KR100700432B1 - Blue light-emitting oranic compound and organic light-emitting diode including the same - Google Patents

Abstract

Disclosed are an organic light emitting compound having high efficiency and high quality blue light and excellent thermal stability, 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, R ₁ is an aryl group or heteroaryl group having 4 to 60 carbon atoms, an alkenyl group or dicyano group having 2 to 10 carbon atoms, R ₂ is H, alkyl having 1 to 20 carbon atoms, alkenes, alkynes, or carbon atoms 4 to 24 aryl group, heteroaryl group or heterocyclic group, Ar ₁ to Ar ₈ is hydrogen, alkenyl group, amino group or conjugated ring group, at least one of Ar ₁ to Ar ₈ is an alkenyl group or a conjugated ring group And X is nitrogen or oxygen.

Blue light emission, organic compound, acridine, organic light emitting diode, heat resistance, stability

Description

Blue organic light-emitting compound and organic light-emitting diode comprising the same {Blue light-emitting oranic 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 blue organic light emitting compound and an organic light-emitting diode (OLED) including the same, and more particularly, not only excellent thermal stability, but also useful for forming a hole and an electron injection / transport layer. It relates to a blue organic light emitting compound and an organic light emitting diode comprising the same.

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. Various organic compounds for forming such an organic light emitting layer are known, for example, US Patent No. 6,455,720 discloses a 2,2- (diaryl) vinylphosphine-based light emitting compound In addition, Korean Patent Publication No. 2002-70333 discloses a blue light emitting compound in which a central portion has a diphenylanthracene structure and an aryl group is substituted at the terminal. However, such a conventional blue organic light emitting compound has a disadvantage in that heat resistance is not sufficient, control of the emission color is not easy, or the synthesis process is complicated. In addition, US Pat. Nos. 5,130,603 and 6,251,531 disclose arylene-based and anthracene-based blue light emitting compounds, respectively, but the compounds also have thermal disadvantages, such as heat resistance, which do not have sufficient shortcomings. .

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

Another object of the present invention is to provide an organic light emitting compound useful for the formation of a hole and an electron injection / transport layer and an organic light emitting diode comprising the same.

In order to achieve the above object, the present invention provides an organic light emitting compound having a structure of formula (1). 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 light emitting compound may be used as a host or dopant material of the light emitting layer.

[Formula 1]

In Formula 1, R ₁ is a substituted or unsubstituted aryl group or heteroaryl group having 4 to 60 carbon atoms, a substituted or unsubstituted alkenyl group or dicyano group ((CN) ₂ ) having 2 to 10 carbon atoms, and R ₂ is H, alkyl having 1 to 20 carbon atoms, alkene or alkyne, or substituted or unsubstituted aryl group having 4 to 24 carbon atoms, heteroaryl group or heterocyclic group, Ar ₁ to Ar ₈ may be the same or different from each other And hydrogen, alkenyl group, amino group, or a substituted or unsubstituted conjugated ring group having 4 to 24 carbon atoms, at least one of Ar ₁ to Ar ₈ forms an alkenyl group or conjugated ring group, and X is nitrogen or oxygen.

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 receives an energy generated by recombination of electron-holes and emits blue light, or has an aridone (acridone) derivative having charge injection / transport characteristics such as electrons and holes. Have

In Formula 1, R ₁ is a substituted or unsubstituted aryl group or heteroaryl group having 4 to 60, preferably 6 to 36 carbon atoms, substituted or unsubstituted alkenyl group or dicyno group having 2 to 10 carbon atoms ( (CN) ₂ ), R ₂ is H, alkyl having 1 to 20 carbon atoms, alkene or alkyne, or substituted or unsubstituted aryl group having 4 to 24 carbon atoms, heteroaryl group, or heterocylation Ar ₁ to Ar ₈ may be the same as or different from each other, and hydrogen, a substituted or unsubstituted, for example, an alkenyl group having 2 to 10 carbon atoms, an amino group, or a substituted or unsubstituted conjugated ring having 4 to 24 carbon atoms As a (fused ring) group, at least one of Ar ₁ to Ar ₈ forms an alkenyl group or a fused ring group, and X is nitrogen or oxygen. Here, the substituent is an alkyl group having 1 to 24 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, aryloxy having 1 to 30 carbon atoms, alkyldioxy having 1 to 20 carbon atoms, alkyl or aryl amine group having 1 to 20 carbon atoms, 6 carbon atoms An allyl thioxyl group of 30 to 30, an arylalkyl group of 7 to 30 carbon atoms, a monocyclic group of 5 to 30 carbon atoms, a condensed polycyclic group of 10 to 30 carbon atoms, a heterocyclic group or a heteroaryl group of 5 to 30 carbon atoms, carbon As an alkenyl group or cyano group (CN) of 4-40, it may be substituted or unsubstituted.

Preferred examples of the organic light emitting compound according to the present invention are those having the structure of Formula 2 or 3.

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등을 예시할 수 있다. In Formula 2, R ^* is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, and R ₂ , Ar ₁ to Ar ₈ and a substituent are represented by Formula 1 As defined in Specific examples of the organic light emitting compound represented by Formula 2

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등을 예시할 수 있다.In Formula 3, R ₂ and Ar ₁ to Ar ₈ are as defined in Formula 1, L is a substituted or unsubstituted aryl group, heteroaryl group of 6 to 60, preferably 6 to 36 carbon atoms as a linking group Or a conjugated ring group or a substituted or unsubstituted alkenyl group having 2 to 40 carbon atoms, and may include heteroatoms such as S, O, and N, as necessary, and n is an integer of 2 to 4. Specific examples of the light emitting organic compound represented by Formula 3

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등을 예시할 수 있다.As another example of the organic light emitting compound according to the present invention is an example of a compound wherein R ₁ is a dicyano group ((CN) ₂ )

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In the organic light emitting compound according to the present invention, since the emission wavelength and the electron / hole injection / transport characteristics change according to the type of the substituent or the linkage substituted with the compound represented by the above formula, by appropriately selecting the substituent or the linkage An organic compound layer having physical properties such as a desired emission wavelength and charge transfer characteristics can be formed. The organic light emitting compound according to the present invention has excellent heat resistance and not only improves the lifespan and productivity of the organic light emitting device, but also emits light of high efficiency and high quality. The organic light emitting compound according to the present invention can be prepared by a variety of conventional organic synthesis method, for example, can be prepared by the polycondensation reaction of halogen and boronic acid groups, as shown in the examples.

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. The light emitting layer 14 including the 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 as disclosed in patent 4,356,429, for example m-MTDATA (4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine) The hole transport layer 22 may include NPB (N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1'-biphenyl) -4,4'-diamine) and triphenyl. Diamine derivatives, styrylamine derivatives, α-NPD (N, N'-diphenyl-N, N'-bis (α-naphthyl)-[1,1'-biphenyl] 4,4'-diamine), etc. It can be formed using a conventional amine derivative having an aromatic condensed ring of the electron injection and transport layers 25, 26 to facilitate the injection of electrons from the electron injection electrode 16 and to stabilize the electrons. The electron transporting and transporting compound, which is not limited to the quinoline derivatives, in particular, tris (8-quinolinorate) aluminum (aluminaquinone, Alq3), LiF, etc. 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 hole injection and transport layers 21 and 22 and the electron injection and transport layers 25 and 26 are not particularly limited and vary depending on the formation method, but usually have a thickness of 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 of the structure shown in FIG. 1 or 2, but also to organic electroluminescent devices and various semiconductor devices having various structures exhibiting light emission phenomenon by hole-electron coupling. 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 2- (pyren-1-yl-amino) -benzoic acid (2- (pyren-1-yl-amino) -benzoic acid)

As shown in Scheme 1, 6.52 g (0.030 mol) of 1-aminopyrene and 4.20 g (0.030 mol) of 2-fluorobenzoic acid were added to 70 mL of tetrahydrofuran (THF). After dissolving, 2.71 g (0.118 mol) of lithium amide was added over 5 minutes, followed by stirring for 72 hours at 60 ° C. in a nitrogen atmosphere. After cooling the reaction solution to room temperature, H ₂ O, concentrated hydrochloric acid (HCl) and methyl-t-butoxide (t-BuOMe) were added to quench the reaction, and the organic layer was separated and then several times with water. Wash and remove solvent. The resulting solid product was dissolved in isopropyl alcohol (IPA) at 70 ° C. and then slowly cooled to −10 ° C. to obtain a precipitate which was filtered off and washed again with isopropyl alcohol to give 40% of the title compound. Obtained in the yield.

B. Synthesis of 12H-12-aza-naphtho [2,1,8-kra] naphthasen-7-one (12H-12-aza-naphtho [2,1,8-qra] naphthacen-7-one)

As shown in Scheme 2 below, 0.5 g (1.7 mmol) of 2- (pyren-1-yl-amino) -benzoic acid obtained in step A was dissolved in 1.86 g (12.1 mmol) of phosphorous oxychloride. After stirring for 45 minutes, water was added to quench the reaction. The precipitate in the reaction solution was filtered, washed with dilute NaOH aqueous solution, and recrystallized with 2-methoxyethanol to give the title compound in a yield of 60%.

C. 7- (4-Bromo-benzylidene) -7,12-dihydro-12-aza-naphtho [2,1,8-kra] naphthacene (7- (4-Bromo-benzylidene) -7 Synthesis of, 12-dihydro-12-aza-naphtho [2,1,8-qra] naphthacene)

First, Mg 0.67 g (0.028 mol) was added to 40 mL of diethyl ether (Et ₂ O), and 6.9 g (0.028 mol) of 4-bromobenzylbromide was dissolved in 60 mL of diethyl ether. A small amount was added and then stirred. After confirming that the reaction started, the remaining solution was added dropwise and refluxed for 1 hour. To the obtained solution, 8.5 g (0.018 mol) of 12H-12-aza-naphtho [2,1,8-kra] naphthacene-7-one prepared in step B was dissolved in 50 mL of THF, and added dropwise to reflux overnight. I was. Water and hydrochloric acid (HCl) were added to the reaction solution, and the mixture was refluxed for 3 hours. The organic layer was separated and the solvent was removed to obtain the title compound in a yield of 50%. The overall scheme of the reaction is as shown in Scheme 3 below.

D. 7- (4-boronic acid-benzylidene) -7,12-dihydro-12-aza-naphtho [2,1,8-kra] naphthacene (7- (4-boronic acid-benzylidene)- Synthesis of 7,12-dihydro-12-aza-naphtho [2,1,8-qra] naphthacene)

 As shown in Scheme 4, 7- (4-bromo-benzylidene) -7,12-dihydro-12-aza-naphtho [2,1,8-kras] naphthace 1.13 obtained in step C. g (2.4 mmol) was dissolved in 40 mL of THF, 1.8 mL (2.8 mmol) of n-butyllithium (n-BuLi) was added at -90 ° C, and the mixture was stirred at -90 ° C for 30 minutes. Next, 0.8 ml (7.0 mmol) of trimethyl borate was added dropwise to the reaction solution, stirred again at -90 ° C. for 20 minutes, then an ether / water mixed solvent was added thereto, and the organic layer was immediately separated. It was used for the next reaction. In this process, the yield of the title compound was 50%.

E. Synthesis of Organic Luminescent Compounds

As shown in Scheme 5, 7- (4-bromo-benzylidene) -7,12-dihydro-12-aza-naphtho [2,1,8-kras] naphthace 4.08 obtained in step C. g (8.64 mmol), 4.54 g of 7- (4-boronic acid-benzylidene) -7,12-dihydro-12-aza-naphtho [2,1,8-krasnaphthacene obtained in step D) 10.4 mmol), 0.36 g (0.3 mmol) of Pd (PPh ₃ ) ₄ , and 6.5 ml of 2M Na ₂ CO ₃ were added to a mixed solution of 24 ml of toluene and 4 ml of ethanol, and reacted at 90 ° C. for 8 hours. The resulting solid was filtered and washed with methylene chloride to give the target compound in 75% yield.

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 kHz as a host, and then Alq3 was deposited to a thickness of 200 Å as the electron transport layer. An electron injection layer was formed by vacuum depositing LiF to a thickness of 10 μm on the electron transport layer, and then an Al was deposited to a thickness of 1200 μm on the electron injection layer to form a cathode, thereby manufacturing an organic light emitting diode. The light emitting color coordinates of the manufactured organic light emitting diodes were (0.17, 0.23), and the luminous efficiency was 1.15 cd / A at 10 mA / cm ^2. The organic light emitting diodes produced high quality blue light and exhibited excellent luminous efficiency.

 As described above, the organic light emitting compound according to the present invention is not only excellent in heat resistance, thermal stability, film forming processability and luminous efficiency, but also has an advantage of showing high quality and blue light emission of various wavelengths depending on substituents. 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 (5)

An organic light emitting compound having the structure of Formula 1. [Formula 1]

In Formula 1, R ₁ is a substituted or unsubstituted aryl group or heteroaryl group having 4 to 60 carbon atoms, a substituted or unsubstituted alkenyl group or dicyano group ((CN) ₂ ) having 2 to 10 carbon atoms, and R ₂ is H, alkyl having 1 to 20 carbon atoms, alkene or alkyne, or substituted or unsubstituted aryl group having 4 to 24 carbon atoms, heteroaryl group or heterocyclic group, Ar ₁ to Ar ₈ may be the same or different from each other Hydrogen, alkenyl group, amino group, or a substituted or unsubstituted conjugated ring group having 4 to 24 carbon atoms, at least one of Ar ₁ to Ar ₈ forms an alkenyl group or conjugated ring group, X is nitrogen or oxygen, When X is oxygen, R ₂ is absent. The organic light emitting compound of claim 1, wherein the organic compound has a structure of Formula 2 below. [Formula 2]

In Formula 2, R ^* is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, and R ₂ and Ar ₁ to Ar ₈ are defined in Formula 1 As shown. An organic light emitting compound having a structure of Formula 3 below. [Formula 3]

In Formula 3, L is a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a heteroaryl group or a conjugated ring group, or a substituted or unsubstituted alkenyl group having 2 to 40 carbon atoms, R ₂ is H, Alkyl, alkene or alkyne having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group, heteroaryl group or heterocyclic group having 4 to 24 carbon atoms, Ar ₁ to Ar ₈ may be the same or different from each other, hydrogen, An alkenyl group, an amino group, or a substituted or unsubstituted conjugated ring group having 4 to 24 carbon atoms, at least one of Ar ₁ to Ar ₈ forms an alkenyl group or a conjugated ring group, X is nitrogen or oxygen, and X is oxygen If, R ₂ is not present, n is an integer of 2 to 4. 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 Formula 1 and comprising at least one organic compound layer positioned between the first and second electrodes. [Formula 1]

In Formula 1, R ₁ is a substituted or unsubstituted aryl group or heteroaryl group having 4 to 60 carbon atoms, a substituted or unsubstituted alkenyl group or dicyano group ((CN) ₂ ) having 2 to 10 carbon atoms, and R ₂ is H, alkyl having 1 to 20 carbon atoms, alkene or alkyne, or substituted or unsubstituted aryl group having 4 to 24 carbon atoms, heteroaryl group or heterocyclic group, Ar ₁ to Ar ₈ may be the same or different from each other Hydrogen, alkenyl group, amino group, or a substituted or unsubstituted conjugated ring group having 4 to 24 carbon atoms, at least one of Ar ₁ to Ar ₈ forms an alkenyl group or conjugated ring group, X is nitrogen or oxygen, When X is oxygen, R ₂ is absent. The organic light emitting diode of claim 4, 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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