KR20080104996A - Material for organic electro-optical device comprising cyclohexane and organic electro-optical device including the same - Google Patents

Abstract

A material for an organic photoelectric device, and an organic photoelectric device using the material are provided to improve luminous efficiency by using phosphorescence and to enhance thermal stability. A material for an organic photoelectric device comprises a symmetric or asymmetric cyclohexane represented by the formula 1, wherein X1 to X10 are C or N; R1 to R10 bonded to X1 to X10 represent a substituent bonded to the carbon atom if X1 to X10 are a carbon atom; R1 to R10 bonded to X1 to X10 represent un unpaired electron pair bonded to the nitrogen atom if X1 to X10 are a nitrogen atom; the substituents represented by R1 to R10 can be fused to form a ring; the substituents represented by R1 to R10 are H, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxy group, a halogen atom, a nitro group, a substituted or unsubstituted arylene group, a substituted or unsubstituted heteroarylene group, or a substituted or unsubstituted alkylene group; Ra, Rb, Rc and Rd are independently H or a C1-C10 alkyl group; Re is H, a C1-C10 amino group, a halogen atom, a C1-C10 alkoxy group, or a C1-C10 alkyl group; n and m are independently an integer of 1-3; and k is an integer of 1-10.

Description

Material for organic photoelectric device comprising cyclohexane and organic photoelectric device comprising same

The present invention relates to a material for an organic photoelectric device and an organic photoelectric device using the same. More specifically, the thermal decomposition temperature is more than 450 ℃ thermal stability, crystals are not easily formed and the amorphous property is improved to improve efficiency and long life The present invention relates to an organic photoelectric device material and an organic photoelectric device including the same.

An electro-optical device is a device that converts light energy into electrical energy or vice versa in a broad sense. Examples of such an optoelectronic device are organic electroluminescent devices and solar cells. , Transistors, and the like.

Among such optoelectronic devices, organic light emitting diodes (OLEDs), in particular, are drawing attention as the demand for flat panel displays increases.

The organic electroluminescent device is a device that converts electrical energy into light by applying a current to an organic light emitting material and has a structure in which a functional organic material layer is inserted between an anode and a cathode.

The electrical characteristics of the device are similar to that of LEDs. After holes are injected from the anode and electrons are injected from the cathode, the holes and electrons move toward each other and then energy is generated by recombination. It forms high excitons. In this case, light having a specific wavelength is generated as the excitons move to the ground state.

In 1987, Eastman Kodak Co., Ltd. developed for the first time an organic electroluminescent device using a low molecular aromatic diamine and an aluminum complex as a material for forming a light emitting layer [Appl. Phys. Lett. 51, 913, 1987]. In 1987, C. W. Tang et al. Reported the device having the practical performance for the organic electroluminescent device [Applied Physics Letters, Vol. 51, No. 12, 913-915 (1987)].

The document describes a structure in which a thin film (hole transport layer) of a diamine derivative and a thin film (electron transport light emitting layer) of Alq3 (tris (8-hydroxy-quinolate) aluminum) are laminated as an organic layer.

In general, an organic electroluminescent device has a structure formed on a glass substrate in order of an anode made of a transparent electrode, an organic thin film including a light emitting region, and a metal electrode. In this case, the organic thin film may include a light emitting layer, a hole injection layer, a hole transport layer, an electron transport layer or an electron injection layer, and may further include an electron blocking layer or a hole blocking layer due to the light emission characteristics of the light emitting layer.

When an electric field is applied to the organic electroluminescent device having such a structure, holes and electrons are injected from the anode and the cathode, respectively, and the injected holes and electrons recombine in the emission layer through the respective hole transport layer and the electron transport layer to form a light emission exciter.

The light-excited excitons thus formed emit light while transitioning to ground states.

Light emission is divided into fluorescence using singlet excitons and phosphorescence using triplet states according to its mechanism.

Recently, it has been known that not only fluorescent light emitting materials but also phosphorescent light emitting materials can be used as light emitting materials of organic electroluminescent devices [D. F.O'Brien et al., Applied Physics Letters, 74 (3), 442-444, 1999; MA Baldo et al., Applied Physics letters, 75 (1), 4-6, 1999]. These phosphorescent luminescences triplet singlet excitons through intersystem crossing after electrons transfer from the ground state to the excited state. After the non-luminescent transition to the excitons, the triplet excitons are made to emit light while transitioning to the ground state.

At this time, the life of the triplet excitons cannot be transferred directly to the ground state (spin forbidden), so the process of transitioning to the ground state after the flipping of the electron spin proceeds (the light emission time). (lifetime) has a long characteristic.

That is, the emission duration of fluorescence emission is only several nanoseconds, but the phosphorescence emission corresponds to several micro seconds, which is a relatively long time.

In addition, in quantum mechanics, when the holes injected from the anode and the electrons injected from the cathode recombine to form luminescence excitons, the formation ratio of the singlet and triplet is 1: 3 in the organic photoelectric device. Triplet emitters are generated three times more than singlet emitters.

Therefore, in the case of fluorescence, the probability of singlet excited state is 25% (triple state 75%) and there is a limit of luminous efficiency, whereas phosphorescence can be used to triplet 75% and singlet excited state 25%. Can be up to 100% internal quantum efficiency. Therefore, in the case of using the phosphorescent material, there is an advantage that can achieve a light emission efficiency about three times higher than the fluorescent light emitting material.

In the organic electroluminescent device having the structure as described above, in order to increase the efficiency and stability of the light emitting state, a light emitting pigment (dopant) may be added to the light emitting layer (host).

In such a structure, the efficiency and performance of the light emitting device varies depending on which host material is used for the light emitting layer, and naphthalene, anthracene, phenanthrene, tetracene, pyrene, benzopyrene, chrysene, pisene, Carbazole, fluorene, biphenyl, terphenyl, triphenylene oxide, dihalobiphenyl, trans-stilbene and 1,4-diphenylbutadiene are shown as examples of organic host materials. Has been.

As a host compound, 4,4'-N, N'-dicarbazole biphenyl (CBP) is mainly used. The compound has a glass transition temperature of 110 ° C. or lower, and the symmetry is too good, making it easy to crystallize. In addition, problems such as short circuits and pixel defects have been found as a result of heat resistance tests of the device.

In recent years, technical advances have been made in organic electroluminescent devices, but light emission efficiency, color purity, electrical and thermal stability, etc., have not been reached to a satisfactory level. Therefore, it is very urgent to develop a phosphorescent material having high efficiency, high color purity, and excellent electrical and thermal stability.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an organic photoelectric device material using phosphorescent light emission and having excellent luminous efficiency.

Another object of the present invention is to provide an organic photoelectric device including the organic photoelectric device material.

Technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to one embodiment of the present invention for achieving the above object, an organic photoelectric device material including a symmetric or asymmetric cyclohexane represented by the following formula 1 is used alone or as a host material that can be combined with a dopant Is provided.

[Formula 1]

(In Formula 1,

X ₁ to X ₁₀ each represent a carbon atom or a nitrogen atom,

When X ₁ to X ₁₀ are carbon atoms, R ₁ to R ₁₀ bonded to X ₁ to X ₁₀ representing a carbon atom each represent a substituent bonded to the carbon atom,

When X ₁ to X ₁₀ are nitrogen atoms, R ₁ to R ₁₀ bonded to X ₁ to X ₁₀ representing a nitrogen atom each represent a non-covalent electron pair,

Substituents represented by R ₁ to R ₁₀ may be fused to each other to form a ring,

The substituents represented by R ₁ to R ₁₀ each represent a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted group, respectively. Alkoxy group, halogen, nitro group, substituted or unsubstituted arylene group, substituted or unsubstituted heteroarylene group, and substituted or unsubstituted alkylene group,

R _a , R _b , R _c , And R _d are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms,

R _e is selected from the group consisting of hydrogen, an amino group having 1 to 10 carbon atoms, a halogen, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms,

n and m are each independently an integer of 1 to 3,

k is an integer from 1 to 10.)

According to another embodiment of the present invention, an organic photoelectric device including the organic thin film layer including the organic photoelectric device material is provided.

Unless stated otherwise in the specification, an "aryl group" means an aryl group having 6 or more carbon atoms, preferably an aryl group having 6 to 60 carbon atoms, and a heteroaryl group having 2 or more carbon atoms, preferably a "heteroaryl group" 60 heteroaryl group, "alkyl group" means an alkyl group having 1 or more carbon atoms, preferably an alkyl group having 1 to 60 carbon atoms, "amino group" means an amino group having 2 or more carbon atoms, preferably an amino group having 2 to 60 carbon atoms, "alkoxy Group "means an alkoxy group having 1 or more carbon atoms, preferably an alkoxy group having 1 to 60 carbon atoms, an arylene group having 6 or more carbon atoms, preferably an arylene group having 6 or 60 carbon atoms, and a" heteroarylene group " Heteroarylene group having 2 or more carbon atoms, preferably heteroarylene group having 2 to 60 carbon atoms, "alkylene group" means an alkylene group having 1 or more carbon atoms, preferably 1 to 1 carbon atoms An alkylene group of 60 is meant.

Unless stated otherwise in the specification, a substituted aryl group, a substituted hetero aryl group, a substituted alkyl group, a substituted amino group, a substituted alkoxy group, a substituted arylene group, a substituted hetero arylene group, and a substituted alkylene group And an aryl group, a heteroaryl group, an alkyl group, an amino group, an alkoxy group, a halogen, and a nitro group .

Other specific details of embodiments of the present invention are included in the following detailed description.

The material for an organic photoelectric device according to the present invention has a molecular structure in which crystals are not easily formed and its amorphous property is improved, and when applied to an organic photoelectric device, it may exhibit high luminous efficiency.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

The material for an organic photoelectric device according to the exemplary embodiment of the present invention may be used alone or as a host material that can be combined with a dopant, and includes a symmetric or asymmetric dimethylcyclohexane core represented by the following Chemical Formula 1.

[Formula 1]

In Chemical Formula 1,

X ₁ to X ₁₀ each represent a carbon atom or a nitrogen atom,

When X ₁ to X ₁₀ are carbon atoms, R ₁ to R ₁₀ bonded to X ₁ to X ₁₀ representing a carbon atom each represent a substituent bonded to the carbon atom,

When X ₁ to X ₁₀ are nitrogen atoms, R ₁ to R ₁₀ bonded to X ₁ to X ₁₀ representing a nitrogen atom each represent a non-covalent electron pair,

Substituents represented by R ₁ to R ₁₀ may be fused to each other to form a ring,

The substituents represented by R ₁ to R ₁₀ each represent a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted group, respectively. Alkoxy group, halogen (wherein halogen means F, Cl, Br, or I), nitro group, substituted or unsubstituted arylene group, substituted or unsubstituted heteroarylene group, and substituted or unsubstituted It may be selected from the group consisting of alkylene groups,

R _a , R _b , R _c , And R _d may be each independently hydrogen or an alkyl group having 1 to 10 carbon atoms,

R _e may be selected from the group consisting of hydrogen, an amino group having 1 to 10 carbon atoms, a halogen, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms, wherein R _e is present in the cyclohexane ring 10 substituents, each of which is independently selected from the group consisting of hydrogen, an amino group having 1 to 10 carbon atoms, a halogen, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms),

n and m may each independently be an integer from 1 to 3,

k is an integer from 1 to 10.

In Formula 1, the dimethylcyclohexane core serves to break the conjugate between the substituents substituted on both sides to help control the conjugate length, and is very advantageous for the synthesis of a material having a large energy band gap. The phosphorescent host material improves device efficiency and lifetime characteristics when the energy bandgap, especially the triplet energy bandgap, is larger than the phosphorescent dopant material. Thus, the compound of Formula 1, which can control the airspace length to have an appropriate energy bandgap, Very suitable. In addition, the introduction of a dimethylcyclohexane core allows the synthesis of materials with the desired energy bandgap between various substituents.

The cyclohexane of the dimethylcyclohexane core has a three-dimensional structure of chair-conformation, thereby solving the crystallinity problem of the material due to the planar structure of the aryl unit such as phenyl, and the methyl group substituted with cyclohexane As a result, the flexibility is further increased, and the amorphous property of the material can be improved.

Furthermore, since the dimethylcyclohexane core is an alkyl unit, solubility in organic solvents is increased compared to a compound consisting only of aromatics, and thus it is expected that the dimethylcyclohexane core may be applied to a device for perfume solution process.

Specific examples of the material for an organic photoelectric device represented by Chemical Formula 1 may include a compound represented by Chemical Formulas 2 to 7, but are not limited thereto.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

In Chemical Formulas 2 to 7,

The substituents represented by R ₁ to R ₁₀ each represent a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted group, respectively. Alkoxy group, halogen, nitro group, substituted or unsubstituted arylene group, substituted or unsubstituted heteroarylene group, and substituted or unsubstituted alkylene group can be selected from R ₁ to R ₁₀ The substituents shown may be fused to each other to form a ring,

R _a , R _b , R _c , And R _d may be each independently hydrogen or an alkyl group having 1 to 10 carbon atoms,

R _e may be selected from the group consisting of hydrogen, an amino group having 1 to 10 carbon atoms, a halogen, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms,

n and m may each independently be an integer from 1 to 3,

k is an integer from 1 to 10.)

More specific examples of the material for an organic photoelectric device represented by Formulas 1 to 7 include the following Compounds 1 to 23 and mixtures thereof, but are not limited thereto.

The organic photoelectric device material may be used alone, or in general, may be used as a host material that may be combined with a dopant.

Dopant is a guest or dopant because it is a compound having a high luminescence ability and is used in a small amount in the host.

That is, the dopant is a material that emits light by doping the host material, and generally, a material such as a metal complex that emits light by multiplet excitaion that excites above a triplet state is used. .

When the organic photoelectric device material is used as a light emitting host material, red (R), green (G), blue (B), white (W) dlm fluorescent or phosphorescent dopant materials may be used as the dopant. However, it is preferable to use a phosphorescent dopant material, and it should basically be a material that can satisfy the property of high luminous quantum efficiency, poor aggregation, and uniform distribution in the host material.

Phosphorescent dopants are organometallic compounds comprising at least one element selected from the group consisting of Ir, Pt, Os, Ti, Zr, Hf, Eu, Tb and Tm.

As a specific example, red phosphorescent dopant may be PtOEP, Ir (Piq) ₂ (acac) (Piq = 1-phenylisoquinoline, acac = pentane-2,4-dione), Ir (Piq) ₃ , or RD 61 from UDC. As the green phosphorescent dopant, Ir (PPy) ₂ (acac), tris (2-phenylpyridine) iridium, UD's GD48, etc. may be used. 6-F2PPy) ₂ Irpic (Ref . Appl . Phys . Lett ., 79, 2082-2084, 2001).

The organic photoelectric device material may be used in an organic thin film layer disposed on the anode and the cathode of the organic photoelectric device. Examples of such an organic photoelectric device may include an organic light emitting diode (OLED), an organic solar cell, an organic photo conductor drum, an organic transistor, an organic memory device, and the like.

1 to 5 are cross-sectional views illustrating various embodiments of organic electroluminescent devices that may be manufactured using the organic photoelectric device material.

1 to 5, in one embodiment of the present invention, the organic electroluminescent device has a structure including at least one organic thin film layer disposed between the anode and the cathode, and the ITO (indium tin oxide) is transparent to the anode. As the electrode, a metal electrode such as aluminum is used as the cathode.

First, referring to FIG. 1, FIG. 1 illustrates an organic electroluminescent device having only a light emitting layer as an organic thin film layer.

Referring to FIG. 2, in FIG. 2, as the organic thin film layer, a light emitting layer + an electron transporting layer and a hole transporting layer exist as a two-layered organic electroluminescent device, in which a film having excellent bonding property or hole transporting property with a transparent electrode such as ITO is separately prepared. It is a structure that serves as a transport layer.

Referring to FIG. 3, in FIG. 3, an organic light emitting layer has an electron transporting layer, a light emitting layer, and a hole transporting layer, in which a light emitting layer is formed in an independent form, and a film having excellent electron transporting and hole transporting properties is stacked in a separate layer. Form.

Referring to FIG. 4, in FIG. 4, a four-layer organic electroluminescent device having an electron injection layer, a light emitting layer, a hole transport layer, and a hole injection layer as an organic thin film layer is characterized by having a three-layer organic photoelectric device shown in FIG. 3. The hole injection layer is added in consideration of the bonding property with ITO used as the layer.

Referring to FIG. 5, in FIG. 5, a five-layered organic electroluminescent device in which five layers having different functions, such as an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer, and a hole injection layer, exist as an organic thin film layer, The injection layer is formed separately, which is effective in reducing the voltage.

In order to form the above-mentioned organic thin film layer of 1 to 5 layers, dry film forming methods such as evaporation, sputtering, plasma plating, and ion plating, spin coating, and dipping methods ( Processes such as dipping, a wet film method such as flow coating, or the like may be used.

Hereinafter, a specific method for manufacturing the material for an organic photoelectric device according to the embodiments of the present invention and the luminous efficiency when the actual organic photoelectric device is manufactured using the organic photoelectric device material of the present invention manufactured using the method This high and long life will be explained with specific examples and comparative examples. However, the content not described herein is omitted because it can be inferred technically sufficient by those skilled in the art.

One. For organic photoelectric device  Synthesis of Compound

Synthesis Example  1: Synthesis of Compound 1

Compound 1 shown as a specific example of the organic photoelectric device material was prepared according to Scheme 1 below.

Scheme 1

25 g of 4-bromobenzylbromide and 26 g of triethylphosphite were dissolved in 200 ml of toluene, refluxed for 12 hours, concentrated under reduced pressure, and then 32 g of white solid powder (A) formed was obtained.

32 g of intermediate (A) and 13 g of potassium t-butoxide were mixed with 300 ml of tetrahydrofuran (THF), stirred at 50 ° C for 1 hour, and then 5 g of 1,4-cyclohexanedione was added dropwise and the reaction temperature was 70 Raised to ℃ and stirred for 24 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure and extracted with chloroform and water. The extracted organic layer was purified by column chromatography under reduced pressure to obtain 10 g of material. After dissolving this material in a mixed solvent of tetrahydrofuran and ethanol, 2 g of palladium (10 wt% on activated carbon, hereinafter referred to as 'Pd-C') was added, and then reacted for 2 hours in a high pressure hydrogen atmosphere. . Thereafter, Pd-C was removed and then concentrated under reduced pressure to form an intermediate (B).

10 g of intermediate (B) was dissolved in 100 ml of tetrahydrofuran, 30 ml of n-butyllithium hexane solution was added at -70 ° C, and the obtained solution was stirred at -70 ° C to 40 ° C for 1 hour. After cooling the reaction fluid to -70 ° C, 10 ml of isopropyltetramethyldioxaborolane was slowly added dropwise, and the temperature was raised to room temperature and stirred for 6 hours. 1 ml of water was added to terminate the reaction, and then concentrated under reduced pressure, and then purified by column chromatography to synthesize 11 g of intermediate (C).

0.5 g of intermediate (C), 0.6 g of compound (D), and 20 mg of palladium catalyst were mixed in 10 ml of toluene, 10 ml of tetrahydrofuran and 10 ml of an aqueous tetraethylammonium hydroxide solution at a concentration of 20% by weight, followed by 80 ° C. Stirred for 8 h. After cooling to room temperature, the aqueous layer was removed, concentrated under reduced pressure, and then Compound 1 was isolated and purified by column chromatography to collect 0.7 g. Mass spectroscopy of the obtained compound is as follows: MS (ESI) m / z 747.37 (M + H) ⁺

Synthesis Example  2: synthesis of compound 15

Compound 15 shown as a specific example of the organic photoelectric device material was prepared according to Scheme 2 below.

Scheme 2

1 g of intermediate (C), 1.2 g of compound (D), and 50 mg of palladium catalyst were mixed in a mixed solution of 20 ml of toluene, 20 ml of tetrahydrofuran and 20 ml of 20% by weight aqueous tetraethylammonium hydroxide solution, Stir at 80 ° C. for 8 hours. Subsequently, after cooling to room temperature, the aqueous layer was removed, concentrated under reduced pressure, and then Compound 15 was purified by column chromatography. Mass spectroscopy of the obtained compound is as follows: MS (ESI) m / z 725.36 (M + H) ⁺

Thermal properties of the synthesized materials were measured by DSC and TGA.

2. Fabrication of organic electroluminescent device

Example  One

Using Compound 1 prepared in Synthesis Example 1 as a host and Ir (PPy) ₃ as a dopant, an organic electroluminescent device having the following structure was prepared.

ITO was used as the cathode at a thickness of 1000 kPa, and aluminum (Al) was used as the cathode at a thickness of 1000 kPa.

The organic electroluminescent device has a five-layer structure. Specifically, NPD (400 kW) / Compound 1+ Ir (PPy) ₃ (10 wt%, 300 kW) / BAlq (50 kW) / Alq 3 (200 kW) / LiF (5 kW) It was prepared in a layered structure.

In detail, a method of manufacturing an organic electroluminescent device is described, in which the anode cuts an ITO glass substrate having a sheet resistance value of 15Ψ / cm ² into a size of 50 mm x 50 mm x 0.7 mm, each of which is acetone, isopropyl alcohol and pure water. Ultrasonic cleaning for minutes was followed by UV ozone cleaning for 30 minutes.

NPD was deposited on the substrate at a vacuum degree of 650 × 10 −7 Pa and a deposition rate of 0.1 to 0.3 nm / s to form a hole transport layer having a film thickness of 400 μs.

Subsequently, a light emitting layer having a film thickness of 300 Pa was formed using the compound of Chemical Formula 8 under the same vacuum deposition conditions, wherein Ir (PPy) ₃ , a phosphorescent dopant, was simultaneously deposited.

At this time, by adjusting the deposition rate of the phosphorescent dopant, when the total amount of the light emitting layer was 100% by weight, the deposition amount was deposited so that the compounding amount of the phosphorescent dopant was 10% by weight.

BAlq was deposited on the light emitting layer using the same vacuum deposition conditions to form a hole blocking layer having a thickness of 50 kHz. Subsequently, Alq ₃ was deposited under the same vacuum deposition conditions to form an electron transport layer having a film thickness of 200 μs. LiF and Al were sequentially deposited on the electron transport layer to complete the organic electroluminescent device.

Example  2

Except for changing the compound 1 prepared in Synthesis Example 1 to compound 15, and in the same manner as in Example 1, ITO / NPD (400 Å) / Compound 15 + Ir (PPy) ₃ (10wt%, 300 Å) / BAlq An organic electroluminescent device having a structure of (50 mV) / Alq ₃ (200 mV) / LiF (5 mV) / Al (1000 mV) was manufactured.

Comparative example  One

ITO / NPD was carried out in the same manner as in Example 1, except that Compound 1, which was used as a host, was changed to 4,4'-N, N'-dicarbazolebiphenyl (CBP) represented by Formula 8 below. An organic electroluminescent device having a structure of (400 μs) / CBP + Ir (PPy) ₃ (10 wt%, 300 μs) / BAlq (50 μs) / Alq ₃ (200 μs) / LiF (5 μs) / Al (1000 μs) was prepared.

[Formula 8]

3. Measurement of current density change, luminance change, and luminous efficiency according to voltage

For each organic electroluminescent device manufactured in Examples 1 to 2 and Comparative Example 1, the current density change, luminance change, and luminous efficiency according to voltage were measured by the following method.

1) Measurement of change of current density according to voltage change

For the manufactured organic electroluminescent device, the current value flowing through the unit device was measured by using a current-voltmeter (Keithley 2400) while increasing the voltage from 0V to 10V, and the measured current value was divided by the area to obtain a result.

2) Measurement of luminance change according to voltage change

The resulting organic electroluminescent device was measured using a luminance meter (Minolta Cs-1000A) while increasing the voltage from 0V to 10V to obtain a result.

3) Luminous efficiency measurement

Luminous efficiency was calculated using the luminance, current density, and voltage measured from 1) and 2).

4. Evaluation result

1) Thermal analysis measurement result and organic electroluminescent device characteristic evaluation result

Table 1 shows thermal analysis results and characteristics evaluation results of the organic light emitting diodes manufactured in Examples 1 to 2 and Comparative Example 1.

For each organic electroluminescent device manufactured as described above, current density change, luminance change, and luminous efficiency according to voltage were measured. The specific measuring method is as follows.

1) Measurement of change of current density according to voltage change

For the manufactured organic electroluminescent device, the current value flowing through the unit device was measured by using a current-voltmeter (Keithley 2400) while increasing the voltage from 0V to 10V, and the measured current value was divided by the area to obtain a result.

2) Measurement of luminance change according to voltage change

The resulting organic electroluminescent device was measured using a luminance meter (Minolta Cs-1000A) while increasing the voltage from 0V to 10V to obtain a result.

3) Luminous efficiency measurement

Luminous efficiency was calculated using the luminance, current density, and voltage measured from 1) and 2).

3. Thermal analysis , Solubility measurement, and evaluation results of organic electroluminescent device characteristics

Table 1 shows thermal analysis results (Tm and Td) of the organic light emitting diodes manufactured by Examples 1 to 2 and Comparative Example 1 and characteristics evaluation results of the organic light emitting diodes.

 Host material of light emitting layer  Tm (℃)  Td (℃)  Luminance (unit)  Drive voltage (V)  Luminous Efficiency (cd / A)  Color coordinates (x, y)  Example 1  Compound 1  271  461  100  7.6  34.0  0.31, 0.60  Example 2  Compound 15  262  470  100  7.4  28.2  0.32, 0.60  Comparative Example 1  CBP  282  392  100  6.2  27.2  0.30, 0.59

DSC analysis of the compounds 1 and 15 used in Examples 1 and 2 showed a very low crystallinity, the crystallization temperature (Tc) did not appear, it was confirmed that the amorphous properties improved, TGA analysis results All of the materials showed a high thermal decomposition temperature (Td) of more than 450 ℃ it was confirmed that the material is very excellent thermal stability.

In addition, as a result of evaluating the characteristics of the organic electroluminescent device, Example 1 of the present invention compared with Comparative Example 1 using 4,4'-N, N'-dicarbazole biphenyl known conventionally as a host material When using the cyclohexane-based host material of compounds 1 and 15 used in the 2 and 2, it was confirmed that the device performance to improve the luminous efficiency of 10% or more.

Therefore, the material for an organic photoelectric device of the present invention can exhibit high thermal stability and excellent luminous efficiency, and thus, device life is expected to increase.

2) Solubility Evaluation

In addition, for the compounds 1 and 15 used in Examples 1 and 2, the solubility in chlorobenzene was measured, showing a solubility of 4% by weight or more. Therefore, it was confirmed that the compounds 1 and 15 of Examples 1 and 2 had high solubility in organic solvents. However, in the case of the compound of 4,4'-N, N'-dicarbazole biphenyl of Comparative Example 1, the solubility in chlorobenzene was very low, 1 wt% or less.

In addition, as a result of dissolving the compounds of Compounds 1 and 15 used in Examples 1 and 2 in toluene, it showed very high solubility, from which the organic photoelectric device material of the present invention is a non-halogenated solvent It was also confirmed that it is very well dissolved.

Thus, the material synthesized in the present invention was able to produce a material for an organic photoelectric device having excellent performance in terms of thermal stability and luminous efficiency due to improved solubility.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings and tables, the present invention is not limited to the above embodiments, but may be manufactured in various forms, and common knowledge in the art to which the present invention pertains. Those skilled in the art can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

1 to 5 are cross-sectional views showing an organic light emitting device manufactured using a material for an organic photoelectric device according to an embodiment of the present invention.

Claims (6)

A material for an organic photoelectric device, which is used alone or as a host material that can be combined with a dopant, and includes a symmetric or asymmetric cyclohexane represented by the following Chemical Formula 1. [Formula 1]

(In Formula 1, X ₁ to X ₁₀ represents a carbon atom or a nitrogen atom, respectively, When X ₁ to X ₁₀ are carbon atoms, R ₁ to R ₁₀ bonded to X ₁ to X ₁₀ representing a carbon atom each represent a substituent bonded to the carbon atom, When X ₁ to X ₁₀ are nitrogen atoms, R ₁ to R ₁₀ bonded to X ₁ to X ₁₀ representing a nitrogen atom each represent a non-covalent electron pair, Substituents represented by R ₁ to R ₁₀ may be fused to each other to form a ring, The substituents represented by R ₁ to R ₁₀ each represent a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted group, respectively. Alkoxy group, halogen, nitro group, substituted or unsubstituted arylene group, substituted or unsubstituted heteroarylene group, and substituted or unsubstituted alkylene group, R _a , R _b , R _c , And R _d are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms, R _e is selected from the group consisting of hydrogen, an amino group having 1 to 10 carbon atoms, a halogen, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms, n and m are each independently an integer of 1 to 3, k is an integer from 1 to 10.)  The method of claim 1, Symmetric or asymmetric cyclohexane represented by Formula 1 is an organic photoelectric device material, characterized in that selected from the group consisting of compounds represented by the following formulas 2 to 7 and mixtures thereof. [Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

(In Chemical Formulas 2 to 7, The substituents represented by R ₁ to R ₁₀ each represent a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted group, respectively. Alkoxy group, halogen, nitro group, substituted or unsubstituted arylene group, substituted or unsubstituted heteroarylene group, and substituted or unsubstituted alkylene group, and is represented by R ₁ to R ₁₀ Substituents may be fused to each other to form a ring, R _a , R _b , R _c , And R _d are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms, R _e is selected from the group consisting of hydrogen, an amino group having 1 to 10 carbon atoms, a halogen, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms, n and m are each independently an integer of 1 to 3, k is an integer from 1 to 10.) The method of claim 1, Symmetric or asymmetric cyclohexane represented by Formula 1 is an organic photoelectric device material, characterized in that selected from the group consisting of the following compounds 1 to 23 and mixtures thereof.

The method of claim 1, The dopant is an organic photoelectric device material, characterized in that the red, green, blue, and white fluorescent or phosphorescent dopant. In an organic electroluminescent device comprising at least one organic thin film layer disposed between the anode and the cathode, At least one of the organic thin film layer is an organic photoelectric device, characterized in that it comprises a material of any one selected from claims 1 to 4. The method of claim 5, wherein The organic thin film layer is a light emitting layer; And An organic photoelectric device comprising at least one layer selected from the group consisting of a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer.

Images