Patent Description:
The present disclosure relates to an organic light emitting device.

The organic material layer frequently has a multilayered structure that comprises different materials in order to enhance efficiency and stability of the organic light emitting device, and for example, the organic material layer may be formed of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and the like.

<CIT>, <CIT> and <CIT> describe organic light emitting devices having hole transport layers formed using certain kinds of polymers.

There is a continuous need to develop new materials for organic materials used in the organic light emitting device as described above.

Meanwhile, recently, in order to reduce process costs, an organic light emitting device using a solution process, particularly an inkjet process, has been developed instead of a conventional deposition process. In the initial stage of development, attempts have been made to develop organic light emitting devices by coating all organic light emitting device layers by a solution process, but current technology has limitations. Therefore, only HIL, HTL, and EML are processed by a solution process, and a hybrid process utilizing traditional deposition processes is being studied as a subsequent process.

Therefore, the present disclosure provides a novel material for an organic light emitting device that can be used for an organic light emitting device and at the same time, can be used for a solution process, and an organic light emitting device comprising the same.

It is an object of the present disclosure to provide an organic light emitting device.

In order to achieve the above object, according to the present disclosure, there is provided an organic light emitting device comprising: an anode, a cathode, a light emitting layer between the anode and the cathode, and a hole transport layer between the anode and the light emitting layer, wherein said hole transport layer may be a hole injection layer, a hole transport layer, or a layer that simultaneously injects and transports holes; and wherein the hole transport layer comprises a polymer containing a repeating unit represented by the following Chemical Formula <NUM>, and an ionic compound containing an anionic group represented by the following Chemical Formula <NUM>:
<CHM>
<CHM>.

The organic light emitting device according to the present disclosure can prepare a hole transport layer by a solution process, and can improve the efficiency, achieve low driving voltage and/or improve lifetime characteristics in the organic light emitting device.

Hereinafter, embodiments of the present disclosure will be described in more detail to assist in the understanding of the invention.

As used herein, the notation
<CHM>
means a bond linked to another substituent group.

As used herein, the term "substituted or unsubstituted" means being unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium; a halogen group; a cyano group; a nitro group; a hydroxy group; a carbonyl group; an ester group; an imide group; an amino group; a phosphine oxide group; an alkoxy group; an aryloxy group; an alkylthioxy group; an arylthioxy group; an alkylsulfoxy group; an arylsulfoxy group; a silyl group; a boron group; an alkyl group; a cycloalkyl group; an alkenyl group; an aryl group; an aralkyl group; an aralkenyl group; an alkylaryl group; an alkylamine group; an aralkylamine group; a heteroarylamine group; an arylamine group; an arylphosphine group; or a heteroaryl containing at least one of N, O and S atoms, or being unsubstituted or substituted with a substituent to which two or more substituents of the above-exemplified substituents are connected. For example, "a substituent in which two or more substituents are connected" may be a biphenyl group. Namely, a biphenyl group may be an aryl group, or it may also be interpreted as a substituent in which two phenyl groups are connected.

In the present disclosure, the carbon number of a carbonyl group is not particularly limited, but is preferably <NUM> to <NUM>. Specifically, the carbonyl group may be a compound having the following structural formulae. <CHM>
<CHM>.

In the present disclosure, an ester group may have a structure in which oxygen of the ester group may be substituted by a straight-chain, branched, or cyclic alkyl group having <NUM> to <NUM> carbon atoms, or an aryl group having <NUM> to <NUM> carbon atoms. Specifically, the ester group may be a compound having the following structural formulae. <CHM>
<CHM>.

In the present disclosure, the carbon number of an imide group is not particularly limited, but is preferably <NUM> to <NUM>. Specifically, the imide group may be a compound having the following structural formulae. <CHM>
<CHM>.

In the present disclosure, a silyl group specifically includes a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, and a phenylsilyl group.

In the present disclosure, a boron group specifically includes a trimethylboron group, a triethylboron group, a t-butyldimethylboron group, a triphenylboron group, and a phenylboron group.

In the present disclosure, the alkyl group may be straight-chain or branched-chain, and the carbon number thereof is not particularly limited, but is preferably <NUM> to <NUM>. According to one embodiment, the carbon number of the alkyl group is <NUM> to <NUM>. According to another embodiment, the carbon number of the alkyl group is <NUM> to <NUM>. According to another embodiment, the carbon number of the alkyl group is <NUM> to <NUM>. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, <NUM>-methyl-butyl, <NUM>-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, <NUM>-methylpentyl, <NUM>-methylpentyl, <NUM>-methyl-<NUM>-pentyl, <NUM>,<NUM>-dimethylbutyl, <NUM>-ethylbutyl, heptyl, n-heptyl, <NUM>-methylhexyl, cyclopentylmethyl, cyclohectylmethyl, octyl, n-octyl, tert-octyl, <NUM>-methylheptyl, <NUM>-ethylhexyl, <NUM>-propylpentyl, n-nonyl, <NUM>,<NUM>-dimethylheptyl, <NUM>-ethyl-propyl, <NUM>,<NUM>-dimethyl-propyl, isohexyl, <NUM>-methylpentyl, <NUM>-methylhexyl, and <NUM>-methylhexyl.

Specific examples thereof include vinyl, <NUM>-propenyl, isopropenyl, <NUM>-butenyl, <NUM>-butenyl, <NUM>-butenyl, <NUM>-pentenyl, <NUM>-pentenyl, <NUM>-pentenyl, <NUM>-methyl-<NUM>-butenyl, <NUM>,<NUM>-butadienyl, allyl, <NUM>-phenylvinyl-<NUM>-yl, <NUM>-phenylvinyl-<NUM>-yl, <NUM>,<NUM>-diphenylvinyl-<NUM>-yl, <NUM>-phenyl-<NUM>-(naphthyl-<NUM>-yl)vinyl-<NUM>-yl, <NUM>,<NUM>-bis(diphenyl-<NUM>-yl)vinyl-<NUM>-yl, a stilbenyl group, and a styrenyl group.

Specific examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, <NUM>-methylcyclopentyl, <NUM>,<NUM>-dimethylcyclopentyl, cyclohexyl, <NUM>-methylcyclohexyl, <NUM>-methylcyclohexyl, <NUM>,<NUM>-dimethylcyclohexyl, <NUM>,<NUM>,<NUM>-trimethylcyclohexyl, <NUM>-tert-butylcyclohexyl, cycloheptyl, and cyclooctyl.

In the present disclosure, an aryl group is not particularly limited, but the carbon number thereof is preferably <NUM> to <NUM>, and it may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the carbon number of the aryl group is <NUM> to <NUM>. According to one embodiment, the carbon number of the aryl group is <NUM> to <NUM>. The aryl group may be a phenyl group, a biphenyl group, or a terphenyl group. The polycyclic aryl group includes a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, a perylenyl group, a chrysenyl group, and a fluorenyl group.

In the present disclosure, the fluorenyl group may be substituted, and two substituents may be linked with each other to form a spiro structure. In the case where the fluorenyl group is substituted,
<CHM>
can be formed.

In the present disclosure, a heteroaryl is a heteroaryl containing one or more of O, N, Si and S as a heteroatom, and the carbon number thereof is not particularly limited, but is preferably <NUM> to <NUM>. Examples of the heteroaryl include xanthene, thioxanthen, a thiophene group, a furan group, a pyrrole group, an imidazole group, a thiazole group, an oxazol group, an oxadiazol group, a triazol group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, an acridyl group, a pyridazine group, a pyrazinyl group, a quinolinyl group, a quinazoline group, a quinoxalinyl group, a phthalazinyl group, a pyridopyrimidinyl group, a pyridopyrazinyl group, a pyrazinopyrazinyl group, an isoquinoline group, an indole group, a carbazole group, a benzoxazole group, a benzoimidazole group, a benzothiazol group, a benzocarbazole group, a benzothiophene group, a dibenzothiophene group, a benzofuranyl group, a phenanthroline group, an isoxazolyl group, a thiadiazolyl group, a phenothiazinyl group, and a dibenzofuranyl group.

In the present disclosure, the aryl group in the aralkyl group, the aralkenyl group, the alkylaryl group, the arylamine group and the arylsily group is the same as the aforementioned examples of the aryl group. In the present disclosure, the alkyl group in the aralkyl group, the alkylaryl group and the alkylamine group is the same as the aforementioned examples of the alkyl group. In the present disclosure, the heteroaryl in the heteroarylamine can be applied to the aforementioned description of the heteroaryl. In the present disclosure, the alkenyl group in the aralkenyl group is the same as the aforementioned examples of the alkenyl group. In the present disclosure, the aforementioned description of the aryl group may be applied except that the arylene is a divalent group. In the present disclosure, the aforementioned description of the heteroaryl group can be applied except that the heteroarylene is a divalent group. In the present disclosure, the aforementioned description of the aryl group or cycloalkyl group can be applied except that the hydrocarbon ring is not a monovalent group but formed by combining two substituent groups. In the present disclosure, the aforementioned description of the heteroaryl can be applied, except that the heterocyclic group is not a monovalent group but formed by combining two substituent groups.

An organic light emitting device according to the present disclosure includes an anode and a cathode.

As the anode material, generally, a material having a large work function is preferably used so that holes can be smoothly injected into the organic material layer. Specific examples of the anode material include metals such as vanadium, chrome, copper, zinc, and gold, or an alloy thereof; metal oxides such as zinc oxides, indium oxides, indium tin oxides (ITO), and indium zinc oxides (IZO); a combination of metals and oxides, such as ZnO:Al or SNO<NUM>:Sb; conductive compounds such as poly(<NUM>-methylthiophene), poly[<NUM>,<NUM>-(ethylene-<NUM>,<NUM>-dioxy)thiophene](PEDOT), polypyrrole, and polyaniline.

Specific examples of the cathode material include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or an alloy thereof; a multilayered structure material such as LiF/Al or LiO<NUM>/Al.

The organic light emitting device according to the present disclosure includes a hole transport layer between the anode and the light emitting layer, wherein the hole transport layer includes a polymer containing a repeating unit represented by Chemical Formula <NUM>, and an ionic compound containing an anionic group represented by Chemical Formula <NUM>. The hole transport layer may be a hole injection layer, a hole transport layer, or a layer that simultaneously injects and transports holes.

Preferably, within the hole transport layer, the weight ratio of the polymer and the ionic compound is <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, or <NUM>:<NUM> to <NUM>:<NUM>.

Hereinafter, each material will be described in detail.

In Chemical Formula <NUM>, preferably, L<NUM> is phenylene, biphenyldiyl, or binaphthyldiyl, with the L<NUM> being unsubstituted or substituted with one or two C<NUM>-<NUM> alkyl, or one or more deuterium.

Preferably, L<NUM> is represented by any one of the following:
<CHM>
wherein, each R' is independently a C<NUM>-<NUM> alkyl.

Preferably, each R' is independently methyl, propyl, butyl, pentyl, or hexyl.

Each L<NUM> is independently phenylene, or biphenyldiyl, with the L<NUM> being unsubstituted or substituted with one or more deuterium. More preferably, each L<NUM> is independently <NUM>,<NUM>-phenylene, or <NUM>,<NUM>-biphenyldiyl, with the L<NUM> being unsubstituted or substituted with one or more deuterium. Preferably, L<NUM> is identical to each other.

Preferably, each Ar is independently phenyl, or biphenylyl, with the Ar being unsubstituted or substituted with a C<NUM>-<NUM> alkyl, a N(C<NUM>-<NUM> aryl)<NUM>, or one or more deuterium. More preferably, Ar is biphenylyl, with the Ar being unsubstituted or substituted with propyl, isopropyl, butyl, isobutyl, N(phenyl)<NUM>, or one or more deuterium. Preferably, Ar is identical to each other.

Preferably, each R is independently hydrogen, deuterium, or methyl.

Preferably, the Chemical Formula <NUM> is represented by any one selected from the group consisting of the following:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

In addition, the repeating unit represented by Chemical Formula <NUM> is derived from the compound represented by the following Chemical Formula <NUM>-<NUM>:
<CHM>
wherein in Chemical Formula <NUM>-<NUM>, the definition of the remaining substituents except for X are the same as defined above, and X is halogen, more preferably chloro or bromo.

The compound represented by Chemical Formula <NUM>-<NUM> can be prepared by the method as shown in the following Reaction Scheme <NUM>. <CHM>
wherein in Reaction Scheme <NUM>, the definition of the remaining substituents except for X are the same as defined above, and X is halogen, more preferably chloro or bromo.

Step <NUM>-<NUM> and step <NUM>-<NUM> in the Reaction Scheme <NUM> are an amine substitution reaction, respectively, which is preferably carried out in the presence of a palladium catalyst and a base, and a reactive group for the amine substitution reaction can be modified as known in the art. The above preparation method may be further embodied in Preparation Examples described hereinafter.

The polymer further contains a repeating unit represented by the following Chemical Formula <NUM>':
<CHM>.

The repeating unit represented by Chemical Formula <NUM>' is a branched repeating unit, and as it is contained in the polymer structure according to the present disclosure, it can improve the solubility in a solvent by making the polymer structure into a branched structure.

The polymer may further include a repeating unit represented by the following Chemical Formula <NUM>":.

The terminal group represented by Chemical Formula <NUM>" is an aromatic cyclic terminal group, and when it is contained in the polymer structure according to the present disclosure, it can improve the solubility in a solvent.

Preferably, Ar" is phenyl, or biphenylyl, with the Ar" being unsubstituted or substituted with a C<NUM>-<NUM> alkyl, a photocurable group, or a thermosetting group.

Preferably, the Chemical Formula <NUM>" is any one selected from the group consisting of the following:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

In addition, the repeating unit represented by Chemical Formula <NUM>" is derived from a compound represented by the following Chemical Formula <NUM>"-<NUM>.

[Chemical Formula <NUM>"-<NUM>]     Ar"-X".

wherein in Chemical Formula <NUM>"-<NUM>, the definition of the remaining substituents except for X" are the same as defined above, and X" is halogen, more preferably chloro or bromo.

The polymer according to the present disclosure can be prepared by polymerizing the monomer represented by Chemical Formula <NUM>-<NUM>. Further, the polymer according to the present disclosure can be prepared by polymerizing the above-mentioned monomer represented by Chemical Formula <NUM>-<NUM> and the above-mentioned monomer represented by Chemical Formula <NUM>'-<NUM>. Further, the polymer according to the present disclosure can be prepared by polymerizing the monomer represented by Chemical Formula <NUM>-<NUM>, the monomer represented by Chemical Formula <NUM>'-<NUM>, and the monomer represented by Chemical Formula <NUM>"-<NUM>. Preferably, the polymer according to the present disclosure is a random copolymer containing the repeating unit.

In the polymer according to the present disclosure, the repeating unit of Chemical Formula <NUM>' is preferably contained in an amount of <NUM> to <NUM> moles relative to <NUM> moles of the repeating unit represented by Chemical Formula <NUM>. More preferably, the repeating unit of Chemical Formula <NUM>' is contained in an amount of <NUM> moles or more, <NUM> moles or more, <NUM> moles or more, or <NUM> moles or more; and <NUM> moles or less, <NUM> moles or less, or <NUM> moles or less, relative to <NUM> moles of the repeating unit represented by Chemical Formula <NUM>.

In the polymer according to the present disclosure, when the repeating unit of Chemical Formula <NUM>" is contained, the repeating unit of Chemical Formula <NUM>" is preferably contained in an amount of <NUM> to <NUM> moles relative to <NUM> moles of the repeating unit represented by Chemical Formula <NUM>. More preferably, the repeating unit of Chemical Formula <NUM>" is contained in an amount of <NUM> moles or more, <NUM> moles or more, <NUM> moles or more, or <NUM> moles or more; and <NUM> moles or less, or <NUM> moles or less relative to <NUM> moles of the repeating unit represented by Chemical Formula <NUM>.

In addition, the reaction molar ratio of the monomer represented by Chemical Formula <NUM>-<NUM>, the monomer represented by Chemical Formula <NUM>'-<NUM>, and/or the monomer represented by Chemical Formula <NUM>"-<NUM> can be adjusted, thereby adjusting the molar ratio of the polymer.

Preferably, the weight average molecular weight (Mw; g / mol) of the polymer is <NUM>,<NUM> to <NUM>,<NUM>,<NUM>, more preferably <NUM>,<NUM> or more, <NUM>,<NUM> or more, <NUM>,<NUM> or more, <NUM>,<NUM> or more, <NUM>,<NUM> or more, <NUM>,<NUM> or more, <NUM>,<NUM> or more, or <NUM>,<NUM> or more; and <NUM>,<NUM> or less, <NUM>,<NUM> or less, <NUM>,<NUM> or less, <NUM>,<NUM> or less, or <NUM>,<NUM> or less.

Preferably, the polydispersity index (PDI; Mw/Mn) of the polymer is <NUM> to <NUM>, more preferably <NUM> or more, <NUM> or more, <NUM> or more, <NUM> or more, <NUM> or more, <NUM> or more, or <NUM> or more; and <NUM> or less, <NUM> or less, <NUM> or less, <NUM> or less, or <NUM> or less.

In Chemical Formula <NUM>, preferably, for the photocurable group; or the thermosetting group of R", the content of R defined in Chemical Formula <NUM> can be applied.

Preferably, each R"<NUM> is independently hydrogen, fluoro, or CF<NUM>.

Preferably, Ar"<NUM> is any one selected from the group consisting of the following:
<CHM>.

Preferably, each R"<NUM> is independently hydrogen, fluoro, CF<NUM>, CF(CF<NUM>)<NUM>, CF<NUM>CF<NUM>CF<NUM>CF<NUM>, a photocurable group, or a thermosetting group. At this time, for the photocurable group or the thermosetting group, the content of R defined in Chemical Formula <NUM> can be applied.

Preferably, Ar"<NUM> is any one selected from the group consisting of the following:
<CHM>
<CHM>
<CHM>
<CHM>.

Representative examples of the anionic group represented by Chemical Formula <NUM> is as follows:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

In addition, the ionic compound according to the present disclosure may further include a cationic group.

Preferably, the cationic group is selected from a monovalent cationic group, an onium compound or the following structural formulas:
<CHM>
<CHM>
<CHM>
wherein,.

Preferably, the cationic group is selected from the group consisting of the following Chemical Formulas:
<CHM>
<CHM>.

Representative examples of the cationic group are as follows:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

Meanwhile, a method of forming the hole transport layer according to the present disclosure will be described below.

The light emitting layer may include a host material and a dopant material. The host material may be a fused aromatic ring derivative, a heterocycle-containing compound or the like. Specific examples of the fused aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, and the like. Examples of the heterocyclic-containing compounds include carbazole derivatives, dibenzofuran derivatives, ladder-type furan compounds, and pyrimidine derivatives.

Examples of the dopant material include an aromatic amine derivative, a styrylamine compound, a boron complex, a fluoranthene compound, a metal complex, and the like. Specifically, the aromatic amine derivative is a substituted or unsubstituted fused aromatic ring derivative having an arylamino group, and examples thereof include pyrene, anthracene, chrysene, periflanthene and the like, which have an arylamino group. The styrylamine compound is a compound where at least one arylvinyl group is substituted in substituted or unsubstituted arylamine, in which one or two or more substituent groups selected from the group consisting of an aryl group, a silyl group, an alkyl group, a cycloalkyl group, and an arylamino group are substituted or unsubstituted. Specific examples thereof include styrylamine, styryldiamine, styryltriamine, and styryltetramine. Further, the metal complex includes an iridium complex, and a platinum complex.

The organic light emitting device according to the present disclosure may include an electron transport layer on the light emitting layer.

The electron transport layer is a layer that receives electrons from an electron injection layer and transports the electrons up to the light emitting layer, and an electron transport material is suitably a material which may receive electrons well from a cathode and transfer the electrons to a light emitting layer, and has a large mobility for electrons. Specific examples thereof include: an Al complex of <NUM>-hydroxyquinoline; a complex including Alq<NUM>; an organic radical compound; and a hydroxyflavone-metal complex. The electron transport layer may be used with any desired cathode material, as used according to a conventional technique. In particular, appropriate examples of the cathode material are a typical material which has a low work function, followed by an aluminum layer or a silver layer. Specific examples thereof include cesium, barium, calcium, ytterbium, and samarium, in each case followed by an aluminum layer or a silver layer.

The organic light emitting device according to the present disclosure may include an electron injection layer between the electron transport layer (or the light emitting layer) and the cathode, if necessary.

The electron injection layer is a layer which injects electrons from an electrode, and is preferably a compound which has a capability of transporting electrons, has an effect of injecting electrons from a cathode and an excellent effect of injecting electrons into a light emitting layer or a light emitting material, prevents excitons produced from the light emitting layer from moving to a hole injection layer, and is also excellent in the ability to form a thin film. Specific examples thereof include fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidene methane, anthrone, and the like, and derivatives thereof, a metal complex compound, and a nitrogen-containing <NUM>-membered ring derivative.

Examples of the metal complex compound include <NUM>-hydroxyquinolinato lithium, bis(<NUM>-hydroxyquinolinato)zinc, bis(<NUM>-hydroxyquinolinato)copper, bis(<NUM>-hydroxyquinolinato)manganese, tris(<NUM>-hydroxyquinolinato)aluminum, tris(<NUM>-methyl-<NUM>-hydroxyquinolinato)aluminum, tris(<NUM>-hydroxyquinolinato)gallium, bis(<NUM>-hydroxybenzo[h]quinolinato)beryllium, bis(<NUM>-hydroxybenzo[h]quinolinato)zinc, bis(<NUM>-methyl-<NUM>-quinolinato)chlorogallium, bis(<NUM>-methyl-<NUM>-quinolinato)(o-cresolato)gallium, bis(<NUM>-methyl-<NUM>-quinolinato)(<NUM>-naphtholato)aluminum, and bis(<NUM>-methyl-<NUM>-quinolinato)(<NUM>-naphtholato)gallium.

In addition to the above-mentioned materials, the light emitting layer, the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer may further include an inorganic compound such as a quantum dot or a polymer compound such as quantum dot.

The quantum dot may be, for example, a colloidal quantum dot, an alloy quantum dot, a core/shell quantum dot, or a core quantum dot. It may be a quantum dot including an element belonging to Groups <NUM> and <NUM>, an element belonging to Groups <NUM> and <NUM>, an element belonging to Groups <NUM> and <NUM>, an element belonging to Groups <NUM> and <NUM>, an element belonging to Groups <NUM> and <NUM>. Quantum dots containing elements such as Cadmium(Cd), selenium(Se), zinc(Zn), sulfur(S), phosphorus(P), indium(In), tellurium(Te), lead(Pb), gallium(Ga), arsenic(As), etc. can be used.

The organic light emitting device according to the present disclosure may be a normal type organic light emitting device in which an anode, one or more organic material layers and a cathode are sequentially stacked on a substrate. Further, the organic light emitting device according to the present disclosure may be an inverted type organic light emitting device in which a cathode, one or more organic material layers and an anode are sequentially stacked on a substrate. For example, the structure of an organic light emitting device according to an embodiment of the present disclosure is illustrated in <FIG>.

<FIG> shows an example of an organic light emitting device comprising a substrate <NUM>, an anode <NUM>, a hole transport layer <NUM>, a light emitting layer <NUM>, and a cathode <NUM>. In such a structure, the hole transport layer includes a polymer containing a repeating unit represented by Chemical Formula <NUM>, and an anionic compound represented by Chemical Formula <NUM>.

<FIG> shows an example of an organic light emitting device comprising a substrate <NUM>, an anode <NUM>, a hole transport layer <NUM>, a light emitting layer <NUM>, an electron transport layer <NUM>, an electron injection layer <NUM> and a cathode <NUM>. In such a structure, the hole transport layer includes a polymer containing a repeating unit represented by Chemical Formula <NUM>, and an anionic compound represented by Chemical Formula <NUM>.

The organic light emitting device according to the present disclosure can be manufactured by materials and methods known in the art, except that the above-mentioned materials are used.

In addition to such a method, the organic light emitting device can be manufactured by sequentially depositing a cathode material, an organic material layer and an anode material on a substrate (International Publication <CIT>).

The organic light emitting device according to the present disclosure may be a front side emission type, a back side emission type, or a double side emission type according to the used material.

Meanwhile, the hole transport layer according to the present disclosure can be formed by a solution process. For this purpose, the present disclosure provides a coating composition for forming a hole transport layer comprising a polymer containing a repeating unit represented by Chemical Formula <NUM>, and an anionic compound represented by Chemical Formula <NUM>.

The solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing the polymer and the compound according to the present disclosure. In one example, the solvent may include chlorine-based solvents such as chloroform, methylene chloride, <NUM>,<NUM>-dichloroethane, <NUM>,<NUM>,<NUM>-trichloroethane, chlorobenzene and o-dichlorobenzene; ether-based solvents such as tetrahydrofuran and dioxane; aromatic hydrocarbon-based solvents such as toluene, xylene, trimethylbenzene, and mesitylene; aliphatic hydrocarbon-based solvents such as cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane and n-decane; ketone-based solvents such as acetone, methyl ethyl ketone, and cyclohexanone; ester-based solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate; polyalcohols such as ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, dimethoxyethane, propylene glycol, diethoxymethane, triethylene glycol monoethyl ether, glycerin and <NUM>,<NUM>-hexanediol, and derivatives thereof; alcohol-based solvents such as methanol, ethanol, propanol, isopropanol and cyclohexanol; sulfoxide-based solvents such as dimethyl sulfoxide; amide-based solvents such as N-methyl-<NUM>-pyrrolidone and N,N-dimethylformamide; benzoate-based solvents such as butylbenzoate, and methyl-<NUM>-methoxybenzoate; tetraline; <NUM>-phenoxy-toluene, and the like. In addition, the above-mentioned solvents may be used singly or in combination of two or more solvents.

In addition, the viscosity of the coating composition is preferably <NUM> cP or more. Further, in consideration of the easiness in coating of the coating composition, the viscosity of the coating composition is preferably <NUM> cP or less. Further, the concentration of the compound according to the present disclosure in the coating composition may be preferably <NUM> wt/v% or more. Further, the concentration of the compound according to the present disclosure in the coating composition is preferably <NUM> wt/v% or less, so that the coating composition can be optimally coated.

Further, the coating composition may further include one, two or more types of additives selected from the group consisting of a thermal polymerization initiator and a photopolymerization initiator.

Examples of the thermal polymerization initiator may include peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, acetyl acetone peroxide, methyl cyclohexanone peroxide, cyclohexanone peroxide, isobutyryl peroxide, <NUM>,<NUM>-dichlorobenzoyl peroxide, bis-<NUM>,<NUM>,<NUM>-trimethylhexanoyl peroxide, lauryl peroxide, benzoyl peroxide, or azo-based such as azobis isobutylnitrile, azobis dimethylvaleronitrile and azobis cyclohexylnitrile.

Examples of the photopolymerization initiator may include acetophenone-based or ketal-based photopolymerization initiators such as diethoxyacetophenone, <NUM>,<NUM>-dimethoxy-<NUM>,<NUM>-diphenylethan-<NUM>-one, <NUM>-hydroxycyclohexyl-phenyl-ketone, <NUM>-(<NUM>-hydroxyethoxy)phenyl-(<NUM>-hydroxy-<NUM>-propyl)ketone, <NUM>-benzyl-<NUM>-dimethylamino-<NUM>-(<NUM>-morpholinophenyl)butanone-<NUM>,<NUM>-hydroxy-<NUM>-methyl-<NUM>-phenylpropan-<NUM>-one, <NUM>-methyl-<NUM>-morpholino(<NUM>-methylthiophenyl)propan-<NUM>-one and <NUM>-phenyl-<NUM>,<NUM>-propanedion-<NUM>-(o-ethoxycarbonyl)oxime, benzoin ether-based photopolymerization initiators such as benzoin, benzoin methyl ether, and benzoin ethyl ether; benzophenone-based photopolymerization initiators such as benzophenone, <NUM>-hydroxybenzophenone, <NUM>-benzoyl naphthalene, <NUM>-benzoylbiphenyl and <NUM>-benzoylphenyl ether; thioxanthone-based photopolymerization initiators such as <NUM>-isopropylthioxanthone, <NUM>-chlorothioxanthone, <NUM>,<NUM>-dimethylthioxanthone, <NUM>,<NUM>-diethylthioxanthone and <NUM>,<NUM>-dichlorothioxanthone; and other photopolymerization initiators such as ethyl anthraquinone, <NUM>,<NUM>,<NUM>-trimethylbenzoyldiphenylphosphine oxide, <NUM>,<NUM>,<NUM>-trimethylbenzoylphenylethoxyphosphine oxide, bis(<NUM>,<NUM>,<NUM>-trimethylbenzoyl)phenylphosphine oxide, and bis(<NUM>,<NUM>-dimethoxy benzoyl)-<NUM>,<NUM>,<NUM>-trimethylpentylphosphine oxide.

Moreover, those having a photopolymerization promoting effect may also be used alone or in combination with the photopolymerization initiator. Examples thereof include triethanolamine, methyldiethanolamine, ethyl <NUM>-dimethylaminobenzoate, isoamyl <NUM>-dimethylamino benzoate, (<NUM>-dimethylamino)ethyl benzoate, and <NUM>,<NUM>'-dimethylaminobenzophenone.

In another embodiment of the present disclosure, there is provided a method for forming a hole transport layer using the above-mentioned coating composition. Specifically, the method includes the steps of: coating the above-mentioned coating composition for forming a hole transport layer onto the anode by a solution process; and heat-treating or photo-treating the coated coating composition.

The solution process uses the above-mentioned coating composition according to the present disclosure, and refers to spin coating, dip coating, doctor blading, inkjet printing, screen printing, spray method, and roll coating.

The heat treatment temperature in the heat treatment step is preferably from <NUM> to <NUM>. Further, a heat treatment time may be <NUM> minute to <NUM> hours, more preferably <NUM> minutes to <NUM> hour. Further, the heat treatment is preferably carried out in an inert gas atmosphere such as argon and nitrogen. In addition, a step of evaporating the solvent may be further included between the coating step and the heat treatment or the photo treatment step.

The preparation of the organic light emitting device according to the present disclosure as described above will be described in detail by way of the following examples.

Compound M1 (<NUM> mmol), Compound B1 (<NUM> mmol) and Compound E1 (<NUM> mmol) were added to a scintillation vial and dissolved in toluene (<NUM>) to prepare a first solution.

A <NUM> Schlenk tube was charged with bis(<NUM>,<NUM>-cyclooctadiene)nickel(<NUM>) (<NUM> mmol). <NUM>,<NUM>'-dipyridyl (<NUM> mmol) and <NUM>,<NUM>-cyclooctadiene (<NUM> mmol) were weighed and added to a scintillation vial, and dissolved in N,N'-dimethylformamide (<NUM>) and toluene (<NUM>) to prepare a second solution.

The second solution was added to a Schlenk tube, and stirred at <NUM> for <NUM> minutes. The first solution was further added to the Schlenk tube and stirred at <NUM> for <NUM> minutes. Then, the Schlenk tube was cooled to room temperature and then poured into HCl/methanol (<NUM>% v/v, concentrated HCl). After stirring for <NUM> minutes, the polymer was collected by vacuum filtration and dried under high vacuum. The polymer was dissolved in toluene (<NUM>% wt/v) and passed through a column containing basic aluminum oxide (<NUM>) layered on silica gel (<NUM>). The polymer/toluene filtrate was concentrated (<NUM>% wt/v toluene) and triturated with <NUM>-pentanone. The toluene/<NUM>-pentanone solution was decanted from the semi-solid polymer, dissolved in toluene (<NUM>) and then poured into stirring methanol to give Copolymer H1 in a yield of <NUM>%.

Compound M1 (<NUM> mmol), Compound B2 (<NUM> mmol), Aliquat <NUM> (<NUM> mmol), <NUM> of potassium carbonate aqueous solution (<NUM>), bis(di-tert-butyl(<NUM>-dimethylaminophenyl)phosphine)dichloropalladium(II) (<NUM>µmol) and toluene (<NUM>) were added to a scintillation vial equipped with a magnetic stir bar under inert gas conditions, The vial is sealed with a screw-cap with septum, inserted into an aluminum block, and heated to an external temperature of <NUM> over a period of <NUM> minutes. The mixture was stirred at that temperature under gentle reflux for <NUM> hours. Then, bis(di-tert-butyl(<NUM>-dimethylaminophenyl)phosphine)dichloropalladium(II) (<NUM>µmol), Compound E2 (<NUM> mmol) and toluene (<NUM>) were filled in the reaction mixture. The reaction mixture was heated again at the temperature specified above for <NUM> hours. Next, iodobenzene (<NUM> mmol) and toluene (<NUM>) were added thereto. The reaction mixture was heated for an additional <NUM> hours and then cooled to room temperature. The aqueous layer was removed and the organic layer was washed twice with <NUM> each of deionized water. The toluene layer was dried by passing it through <NUM> of silica gel and the silica was rinsed with toluene. The solvent was removed to give <NUM> of crude product. The crude product was further purified by passing the toluene solution through alumina, silica gel and Florisil®. After concentration, the solvent-soaked product was diluted to about <NUM> with toluene, and then ethyl acetate (<NUM>) was added to give about <NUM> of Copolymer. The product toluene solution was reprecipitated in <NUM>-pentanone to give <NUM> of final Copolymer H2.

Copolymer H3 was prepared in the same manner as in the Preparation method of Copolymer H1, except that Compounds M2 and E3 were used instead of Compounds M1 and E1, respectively.

Copolymer H4 was prepared in the same manner as in the Preparation method of Copolymer H2, except that Compounds M3, B3 and E3 were used instead of Compounds M1, B2 and E2, respectively.

Copolymer H5 was prepared in the same manner as in the Preparation method of Copolymer H1, except that Compounds M4 and E4 were used instead of Compounds M1 and E1, respectively.

Copolymer H6 was prepared in the same manner as in the Preparation method of Copolymer H1, except that Compounds M5 and E5 were used instead of Compounds M1 and E1, respectively.

Copolymer H7 was prepared in the same manner as in the Preparation method of Copolymer H2, except that Compounds M6, B3 and E4 were used instead of Compounds M1, B2 and E2, respectively.

The weight average molecular weight (Mw) and the polydispersity index (PDI, Mw/Mn) of the prepared copolymer were measured by GPC (Agilent <NUM> series) using a PS standard, and the prepared copolymer was measured using a solution dissolved in THF at a concentration of <NUM>/<NUM>.

Mg (<NUM>, <NUM> mmol), I<NUM> (<NUM>) and THF (<NUM>) were added to a <NUM> round-bottom flask under a nitrogen atmosphere, and the mixture was stirred for <NUM> minutes. <NUM>-Bromostyrene (<NUM>, <NUM> mmol) was added thereto, and a <NUM> water tank was placed under the round bottom flask and stirred for one day. It was confirmed that the reaction solution turned black and Mg was dissolved. Ether (<NUM>) was added thereto to dilute the reaction solution. Tris(pentafluorophenyl)borane (<NUM>, <NUM> mmol) was dissolved in ether (<NUM>) and slowly added to the reaction solution for <NUM> minutes. The solution was stirred for one day. Na<NUM>CO<NUM> (<NUM>, <NUM>, <NUM> mmol) was slowly added to the reaction solution. The organic solvent was extracted using ethyl acetate (<NUM>×<NUM>) and residual water was removed with MgSO<NUM>. In order to additionally remove the residual water and impurities, the resultant was distilled with benzene using a Dean-stock. When about <NUM> of the solvent remained, the solution was cooled and filtered to prepare Compound D1' (<NUM>, yield: <NUM>%).

Compound D1' (<NUM>, <NUM> mmol), distilled water (<NUM>) and Ph<NUM>lCl (<NUM>, <NUM> mmol) were added to a <NUM> round bottom flask, and the mixture was stirred for <NUM> hour. Acetone (<NUM>) is added to the reaction solution to form a precipitate, and the precipitate was filtered and dried to prepare Compound D1 (<NUM>, yield: <NUM>%).

Methyltriphenyl potassium bromide (<NUM>, <NUM> mmol) and THF (<NUM>) were added to a <NUM> round bottom flask, and the mixture was stirred at <NUM> for <NUM> minutes. n-BuLi (<NUM>, <NUM> mmol, <NUM> in hexane) was slowly added to the reaction solution, and the mixture was stirred at <NUM> for <NUM> minutes. <NUM>-Formyl-<NUM>,<NUM>,<NUM>,<NUM>-tetrafluoro-<NUM>-bromobenzene (<NUM>, <NUM> mmol, in <NUM> THF) was slowly added to the reaction solution at <NUM>. The reaction solution was stirred while slowly raising the temperature to room temperature. After <NUM> hours, ether (<NUM>) and NH<NUM>Cl saturated solution (<NUM>) were added to the reaction solution. The organic solvent was extracted using ether (<NUM> × <NUM>), and residual water was removed with MgSO<NUM>. The resultant was subjected to column with ethyl acetate:hexane = <NUM>:<NUM> (v:v) to prepare Compound D2' (<NUM>, yield: <NUM>%).

Mg (<NUM>, <NUM> mmol), THF (<NUM>) and I<NUM> (<NUM>) were added to a <NUM> round bottom flask, and the mixture was stirred. Compound D2' (<NUM>, <NUM> mmol) was added to the reaction solution, and stirred at room temperature. After <NUM> hours, it was confirmed that the solution turned black and Mg was completely dissolved, and ether (<NUM>) and BCl<NUM> (<NUM>, <NUM> mmol, <NUM> in hexanes) were added over <NUM> minutes. The reaction solution was stirred for one day, and then Na<NUM>CO<NUM> (<NUM>, <NUM> mmol, <NUM> in H<NUM>O) was added. The synthetic material was extracted with ethyl acetate (<NUM> × <NUM>), and then residual water was removed with MgSO<NUM>. After removing all the solvent, water was completely removed with benzene using a Dean-stock and the solid was filtered to prepare Compound D2" (<NUM>, yield: <NUM>%).

Compound D2" (<NUM>, <NUM> mmol), <NUM>-(<NUM>-vinylbenzyl)pyridin-<NUM>-ium chloride (<NUM>, <NUM> mmol), H<NUM>O (<NUM>) and methylene chloride (<NUM>) were added to a <NUM> round bottom flask, and the mixture was vigorously stirred for <NUM> minutes. The organic solvent was extracted using ether (<NUM> × <NUM>) and residual water was removed with MgSO<NUM>. The solvent was removed and vacuum dried to prepare Compound D2 (<NUM>, yield: <NUM>%).

<NUM>-Bromo-<NUM>,<NUM>,<NUM>,<NUM>-tetrafluoro-<NUM>-vinylbenzene (<NUM>, <NUM> mmol) was added to THF (<NUM>) in a <NUM> round bottom flask, and the mixture was stirred at -<NUM> for <NUM> minutes. n-BuLi in hexane (<NUM>, <NUM> mmol, <NUM>) was slowly added to the solution, and the mixture was stirred at -<NUM> for <NUM> minutes. BCl<NUM> (<NUM>, <NUM> mmol, <NUM> in hexanes) was added to the reaction solution at -<NUM> for <NUM> minutes. The reaction solution was stirred for one day while slowly raising the temperature to room temperature, and then water (<NUM>) was added thereto. The synthetic material was extracted with ethyl acetate (<NUM> × <NUM>), and then all the solvent was removed. Water was completely removed with benzene using a Dean-stock, and the solid was filtered to prepare Compound D3' (<NUM>, yield: <NUM>%).

Compound D3' (<NUM>, <NUM> mmol), diphenyliodonium chloride (<NUM>, <NUM> mmol), water (<NUM>) and acetone (<NUM>) were added to a <NUM> round bottom flask, and the mixture was vigorously stirred for <NUM> minutes. The reaction mixture was extracted using dichloromethane (<NUM> × <NUM>), and the solvent was removed and dried to prepare Compound D3 (<NUM>, yield: <NUM>%).

Potassium carbonate (<NUM>, <NUM> mmol) was added to DMF (<NUM>) in a <NUM> round bottom flask. <NUM>,<NUM>,<NUM>,<NUM>-Tetrafluorophenol (<NUM>, <NUM> mmol) was added to the flask, and the mixture was stirred at <NUM> for <NUM> minutes. <NUM>-Vinylbenzyl chloride (<NUM>, <NUM> mmol) was slowly added to the reaction solution, and the mixture was stirred at <NUM> for <NUM> hours. Then, water (<NUM>) and ethyl acetate (<NUM>) were added thereto. The organic layer was extracted with ethyl acetate (<NUM>×<NUM>) and residual water was removed with MgSO<NUM>. The resultant was subjected to column with ethyl acetate:hexane = <NUM>:<NUM> (v:v) to prepare Compound D4' (<NUM>, yield: <NUM>%).

Compound D4' (<NUM>, <NUM> mmol) was added to a <NUM> round bottom flask, to which ether (<NUM>) was added and stirred. The reaction solution was cooled to -<NUM>, and the mixture was stirred for <NUM> minutes. n-BuLi (<NUM>, <NUM> mmol, <NUM> in hexane) was slowly injected over <NUM> minutes. Then, the mixture was stirred for <NUM> hour. BCl<NUM> (<NUM>, <NUM> mmol, <NUM> in hexane) was slowly added over <NUM> minutes. The temperature of the reaction solution was slowly raised to room temperature. After stirring the reaction solution for one day, water (<NUM>) was added thereto. The synthetic material was extracted with ether (<NUM> × <NUM>) and all the solvent was removed. Then, water was completely removed with benzene using a Dean-stock and the solid was filtered to prepare Compound D4" (<NUM>, yield: <NUM>%).

Compound D4" (<NUM>, <NUM> mmol), diphenylidonium chloride (<NUM>, <NUM> mmol), water (<NUM>) and acetone (<NUM>) were added to a <NUM> round bottom flask, and the mixture was vigorously stirred for <NUM> minutes. The organic solvent was extracted using methylene chloride (<NUM> × <NUM>) and the solvent was removed. The resultant was subjected to column with methylene chloride:acetone = <NUM>:<NUM> (v:v) to prepare Compound D4 (<NUM>, yield: <NUM>%).

A glass substrate on which ITO was coated as a thin film to a thickness of <NUM>Å was ultrasonically cleaned using an acetone solvent for <NUM> minutes. The substrate was then put into distilled water in which a detergent was dissolved, ultrasonically cleaned for <NUM> minutes, and then ultrasonic cleaning was repeated twice using distilled water for <NUM> minutes. After the cleaning with distilled water was completed, the substrate was ultrasonically cleaned with a solvent of isopropyl alcohol for <NUM> minutes, and then dried. The substrate was then transported to a glove box.

On the transparent ITO electrode prepared as above, a <NUM> wt% cyclohexanone solution containing the previously prepared Copolymer H1 and Compound D1 in a weight ratio of <NUM>:<NUM> was spin-coated and heat-treated at <NUM> for <NUM> minutes to form a hole injection layer with a thickness of <NUM>Å. A <NUM> wt% toluene solution containing the following Polymer HTL (weight average molecular weight: <NUM>,<NUM>; measured by GPC (Agilent <NUM> series) using a PS standard) was spin-coated onto the hole injection layer to form a hole transport layer with a thickness of <NUM>.

Then, on the hole transport layer, a <NUM> wt% solution containing the following Compound A and the following Compound B in a weight ratio of <NUM>:<NUM> was prepared and then subjected to a solution process to form a light emitting layer with a thickness of <NUM>Å. The following Compound C was vacuum-deposited on the light emitting layer to form an electron injection and transport layer with a thickness of <NUM>Å. LiF having a thickness of <NUM>Å and aluminum having a thickness of <NUM>Å were sequentially deposited on the electron injection and transport layer, thereby forming a cathode.

In the above-mentioned processes, the deposition rates of the organic materials were maintained at <NUM> to <NUM>Å/sec, the deposition rates of the LiF and the aluminum were maintained at <NUM>Å/sec and <NUM>Å/sec, respectively, and the degree of vacuum during the deposition was maintained at <NUM>×<NUM>-<NUM> to <NUM>×<NUM>-<NUM> torr.

The organic light emitting devices were manufactured in the same manner as in Example <NUM>, except that during the manufacture of the hole injection layer, Compounds described in Table <NUM> below were used instead of Copolymer H1 and/or Compound D1.

The organic light emitting devices were manufactured in the same manner as in Example <NUM>, except that during the manufacture of the hole injection layer, Compounds described in Table <NUM> below were used instead of Copolymer H1 and/or Compound D1. Comparative Compounds shown in Table <NUM> below are as follows.

For the organic light emitting devices manufactured in Examples and Comparative Examples, the driving voltage, external quantum efficiency (EQE) and lifetime were measured at a current density of <NUM> mA/cm<NUM>, and the results are shown in Table <NUM> below. The external quantum efficiency was determined by (number of photons emitted)/(number of charge carriers injected), and the lifetime(T95) means the time required for the luminance to be reduced to <NUM>% of the initial luminance.

As shown in Table <NUM>, it was confirmed that when the polymer containing the repeating unit represented by Chemical Formula <NUM> and the ionic compound containing the anionic group represented by Chemical Formula <NUM> according to the present disclosure were used in the hole transport layer, the external quantum efficiency and lifetime were excellent.

On the other hand, it was confirmed that in the case of Comparative Example <NUM>, in which the ionic compound containing an anionic group represented by Chemical Formula <NUM> according to the present disclosure was not used in the hole transport layer, the lifetime was extremely short, and it could not be actually used as an organic light emitting device, and also that unlike the ionic compound containing an anionic group represented by Chemical Formula <NUM> according to the present disclosure, in the case of Comparative Example <NUM>, in which Comparative Compound <NUM> without a photocurable group or a thermosetting group was used as a dopant for the hole transport layer, the external quantum efficiency and lifetime were significantly reduced.

As shown in Table <NUM> below, a <NUM> wt% cyclohexanone solution made with the previously prepared Copolymer alone, or a <NUM> wt% cyclohexanone solution containing the copolymer and the dopant compound prepared above in a weight ratio of <NUM>:<NUM> was prepared, and then each of them was spin-coated and heat-treated at <NUM> for <NUM> minutes to obtain a thin film. The UV-vis absorption spectrum of the thin film was measured, and the absorbance index (a1) at the point where the maximum absorption appeared was measured. Then, the thin film was immersed in cyclohexanone for <NUM> minutes, then taken out, and the UV-vis absorption spectrum was measured and the absorbance index (a2) at the point where the maximum absorption appeared was measured. The curing conversion rate was calculated from the two measured values according to the following Equation <NUM>.

As shown in Table <NUM>, it was confirmed that compared to the case of using the copolymer alone, the case of using it together with the dopant was significantly increased in the curing conversion rate. Without being theoretically limited, the above result shows that curing proceeds more smoothly by the photocurable group or thermosetting group of the ionic compound containing an anionic group represented by Chemical Formula <NUM> according to the present disclosure.

Claim 1:
An organic light emitting device comprising:
an anode (<NUM>),
a cathode (<NUM>),
a light emitting layer (<NUM>) between the anode and the cathode, and
a hole transport layer (<NUM>) between the anode and the light emitting layer,
wherein said hole transport layer may be a hole injection layer, a hole transport layer, or a layer that simultaneously injects and transports holes; and
wherein said hole transport layer comprises a polymer containing a repeating unit represented by the following Chemical Formula <NUM>, and an ionic compound containing an anionic group represented by the following Chemical Formula <NUM>:
<CHM>
wherein in Chemical Formula <NUM>,
L<NUM> is a substituted or unsubstituted C<NUM>-<NUM> arylene,
each L<NUM> is independently a substituted or unsubstituted C<NUM>-<NUM> arylene,
each Ar is independently a substituted or unsubstituted C<NUM>-<NUM> aryl,
each R is independently hydrogen, deuterium, or a substituted or unsubstituted C<NUM>-<NUM> alkyl,
<CHM>
wherein in Chemical Formula <NUM>,
n1 and n2 are each independently an integer of <NUM> to <NUM>, with the proviso that n1+n2 is <NUM>,
Ar"<NUM> is
<CHM>
R" is a photocurable group; or a thermosetting group,
each R"<NUM> is independently hydrogen, halogen, or a C<NUM>-<NUM> haloalkyl, n3 is an integer of <NUM> to <NUM>,
Ar"<NUM>is
<CHM>
each R"<NUM> is independently hydrogen, halogen, a C<NUM>-<NUM> haloalkyl, a photocurable group, or a thermosetting group, and
n4 is an integer of <NUM> to <NUM>;
wherein the polymer further comprises a repeating unit selected from the group consisting of the following:
<CHM>