KR20060071550A - Cyanostilbene based organic electroluminescent compound and organic electroluminescent device using the same - Google Patents

Abstract

The light emitting compound for an organic light emitting device of the present invention includes a cyanostilbene compound represented by the following Chemical Formula 1 or Chemical Formula 2. The cyanostilbene-based light emitting compound of the present invention has AIEE (Aggregation Induced Enhanced Emission) characteristics and has excellent luminescence properties.

[Formula 1] [Formula 2]

Organic light emitting device, light emitting compound, cyanostilbene, AIEE, electroluminescent display

Description

Cyanostilbene based Organic Electroluminescent Compound and Organic Electroluminescent Device Using the Same}             

1 is one embodiment showing the structure of an organic light emitting diode (OLED) of the present invention.

FIG. 2 shows an NMR spectrum of 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 1. FIG.

FIG. 3 shows UV-vis spectrum in solution of 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 1. FIG.

FIG. 4 shows the photoluminescence spectra in the solid film state of 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 1. FIG. .

Figure 5 shows the electroluminescence spectra in the solid film state of 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 1 .

6 is a CIE color coordinates of a photoluminescence spectrum in the solid film state of 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 1 It is shown.

7 is a CIE for electroluminescence spectra in the solid film state of 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 1 It is a figure which shows the color coordinate.

8 is a UV-vis and photoluminescence spectra in a solution of 4-[(Z) -1-cyano-2- (4-diphenylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 3 It is shown.

9 shows a photoluminescence spectrum of a solid film of 4-[(Z) -1-cyano-2- (4-diphenylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 3 .

FIG. 10 shows the photoluminescence spectra in the solution and solid film state of 4-[(Z) -1-cyano-2- (4-diphenylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 3. FIG. It shows the CIE color coordinates.

Brief description of the main symbols in the drawing

1: glass 2: ITO (anode transparent electrode)

3: hole injection layer 4: hole transport layer

5: light emitting layer 6: electron transport layer

7: Al / LiF 8: Power

 Field of invention

The present invention relates to a cyanostilbene-based organic light emitting compound having a novel structure that can be used as an organic light emitting device. More specifically, the present invention relates to a cyanostilbene-based compound having a specific structure having an fluorescence enhancement (AIEE) characteristic by induction of an aggregate and an organic light emitting device using the same.

Background of the Invention

Liquid crystal display (LCD), which is the most widely used at present, is a non-light emitting display device, which consumes little power and is light. However, the device driving system is complicated and characteristics such as response time and contrast are not satisfactory. Therefore, research on organic light emitting diodes, which are recently attracting attention as a next-generation flat panel display, is being actively conducted. The organic light emitting device is a self-luminous device and has various advantages such as excellent brightness, driving voltage, and response speed, and no viewing angle dependency, compared to the liquid crystal display.

The light emitting mechanism of the organic EL device is as follows. Holes injected from the anode into the valence band or highest occupied molecular orbital (HOMO) of the hole injection layer (HIL) proceed to the emitting layer through the hole transporting layer (HTL). At the same time, electrons move from the cathode to the emission layer through the electron injection layer to combine with holes to form excitons. The exciton falls to the ground and emits light.

Using the principle of the organic EL device described above, Eastman Kodak Co., Ltd. in 1987 used TPD (N-N'-DiphenyI-N-N'-bis (methylphenyl-1,1'-biphenyl-4) as a hole transporting layer. We developed an electroluminescent device using Alq ₃ (tris (8-hydroxy-quinoline) aluminum complex) as the light emitting layer ( Appl. Phys. Lett. , 51, 913, 1987). The research on the electroluminescent element used is becoming active.

To date, red light emitting materials have inherently low luminous efficiency, quenching effects due to intermolecular dipole-dipole interactions caused by expanded π electrons at high concentrations, and deterioration of color purity due to wide emission bands. There are problems. Therefore, a method using energy transfer from the host material to the red light emitting material which is less than 2% of the dopant is used ( Appl. Phys. Lett. 65, 3610, 1989). Among the dopants used in such a doping system are Eastman Kodak's DCM derivatives (US Pat. No. 5,853,81, US Pat. 5,357,020).

However, there is a difficulty in reproducibility in device fabrication compared to the actual undoped host light emitter. In order to solve this problem, Sony's 1,1'-dicyano-substituted bisstrylnaphthalene (BSN) has recently been used as red host light emitting materials for undoping systems. Patent No. 6765108, U.S. Patent 6,742,57, U.S. Pat.No.6790974), and many red light emitting materials are currently being developed.

However, among the three color light emitting materials known to be used for organic light emitting devices, materials having excellent brightness and efficiency have been developed in the green and blue colors, but in the case of red, the full color organic light emitting devices have significantly lower brightness and efficiency than green and blue colors. Not enough to produce.

Therefore, the present inventors apply a cyanostilbene-based compound having naphthyl, anthryl, phenanthryl and pyrenyl structures substituted with H, CN, CF ₃ and a halogen atom at the terminal to an organic light emitting device, whereby light emission efficiency in a solid state It is excellent to develop organic light emitting compounds that can control the color from green to red.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cyanostilbene-based light emitting compound having an AgEE (Aggregation Induced Enhanced Emission) characteristic which is particularly excellent in luminous efficiency in the solid state.

Another object of the present invention is to provide a cyanostilbene-based light emitting compound capable of controlling color from green to red by modifying the conjugate length of the core or the terminal of the branched phosphor.

Still another object of the present invention is to provide an organic light emitting device using the light emitting compound.

The above and other objects of the present invention can be achieved by the present invention described in detail below.

The light emitting compound for an organic light emitting device of the present invention includes a cyanostilbene compound represented by the following Chemical Formula 1.

[Formula 1]

In which R ¹ is selected from the group consisting of the following formulas 1a to 13a;

(Wherein R ₁ to R ₁₀₉ are selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, and are the same or different from each other)

R ² is a substituted or unsubstituted heterocycle group, and the substituent of R ² is a linear, nonlinear, and cyclic alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group, a halogen atom, and a cyano group , Nitro groups, trifluoromethyl groups, the same or different independently from each other.

In the above, R ² is a saturated or unsaturated aromatic heterocycle group containing at least one substituted or unsubstituted nitrogen, oxygen, or sulfur atom and having 3 to 10 components.

The heterocycle group represented by R ² has a single ring structure or a structure fused with other rings, preferably a 5-6 ring aromatic heterocycle group containing a nitrogen, oxygen, or sulfur atom, more preferably It is a 5-6 ring aromatic heterocycle group containing 1-2 nitrogen atoms or 1-2 sulfur atoms.

The aromatic heterocycle group represented by R ² is an oxygen atom, a nitrogen atom, a sulfur atom, methylene, vinyl, acetylene, thiophene, pyrrole, furan, selenophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, Triazine, indole, indazole, purine, thiazolin, thiazole, thiadiazole, oxazoline, or oxadiazole, and the like formed by a combination of these groups to form a fused ring. More preferably substituted or unsubstituted thiophene, pyrrole, furan, selenophene, pyridine, pyridazine, pyrimidine, azulene, carbazole, arylenevinylene, aryleneethylylene, juliolidine And arylenephenylene (arylene is phenylene, thiophene, pyrrole, furan, selenophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indole, purine, thia Sleepy, thiazole, thiadiazole, oxazoline, oxazole, and oxadiazole).

In addition, the light emitting compound for an organic light emitting device of the present invention includes a cyanostilbene compound represented by the following formula (2).

 [Formula 2]

Wherein R ²¹ is selected from the group consisting of the following Chemical Formulas 1b to 13b;

(Wherein R ₁ to R ₁₀₉ are selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, and are the same or different from each other)

Ar ²¹ is a substituted or unsubstituted divalent aryl group or heterocycle group, which is the same as or different from each other, R ²² is a substituted or unsubstituted aryl group, heterocycle group, or aliphatic hydrocarbon group, which is the same as or different from each other (the Substituents for Ar ²¹ and R ²² include linear, nonlinear, and cyclic alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, aryloxy groups, halogen atoms, cyano groups, nitro groups, and trifluoromethyl groups. , Same or different independently of each other); m is 1-3 and n is 1-2.

Ar ²¹ and R ²² are the same as, different from, and independent of each other, and the aryl group represented by Ar ²¹ and R ²² is represented by a single ring or 2 to 4 rings containing 6 to 30 carbon atoms which is substituted or unsubstituted. An aryl group; The substituted or unsubstituted heterocycle group represented by Ar ²¹ and R ²² is a saturated or unsaturated aromatic heterocycle group having at least one nitrogen, oxygen, and sulfur atom and having 3 to 10 components; The aliphatic hydrocarbon group represented by R ²² is characterized by being a linear, branched, cyclic alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

When m is 2 to 3, Ar ²¹ is the same as or different from each other, and when m is 1, two R ²² are the same or different, and at least one R ²² is a substituted or unsubstituted aryl group or heterocycle group. .

Aryl groups represented by Ar ²¹ and R ²² include phenyl, naphthyl, anthryl, phenanthryl, pyrenyl, indenyl, and the like; Substituted or unsubstituted heterocycle groups represented by Ar ²¹ and R ²² are pyrrolidine, piperidine, piperazine, morpholin, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine , Triazole, triazine, indole, indazole, purine, thiazolin, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quina Sleepy, cinnoline, pteridine, acridinephenanthrol, phenazine, tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, juliolidine, tetrazainden and the like; The aliphatic hydrocarbon group represented by R ²² includes methyl group, ethyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, methoxy group, ethoxy group, butoxy group and the like.

Specific examples of the cyanostilbene-based compound of the present invention represented by the formula (1) or (2) include compounds having the following structure.

The light emitting compound of the present invention can be used in organic light emitting device material in the form of powder, solution or film. The light emitting compound of the present invention is characterized in that the efficiency of light emission is low in the solution state, but rather has an AIEE characteristic having a high light emission efficiency in the film state.                     

The cyanostilbene-based light emitting compound of the present invention has a maximum emission value in the range of 600 to 700 nm in the organic electroluminescent region.

In the organic light emitting device in which an organic film is formed between a pair of electrodes including an anode and a cathode, the cyanostilbene-based light emitting compound may be used as an organic film alone or as a mixture thereof.

In an embodiment of the present invention, in the organic film having an organic laminated structure in which a hole transport layer and an electron transport layer are laminated, the cyanostilbene-based light emitting compound may be used for the electron transport layer and / or the hole transport layer.

According to another embodiment of the present invention, in the organic film having an organic laminated structure in which a hole transporting layer, a light emitting layer and an electron transporting layer are stacked, the cyanostilbene-based light emitting compound may be used for both the light emitting layer or the light emitting layer and the electron transporting layer.

In applying the cyanostilbene-based light emitting compound to the organic film, it can be used as a mixed layer in which the light emitting compound of the present invention is mixed in a concentration range of 0.5 to 100% with a material having charge transporting ability.

The cyanostilbene-based light emitting compound of the present invention is capable of controlling the color from green to red by modifying the conjugated length of the core or the terminal of the branched phosphor, and also exhibits luminescence properties in all powders, solutions and films. It can be said that the organic light emitting device material is very useful for the production of.

The present invention will be further illustrated by the following examples, which are only specific examples of the present invention, and are not intended to limit or limit the protection scope of the present invention.

Example 1 Preparation of 4-[(Z) -1-Cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile

0.4 g (2.393 mmol) of 4- (cyanomethyl) phthalonitrile and 0.356 g (2.393 mmol) of p-dimethylamino benzaldehyde are completely dissolved in benzene, and catalytic amounts of acetic acid and piperidine are added. Stirred. After completion of the reaction, the solvent was evaporated under reduced pressure, recrystallized with dichloromethane and n-nucleic acid, and then filtered and dried under reduced pressure: 88% yield; ¹ H-NMR (CDCl ₃ , ppm): 7.79-8.01 (5H, Ar-H), 7.52 (1H, vinyl H), 6.75 (2H, Ar-H), 3.12 (6H, CH3), MS (EI) (calcd for C 19 H 14 N 4, 298.12; found, 299.3), Elem. Anal. (calcd .: C, 76.49; H, 4.73; N, 18.78, Estimated value: C, 76.11 H, 4.66 N, 18.08).

NMR of the prepared 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile is shown in FIG. 2. The UV-vis spectrum in solution of 4-[(Z) -1-cyano-2- (4-dimethylamino-phenyl) -vinyl] -phthalonitrile is shown in FIG. 3. Photoluminescence spectra and electroluminescence spectra in the solid film state are shown in FIGS. 4 and 5, respectively. 6 and 7 show CIE color coordinates for the photoluminescence spectrum in the solid film state, CIE color coordinates for the electroluminescence spectrum in the solid film state, respectively.

Example 2: Preparation of 4-[(Z) -1-Cyano-2-zololidyl-vinyl] -phthalonitrile

Except for using 6- julolidine carbaldehyde (6- juloidine carbaldehyde) instead of p-dimethylamino benzaldehyde was carried out in the same manner as in Example 1, 4-[(Z) -1 having the following structure -Cyano-2-zololidyl-vinyl] -phthalonitrile was prepared.

1 H-NMR (CDCl 3, ppm): 7.49-7.96 (5H, Ar-H), 7.38 (s, 1H vinyl H), 3.33 (t, 4H, -CH 2), 2.77 (t, 4H, -CH 2), 0.98 (q, 4H, -CH 2).

Example 3: Preparation of 4-[(Z) -1-Cyano-2- (4-diphenylamino-phenyl) -vinyl] -phthalonitrile

Except for using p-diphenylamino benzaldehyde instead of p-dimethylamino benzaldehyde was carried out in the same manner as in Example 1, 4-[(Z) -1-cyano-2- ( 4-diphenylamino-phenyl) -vinyl] -phthalonitrile was prepared.

1 H-NMR (CDCl 3, ppm): 7.01-8.04 (17H, Ar-H), 7.53 (s, 1H vinyl H

UV-vis and photoluminescence spectra of the solution of 4-[(Z) -1-cyano-2- (4-diphenylamino-phenyl) -vinyl] -phthalonitrile are shown in FIG. The photoluminescence spectrum in the film state is shown in FIG. 9. FIG. 10 shows the photoluminescence spectra in the solution and solid film state of 4-[(Z) -1-cyano-2- (4-diphenylamino-phenyl) -vinyl] -phthalonitrile synthesized in Example 3. FIG. It shows the CIE color coordinates.

According to the present invention, by applying a specific cyanostilbene-based compound having an aromatic structure substituted with H, CN, CF ₃ and a halogen atom at the terminal to an organic light emitting device, it is excellent in luminous efficiency in the solid state, color control of green to red The invention has the effect of providing a possible organic light emitting compound.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (11)

A light emitting compound for an organic light emitting device comprising a cyanostilbene compound represented by Formula 1 below: [Formula 1]

In which R ¹ is selected from the group consisting of the following formulas 1a to 13a;

(Wherein R ₁ to R ₁₀₉ are selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, and are the same or different from each other) R ² is a substituted or unsubstituted heterocycle group, and the substituent of R ² is a linear, nonlinear, and cyclic alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group, a halogen atom, and a cyano group , Nitro groups, trifluoromethyl groups, the same or different independently from each other. The organic light emitting device of claim 1, wherein R ² is a saturated or unsaturated aromatic heterocycle group containing at least one of substituted or unsubstituted nitrogen, oxygen, or sulfur atoms and having 3 to 10 components. Light emitting compound. The compound of claim 2, wherein R ² is substituted or unsubstituted thiophene, pyrrole, furan, selenophene, pyridine, pyridazine, pyrimidine, azulene, carbazole, arylenevinylene, aryleneethylylene, jul Julolidine, and arylenephenylene (arylene is phenylene, thiophene, pyrrole, furan, selenophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, inda) It comprises a stone, purine, thiazolin, thiazole, thiadiazole, oxazoline, oxazole, and oxadiazole). A light emitting compound for an organic light emitting device comprising the cyanostilbene compound represented by the formula (2): [Formula 2]

In which R ²¹ is selected from the group consisting of the following Chemical Formulas 1b to 13b;

(Wherein R ₁ to R ₁₀₉ are selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, and are the same or different from each other) Ar ²¹ is a substituted or unsubstituted divalent aryl group or heterocycle group, which is the same as or different from each other, R ²² is a substituted or unsubstituted aryl group, heterocycle group, or aliphatic hydrocarbon group, which is the same as or different from each other (the Substituents for Ar ²¹ and R ²² include linear, nonlinear, and cyclic alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, aryloxy groups, halogen atoms, cyano groups, nitro groups, and trifluoromethyl groups. , Same or different independently of each other); m is 1 to 3, n is 1 to 2, and when m is 1, at least one R ²² is a substituted or unsubstituted aryl group or heterocycle group. The aryl group represented by Ar ²¹ and R ²² is a substituted or unsubstituted aryl group represented by a single ring or 2 to 4 rings containing 6 to 30 carbon atoms; The substituted or unsubstituted heterocycle group represented by Ar ²¹ and R ²² is a saturated or unsaturated aromatic heterocycle group having at least one nitrogen, oxygen, and sulfur atom and having 3 to 10 components; An aliphatic hydrocarbon group represented by R ²² is a C1-C20 linear, branched, cyclic alkyl group, or a C1-C20 alkoxy group. The compound of claim 4, wherein the aryl group represented by Ar ²¹ and R ²² is selected from the group consisting of phenyl, naphthyl, anthryl, phenanthryl, pyrenyl, indenyl; Substituted or unsubstituted heterocycle groups represented by Ar ²¹ and R ²² are pyrrolidine, piperidine, piperazine, morpholin, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine , Triazole, triazine, indole, indazole, purine, thiazolin, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quina From the group consisting of sleepy, cinnoline, putridine, acridine phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, juliolidine, tetrazaindene Selected; The aliphatic hydrocarbon group represented by R ²² is selected from the group consisting of methyl group, ethyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, methoxy group, ethoxy group and butoxy group A light emitting compound for an organic light emitting device characterized in that. The light emitting compound according to any one of claims 1 to 6, wherein the light emitting compound is used in an organic light emitting device material in the form of a powder, a solution, or a film. An organic light-emitting device comprising: a light emitting compound selected from any one of claims 1 to 6 or a mixture thereof as an organic film formed between a pair of electrodes including an anode and a cathode. The organic light emitting device according to claim 8, wherein the organic film has an organic laminated structure in which a hole transport layer and an electron transport layer are stacked, and the light emitting compound is used for the electron transport layer and / or the hole transport layer. The organic light emitting device of claim 8, wherein the organic film has an organic laminated structure in which a hole transporting layer, a light emitting layer, and an electron transporting layer are stacked, and the light emitting compound is used in the light emitting layer or the light emitting layer and the electron transporting layer. The organic light emitting device according to any one of claims 9 to 10, wherein the organic film is a mixed layer in which the light emitting compound is mixed in a concentration range of 0.5 to 100% with a material having charge transport ability.

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