrylate, a copolymer containing polysulfoethyl methacrylate, and poly (4-sulfone) are preferable in view of solvent solubility and conductivity. Butyl methacrylate), copolymers containing poly (4-sulfobutyl methacrylate), polymethallyloxybenzene sulfonic acid, copolymers containing polymethallyloxybenzene sulfonic acid, polystyrene sulfonic acid, copolymer containing polystyrene sulfonic acid A coalescence or the like is preferable.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

  The content of the polyanion is preferably in the range of 0.1 to 10 mol, and more preferably in the range of 1 to 7 mol, with respect to 1 mol of the π-conjugated conductive polymer. If the polyanion content is less than 0.1 mol, the doping effect on the π-conjugated conductive polymer tends to be weakened, and the resulting conductive coating film may lack conductivity. In addition, the dispersibility and solubility in the solvent are lowered, making it difficult to obtain a uniform paint. On the other hand, when the polyanion content is more than 10 mol, the content of the π-conjugated conductive polymer is decreased, and it is difficult to obtain sufficient conductivity.

[Fluorine-containing epoxy compound]
The fluorine-containing epoxy compound is a compound in which at least a part of hydrogen atoms of the epoxy compound is substituted with fluorine atoms.
The fluorine-containing epoxy compound is preferably an aliphatic compound from the viewpoint of compatibility with the π-conjugated conductive polymer. Further, a linear structure is preferable to a branched structure.
Examples of the linear fluorine-containing epoxy compound include those having the following general formula.
_{Gu- (OCH 2) p - {} (CF 2 O) q- (CnF 2 (n-m))} r - (CH 2 O) p -Gu
Here, Gu is a glycidyl group. n is an integer of 1 or more, and is preferably 1 to 8 in terms of exhibiting excellent moldability. m, p, and q are each 0 to 1 (where m <n), and r is 1 to 3.

The linear fluorine-containing epoxy compound preferably has two epoxy groups and an ether bond from the viewpoint of further improving storage stability.
Epoxy compounds having two epoxy groups and ether bonds are fluorinated triethylene glycol diepoxide (product name: C6GDEP) and fluorinated tetraethylene glycol diepoxide (product name: C8GDEP) from Exflow Corporation of the United States. 1H, 1H, 4H, 4H-perfluoro-1,4-butanediol diepoxide (product name: C4DEP), 1H, 1H, 5H, 5H-perfluoro-1,5-pentanediol diepoxide (product name: C5DEP), 1H, 1H, 6H, 6H-perfluoro-1,6-hexanediol diepoxide (product name: C6DEP), 1H, 1H, 8H, 8H-perfluoro-1,8-octanediol diepoxide (product) Name: C8DEP), 1H, 1H, 10H, 10H-perfluoro 1,10-decanediol diepoxide (product name: C10DEP) are commercially available.
For example, the product name C6GDEP has m = 0, n = 1, p = 1, q = 1, r = 2 in the above general formula, and C5DEP has m = 0, n = 3, p = 1, q = 0, r = 0. In addition, as a fluorine-containing epoxy compound having no ether bond, 1,6-bis (2 ′, 3′-epoxypropyl) -perfluoro-n-hexane, 1,4-bis from Daikin Industries, Ltd. (2 ′, 3′-epoxypropyl) -perfluoro-n-butane, 1,2-bis (2 ′, 3′-epoxypropyl) -perfluoro-n-ethane is commercially available. The said fluorine-containing epoxy compound may be used individually by 1 type, and may use 2 or more types together. Furthermore, you may use as a mixture of another epoxy resin or an acrylic resin as needed.

  The content of the fluorine-containing epoxy compound is such that the mass ratio of the fluorine-containing epoxy compound when the total mass of the π-conjugated conductive polymer and the polyanion is 1, is 0.5 to 3.0, and 0.6 to It is more preferable that it is 2.9. When the content of the fluorine-containing epoxy compound is within the above range, both electrical conductivity by the π-conjugated conductive polymer and water blocking property by the fluorine-containing epoxy compound can be achieved. However, if the content of the fluorine-containing epoxy compound is less than the lower limit value, it may not be possible to prevent water from entering the hole injection layer. If the content exceeds the upper limit value, a sufficient charge transfer route can be secured. The conductivity tends to decrease.

[solvent]
As a solvent, methanol, ethanol, 1-propanol, isopropyl alcohol, n-butanol, s-butanol, t-butanol, n-amyl alcohol, s-amyl alcohol, t-amyl alcohol, allyl alcohol, isoamyl alcohol, isobutyl alcohol 2-ethylbutanol, 2-octanol, n-octanol, cyclohexanol, tetrahydrofurfuryl alcohol, furfuryl alcohol, n-hexanol, n-heptanol, 2-heptanol, 3-heptanol, benzyl alcohol, methylcyclohexanol, ethylene Glycols, ethylene glycol monomethyl ether, glycerin, diethylene glycol, propylene carbonate, propylene glycol and other alcohols, , Methyl ethyl ketone, diethyl ketone, cyclohexanone, methyl isobutyl ketone, methyl-n-propyl ketone and other ketones, ethyl acetoacetate, ethyl benzoate, methyl benzoate, isobutyl formate, ethyl formate, propyl formate, methyl formate, isobutyl acetate , Esters such as ethyl acetate, propyl acetate, methyl acetate, methyl salicylate, diethyl oxalate, diethyl tartrate, dibutyl tartrate, ethyl phthalate, methyl phthalate, butyl phthalate, γ-butyrolactone, ethyl malonate, methyl malonate Etc. Of these, methanol, ethanol, isopropyl alcohol, and methyl ethyl ketone are more preferable from the viewpoint of compatibility with the resin component.

  The amount of the solvent used is preferably 40 to 99% by mass and more preferably 50 to 98% by mass because the fluorine-containing epoxy compound can be sufficiently dissolved. When the amount of the solvent used is 40% by mass or more, the solubility of the fluorine-containing epoxy compound is improved, and the storage stability of the obtained conductive paint is increased. When the amount is 99% by mass or less, the π-conjugated system has high conductivity. Increases molecular dispersibility.

[Other ingredients]
The conductive paint preferably contains a highly conductive agent. Here, the highly conductive agent interacts with a dopant of a π-conjugated conductive polymer or a π-conjugated conductive polymer to improve the conductivity of the π-conjugated conductive polymer.
Examples of the highly conductive agent include nitrogen-containing aromatic cyclic compounds, compounds containing two or more hydroxyl groups, compounds containing two or more carboxyl groups, one or more hydroxyl groups, and one or more carboxyls A compound containing a group, a compound containing a sulfo group and a carboxyl group, a compound containing an amide group, a compound containing an imide group, a lactam compound, a compound having a glycidyl group, and the like.
Among the highly conductive agents, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and glycols are preferable.

  The content of the high conductivity agent is preferably 1 to 1000 times, more preferably 2 to 100 times the total mass of the π-conjugated conductive polymer and the polyanion. If the content of the high conductive agent is not less than the lower limit, the effect of adding the high conductive agent can be sufficiently obtained, and if the content is not more than the upper limit, the π-conjugated conductive polymer concentration is sufficiently high. High conductivity can be secured.

[Formation method]
The hole injection layer 41 is formed by applying a conductive paint to the substrate 10 and heating.
Coating methods include, for example, gravure coater, roll coater, curtain flow coater, spin coater, bar coater, reverse coater, kiss coater, phanten coater, rod coater, air doctor coater, knife coater, blade coater, cast coater, screen coater. Examples thereof include a coating method using a coating machine such as a spraying method such as spray coating such as air spray and airless spray, and a dipping method such as dip.

It heats after apply | coating a conductive paint, water and a solvent are evaporated and it is dried, and a fluorine-containing epoxy compound is hardened. In the case of heat drying, a hot air dryer or an infrared dryer can be used. Before heating and drying, if necessary, air may be blown and dried without heating.
Although heating temperature is based also on melting | fusing point of the base material 10, it is preferable to set it as 100-300 degreeC. If the heating temperature is 100 ° C. or higher, the fluorine-containing epoxy compound can be sufficiently crosslinked and cured, and if it is 300 ° C. or lower, deterioration due to heat can be prevented.

[thickness]
The thickness of the hole injection layer 41 is preferably 0.5 nm to 1000 nm, and more preferably 10 nm to 500 nm.

(Hole transport layer)
The hole transport layer 42 is a layer for transporting holes from the hole injection layer 41 to the light emitting layer 43.
Examples of the material constituting the hole transport layer 42 include arylamines; phthalocyanines; oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, and titanium oxide; amorphous carbon; polyaniline, polyphenylene vinylene, and these Conductive polymers such as derivatives; and the like. Specific examples include bis (N- (1-naphthyl-N-phenyl) benzidine (α-NPD), 4,4,4-tris (3-methylphenylphenylamino) triphenylamine (MTDATA), and the like. .
The thickness of the hole transport layer 42 is preferably 0.5 nm to 1000 nm, and more preferably 10 nm to 500 nm.

(Light emitting layer)
The light emitting layer 43 is a layer containing a light emitting material. Here, examples of the luminescent material include a dye-based luminescent material, a metal complex-based luminescent material, and a polymer-based luminescent material.
Examples of dye-based light-emitting materials include cyclopentamine derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazol derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silole derivatives, thiophene ring compounds. Pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, pyrazoline dimers, and the like.
Examples of the metal complex light emitting material include an aluminum quinolinol complex, a benzoquinolinol beryllium complex, a benzoxazole zinc complex, a benzothiazole zinc complex, an azomethylzinc complex, a porphyrin zinc complex, a europium complex, or a central metal such as Al, Zn, Examples of the metal complex include Be or the like, or a rare earth metal such as Tb, Eu, or Dy, and a ligand having an oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure, or the like.
Examples of the polymer light-emitting material include polyparaphenylene vinylene derivatives, polythiophene derivatives (those not doped with acid), polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and the like. . Moreover, what polymerized said pigment-type luminescent material and metal complex type | system | group light-emitting material etc. are mentioned.

  The thickness of the light emitting layer 43 is appropriately selected depending on the light emitting material to be used, but considering the driving voltage and the light emission efficiency, it is preferably 1 nm to 1 μm, more preferably 2 nm to 500 nm, and more preferably 5 nm. More preferably, it is -200 nm.

Examples of the method for forming the light emitting layer 43 include vapor deposition, ink jet, spin coating, casting, dipping, bar coating, blade coating, roll coating, gravure coating, flexographic printing, and spray coating. Etc. Of these, the vapor deposition method, the spin coating method, and the ink jet method are preferable.
You may pattern a light emitting layer by a well-known method as needed.

(Electron transport layer)
The electron transport layer 44 is a layer for transporting electrons from the cathode 30 to the light emitting layer 43.
Examples of the material constituting the electron transport layer 44 include tris (8-quinolinoate) aluminum (Alq ₃ ), 2,9-dimethyl-4,7-diphenyl-1,20-phenanthroline (BCP), 2- (4-biphenylyl). ) -5- (4-tert-butylphenyl-1,3,4-oxadiazole (PBD), silole derivatives and the like.
The thickness of the electron transport layer 44 is preferably 0.5 nm to 1000 nm, and more preferably 10 nm to 500 nm.

<Base material>
The substrate 10 is made of a transparent sheet or plate.
Specific examples of the substrate 10 include sheets mainly composed of glass such as soda lime glass and quartz glass, and a transparent thermoplastic resin such as polyvinyl chloride, acrylic resin, polystyrene, and amorphous polyethylene terephthalate. Moreover, the transparent electrode may be previously provided by vapor deposition etc. as needed.

<Anode>
The anode 20 is an electrode made of a transparent conductive layer. Examples of the transparent conductive layer include a conductive metal oxide layer and a metal layer. Examples of the conductive metal oxide include indium oxide, zinc oxide, tin oxide, and tin-doped indium oxide (ITO). Of these, ITO is preferable. Gold, platinum, silver, copper etc. are mentioned as a metal.
Examples of the method for forming the anode 20 include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method.

  The thickness of the anode 20 is preferably 10 nm to 10 μm, more preferably 20 nm to 1 μm, and further preferably 50 nm to 500 nm. If the thickness of the anode 20 is not less than the lower limit value, the conductivity of the anode 20 is improved, and if it is not more than the upper limit value, the transparency of the anode 20 is improved.

<Cathode>
The cathode 30 is a layer made of a material having a small work function.
Examples of the material having a low work function include indium, aluminum, magnesium, calcium, magnesium-indium alloy, magnesium-aluminum alloy, aluminum-lithium alloy, aluminum-scandium-lithium alloy, and magnesium-silver alloy.

  The thickness of the cathode 30 is preferably 10 nm to 10 μm, more preferably 20 nm to 1 μm, and further preferably 50 nm to 500 nm. When the thickness of the cathode 30 is equal to or greater than the lower limit, the conductivity of the cathode 30 is improved, and when the thickness is equal to or less than the upper limit, the durability of the cathode 30 is improved.

<Operation effect of OEL element>
The hole injection layer 41 constituting the OEL element 1 of the above embodiment is formed of a conductive paint containing a fluorine-containing epoxy compound, and prevents moisture from entering. Therefore, the moisture resistance is high, and the initial performance (especially conductivity) is easily maintained. Furthermore, since it is not easily affected by moisture in the atmosphere and the performance does not deteriorate even when left for a long period of time, the degree of freedom in manufacturing the organic electroluminescence element is increased.

<Other Embodiments of OEL Element>
In addition, this invention is not limited to the said embodiment.
The light emitting part in the present invention may be provided with a light emitting layer and a hole injection layer, and the hole transport layer and the electron transport layer in the above embodiment may be omitted. For example, Alq ₃ exemplified as a material constituting the electron transporting layer also serves as a light emitting material. Therefore, when Alq ₃ is used, the electron transporting layer and the light emitting layer can be used together. An electron injection layer may be provided between the electron transport layer and the cathode.

Examples of the present invention will be described below, but the present invention is not limited to the examples.
(Production Example 1) Preparation of polystyrene sulfonic acid 206 g of sodium styrene sulfonate was dissolved in 1000 ml of ion-exchanged water, and 1.14 g of ammonium persulfate oxidizing agent solution previously dissolved in 10 ml of water was stirred at 80 ° C. The solution was added dropwise for 20 minutes, and the solution was stirred for 2 hours.
1000 ml of sulfuric acid diluted to 10% by mass and 10000 ml of ion-exchanged water were added to the sodium styrenesulfonate-containing solution thus obtained, and about 10,000 ml of the polystyrenesulfonic acid-containing solution was removed using an ultrafiltration method. 10000 ml of ion-exchanged water was added to the remaining solution, and about 10,000 ml of solution was removed using an ultrafiltration method. The above ultrafiltration operation was repeated three times.
Furthermore, about 10,000 ml of ion-exchanged water was added to the obtained filtrate, and about 10,000 ml of solution was removed using an ultrafiltration method. This ultrafiltration operation was repeated three times.
The ultrafiltration conditions were as follows (the same applies to other examples).
Molecular weight cut off of ultrafiltration membrane: 30K
Cross flow type Supply liquid flow rate: 3000 ml / min Membrane partial pressure: 0.12 Pa
Water in the obtained solution was removed under reduced pressure to obtain colorless solid polystyrene sulfonic acid.

(Production Example 2) Preparation of Polystyrenesulfonic Acid Doped Poly (3,4-ethylenedioxythiophene) Aqueous Solution 14.2 g of 3,4-ethylenedioxythiophene and 36.7 g of polystyrenesulfonic acid obtained in Production Example 1 A solution dissolved in 2000 ml of ion-exchanged water was mixed at 20 ° C.
While maintaining the mixed solution thus obtained at 20 ° C. and stirring, 29.64 g of ammonium persulfate dissolved in 200 ml of ion exchange water and 8.0 g of ferric sulfate oxidation catalyst solution were slowly added, The reaction was stirred for 3 hours.
2000 ml of ion-exchanged water was added to the resulting reaction solution, and about 2000 ml of solution was removed using an ultrafiltration method. This operation was repeated three times.
Then, 200 ml of sulfuric acid diluted to 10% by mass and 2000 ml of ion-exchanged water are added to the treatment liquid that has been subjected to the filtration treatment, and about 2000 ml of the treatment liquid is removed using an ultrafiltration method. Ion exchange water was added and about 2000 ml of liquid was removed using ultrafiltration. This operation was repeated three times.
Furthermore, 2000 ml of ion-exchanged water was added to the obtained treatment liquid, and about 2000 ml of the treatment liquid was removed using an ultrafiltration method. This operation was repeated five times to obtain about 1.2% by mass of a blue polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) (PEDOT-PSS) aqueous solution.

(Production Example 3) Preparation of polystyrene sulfonate-doped poly (3,4-ethylenedioxythiophene) solution 125 g of PEDOT-PSS aqueous solution obtained in Production Example 2 was mixed with 75 g of pure water, 275 g of 2-propanol, and 25 g of dimethyl sulfoxide and stirred. As a result, 500 g of PEDOT-PSS solution (I) was obtained. The solid content concentration of PEDOT-PSS in this solution (I) was 0.3% by mass.

Example 1
Fluorine-containing epoxy compound (manufactured by Tosoh F-Tech Co., Ltd., product name: H022, 1,4-bis (2,3-epoxypropyl) -perfluoro-n-butane, see chemical formula (1)) 10 g and 2-propanol 90 g Were mixed and stirred to obtain a fluorine-containing epoxy compound solution. To 10 g of the solution (I) obtained in Production Example 3, 0.3 g of the fluorine-containing epoxy compound solution (the mass ratio when the total mass of the π-conjugated conductive polymer and the polyanion is 1, is 1.0). Mixing and stirring were performed to obtain a conductive polymer solution.
The conductive polymer solution was applied to a 75 × 75 × 0.5 mm soda glass substrate using a spin coater at 3,000 rotations / minute for 30 seconds, and then dried using a dryer. The conductive base material 1 was obtained by heating at 15 ° C. for 15 minutes, drying and curing to form a conductive coating film.

(Example 2)
The electroconductive base material 2 was obtained like Example 1 except having changed the fluorine-containing epoxy compound into the product name: C6GDEP (refer chemical formula (2)) by the Exflow company.

(Example 3)
Except that the fluorine-containing epoxy compound was changed to Exflow, product name: C5DEP, 1H, 1H, 5H-perfluoro-1,5-pentadiol-diepoxide (see chemical formula (3)), Example 1 and In the same manner, a conductive substrate 3 was obtained.

(Comparative Example 1)
Epoxy compound not containing fluorine (Sakamoto Yakuhin Kogyo Co., Ltd., product name: SR-GLG, see chemical formula (4)) and 90 g of 2-propanol were mixed and stirred to prepare an epoxy compound solution containing no fluorine. Obtained. To 10 g of the solution (I) obtained in Production Example 3, 0.3 g of the epoxy compound solution containing no fluorine was mixed and stirred to obtain a conductive polymer solution. A conductive substrate 4 was obtained in the same manner as in Example 1 except that the conductive polymer solution was used.

(Comparative Example 2)
A conductive substrate 5 was obtained in the same manner as in Comparative Example 1 except that the epoxy compound containing no fluorine was changed to Sakamoto Yakuhin Kogyo Co., Ltd., product name: SR-4GL (see chemical formula (5)). .

(Comparative Example 3)
A conductive substrate 6 was obtained in the same manner as in Comparative Example 1 except that the epoxy compound containing no fluorine was changed to Sakamoto Yakuhin Kogyo Co., Ltd., product name: SR-SEP (see chemical formula (6)). .

Example 4
The amount of the fluorine-containing epoxy compound solution added to 10 g of the solution (I) obtained in Production Example 3 was 0.15 g (the mass ratio when the total mass of the π-conjugated conductive polymer and the polyanion was 1 was 0. A conductive substrate 7 was obtained in the same manner as in Example 1 except that the procedure was changed to 5).

(Example 5)
The amount of the fluorine-containing epoxy compound solution added to 10 g of the solution (I) obtained in Production Example 3 was 0.18 g (the mass ratio when the total mass of the π-conjugated conductive polymer and the polyanion was 1 was 0. A conductive substrate 8 was obtained in the same manner as in Example 1 except that the procedure was changed to 6).

(Example 6)
The amount of the fluorine-containing epoxy compound solution added to 10 g of the solution (I) obtained in Production Example 3 is 0.87 g (the mass ratio when the total mass of the π-conjugated conductive polymer and the polyanion is 1 is 2. Except having changed to 9), the electroconductive base material 9 was obtained like Example 1 except having changed.

(Example 7)
The amount of the fluorine-containing epoxy compound solution added to 10 g of the solution (I) obtained in Production Example 3 was 0.9 g (the mass ratio when the total mass of the π-conjugated conductive polymer and the polyanion was 1 was 3. A conductive substrate 10 was obtained in the same manner as in Example 1 except that it was changed to 0).

(Comparative Example 4)
The amount of the fluorine-containing epoxy compound solution added to 10 g of the solution (I) obtained in Production Example 3 was 0.12 g (the mass ratio when the total mass of the π-conjugated conductive polymer and the polyanion was 1 was 0. A conductive substrate 11 was obtained in the same manner as in Example 1 except that it was changed to 4).

(Comparative Example 5)
The amount of the fluorine-containing epoxy compound solution added to 10 g of the solution (I) obtained in Production Example 3 was 0.93 g (the mass ratio when the total mass of the π-conjugated conductive polymer and the polyanion was 1 was 3. Except having changed into 1), it carried out similarly to Example 1, and obtained the electroconductive base material 12.

[Environmental test of conductive substrate]
The conductive substrates 1 to 12 were left in a high-temperature and high-humidity environment tester (model name: ETAC HIFLEX FH24C) adjusted to a temperature of 60 ° C. and a relative humidity of 95% for 1000 hours, and the surface resistance values before and after that were measured. Measurements were made.

[Measurement of surface resistance of conductive substrate]
The surface resistivity was measured using an electrical resistance measuring instrument (product name: Lauresta GP MCP-T600, electrode probe: ESP) manufactured by Mitsubishi Chemical Corporation. Tables 1 and 2 show the value of log (surface resistivity B after environmental test) −log (surface resistivity A before environmental test) as a variation value of the surface resistivity. Note that the hole injection layer of the OEL element is required to have an absolute value of surface resistivity of 1 × 10 ⁴ to 1 × 10 ⁸ and a fluctuation value of within ± 0.5.

  The conductive base materials of Examples 1 to 7 containing a fluorine-containing epoxy compound hardly change in surface resistance even when left in a high temperature and high humidity environment, and are within the range required for the hole injection layer. It was. In Examples 4 to 7, as the content of the fluorine-containing epoxy compound increases, the surface resistivity increases. Further, if the mass ratio of the fluorine-containing epoxy compound is 0.5 to 3.0, a positive value is obtained. It was confirmed that the surface resistivity required for the hole injection layer was obtained. Therefore, when an OEL element is used, it is presumed that the light emission efficiency is high and the life is long.

In contrast to the above examples, Comparative Examples 1 to 3 using an epoxy compound that does not contain a fluorine compound have a large variation in surface resistivity under a high temperature and high humidity environment. Specifically, the surface resistivity is several hundreds. It has risen by several to several thousand times.
Moreover, in Comparative Examples 4 and 5 in which the content of the fluorine-containing epoxy compound was not within the predetermined range, the surface resistivity range deviated from the range required for the hole injection layer of the OEL element.

  In addition to the hole injection layer of the OEL element, the conductive coating obtained by the present invention can be used for conductive packaging materials, electronic component containers (carrier tape, cover tape, tray, magazine, bulk case, OA equipment cover, etc. ) And other products that require antistatic properties. For example, semiconductor devices such as IC, LSI, VLSI, LCD (liquid crystal display), PDP (plasma display), silicon wafer, hard disk, liquid crystal substrate, magnetic device , Optical devices, magneto-optical devices, and electronic components forming these. Furthermore, the electroconductive coating film in this invention can be utilized also for the household appliances, daily necessities, etc. in which antistatic property is calculated | required.

1 Organic electroluminescence device (OEL device)
DESCRIPTION OF SYMBOLS 10 Base material 20 Anode 30 Cathode 40 Light emission part 41 Hole injection layer 42 Hole transport layer 43 Light emission layer 44 Electron transport layer

Claims (1)

In an organic electroluminescence device having a light emitting part provided with at least a hole injection layer and a light emitting layer between a pair of electrodes,
The hole injection layer is composed of a conductive coating film formed from a conductive paint, and the conductive paint includes at least part of hydrogen atoms of a π-conjugated conductive polymer, a polyanion, and an epoxy compound as fluorine atoms. The mass ratio of the fluorine-containing epoxy compound is 0.5 to 3.0 when the total of the mass of the π-conjugated conductive polymer and the polyanion is 1 including the substituted fluorine-containing epoxy compound and the solvent. An organic electroluminescence device characterized by the above.

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