KR101393880B1 - Organosilane Compounds, Electroluminescent Materials Comprising The Same, and Organic Electroluminescent Device - Google Patents

Abstract

The present invention provides an organosilane compound and an organic electroluminescent device represented by formula (1) which are excellent in light emission luminance and luminous efficiency and are particularly useful as a blue organic electroluminescent material.

[Chemical Formula 1]

Organic electroluminescent device, luminescent material, luminescent host, luminescent layer,

Description

[0001] The present invention relates to an organosilane compound, a light emitting material containing the same, and an organic electroluminescent device,

1 is a view illustrating a structure of an organic electroluminescent device according to an embodiment of the present invention.

Fig. 2 is a graph showing the UV-vis absorption spectrum and the luminescence spectrum of Compound 1, which is an embodiment of the present invention, in a solution state,

3 is a graph showing the results of differential scanning thermal (DSC) measurement of Compound 1, which is an embodiment of the present invention,

4 is a graph showing a result of measurement of thermogravimetric analysis (TGA) of Compound 1, which is an embodiment of the present invention,

FIG. 5 is a diagram illustrating the color coordinates of the luminescence spectrum measured by applying Compound 1, which is an embodiment of the present invention, to the light emitting layer of an organic electroluminescent device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

1: substrate 2: anode

3: Hole injection layer 4: Hole transport layer

5: luminescent layer 6: electron transport layer

7: cathode 8: power source

The present invention relates to an organosilane compound, a light emitting material containing the same, and an organic electroluminescent device.

The most widely used liquid crystal display (LCD) is a non-light emitting type display device which consumes less power and is light, but the device driving system is complicated and response time and contrast characteristics are not satisfactory. Therefore, research on an organic electroluminescent device, which has recently attracted attention as a next generation flat panel display, has been actively conducted. The organic electroluminescent device is a self-luminous type device having many advantages such as brightness, driving voltage, response speed, etc. and has no viewing angle dependency compared to a liquid crystal display.

The emission mechanism of the organic electroluminescent device will be described below. Holes injected from a positive electrode into a valance band or a HILO of a Hole Injection Layer (HIL) proceed through an HIL (Emitting Layer) through a Hole Transporting Layer (HTL) At the same time, electrons move from the cathode to the light emitting layer through the electron injection layer to form an exciton. This exciton emits light as it falls to the ground state.

Eastman Kodak Company, in 1987, using the principle of the organic electroluminescent device as described above, developed TPD (N-N'-DiphenyI-N'-bis- (methylphenyl- 4,4'-diamine) as a light emitting layer was developed using Alq3 (tris (8-hydroxy-quinoline) aluminum complex).

Blue is doped with a blue dopant to a blue host and Alq3 is used as an electron transport layer (ETL), and Alq3 may be omitted depending on the characteristics of a blue host.

Further, a blue light emitting element using an anthracene compound derivative such as a diphenylanthracene structure is known.

In the case of constituting a display device using an organic electroluminescent device, it is one of the most important problems to secure long life and reliability of the organic electroluminescent device.

However, such conventional anthracene derivatives are not excellent in film forming workability and are not excellent in heat resistance because they are not easily formed into uniform thin films, and aggregation between molecules occurs during deposition due to the plate-like structure, resulting in high efficiency and high quality There is a problem in that it can not emit light.

In addition, conventional light emitting materials are still required to exhibit high brightness and long life at low voltage when applied to organic electroluminescent devices due to physical and chemical changes, photochemical and electrochemical changes, peeling phenomena, melting, crystallization and thermal decomposition And at the same time, there is a problem that the durability and reliability of the device are low. Due to such a problem, it is difficult to commercialize an organic electroluminescent device, and application to various displays is limited.

In order to solve the above problems, the present inventors have developed an organosilane compound light emitting material having a high color purity with excellent heat resistance and excellent luminous efficiency by introducing a silane group.

An object of the present invention is to synthesize an organosilane compound introducing an anthracene group having excellent electron transport properties and a silane group exhibiting steric hindrance characteristics to prevent excimer and exciplex which inhibit thermal stability and luminescence characteristics.

It is another object of the present invention to provide an organic electroluminescent device having high efficiency, high color purity, low driving voltage and long driving life by applying the synthesized compounds to an organic compound layer material such as a light emitting layer of an organic electroluminescent device do.

According to an aspect of the present invention,

There is provided an organosilane compound represented by the following formula (1).

[Chemical Formula 1]

Wherein Ar1, Ar2, Ar3, Ar7 and Ar8 are independent of each other and are the same or different and selected from one of an aryl group having 6 to 20 carbon atoms, Ar4, Ar5 and Ar6 are independently the same or different and have 6 to 20 And n is an integer of 1 to 3. When n is 2 or more, Ar5 is the same or different from each other, provided that when Ar1, Ar2, and Ar3 are all phenyl groups, the phenyl group is excluded from Ar4)

Also, at least one of Ar1, Ar2, Ar3, Ar7, and Ar8 is selected from the following formulas (2) to (14).

(The above formulas may have a substituent at one or more hydrogen positions, and the substituents are independently selected from the group consisting of a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms , An aryl group having 1 to 20 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, and a trifluoromethyl group.

Also, at least one of Ar4, Ar5 and Ar6 is selected from the following formulas (15) to (23).

(The above formulas may have a substituent at one or more hydrogen positions, and the substituents are independently selected from the group consisting of a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms , An aryl group having 1 to 20 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, a trifluoromethyl group, and a solid line indicating a bonding position, But this means that the positions of Ar4 and Ar5, and the bonding position of Ar5 and Ar6 may be any position in the polyvalent ring.)

In addition, the above-mentioned formula (1) provides an organosilane compound represented by the following formulas (1) to (14).

The present invention also provides a light-emitting material comprising the organosilane compound.

The present invention also provides an organic electroluminescence device comprising a plurality of organic compound layers including a cathode, a cathode, and a light emitting layer disposed between the anode and the cathode, wherein the organic silane compound of any one of claims 1 to 4, The organic electroluminescent device is characterized in that it is contained in all or part of a plurality of organic compound layers.

Wherein the organic compound layer includes at least one of a light emitting layer, an electron injecting layer and an electron transporting layer, and the organic silane compound is contained in at least one of the light emitting layer, the electron injecting layer, and the electron transporting layer. to provide.

Hereinafter, the present invention will be described in more detail.

The following detailed description is provided to illustrate the present invention by way of example only, and thus the present invention is not limited thereto.

The present invention provides an organosilane compound represented by the following formula (1).

1. An organosilane compound represented by the following formula (1).

[Chemical Formula 1]

In the above formula, Ar1, Ar2, Ar3, Ar7 and Ar8 are independent of each other and are the same or different and selected from one or more of C6-C20 aryl groups in which part or all of hydrogen is substituted or unsubstituted. More preferably a phenyl anthryl group, an anthryl group, a naphthyl group or a phenyl group.

Ar4, Ar5 and Ar6 are independently selected from the group consisting of aryl groups having 6 to 20 carbon atoms in which some or all of hydrogen is substituted or unsubstituted with substituents, provided that when Ar1, Ar2 and Ar3 are all phenyl groups , And the phenyl group in Ar4 is excluded.

The substituent includes, but is not limited to, a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms, To 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, and a trifluoromethyl group.

n is an integer of 1 to 3, and when n is 2 or more, Ar5 is the same or different from each other.

Although not limited, it is preferable that at least one of Ar1, Ar2, Ar3, Ar7, and Ar8 is selected from the following formulas (2) to (14).

The above-mentioned formulas may have a substituent at one or more hydrogen positions, and the substituents are independently selected from the group consisting of a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, An aryl group having 1 to 20 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, and a trifluoromethyl group.

At least one of Ar4, Ar5 and Ar6 is preferably selected from the following formulas (15) to (23).

The above-mentioned formulas may have a substituent at one or more hydrogen positions, and the substituents are independently selected from the group consisting of a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, An aryl group having 1 to 20 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, and a trifluoromethyl group.

In the above formulas, the solid line indicating the bonding position is drawn through all the rings constituting each polycyclic ring, but this means that the bonding position of Ar4 and Ar5, Ar5 and Ar6 may be any position in the polycyclic ring.

Hereinafter, specific examples of the organosilane compound represented by the formula (1) of the present invention are shown, but the present invention is not limited to these exemplified compounds.

Hereinafter, a light emitting material and an organic electroluminescence device according to the present invention will be described.

The present invention provides a light emitting material for an organic electroluminescent device comprising the organosilane compound of Formula 1. Any material for the organic electroluminescence device containing the organosilane compound of Formula 1 is included in the present invention. The material for the organic electroluminescent device that can be used in combination with the organosilane compound of Formula 1 is not limited to those well known in the art and will not be described in detail. ), Which can be made by mixing them with the organic compound of the formula (1), and they are included in the present invention.

The organic electroluminescent device according to the present invention is an organic electroluminescent device comprising a plurality of organic compound layers including a cathode, a cathode and a light emitting layer disposed between the anode and the cathode, Or a part thereof. The organic compound layer includes at least one of a light emitting layer, an electron injection layer, and an electron transport layer, and the organic silane compound is contained in at least one of the light emitting layer, the electron injection layer, and the electron transport layer.

A more concrete example is as follows.

1, an organic electroluminescent device according to an embodiment of the present invention includes a substrate 1, an anode 2, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, a cathode 7). An electron injection layer may be further provided between the electron transport layer 6 and the cathode 7 and a hole injection layer 3 may be further provided between the anode 2 and the hole transport layer 4. [

The organic compound layer means a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injecting layer.

Examples of the anode (2) material include metal oxides or metal nitrides such as ITO, IZO, tin oxide, zinc oxide, zinc aluminum oxide, and titanium nitride; Metals such as gold, platinum, silver, copper, aluminum, nickel, cobalt, lead, molybdenum, tungsten, tantalum and niobium; An alloy of such a metal or an alloy of copper iodide; And conductive polymers such as polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, poly (3-methylthiophene), and polyphenylene sulfide. The anode 2 may be formed of only one of the above-mentioned materials or may be formed of a mixture of a plurality of materials. Further, a multi-layer structure composed of a plurality of layers of the same composition or different compositions may be formed.

The hole injecting layer 3 of the present invention can be formed using materials known in the art, including but not limited to PEDOT / PSS or copper phthalocyanine (CuPc), 4,4 ', 4 "-tris (3-methylphenylphenylamino) Triphenylamine (m-MTDATA) are formed to a thickness of 5 nm to 40 nm.

The hole transport layer 4 may be formed of a material selected from the group consisting of 4,4'-bis [N- (1-naphthyl) -N-phenyl-amino] (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (TPD) can be used.

The light emitting layer 5 may be made of materials known in the art, including but not limited to (4,4'-bis (2,2-diphenyl-ethen-1-yl) diphenyl (DPVBi) (2-methyl-8-quinolinolato) (triphenylsiloxy) aluminum (III) (SAlq), bis Para-phenolato) aluminum (III) (BAlq), bis (salen) zinc (II), 1,3-bis [4- (N, N- dimethylamino) phenyl-1,3,4-oxadiazolyl] Benzene (OXD8), 3- (biphenyl-4-yl) -5- (4-dimethylamino) 4- (4-ethylphenyl) -1,2,4- triazole (p- Biphenyl) -4-phenyl-5- (4-tertiary-butylphenyl) -1,2,4-triazole (TAZ), 2,2 ', 7,7'-tetrakis 4-yl) -9,9'-spirofluorene (Spiro-DPVBI), tris (para-phenyl-4-yl) amine (p- -2,2-bithiophene (BMB-2T) and perylene.

(4-dicyanomethylene-2-methyl-6- (para-dimethylaminostyryl) -4H-pyran), DCM2 (4- (Dicyanomethylene) -2-methyl-6- (1,1, 7, -dichloromethyl) 9H-pyran), DCJTB (4- (dicyanomethylene) -2-tertiarybutyl-6- (1,1,7,7-tetramethylpyrrolidyl -9-enyl) -4H-pyran, DCJTI (4-dicyanomethylene) -2-isopropyl-6- (1,1,7,7-tetramethyljulolidyl- ) And Nile red, Rubrene and the like can be used as a host or a dopant.

The dopant may be omitted or optionally added, and it is preferable to use one listed in the host material, although not limited thereto.

The electron transport layer 6 may comprise an aryl substituted oxadiazole, an aryl-substituted triazole, an aryl-substituted phenanthroline, a benzoxazole, or a benzothiazole compound, for example 1,3 -Bis (N, Nt-butyl-phenyl) -1,3,4-oxadiazole (OXD-7); 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole (TAZ); 2,9-dimethyl-4,7-diphenyl-phenanthroline (basocuproin or BCP); Bis (2- (2-hydroxyphenyl) -benzoxazolate) zinc; Or bis (2- (2-hydroxyphenyl) benzothiazolate) zinc; The electron transporting material may be (4-biphenyl) (4-t-butylphenyl) oxydiazole (PDB) and tris (8- quinolinato) aluminum (Alq3), preferably tris Quinolinato) aluminum (III) (Alq3) are preferable.

The electron injecting layer and the cathode 7 may be made of any material known in the art and include, but are not limited to, LiF as an electron injecting layer and a metal having a low work function such as Al, Ca, Mg, And preferably Al is preferable.

Hereinafter, the present invention will be described in more detail with reference to Synthesis Examples and Examples. Compound 1 is prepared by the following synthesis route, and other compounds can be synthesized by using the synthesis method or the like. It is possible.

<Examples>

Synthesis Example 1 Synthesis of Compound A.

4 g (14 mmol) of dibromonaphthalene was dissolved in ether, and the temperature was lowered to add n-BuLi. Then, triphenylsilyl chloride was added thereto and reacted at room temperature. After the reaction was completed, the reaction product was extracted with ether, and the solvent was removed under reduced pressure. The product was separated into a column and dried under reduced pressure. 66% yield was obtained.

MS (EI) (calcd for C26H21BrSi, 464.06; Found: 464).

Synthesis Example 2 Synthesis of Compound B

8.3 g (17.83 mmol) of 4-bromophenyl-triphenylsilane are dissolved in THF and the temperature is lowered to add 1 equivalent of n-BuLi. Two equivalents of trimethylborate were added thereto and reacted at room temperature. Poured into diluted hydrochloric acid and stirred for 30 minutes. After extracting with methylene chloride, the solvent was removed under reduced pressure, and the product was separated into a column, followed by filtration under reduced pressure to obtain a yield of 50%.

MS (EI) (calcd for C24H21BO2Si, 430.16 found, 430).

Synthesis Example 3 Synthesis of Compound C

(38.34 mmol) of 9-bromoanthracene, 250 mL of 1,2-dimethoxyethane, 1.0 g (0.871 mmol) of tetrakistriphenylphosphine palladium, ), 131 mL of a 2N sodium carbonate aqueous solution was added, and the mixture was refluxed at 85 DEG C for 18 hours. After completion of the reaction, the reaction temperature was lowered to room temperature, and the resulting solid was filtered, sufficiently washed with methanol and water, and vacuum dried. 17.26 g (80%) of product were obtained.

MS (EI) (calcd for C42H30Si, 562.21; Found: 562).

Synthesis Example 4 Synthesis of Compound 1-1

7.45 g (13.24 mmol) of Compound C, 3.77 g (21.18 mmol) of NBS and 50 mL of N, N-dimethylformamide (DMF) were added to a 250 mL three-necked flask and stirred at room temperature for 6 hours. The resulting solid was filtered and thoroughly washed with 1000 mL of methanol. After drying, 6.62 g (78%) of Compound 1-1 was obtained.

MS (EI) (calcd for C42H29BrSi, 640.12; Found: 640).

Synthesis Example 5 Synthesis of Compound 1

Into a 500 mL three-necked flask, 6.06 g (9.44 mmol) of Compound 1-1, 3.12 g (0.01039 mmol) of 4- (2,2-diphenylvinyl) phenyl-1-boronic acid, 70 mL of toluene, 0.546 g (0.472 mmol) of triphenylphosphine palladium and 35 mL of a 2N sodium carbonate aqueous solution were added and the mixture was refluxed at 95 DEG C for 12 hours. After completion of the reaction, the organic layer was extracted with 100 mL of toluene and 300 mL of water, and the solvent was removed under reduced pressure. The washed solid was completely dissolved with 300 mL of THF, then re-precipitated with 1200 mL of n-n-hexane and separated by filtration. After vacuum drying, 6.78 g (88%) of product was obtained.

MS (EI) (calcd for C62H44Si, 816.32; Found: 816).

The electroluminescent device thus manufactured, i.e., the driving voltage, the color coordinate, and the efficiency were measured in the following manner, and the results are shown in Table 1 .

1) Driving voltage

The organic electroluminescent device manufactured was measured for the change of the current density according to the voltage change. The measurement was carried out by using a current-voltmeter (Kethley SMU 236) while increasing the current density from 2.5 mA / cm 2 to 100 mA / cm 2 by 2.5 mA.

2) Color coordinates

The prepared organic electroluminescent device was measured using a colorimeter (Minolta CS-100A) while increasing the current density from 2.5 mA / cm 2 to 100 mA / cm 2 by 2.5 mA.

3) Efficiency

The luminous efficiency was calculated using the luminance and current density measured above.

4) ELmax

Power was supplied from a power supply (Kethley SMU 236) and the wavelength was set to ELmax at the highest intensity of the spectrum taken from the photodiode (Ocean Optics).

< Example  1>  Device fabrication and evaluation of compound 1

After the ITO electrode was formed on the glass substrate, UV-ozone cleaning or oxygen plasma cleaning was performed. Then, a phthalocyanine copper complex (CuPc) having a structure represented by the following formula (2-1) was vapor- . Next, NPD (N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) benzidine) having the structure of Formula 2-2 was vapor- And Compound 1 was formed as a blue light emitting material to form a 300 Å thick light emitting layer. Alq3 (tris- (8-hydroxyquinoline) aluminum (III)) having a structure represented by the following Formula 2-3 was vacuum deposited as the electron transfer layer to a thickness of 300 Å. Then, an Al: Li layer was vacuum-deposited on the upper part to form an aluminum-lithium electrode having a thickness of 1000 Å, thereby manufacturing a blue organic electroluminescent device.

< Comparative Example  1>

A blue organic electroluminescent device was manufactured and measured in the same manner as in Example 1, except that DPVBi having the structure of the following Formula 2-4 was used as a blue luminescent material when forming the luminescent layer.

[화학식 2-4]

[Chemical Formula 2-4]

[Table 1]

Current density
(mA / cm ² ) Driving voltage
(V) Luminance
(cd / m ² ) Color coordinates CIE1931
(x, y) efficiency
(cd / A) Example 1 10 8.54 385 (0.146, 0.106) 3.85 Comparative Example 1 10 9 312 (0.15, 0.16) 3.12

According to the present invention, it is possible to provide an organic electroluminescent device, which comprises an excimer which hinders thermal stability and luminescence characteristics, and an asymmetric silane group which exhibits steric hindrance characteristics to prevent exciplex and an anthracene group- The device exhibited excellent electric organic luminescence performance with high efficiency and good color purity.

Claims (7)

1. An organosilane compound represented by the following formula (1). [Chemical Formula 1]

Wherein Ar1, Ar2, Ar3, Ar7 and Ar8 are independent of each other and are the same or different and selected from one of an aryl group having 6 to 20 carbon atoms, Ar4, Ar5 and Ar6 are independently the same or different and have 6 to 20 And n is an integer of 1 to 3. When n is 2 or more, Ar5 is the same or different from each other, provided that when Ar1, Ar2, and Ar3 are all phenyl groups, the phenyl group is excluded from Ar4) The organosilane compound according to claim 1, wherein at least one of Ar1, Ar2, Ar3, Ar7 and Ar8 is selected from the following formulas (2) to (14).

(The above formulas may have a substituent at one or more hydrogen positions, and the substituents are independently selected from the group consisting of a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms , An aryl group having 1 to 20 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, and a trifluoromethyl group. The organosilane compound according to claim 1, wherein at least one of Ar4, Ar5 and Ar6 is selected from the following formulas (15) to (23).

(The above formulas may have a substituent at one or more hydrogen positions, and the substituents are independently selected from the group consisting of a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms , An aryl group having 1 to 20 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, a trifluoromethyl group, and a solid line indicating a bonding position, But this means that the positions of Ar4 and Ar5, and the bonding position of Ar5 and Ar6 may be any position in the polyvalent ring.) The organosilane compound according to claim 1, wherein the compound represented by the formula (1) is represented by the following formulas (1) to (14).

A light-emitting material comprising an organosilane compound according to any one of claims 1 to 4. An organic electroluminescence device comprising a plurality of organic compound layers including a cathode, an anode, and a light emitting layer disposed between the anode and the cathode, wherein the organic silane compound according to any one of claims 1 to 4, Or a part of the organic electroluminescent device. 7. The organic electroluminescent device according to claim 6, wherein the organic compound layer contains at least one of a light emitting layer, an electron injection layer and an electron transport layer, and the organosilane compound is contained in at least one of the light emitting layer, Electroluminescent device.

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