KR102549458B1 - Novel polymer and organic light emitting device comprising the same - Google Patents

Abstract

The present invention provides a polymer compound and an organic light emitting device using the same.

Description

Novel polymer and organic light emitting device using the same {Novel polymer and organic light emitting device comprising the same}

The present invention relates to a novel polymer and an organic light emitting device including the same.

In general, the organic light emitting phenomenon refers to a phenomenon in which electrical energy is converted into light energy using an organic material. An organic light emitting device using an organic light emitting phenomenon has a wide viewing angle, excellent contrast, and a fast response time, and has excellent luminance, driving voltage, and response speed characteristics, and thus many studies are being conducted.

An organic light emitting device generally has a structure including an anode, a cathode, and an organic material layer between the anode and the cathode. In order to increase the efficiency and stability of the organic light emitting device, the organic material layer is often composed of a multi-layered structure composed of different materials, and may include, for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. In the structure of this organic light emitting device, when a voltage is applied between the two electrodes, holes are injected from the anode and electrons from the cathode are injected into the organic material layer, and when the injected holes and electrons meet, excitons are formed. When it falls back to the ground state, it glows.

The development of new materials for organic materials used in the organic light emitting device as described above is continuously required.

Meanwhile, in recent years, an organic light emitting device using a solution process, particularly an inkjet process, instead of a conventional deposition process has been developed to reduce process costs. In the early days, an attempt was made to develop an organic light emitting device by coating all organic light emitting device layers with a solution process, but the current technology has limitations, so only HIL, HTL, and EML in the form of a regular structure are carried out as a solution process, and the subsequent process is the existing deposition process A hybrid process that utilizes is being studied.

Accordingly, the present invention provides a novel material for an organic light emitting device that can be used for an organic light emitting device and can be deposited in a solution process at the same time.

Korean Patent Publication No. 10-2000-0051826

The present invention relates to a novel polymer and an organic light emitting device including the same.

The present invention provides a polymer comprising a repeating unit represented by Formula 1 below:

[Formula 1]

In Formula 1,

Ar ₁ to Ar ₃ are each independently a substituted or unsubstituted C _6-60 aryl; Or a C _2-60 heteroaryl containing at least one selected from the group consisting of substituted or unsubstituted N, O and S,

L is a single bond; Substituted or unsubstituted C _6-60 arylene; Or a C _2-60 heteroarylene containing at least one selected from the group consisting of substituted or unsubstituted N, O and S,

R ₁ is hydrogen; heavy hydrogen; halogen; cyano; nitro; amino; Substituted or unsubstituted C _1-60 Alkyl; Substituted or unsubstituted C _3-60 cycloalkyl; Substituted or unsubstituted C _2-60 alkenyl; Substituted or unsubstituted C _6-60 aryl; Or a C _2-60 heteroaryl containing any one or more heteroatoms selected from the group consisting of substituted or unsubstituted N, O and S,

Q is substituted or unsubstituted phenylene or substituted or unsubstituted naphthylene;

m is an integer between 3 and 10;

a1 is an integer between 0 and 4.

In addition, the present invention is a positive electrode; a cathode provided to face the anode; a light emitting layer provided between the anode and the cathode; and a hole transport layer provided between the anode and the light emitting layer, wherein the hole transport layer includes the polymer.

The polymer according to the present invention can be used as a material for a hole transport layer of an organic light emitting device, can be deposited through a solution process, and can improve efficiency, low driving voltage and/or lifetime characteristics of an organic light emitting device.

1 shows an example of an organic light emitting device including a substrate 1, an anode 2, a hole transport layer 3, a light emitting layer 4, and a cathode 5.
2 is composed of a substrate (1), an anode (2), a hole injection layer (6), a hole transport layer (3), a light emitting layer (4), an electron transport layer (7), an electron injection layer (8) and a cathode (5). An example of an organic light emitting device is shown.

Hereinafter, in order to aid understanding of the present invention, it will be described in more detail.

는 다른 치환기에 연결되는 결합을 의미한다. In this specification,

means a bond connected to another substituent.

In this specification, the term "substituted or unsubstituted" means deuterium; halogen group; nitrile group; nitro group; hydroxy group; carbonyl group; ester group; imide group; amino group; phosphine oxide group; alkoxy group; aryloxy group; Alkyl thioxy group; Arylthioxy group; an alkyl sulfoxy group; aryl sulfoxy groups; silyl group; boron group; an alkyl group; cycloalkyl group; alkenyl group; aryl group; aralkyl group; Aralkenyl group; Alkyl aryl group; Alkylamine group; Aralkylamine group; heteroarylamine group; Arylamine group; Arylphosphine group; Or substituted or unsubstituted with one or more substituents selected from the group consisting of a heterocyclic group containing at least one of N, O, and S atoms, or substituted or unsubstituted with two or more substituents linked to each other among the substituents exemplified above. . For example, "a substituent in which two or more substituents are connected" may be a biphenyl group. That is, the biphenyl group may be an aryl group, and may be interpreted as a substituent in which two phenyl groups are connected.

In the present specification, the number of carbon atoms of the carbonyl group is not particularly limited, but is preferably 1 to 40 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

In the present specification, the ester group may be substituted with an aryl group having 6 to 25 carbon atoms or a straight-chain, branched-chain or cyclic chain alkyl group having 1 to 25 carbon atoms in the ester group. Specifically, it may be a compound of the following structural formula, but is not limited thereto.

In the present specification, the number of carbon atoms of the imide group is not particularly limited, but is preferably 1 to 25 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

In the present specification, the silyl group is specifically a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, and the like. but not limited to

In the present specification, the boron group specifically includes a trimethyl boron group, a triethyl boron group, a t-butyldimethyl boron group, a triphenyl boron group, a phenyl boron group, but is not limited thereto.

In this specification, examples of the halogen group include fluorine, chlorine, bromine or iodine.

In the present specification, the alkyl group may be straight-chain or branched-chain, and the number of carbon atoms is not particularly limited, but is preferably 1 to 40. According to one embodiment, the number of carbon atoms of the alkyl group is 1 to 20. According to another exemplary embodiment, the number of carbon atoms of the alkyl group is 1 to 10. According to another exemplary embodiment, the alkyl group has 1 to 6 carbon atoms. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n -pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl , n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2 -Dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, etc., but is not limited thereto.

In the present specification, the alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. According to one embodiment, the alkenyl group has 2 to 20 carbon atoms. According to another exemplary embodiment, the alkenyl group has 2 to 10 carbon atoms. According to another exemplary embodiment, the alkenyl group has 2 to 6 carbon atoms. Specific examples include vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1- Butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-( naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, stilbenyl group, styrenyl group, etc., but is not limited thereto.

In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms, and according to an exemplary embodiment, the cycloalkyl group has 3 to 30 carbon atoms. According to another exemplary embodiment, the number of carbon atoms of the cycloalkyl group is 3 to 20. According to another exemplary embodiment, the number of carbon atoms of the cycloalkyl group is 3 to 6. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3, 4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, and the like, but are not limited thereto.

In the present specification, the aryl group is not particularly limited, but preferably has 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the number of carbon atoms of the aryl group is 6 to 30. According to one embodiment, the number of carbon atoms of the aryl group is 6 to 20. The aryl group may be a phenyl group, a biphenyl group, a terphenyl group, etc. as a monocyclic aryl group, but is not limited thereto. The polycyclic aryl group may be a naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, perylenyl group, chrysenyl group, fluorenyl group, and the like, but is not limited thereto.

등이 될 수 있다. 다만, 이에 한정되는 것은 아니다.In the present specification, the fluorenyl group may be substituted, and two substituents may be bonded to each other to form a spiro structure. When the fluorenyl group is substituted,

etc. However, it is not limited thereto.

In the present specification, the heterocyclic group is a heterocyclic group containing at least one of O, N, Si, and S as heterogeneous elements, and the number of carbon atoms is not particularly limited, but preferably has 2 to 60 carbon atoms. Examples of the heterocyclic group include a thiophene group, a furan group, a pyrrole group, an imidazole group, a thiazole group, an oxazole group, an oxadiazole group, a triazole group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, and an acridyl group. , pyridazine group, pyrazinyl group, quinolinyl group, quinazoline group, quinoxalinyl group, phthalazinyl group, pyridopyrimidinyl group, pyridopyrazinyl group, pyrazinopyrazinyl group, isoquinoline group, indole group , carbazole group, benzoxazole group, benzoimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, isoxazolyl group, thiadia A zolyl group, a phenothiazinyl group, and a dibenzofuranyl group, but are not limited thereto.

In the present specification, an aralkyl group, an aralkenyl group, an alkylaryl group, and an aryl group among arylamine groups are the same as the examples of the aryl group described above. In the present specification, the alkyl group among the aralkyl group, the alkylaryl group, and the alkylamine group is the same as the examples of the above-mentioned alkyl group. In the present specification, the description of the heterocyclic group described above may be applied to the heteroaryl of the heteroarylamine. In the present specification, the alkenyl group among the aralkenyl groups is the same as the examples of the alkenyl group described above. In the present specification, the description of the aryl group described above may be applied except that the arylene is a divalent group. In the present specification, the description of the heterocyclic group described above may be applied except that the heteroarylene is a divalent group. In the present specification, the hydrocarbon ring is not a monovalent group, and the description of the aryl group or cycloalkyl group described above may be applied, except that the hydrocarbon ring is formed by combining two substituents. In the present specification, the heterocyclic group is not a monovalent group, and the description of the above-described heterocyclic group may be applied, except that it is formed by combining two substituents.

The present invention provides a polymer including a repeating unit represented by Chemical Formula 1 above.

Conjugated polymers conventionally used as hole transport materials have problems in that they are difficult to purify after polymerization and are not suitable for mass production due to low reproducibility of polymerization reactions.

However, the polymer containing the repeating unit represented by Chemical Formula 1 according to the present invention has high polymerization reproducibility due to the reaction mechanism and is suitable as a hole transport material for organic light emitting devices because it does not use a catalyst or a halogen-containing monomer during the polymerization reaction. .

In addition, the polymer including the repeating unit represented by Chemical Formula 1 according to the present invention has excellent solubility in organic solvents and exhibits excellent hole transport properties in the device after film formation, thereby forming a solution for forming a hole transport layer (HTL). It was confirmed that it can be suitably used as a soluble OLED material.

The polymer including the repeating unit represented by Chemical Formula 1 is not deformed by an additional solution process performed after the solution coating and heat treatment processes, and it is possible to improve the efficiency and lifespan of the device. Hereinafter, the present invention will be described in detail.

(repeated unit)

In the present specification, a 'repeating unit' is a repeating unit represented by Chemical Formula 1 included in the polymer according to the invention, and has excellent hole transport properties and a high HOMO energy level.

Preferably, Ar ₁ to Ar ₃ are each independently substituted or unsubstituted C _6-20 aryl, more preferably, Ar ₁ to Ar ₃ are each independently substituted or unsubstituted biphenylyl; Substituted or unsubstituted terphenylyl or phenyl-dimethylfluorenyl, and most preferably, Ar ₁ to Ar ₃ are each independently substituted with biphenylyl, 4-hexylbiphenylyl, or 2 tertbutyl terphenylyl, or 9,9-dimethyl-2-phenyl-9H-fluorenyl,

Preferably, Ar ₁ and Ar ₂ are identical to each other.

Preferably, L is a single bond; or a substituted or unsubstituted C _6-20 arylene, more preferably, L is phenylene.

Preferably, R ₁ is hydrogen.

Preferably, m is an integer between 3 and 8, more preferably an integer between 3 and 5.

Preferably, -(Q) _m - is of formula 2:

[Formula 2]

In Formula 2,

each Q ₁ is independently phenylene substituted with one or more C _1-30 alkyl or naphthylene substituted with one or more C _1-30 alkyl;

m1 is an integer between 1 and 8.

More preferably -(Q ₁ ) _m1 - is 1,4-dihexylphenylene, 2,2',5,5'-tetrahexylbiphenylylene, or 7,7'-dioctyl-1,1' -It is binaphthylene.

Preferably, the repeating unit represented by Chemical Formula 1 is any one selected from the group consisting of:

Meanwhile, the compound represented by Formula 1 is derived from a monomer represented by Formula 1-1 below:

[Formula 1-1]

In Formula 1-1,

Ar ₁ to Ar ₃ , L, R ₁ , Q, m and a1 are as defined in Chemical Formula 1 above.

Among the compounds represented by Formula 1-1, when -(Q) _m- is Formula 2, it can be prepared by, for example, the preparation method shown in Scheme 1 below, and other compounds can be prepared similarly. .

[Scheme 1]

In Reaction Scheme 1, Ar ₁ to Ar ₃ , L, R ₁ , Q ₁ , m1 and a1 are as defined in Formula 1 and Formula 2, X is halogen, preferably X is chloro or bromo.

In Reaction Scheme 1, an amine substitution reaction proceeds. In the case of the amine substitution reaction, it is preferable to carry out in the presence of a palladium catalyst and a base, and the reactor for the reaction can be changed as known in the art. The manufacturing method may be more specific in Preparation Examples to be described later.

(polymer)

The polymer according to the present invention may be prepared by polymerizing the monomer represented by Formula 1-1.

A method for preparing the polymer as described above is not particularly limited. For example, it can be polymerized by LRP (Living Radical Polymerization) method, for example, using an organic rare earth metal complex as a polymerization initiator, or using an organic alkali metal compound as a polymerization initiator to form inorganic salts of alkali metals or alkaline earth metals. Anionic polymerization synthesized in the presence of an acid acid, anionic polymerization method synthesized in the presence of an organic aluminum compound using an organic alkali metal compound as a polymerization initiator, atom transfer radical polymerization method (ATRP) using an atom transfer "radical" polymerizer as a polymerization control agent , ARGET (Activators Regenerated by Electron Transfer) atomic transfer radical polymerization method (ATRP), ICAR (Initiators for continuous activator regeneration ) atom transfer 　 radical polymerization method (ATRP), reversible addition-cleavage chain transfer polymerization method using an inorganic reducing agent reversible addition-cleavage chain transfer agent (RAFT), or a method using an organic tellurium compound as an 　 initiator. Among these methods, An appropriate method may be selected and applied.

For example, the polymer may be prepared in a manner that includes polymerizing a reactant including the monomer by a living radical polymerization method in the presence of a "radical" initiator and a living "radical" polymerization reagent. The manufacturing process of the polymer may further include, for example, a process of precipitating the polymerization product produced through the above process in a non-solvent.

The type of radical initiator is not particularly limited, and for example, AIBN (azobisisobutyronitrile) or 2,2'-azobis-2,4-dimethylvaleronitrile (2,2'-azobis-(2,4-dimethylvaleronitrile) ), or a peroxide series such as benzoyl peroxide (BPO) or di-t-butyl peroxide (DTBP).

The living "radical" polymerization process is, for example, methylene chloride, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, benzene, toluene, acetone, chloroform, tetrahydrofuran, dioxane, monoglyme, diglyme, dimethylform amide, dimethylsulfoxide or dimethylacetamide and the like.

As the non-solvent, for example, alcohols such as methanol, ethanol, normal propanol or isopropanol, glycols such as ethylene glycol, ethers such as n-hexane, cyclohexane, n-heptane or petroleum ether may be used, It is not limited thereto.

Preferably, the polymer including the repeating unit represented by Chemical Formula 1 may have a weight average molecular weight of 1,000 to 1,000,000 g/mol. More preferably, the polymer may have a weight average molecular weight of 5,000 to 100,000 g/mol or 5,000 to 50,000 g/mol.

In the present specification, the terms "weight average molecular weight (Mw)" and "number average molecular weight (Mn)" are values in terms of standard polystyrene measured using gel permeation chromatograph (GPC). In this specification, the term "molecular weight" means a weight average molecular weight unless otherwise specified.

For example, molecular weight is determined using an Agilent PL-GPC 220 instrument equipped with a 300 mm long PLgel MIXED-B column (Polymer Laboratories). The measurement temperature is 160°C, 1,2,4-trichlorobenzene is used as a solvent, and the flow rate is measured at a rate of 1 mL/min. The sample is prepared at a concentration of 10mg/10mL and then supplied in an amount of 200 μL. The values of Mw and Mn are derived with reference to a calibration curve formed using polystyrene standards. The molecular weight (g/mol) of the polystyrene standard uses nine types of 2,000/ 10,000/ 30,000/ 70,000/ 200,000/ 700,000/ 2,000,000/ 4,000,000/ 10,000,000.

(coating composition)

The polymer according to the present invention can form an organic material layer, particularly a hole transport layer, of an organic light emitting device through a solution process. To this end, the present invention provides a coating composition comprising the above-described polymer and a solvent according to the present invention.

The solvent is not particularly limited as long as it can dissolve or disperse the polymer according to the present invention. For example, chloroform, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene, o -Chlorinated solvents such as dichlorobenzene; ether solvents such as tetrahydrofuran and dioxane; aromatic hydrocarbon 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 solvents, such as acetone, methyl ethyl ketone, and cyclohexanone; Ester solvents, such as ethyl acetate, butyl acetate, and ethyl cellosolve acetate; Ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, dimethoxyethane, propylene glycol, diethoxymethane, triethylene glycol monoethyl ether, glycerin, 1,2-hexanediol, etc. alcohol and its derivatives; alcohol solvents such as methanol, ethanol, propanol, isopropanol, and cyclohexanol; sulfoxide solvents such as dimethyl sulfoxide; and amide solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide; benzoate solvents such as butyl benzoate and methyl-2-methoxy benzoate; tetralin; and solvents such as 3-phenoxy-toluene. In addition, the above-mentioned solvent may be used alone or in combination of two or more solvents.

In addition, the viscosity of the coating composition is preferably 1 cP to 10 cP, and coating is easy within the above range. In addition, the concentration of the polymer according to the present invention in the coating composition is preferably 0.1 wt / v% to 20 wt / v%.

In addition, the present invention provides a method of forming a hole transport layer using the coating composition described above. Specifically, coating the coating composition according to the present invention described above by a solution process on the anode or on the hole injection layer formed on the anode; and heat-treating or light-treating the coated coating composition.

The solution process uses the above-described coating composition according to the present invention, and includes spin coating, dip coating, doctor blading, inkjet printing, screen printing, spraying, roll coating, etc., but is not limited thereto.

In the heat treatment step, the heat treatment temperature is preferably 150 to 230 °C. In addition, the heat treatment time is 1 minute to 3 hours, more preferably 10 minutes to 1 hour. In addition, the heat treatment is preferably performed in an inert gas atmosphere such as argon or nitrogen. In addition, a step of evaporating a solvent may be further included between the coating step and the heat treatment or light treatment step.

(organic light emitting device)

In addition, the present invention provides an organic light emitting device comprising the polymer according to the present invention described above. Specifically, the present invention is a positive electrode; a cathode provided to face the anode; a light emitting layer provided between the anode and the cathode; and a hole transport layer provided between the anode and the light emitting layer, wherein the hole transport layer includes the polymer according to the present invention.

The structure of an organic light emitting device according to an embodiment of the present invention is illustrated in FIGS. 1 and 2 .

1 shows an example of an organic light emitting device including a substrate 1, an anode 2, a hole transport layer 3, a light emitting layer 4, and a cathode 5. 2 is composed of a substrate (1), an anode (2), a hole injection layer (6), a hole transport layer (3), a light emitting layer (4), an electron transport layer (7), an electron injection layer (8) and a cathode (5). An example of an organic light emitting device is shown.

The organic light emitting device according to the present invention may be manufactured using materials and methods known in the art, except that the hole transport layer includes the polymer according to the present invention and is manufactured as described above.

For example, the organic light emitting device according to the present invention may be manufactured by sequentially stacking an anode, an organic material layer, and a cathode on a substrate. At this time, using a physical vapor deposition (PVD) method such as sputtering or e-beam evaporation, depositing a metal or a metal oxide having conductivity or an alloy thereof on the substrate to form an anode After forming an organic material layer including a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer thereon, and depositing a material that can be used as a cathode thereon, it can be prepared.

In addition to this method, an organic light emitting device may be manufactured by sequentially depositing an organic material layer and an anode material on a substrate from a cathode material (WO 2003/012890). However, the manufacturing method is not limited thereto.

As the anode material, a material having a high work function is generally preferred so that holes can be smoothly injected into the organic layer. Specific examples of the cathode material include metals such as vanadium, chromium, copper, zinc, and gold or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SNO ₂ :Sb; conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline, but are not limited thereto.

The cathode material is preferably a material having a small work function so as to easily inject electrons into the organic material layer. Specific examples of the anode material include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; There are multi-layered materials such as LiF/Al or LiO ₂ /Al, but are not limited thereto.

The hole injection layer is a layer for injecting holes from the electrode, and the hole injection material has the ability to transport holes and has a hole injection effect at the anode, an excellent hole injection effect for the light emitting layer or the light emitting material, and generated in the light emitting layer A compound that prevents migration of excitons to the electron injecting layer or electron injecting material and has excellent thin film formation ability is preferred. It is preferable that the highest occupied molecular orbital (HOMO) of the hole injection material is between the work function of the anode material and the HOMO of the surrounding organic layer. Specific examples of the hole injection material include metal porphyrins, oligothiophenes, arylamine-based organic materials, hexanitrilehexaazatriphenylene-based organic materials, quinacridone-based organic materials, and perylene-based organic materials. of organic matter, anthraquinone, and polyaniline and polythiophene-based conductive polymers, but are not limited thereto.

The light emitting material is a material capable of emitting light in the visible ray region by receiving and combining holes and electrons from the hole transport layer and the electron transport layer, respectively, and a material having good quantum efficiency for fluorescence or phosphorescence is preferable. Specific examples include 8-hydroxy-quinoline aluminum complex (Alq ₃ ); carbazole-based compounds; dimerized styryl compounds; BAlq; 10-hydroxybenzoquinoline-metal compounds; compounds of the benzoxazole, benzthiazole and benzimidazole series; poly(p-phenylenevinylene) (PPV)-based polymers; spiro compounds; Polyfluorene, rubrene, etc., but are not limited thereto.

The light emitting layer may include a host material and a dopant material. The host material includes a condensed aromatic ring derivative or a compound containing a hetero ring. Specifically, condensed aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, etc., and heterocyclic-containing compounds include carbazole derivatives, dibenzofuran derivatives, ladder type furan compounds, pyrimidine derivatives, etc., but are not limited thereto.

Dopant materials include aromatic amine derivatives, strylamine compounds, boron complexes, fluoranthene compounds, metal complexes, and the like. Specifically, aromatic amine derivatives are condensed aromatic ring derivatives having a substituted or unsubstituted arylamino group, such as pyrene, anthracene, chrysene, periplanthene, etc. having an arylamino group, and styrylamine compounds include substituted or unsubstituted arylamine is substituted with at least one arylvinyl group, wherein one or two or more substituents 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. Specifically, there are styrylamine, styryldiamine, styryltriamine, styryltetraamine, etc., but is not limited thereto. In addition, metal complexes include, but are not limited to, iridium complexes and platinum complexes.

The electron transport layer is a layer that receives electrons from the electron injection layer and transports electrons to the light emitting layer. As the electron transport material, a material capable of receiving electrons from the cathode and transferring them to the light emitting layer is suitable. do. Specific examples include Al complexes of 8-hydroxyquinoline; Complexes containing Alq ₃ ; organic radical compounds; hydroxyflavone-metal complexes and the like, but are not limited thereto. The electron transport layer can be used with any desired cathode material as used according to the prior art. In particular, examples of suitable cathode materials are conventional materials having a low work function followed by a layer of aluminum or silver. Specifically cesium, barium, calcium, ytterbium and samarium, followed in each case by a layer of aluminum or silver.

The electron injection layer is a layer for injecting electrons from an electrode, has the ability to transport electrons, has an excellent electron injection effect from a cathode, an excellent electron injection effect for a light emitting layer or a light emitting material, and injects holes of excitons generated in the light emitting layer. A compound that prevents migration to a layer and has excellent thin film forming ability is preferred. Specifically, fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, preonylidene methane, anthrone, etc. and their derivatives, metals complex compounds and nitrogen-containing 5-membered ring derivatives, but are not limited thereto.

Examples of the metal complex compound include 8-hydroxyquinolinato lithium, bis(8-hydroxyquinolinato)zinc, bis(8-hydroxyquinolinato)copper, bis(8-hydroxyquinolinato)manganese, Tris(8-hydroxyquinolinato) aluminum, tris(2-methyl-8-hydroxyquinolinato) aluminum, tris(8-hydroxyquinolinato) gallium, bis(10-hydroxybenzo[h] Quinolinato) beryllium, bis(10-hydroxybenzo[h]quinolinato)zinc, bis(2-methyl-8-quinolinato)chlorogallium, bis(2-methyl-8-quinolinato)( There are o-cresolato) gallium, bis(2-methyl-8-quinolinato)(1-naphtolato)aluminum, and bis(2-methyl-8-quinolinato)(2-naphtolato)gallium. Not limited to this.

The organic light emitting device according to the present invention may be a top emission type, a bottom emission type, or a double side emission type depending on the material used.

In addition, the polymer according to the present invention may be included in an organic solar cell or an organic transistor in addition to an organic light emitting device.

The invention is explained in more detail in the following examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

Preparation Example 1: Preparation of Polymer 1

(Synthesis of monomer 1-1)

(Synthesis of polymer 1)

After dissolving monomer 1-1 (0.22 g, 0.163 mmol) in THF (5 mL), adding AIBN (3 mg), reacting at 60 ° C for 4 hours, lowering the temperature to room temperature, and precipitating in ethanol to prepare synthesized polymer 1 .

Values of weight average molecular weight and number average molecular weight measured by GPC using PS standard using Agilent 1200 series are as follows.

Mn: 26,000g/mol, Mw: 49,000g/mol

Preparation Example 2: Preparation of Polymer 2

(Synthesis of monomer 2-1)

(Synthesis of polymer 2)

After dissolving monomer 2-1 (0.24g, 0.163mmol) in THF (5mL), adding AIBN (3mg), reacting at 60 ° C for 4 hours, lowering the temperature to room temperature, and precipitating in ethanol to prepare synthesized polymer 2 .

Values of weight average molecular weight and number average molecular weight measured by GPC using PS standard using Agilent 1200 series are as follows.

Mn: 31,000g/mol, Mw: 48,000g/mol

Preparation Example 3: Preparation of Polymer 3

(Synthesis of monomer 3-1)

(Synthesis of polymer 3)

After dissolving monomer 3-1 (0.24 g, 0.163 mmol) in THF (5 mL), adding AIBN (3 mg), reacting at 60 ° C for 4 hours, lowering the temperature to room temperature, and precipitating in ethanol to prepare synthesized polymer 3 .

Values of weight average molecular weight and number average molecular weight measured by GPC using PS standard using Agilent 1200 series are as follows.

Mn: 19,000g/mol, Mw: 38,000g/mol

Comparative Preparation Example 1: Preparation of polymer a

(Synthesis of monomer a-1)

(Synthesis of polymer a)

As a comparative preparation example, the monomer a-1 (0.23g, 0.163mmol) was dissolved in THF (5mL), AIBN (3mg) was added, reacted at 60 degrees for 4 hours, cooled to room temperature, and synthesized by precipitation in ethanol. Polymer a was prepared.

Values of weight average molecular weight and number average molecular weight measured by GPC using PS standard using Agilent 1200 series are as follows.

Mn: 65,000 g/mol, Mw: 101,000 g/mol

Example 1

A glass substrate on which indium tin oxide (ITO) was deposited with a thickness of 1500 Å was placed in distilled water in which detergent was dissolved and washed with ultrasonic waves. After washing the ITO for 30 minutes, ultrasonic cleaning was performed twice with distilled water for 10 minutes. After the distilled water washing was completed, the substrate was ultrasonically washed with solvents such as isopropyl alcohol and acetone for 30 minutes each, dried, and transported to a glove box.

On the prepared ITO transparent electrode, a solution in which compound A and compound B were mixed in a weight ratio of 8:2 and dissolved in cyclohexanone was spin-coated to form a film with a thickness of 400 Å. This was heated at 220 DEG C for 30 minutes in a nitrogen atmosphere to form a hole injection layer. Thereafter, polymer 1 according to Preparation Example 1 was dissolved in toluene, spin-coated on the hole injection layer to form a film of 200 Å, and heated at 190° C. for 1 hour under a nitrogen atmosphere to form a hole transport layer. Thereafter, the following compound C and compound D were dissolved in cyclohexanone at a weight ratio of 92:8 on the hole transport layer to form a film of 200 Å and heated at 120° C. for 1 hour under a nitrogen atmosphere to form a light emitting layer. Compound E was vacuum-deposited to a thickness of 35 nm on the light emitting layer to form an electron injection and transport layer. A cathode was formed by sequentially depositing LiF to a thickness of 1 nm and aluminum to a thickness of 100 nm on the electron injection and transport layer.

Thereafter, sealing was performed by bonding the sealing glass and the glass substrate to the glass using a photocurable epoxy resin to produce an organic EL element having a multilayer structure. Subsequent operations were performed in the air at room temperature (25°C).

In the above process, the deposition rate of the organic material was maintained at 0.4 ~ 0.7Å / sec, the deposition rate of lithium fluoride on the cathode was 0.3Å / sec, and the deposition rate of aluminum was 2Å / sec, and the vacuum level during deposition was 2ⅹ10 ^-7 ~ Maintaining 5x10 ^-6 torr, an organic light emitting device was manufactured.

Example 2

An organic light-emitting device was manufactured in the same manner as in Example 1, except that Polymer 2 according to Preparation Example 2 was used instead of Polymer 1 as the hole transport layer in Example 1.

Example 3

An organic light emitting device was manufactured in the same manner as in Example 1, except that Polymer 3 according to Preparation Example 3 was used instead of Polymer 1 as the hole transport layer in Example 1.

Comparative Example 1

An organic light-emitting device was manufactured in the same manner as in Example 1, except that the polymer a according to Comparative Preparation Example 1 was used instead of the polymer 1 as the hole transport layer in Example 1.

Experimental Example 1

The HOMO energy level of each material was measured by measuring AC3 by spin-coating the Preparation Examples 1 to 3, Comparative Preparation Example 1 and the Compound C on ITO.

HOMO (eV) Preparation Example 1 polymer 1 5.5 Preparation Example 2 polymer 2 5.6 Preparation Example 3 polymer 3 5.6 Comparative Preparation Example 1 polymer a 5.3 emissive layer host compound C 5.8

Referring to Table 1, the HOMO energy levels of polymers 1 to 3 according to Preparation Examples 1 to 3 are larger than the absolute value of the HOMO energy level of polymer a according to Comparative Preparation Example 1, and the HOMO energy level of Compound C (5.8 eV), the case of polymer 1 to polymer 3 appears smaller than that of polymer a.

This means that polymers 1 to 3 are required to overcome a smaller energy difference than polymer a of Comparative Preparation Example 1 in the process of transferring holes to the compound C, which is the host material of the light emitting layer, so that hole transfer is more advantageous than polymer a. suggests

The reason why the absolute value of the HOMO energy level of the polymer a is smaller than that of the polymers 1 to 3 is expected to be because the distance between two Ns in the molecule is close and it has abundant electrons.

Experimental Example 2

Driving voltage, current efficiency, external quantum efficiency (EQF), and lifetime of the organic light emitting devices prepared in Examples 1 to 3 and Comparative Example 1 were measured at a current density of 10 mA/cm ² , The results are shown in Table 1 below. The external quantum efficiency was calculated as (number of emitted photons)/(number of charge carriers injected). T95 means the time required for the luminance to decrease from the initial luminance (current density of 10 mA/cm ² ) to 95%.

hole transport layer driving voltage
(V@10mA/cm ² ) current efficiency
(cd/A@10mA/cm ² ) EQE (%) life span
(T95,hr) Example 1 polymer 1 3.86 6.99 7.05 22.7 Example 2 polymer 2 4.07 8.21 8.37 28.2 Example 3 polymer 3 4.06 8.13 8.32 21.7 Comparative Example 1 polymer a 4.13 6.04 6.39 2.0

As shown in Table 2, the organic light emitting device manufactured using the compound of the present invention as a hole transport layer exhibited excellent characteristics in terms of driving voltage, current efficiency, EQE, and lifetime.

Although the preferred embodiment (hole transport layer) of the present invention has been described above, the present invention is not limited thereto, and various modifications and implementations are possible within the scope of the claims and detailed description of the invention, and this is also the basis of the invention. belong to the category

1: substrate 2: anode
3: hole transport layer 4: light emitting layer
5: cathode 6: hole injection layer
7: electron transport layer 8: electron injection layer

Claims (10)

A polymer comprising a repeating unit represented by Formula 1 below:
[Formula 1]

In Formula 1,
Ar ₁ to Ar ₃ are each independently a substituted or unsubstituted C _6-60 aryl; Or a C _2-60 heteroaryl containing at least one selected from the group consisting of substituted or unsubstituted N, O and S,
L is phenylene;
R ₁ is hydrogen; heavy hydrogen; halogen; cyano; nitro; amino; Substituted or unsubstituted C _1-60 Alkyl; Substituted or unsubstituted C _3-60 cycloalkyl; Substituted or unsubstituted C _2-60 alkenyl; Substituted or unsubstituted C _6-60 aryl; Or a C _2-60 heteroaryl containing any one or more heteroatoms selected from the group consisting of substituted or unsubstituted N, O and S,
Q is substituted or unsubstituted phenylene or substituted or unsubstituted naphthylene;
m is an integer between 3 and 10;
a1 is an integer between 0 and 4.
According to claim 1,
Ar ₁ to Ar ₃ are each independently substituted or unsubstituted biphenylyl, substituted or unsubstituted terphenylyl, or phenyl-dimethylfluorenyl;
polymer.
According to claim 1,
Ar ₁ and Ar ₂ are the same as each other;
polymer.
delete According to claim 1,
R ₁ is hydrogen;
polymer.
According to claim 1,
- (Q) _m - is the following Formula 2,
Polymer:
[Formula 2]

In Formula 2,
each Q ₁ is independently phenylene substituted with one or more C _1-30 alkyl or naphthylene substituted with one or more C _1-30 alkyl;
m1 is an integer between 1 and 8.
According to claim 1,
The repeating unit represented by Formula 1 is any one selected from the group consisting of
Polymer:

.
According to claim 1,
having a weight average molecular weight of 1,000 to 1,000,000 g/mol;
polymer.
According to claim 1,
The HOMO energy level is 5.4 to 5.7 eV,
polymer.
anode; a cathode provided to face the anode; a light emitting layer provided between the anode and the cathode; and a hole transport layer provided between the anode and the light emitting layer, wherein the hole transport layer includes the polymer according to any one of claims 1 to 3 and 5 to 9. light emitting element.

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