KR100618945B1 - Red organic light-emitting compound and organic light-emitting diode including the same - Google Patents

Abstract

Disclosed are an organic light emitting compound that emits red light with high efficiency and high quality, and has excellent thermal stability and lifetime characteristics, and an organic light emitting diode including the same. The organic light emitting compound has the following formula, and the organic light emitting diode includes a first electrode having a high work function, a second electrode having a low work function, and the organic light emitting compound, At least one organic compound layer located between.

In the above formula, K may be the same or different from each other, a ring compound having one or more hetero atoms, R ₁ to R ₁₂ may be the same or different from each other, hydrogen, halogen, cyano group, substituted or unsubstituted carbon number Or an alkyl or alkoxy group having 1 to 3 or an aryl group having 6 to 24 carbon atoms.

Red light emission, organic compound, hetero ring, fumaronitrile, distilbene, heat resistance

Description

Red organic light-emitting compound and organic light-emitting diode including the same}             

1 is a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention.

2 is a cross-sectional view of an organic light emitting diode according to another embodiment of the present invention.

The present invention relates to a red organic light emitting compound and an organic light emitting diode (OLED) including the same, and more particularly to a red organic light emitting compound having excellent thermal stability and lifespan and an organic light emitting diode including the same. It is about.

Organic Light-Emitting Diodes (OLEDs), also commonly called EL (Electroluminescence Devices), are liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (Field Emissions). As one of the representative flat panel display devices with Display: FED, etc., it does not need a backlight for light emission, it is possible to manufacture a device in a thin film and bendable form, and it is easy to form patterns and mass production by film manufacturing technology. There is this. In addition, since EL is a spontaneous light emitting device, it has the advantage of excellent luminance and viewing angle characteristics, fast response speed, low driving voltage, and theoretically light emission of all colors in the visible region.

The organic light emitting diode forms an organic light emitting layer having a light emitting property between a transparent electrode such as ITO having a large work function and a metal electrode such as Mg having a small work function, and applies a voltage to the electrode to generate holes and When the electrons combine in the organic light emitting layer, the organic light emitting layer uses the property of generating light. Among the materials for forming such an organic light emitting layer, a material for generating light in the red region (590 nm) is 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran ( 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran: DCM) is typically used and other US Patent Nos. 3,852,683, 3,986,140, 4,012,376, 4,146,707, and 4,769,292, 5,018,160, 5,294,869, 5,409,783, 5,492,942, 5,908,581, 5,935,720, and the like. Such conventional DCM-based red light-emitting compounds are mainly substituted with a substituent such as an alkyl group to nitrogen, they have a low heat resistance, there is a disadvantage in short life of the organic light emitting device using them. In addition, US Pat. No. 6,338,910 discloses a fumaronitrile distilbene derivative as a red light emitting organic compound, but such a compound also does not have sufficient heat resistance, and thus has a disadvantage in that the life of the organic light emitting device is not satisfactory. .

Accordingly, an object of the present invention is to provide a red organic light emitting compound having excellent thermal stability and lifespan characteristics and an organic light emitting diode including the same.

Another object of the present invention is to provide an organic light emitting compound which not only easily adjusts the emission color but also emits high-quality red light with high efficiency and an organic light emitting diode including the same.

In order to achieve the above object, the present invention provides a novel organic light emitting compound having a structure of the following formula. The present invention also includes a first electrode having a high work function, a second electrode having a low work function, and the organic light emitting compound, and including at least one organic compound layer positioned between the first and second electrodes. It provides an organic light emitting diode. The organic compound layer may be a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer, or an electron transport layer, and the organic compound may be used as a host or dopant material of the light emitting layer.

In the above formula, K may be the same or different from each other, a ring compound having one or more hetero atoms, R ₁ to R ₁₂ may be the same or different from each other, hydrogen, halogen, cyano group, substituted or unsubstituted carbon number Or an alkyl or alkoxy group having 1 to 3 or an aryl group having 6 to 24 carbon atoms.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The organic light emitting compound according to the present invention is an anthracene-based compound which emits light by receiving energy generated by recombination of electron-holes, and has a structure represented by the following Chemical Formula 1.

,

,

,

,

,

,

(이들의 결합 위치는 특별히 제한되지 않는다.) 등을 예시할 수 있다. 상기 헤테로 원자로는 N, S, O, Si, P 등을 예시할 수 있으며, R₁₃은 서로 같거나 다를 수 있으며, 수소, 히드록시기, 시아노기, 아민기, 또는 치환되거나 치환되지 않은 탄소수 1 내지 20의 알킬, 아릴, 헤테로아릴 또는 알콕시이고, 예를 들면, 아미노아릴기, 아릴아미노기, 알킬아미노기, 피라졸린 등을 포함한다. In Formula 1, K may be the same or different from each other, a ring compound having one or more hetero atoms, R ₁ to R ₁₂ may be the same or different from each other, hydrogen, halogen, cyano group, substituted or unsubstituted An alkyl or alkoxy group having 1 to 3 carbon atoms or an aryl group having 6 to 24 carbon atoms. The cyclic compound represented by K includes all fused rings capable of forming hetero conjugation, and may be combined with adjacent substituents to form a cyclic compound, for example

,

,

,

,

,

,

(The combination position thereof is not particularly limited.) And the like can be exemplified. Examples of the hetero atom include N, S, O, Si, P, etc., R ₁₃ may be the same or different from each other, hydrogen, hydroxy group, cyano group, amine group, or substituted or unsubstituted carbon number 1 to 20 Alkyl, aryl, heteroaryl or alkoxy, and includes, for example, an aminoaryl group, an arylamino group, an alkylamino group, pyrazoline and the like.

Preferred examples of the red organic light emitting compound according to the present invention are

,

,

,

,

,

,

,

,

등을 예시할 수 있다.

,

,

,

,

,

,

,

,

Etc. can be illustrated.

The red organic light emitting compound according to the present invention changes the emission wavelength and the electron / hole injection / transport characteristics according to the type of the heterocyclic compound and the substituent bonded to the fumaronitrile distilbene, and thus the desired emission wavelength by appropriately selecting the substituent And an organic compound layer having physical properties such as charge transfer characteristics. The organic light emitting compound according to the present invention has excellent heat resistance and not only improves the lifespan and productivity of the light emitting device, but also emits high efficiency and high quality red light. Since the luminescent anthracene-based compound according to the present invention can be prepared by various conventional organic synthesis methods, the synthesis method is not particularly limited.

1 is a cross-sectional view of an organic light emitting diode according to an exemplary embodiment of the present invention. As shown in FIG. 1, an organic light emitting diode has a hole formed in a first electrode 12 having a high work function on the substrate 10. A light emitting layer 14 including a light emitting organic compound according to the present invention is formed on the first electrode 12 and formed as a hole injection electrode (anode). In addition, the light emitting layer 14 may include a conventional host, a conventional light emitting compound, a fluorescent dye, and / or a dopant together with the light emitting organic compound according to the present invention. When the compound of the present invention is used as a dopant with a conventional host material such as 9,10-di (2-naphthyl) anthracene (9,10-di (2-naphthyl) anthracene: ADN), the dopant The content of is preferably 1 to 20% by weight, more preferably 5 to 10% by weight based on the entire host / dopant. A second electrode 16 having a low work function is formed on the emission layer 14 so as to face the first electrode 12 as an electron injection electrode (cathode). When voltage is applied to the first and second electrodes 12 and 16 of the organic light emitting diode, holes and electrons generated in the first and second electrodes 12 and 16 are injected into the light emitting layer 14, and the light emitting layer In the molecular structure of (14), electrons and holes are combined to emit light, and the emitted light passes through the first electrode 12 and the substrate 10 made of a transparent material to display an image. The substrate 10 of the organic light emitting diode is electrically insulative, and in particular, when fabricating a device emitting light toward the first electrode 12, the substrate 10 is made of a transparent material, preferably made of glass or transparent plastic film. The first electrode 12 may be made of indium tin oxide (ITO), polyaniline, silver (Ag), or the like, and the second electrode 16 may be formed of a metal such as Al, Mg, Ca, or LiAl, It may be made of a metal alloy such as Mg-Ag.

FIG. 2 is a cross-sectional view of an organic light emitting diode according to another embodiment of the present invention. In the organic light emitting diode illustrated in FIG. 2, holes and electrons generated in the first and second electrodes 12 and 16 are respectively formed in the light emitting layer 14. The hole injection and transport layers 21 and 22 and the electron injection and transport layers 25 and 26 are further formed so that they can be easily injected into the? The hole injection and transport layers 21 and 22 have a function of facilitating the injection of holes from the hole injection electrode 12 and a function of stably transporting the holes, and the hole injection layer 21 is not limited to the US. Porphyrinic compounds, such as phthalocyanine copper, disclosed in patent 4,356,429, for example m-MTDATA (4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine), The hole transport layer 22 is NPB (N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1'-biphenyl) -4,4'-diamine), triphenyldiamine Derivatives, styrylamine derivatives, α-NPD (N, N'-diphenyl-N, N'-bis (α-naphthyl)-[1,1'-biphenyl] 4,4'-diamine) It can be formed using a conventional amine derivative having an aromatic condensed ring The electron injection and transport layer (25, 26) has a function to facilitate the injection of electrons from the electron injection electrode 16 and to stabilize the electrons. As a function of transporting, non-limiting chinoline derivatives, in particular, conventional electron injection and transport compounds such as tris (8-kinolinorate) aluminum (aluminaquinone, Alq3), LiF, and the like form the electron transport layer 26. These layers 21, 22, 25, and 26 function to augment, confine, and combine holes and electrons injected into the light emitting layer 14, and to improve luminous efficiency. The thickness of the hole injection and transport layers 21 and 22 and the electron injection and transport layers 25 and 26 is not particularly limited, and depending on the formation method, the thickness is usually about 5 to 500 nm.

The organic light emitting compound according to the present invention may be used as a host or dopant material of the light emitting layer 14, and according to the potential difference with other layers, the hole injection and transport layers 21 and 22 and / or the electron injection and transport layer ( 25, 26), it may also function to inject / transport electrons and holes. The organic layers may be formed by a vacuum deposition method, a spin coating method, or the like, which is commonly used for fabricating an organic electroluminescent device, and may be preferably formed by a vacuum deposition method. The organic light emitting compound of the present invention can be applied not only to the organic light emitting diode having the structure shown in FIG. Such structures of various organic light emitting diodes are disclosed in, for example, US Pat. Nos. 4,539,507, 5,151,629, 6,214,481, 6,387,544, and the like.

Next, preferred examples are provided to help understanding of the present invention. However, the following examples are intended to illustrate the invention, not to limit the invention. In the examples below all experiments were performed in an inert atmosphere such as a nitrogen atmosphere.

Example 1 Synthesis of Organic Light Emitting Compound

A. Synthesis of 4,4'-dimethyl-α, β-dicyanostilbene (4,4'-dimethyl-α, β-dicyanostilbene).

As shown in the following Scheme 1, 5 g (38 mmol) of 4-methylbenzyl cyanide and 9.7 g (38 mmol) of iodine were dissolved in ether, and the temperature of the reaction solution was-. After lowering to 78 ° C., 6.23 g (76 mmol) of NaOMe as a 28 wt% aqueous solution was droppedwise. Then the temperature was slowly raised to 0 ° C. and the reaction was filtered. Next, the filtered solid was poured into cold methanol (iced-MeOH), stirred for 1 hour, filtered and dried to obtain 4 g of the title white solid (yield = 80%).

B. Synthesis of 4,4'-dimethylbromo-α, β-dicyanostilbene (4,4'-dimethylbromo-α, β-di cyanostilbene)

As shown in Scheme 2 below, 1 g (3.9 mmol) of 4,4'-dimethyl-α, β-dicyanostilbene (3.9 mmol) and dibenzoyl obtained in step A were obtained. 0.03 g (0.1 mmol) of dibenzoylperoxide is dissolved in 40 ml of tetrachloromethane, and 1.4 g (7.8 mmol) of N-bromo-succinimide (NBS) is added at room temperature. It was. Stirred at room temperature for 24 hours, then filtered and dried to give 1.1 g of the title white solid (yield = 70%).

C. Synthesis of 4,4'-dimethylphosphate-α, β-dicyanostilbene (4,4'-dimethylphosphate-α, β-dicyanostilbene)

As shown in Scheme 3, 1.1 g (2.8 mmol) of 4,4'-dimethylbromo-α, β-dicyanostilbene obtained in step B was used in 1 ml (5.7 mmol) of triethoxy phosphate. To, stirred at 160 ° C. for 18 h, then cooled and filtered to give 1.0 g of the title yellow solid (yield = 64%).

D. Synthesis of 9-julolidine-aldehyde

As shown in Scheme 4, 8.5 g of POCl ₃ was dropped dropwise into 160 ml of dimethyl formamide (DMF) at 0 ° C., 8 g (46 mmol) of Julolidine was added at 0 ° C., and 20 Stirred for a minute, and then stirred at 100 ° C. for 1 hour. After cooling the reaction solution, 200 ml of water was added and filtered to give 8 g of the titled brown solid (yield = 87%).

E. 2,3-bis- {4- [2- (2,3,6,7-tetrahydro-1H, 5H-pyrido [3,2,1-ij] quinolin-9-yl) -vinyl] -Phenyl} -but-2-enedinitrile (2,3-Bis- {4- [2- (2,3,6,7-tetrahydro-1H, 5H-pyrido [3,2,1-ij] quinolin- 9-yl) -vinyl] -phenyl} -but-2-enedinitrile)

As shown in Scheme 5, 0.5 g (1 mmol) of 4,4'-dimethylphosphate-α, β-dicyanostilbene obtained in step C and 0.4 g (1.9) of 9-julolidinealdehyde obtained in step D were obtained. mmol) was dissolved in 20 ml of tetrahydrofuran, 0.58 g (2.3 mmol) of Kt-butoxide was added thereto, followed by stirring at room temperature for 24 hours. After the reaction, 4 ml of HCl was added as a 10 wt% aqueous solution, 20 ml of water was added, methylene chloride was added to form an organic layer and an aqueous layer, and the organic layer was separated to remove an organic solvent, thereby obtaining 0.3 g of the titled red solid. (Yield = 50%).

Example 2 Fabrication of Organic Light Emitting Diode

The glass substrate coated with indium tin oxide (ITO) was ultrasonically cleaned, washed again with deionized water, then degreased with toluene gas and dried. Next, a hole injection layer was formed by vacuum evaporation of m-MTDATA on the ITO electrode at a 500 kW thickness, and a hole transport layer was formed by vacuum evaporation of α-NPD at a thickness of 200 kW on the hole injection layer. The organic light emitting compound synthesized in Example 1 was deposited on the hole transport layer to a thickness of 300 mW, and then Alq3 was deposited to a thickness of 200 mW as the electron transport layer. LiF was vacuum deposited on the electron transport layer to form a electron injection layer, and Al was deposited to a thickness of 1200 mA on the electron injection layer to form a cathode, thereby manufacturing an organic light emitting diode. The light emission color coordinates of the manufactured organic light emitting diodes were (0.66, 0.35), and the light emitting efficiency was 2.54 lm / W at 10 mA / cm ^2. The organic light emitting diodes produced high-quality red light and exhibited excellent light emitting efficiency.

 As described above, the organic light emitting compound according to the present invention not only has excellent heat resistance, thermal stability, luminous efficiency and lifetime characteristics, but also emits red light of high quality and various wavelengths depending on the substituent. The organic light emitting compound according to the present invention is useful for the production of full color organic light emitting diodes, and is a field effect transistor, a photodiode, a photovoltaic cell, a solar cell, and an organic laser. It can be widely applied to various organic semiconductor devices such as a laser and a laser diode.

Claims (6)

An organic light emitting compound having a structure of the following formula.

In Formula 1, K may be the same or different from each other, a ring compound having one or more hetero atoms, R ₁ to R ₁₂ may be the same or different from each other, hydrogen, halogen, cyano group, substituted or unsubstituted An alkyl or alkoxy group having 1 to 3 carbon atoms or an aryl group having 6 to 24 carbon atoms. The organic light emitting compound of claim 1, wherein the ring compound represented by K is a conjugated ring group. According to claim 1, wherein the cyclic compound represented by K

,

,

,

,

,

, And

Wherein R ₁₃ may be the same or different from each other, and is hydrogen, a hydroxy group, a cyano group, an amine group, or a substituted or unsubstituted alkyl having 1 to 20 carbon atoms, aryl, heteroaryl or alkoxy. It is an organic light emitting compound. The method of claim 1, wherein the organic light emitting compound

,

,

,

,

,

,

,

, And

An organic light emitting compound selected from the group consisting of. A first electrode having a high work function; A second electrode having a low work function; And An organic light emitting diode comprising an organic compound of the following formula, and comprising at least one organic compound layer positioned between the first and second electrodes.

In Formula 1, K may be the same or different from each other, a ring compound having one or more hetero atoms, R ₁ to R ₁₂ may be the same or different from each other, hydrogen, halogen, cyano group, substituted or unsubstituted An alkyl or alkoxy group having 1 to 3 carbon atoms or an aryl group having 6 to 24 carbon atoms. The organic light emitting diode of claim 5, wherein the organic compound layer is selected from the group consisting of a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer.

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