KR100950261B1 - Blue luminescent organic compound containing fluorene and silicon groups, and organic light-emitting diode including the same - Google Patents

Abstract

Disclosed are an organic compound including a fluorene group and a silicon group, which emit high efficiency blue light with high efficiency and high thermal stability, and an organic light emitting diode including the same. The blue light emitting organic compound including the fluorene group and the silicon group has a structure of the following formula.

Here, R ₁ and R ₂ are each independently a substituted or unsubstituted aryl or heteroaryl group having 4 to 24 carbon atoms, A each independently represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, R ₃ to R ₅ are each independently a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, an aryl group having 4 to 24 carbon atoms, a heteroaryl group, or a heterocyclic group.

Fluorene, Silicon, Blue Light, Organic Light Emitting Diode, Heat Resistance

Description

Blue luminescent organic compound containing fluorene and silicon groups, and organic light-emitting diode including the same}

The present invention relates to a blue light emitting organic compound including a fluorene group and a silicon group, and an organic light emitting diode including the same. More specifically, the high-efficiency and high-quality blue light emission, and includes a fluorene group and a silicon group excellent in thermal stability An organic compound and an organic light emitting diode comprising the same.

Organic Light-Emitting Diodes (OLEDs), commonly referred to as ELs (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 backlight for emitting light, and it is possible to manufacture devices in the form of thin films and bends, and to form patterns and mass production easily by film manufacturing technology. There is a point. In addition, since EL is a spontaneous light emitting diode, it has excellent luminance and viewing angle characteristics, fast response speed, low driving voltage, and theoretically, it is possible to emit light 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 generated at each electrode. And when the electrons combine in the organic light emitting layer, the organic light emitting layer generates light. As a blue light emitting material of such an organic light emitting diode, a styrylbenzene compound is known. For example, US Pat. No. 6,743,948 discloses a blue light emitting monomolecular compound into which a styrylbenzene derivative is introduced. However, since styrylbenzene derivatives are difficult to form a uniform amorphous thin film, to solve this problem, a large number of substituents should be introduced, and the styrylbenzene derivatives with substituents generally have insufficient disadvantages in luminescence efficiency and heat resistance. have. Therefore, the synthesis | combination of the new blue light emitting material excellent in film-forming workability, the light emission wavelength range is comparatively narrow, excellent luminous efficiency, and heat resistance is calculated | required.

Accordingly, an object of the present invention is to provide an organic compound including a fluorene group and a silicon group that emits blue light with high efficiency and high quality, and an organic light emitting diode including the same. Another object of the present invention is to provide a blue light emitting organic compound including a fluorene group and a silicon group having excellent thermal stability and film forming processability, and an organic light emitting diode including the same.

In order to achieve the above object, the present invention provides an organic compound containing a fluorene group and a silicon group 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 an organic compound comprising the fluorene group and the silicon group, the at least one being positioned between the first and second electrodes. An organic light emitting diode including one organic compound layer is provided.

[Formula 1]

Here, R ₁ and R ₂ are each independently a substituted or unsubstituted aryl or heteroaryl group having 4 to 24 carbon atoms, A each independently represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, R ₃ to R ₅ are each independently a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, an aryl group having 4 to 24 carbon atoms, a heteroaryl group, or a heterocyclic group.

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

The organic compound including the fluorene group and the silicon group according to the present invention is a compound that emits blue light by receiving energy generated by recombination of electron-holes, and has a structure represented by the following Chemical Formula 1.

In Formula 1, R ₁ and R ₂ are each independently a substituted or unsubstituted aryl or heteroaryl group having 4 to 24 carbon atoms, preferably 6 to 24 carbon atoms, and A is each independently substituted or An unsubstituted alkyl group having 1 to 5 carbon atoms, R ₃ to R ₅ are each independently a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, an aryl group having 4 to 24 carbon atoms, preferably 6 to 24 carbon atoms, Heteroaryl group or heterocyclic group.

,

,

,

,

, 카바졸(carbazole)기, 플루오렌(fluorene)기 등을 예시할 수 있다. 상기 A의 구체적인 예로는,

,

,

,

,

,

,

등을 예시할 수 있다. 상기 R₃ 내지 R₅의 구체적인 예로는

,

,

,

,

,

등을 예시할 수 있다. (*는 결합부위를 나타낸다)Specific examples of the R ₁ and R ₂ ,

,

,

,

,

, A carbazole group, a fluorene group and the like can be exemplified. Specific examples of the A,

,

,

,

,

,

,

Etc. can be illustrated. Specific examples of the R ₃ to R ₅

,

,

,

,

,

Etc. can be illustrated. (* Indicates a binding site)

In the blue light emitting organic compound including the fluorene group and the silicon group according to the present invention, the emission wavelength and the charge / hole injection / transport characteristics change according to the substituents substituted in the basic skeleton of the compound represented by Formula 1, By selecting suitably, the organic compound which has physical properties, such as desired emission wavelength and a charge transfer characteristic, can be obtained. In particular, the blue light emitting organic compound including the fluorene group and the silicon group according to the present invention is excellent in heat resistance and not only improves the lifespan and productivity of the light emitting diode, but also emits blue light with high efficiency and high quality, and is also used as a hole injection and transport material. useful. The organic compound containing the fluorene group and the silicon group according to the present invention can be prepared by a known organic synthesis method, for example, as shown in the following examples, after introducing an amine group and a styrene group to the fluorene derivative, It can manufacture by introducing a silicone group.

1 illustrates a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention. As shown in FIG. 1, the organic light emitting diode includes a first electrode 12 having a high work function on the substrate 10. It is formed as a hole injection electrode (anode), and the light emitting layer 14 including the organic light emitting compound according to the present invention is formed on the first electrode 12. The organic light emitting compound according to the present invention may be used as a host or a dopant of the light emitting layer 14, and the light emitting layer 14 may include a conventional Alq ₃ or the like, together with the organic light emitting compound according to the present invention. It may further comprise an organic luminescent compound, conventional fluorescent dyes and / or dopants. 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 diode 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), and the like, and the second electrode 16 may be made of Al, Mg, Ca, or LiAl, Mg-Ag. It may be made of a metal alloy such as.

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 to transport, without limitation, keys Quinoline derivatives, in particular, the conventional compounds such as tris (8-kinol Reno rate) aluminum (alumina quinone, Alq ₃₎ may be used to form the electron transport layer 26 These layers 21, 22, 25, and 26 function to augment, confine, and combine the holes and electrons injected into the light emitting layer 14. The light emitting layer 14, the hole injection and transport layer The thicknesses of the 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 blue light emitting organic compound including the fluorene group and the silicon group according to the present invention may be formed by the hole injection and transport layers 21 and 22 and / or the electron injection and transport layers 25 and 26 according to an energy relationship with the light emitting layer 14. ) May be used to inject / transport electrons and holes, and may be preferably used as the hole injection layer 21 and / or the hole transport layer 22. 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 light emitting diode. 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. 1 or 2 but also to organic electroluminescent devices and various semiconductor devices having various structures that exhibit light emission by hole-electron coupling. The structure of such various organic light emitting diodes is disclosed, for example, in US Pat. Nos. 4,539,507, 5,151,629, and the like.

The organic compound containing the fluorene group and the silicon group according to the present invention is a novel blue light emitting material, which emits blue light with high efficiency and high quality, and is particularly useful in the manufacture of organic electroluminescent devices because of excellent thermal stability and film forming processability. . The organic compound containing the fluorene group and the silicon group according to the present invention may be a field effect transistor, a photodiode, a photovoltaic cell, a solar cell, an organic laser, a laser diode. It can also be widely used in the manufacture of various semiconductor devices such as).

Next, a preferred embodiment for aiding the understanding of the present invention is presented. 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.

Example 1 Fluorene Group Synthesis of Blue Light Emitting Organic Compound Containing Silicon Group

end. Synthesis of 2,7 -Dibromo- 9,9-dimethyl-9H- fluorene

As shown in Scheme 1 below, 25 g (77.1 mmol) of 2,7-dibromo fluorene was added thereto, and 250 ml of dimethyl sulfoxide (DMSO) was added thereto, followed by potassium hydroxide (KOH) 21.6. g (386.5 mmol) and 1.28 g (7.71 mmol) of potassium iodide (KI) were added thereto, followed by stirring for 30 minutes. 10.6ml (169.6mmol) of methyl iodide (CH ₃ I) was added at 10 ° C, stirred for 30 minutes, raised to room temperature, and stirred for 12 hours. The reaction is terminated with water and the resulting solid is filtered off, then the filtered solid is extracted with excess water and methylene chloride (MC). After the solvent was removed, methanol was added to form a solid, which was then filtered to give 2,7-dibromo-9,9-dimethyl-9H-fluorene (2,7-Dibromo-9,9-dimethyl-9 H- fluorene) was synthesized in a yield of 83% (22.6 g). The Rf value in the thin-layer chromatography (TLC) experiment using n-hexane (n-Hexane) of the synthesized material was 0.41.

I. Synthesis of 7-bromo-9,9-dimethyl-9H-fluorene-2-carbaldehyde

As shown in Scheme 2 below, 10 g (28.4 mmol) of 2,7-dibromo-9,9-dimethyl-9H-fluorene was charged into tetrahydrofuran (THF) in a flask containing N ₂ gas. After adding 60 ml, 19.5 ml (31.2 mmol) of n -butyllithium ( n- BuLi) was added dropwise at -78 ° C, followed by stirring for 1 hour, and 4.38 ml (56.8 mmol) of dimethylformamide (DMF). After the addition, the mixture was stirred at room temperature for 12 hours. Saturated ammonium chloride (Sat.NH ₄ Cl) was added to terminate the reaction, followed by extraction with methylene chloride and separation and purification by column, 7-bromo-9,9-dimethyl-9H-fluorene-2 -Carbaldehyde (7-Bromo-9,9-dimethyl-9 H -fluorene-2-carbaldehyde) was synthesized in a yield of 62% (4 g). In a thin-layer chromatography (TLC) experiment using n-hexane of the synthesized material, a blue PL spot was identified at the bottom.

All. Synthesis of 7-diphenylamine-9,9-dimethyl-9H-fluorene-2-carbaldehyde

As shown in Scheme 3 below, 7 g (23.2 mmol) of 7-bromo-9,9-dimethyl-9H-fluorene-2-carbaldehyde, 5.89 g (34.8 mmol) of diphenylamine, and cesium carbonate ( 11.3 g (34.8 mmol) of CsCO ₃ ) and 100 ml of toluene are added thereto. 0.13 g (0.58 mmol) of diacetoxy palladium (Pd (OAc) ₂ ) was added to 0.24 g (1.2 mmol) of tri (t-butyl) phosphine (P ( t -Bu) ₃ ), followed by reaction for 15 minutes. Reflux at 120 ° C. overnight. After the reaction, the solvent was removed and purified by a crude column, 7-diphenylamine-9,9-dimethyl-9H-fluorene-2-carbaldehyde (7-Diphenylamine-9,9-dimethyl- 9 H -fluorene-2-carbaldehyde) was synthesized in a yield of 87% (10.8 g). The Rf value in the TLC experiment using n-hexane and ethyl acetate (EtOAc) of the synthesized material at 8: 2 (volume ratio) was 0.49.

la. Synthesis of (4-bromo-benzyl) -phosphonic acid diethyl ester

As shown in Scheme 4, 100 g (400 mmol) of 4-bromo benzyl bromide and 139 ml (800 mmol) of triethylphosphite (P (OEt) ₃ ) were added thereto, and the mixture was stirred at 160 ° C. overnight. Reflux and purification by vacuum distillation yielded (4-bromo-benzyl) -phosphonic acid diethyl ester in 91% (111 g) yield. Synthesized. The Rf value in the TLC experiment using ethyl acetate of the synthesized material was 0.58.

hemp. Synthesis of {7- [2- (4-bromophenyl) -vinyl] -9,9-dimethyl-9H-fluoren-2-yl} -diphenylamine

As shown in Scheme 5 below, 10 g (25.64 mmol) of 7-diphenylamine-9,9-dimethyl-9H-fluorene-2-carbaldehyde, (4-bromo-benzyl) -phosphonic acid diethyl ester 8.67 g (28.24 mmol) and 0.25 ml (1.28 mmol) of 15-crown-5-ether are dissolved in tetrahydrofuran and then 1.13 g (28.24 mmol) of sodium hydride (NaH) at 0 ° C. ) Drop by drop and react overnight at room temperature. After the reaction was terminated with water, the resulting precipitate was filtered (if the precipitate is less likely to be extracted, the organic layer was extracted using methylene chloride), {7- [2- (4-bromophenyl) -vinyl] -9 , 9-dimethyl-9H-fluoren-2-yl} -diphenylamine ({7- [2- (4-Bromophenyl) -vinyl] -9,9-dimethyl-9 H -fluorene-2-yl} -diphenyl-amine) was synthesized in a yield of 38% (5.4 g). The Rf value in the TLC experiment using n-hexane and ethyl acetate of the synthesized material at 9: 1 (volume ratio) was 0.43.

bar. Synthesis of 4,4,5,5-tetramethyl-2- (4-trimethylsilanyl-phenyl)-[1,3,2] dioxaborolane

As shown in Scheme 6, 11 g (48.29 mmol) of (4-bromo-phenyl) -trimethyl silane) and 70 ml of tetrahydrofuran were added to a flask in which nitrogen gas was flowed. . After dropping 36 ml (57.6 mmol) of n-butyllithium at -78 ° C dropwise, the mixture was stirred for 1 hour, then the temperature was raised to room temperature, and 2-isopropoxy-4,4,5,5-tetramethyl- 19.70 ml (96.58 mmol) of 1,3,2-dioxaborolane (2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane) are added dropwise. Stir overnight at room temperature and add 50 ml of cold saturated ammonium chloride (NH ₄ Cl) solution after the reaction. After extraction with ether, the solvent was removed to give 4,4,5,5-tetramethyl-2- (4-trimethylsilanyl-phenyl)-[1,3,2] dioxaborolane (4,4, 5,5-Tetramethyl-2- (4-trimethylsilanyl-phenyl)-[1,3,2] dioxaborolane) was synthesized at a yield of 76% (10.2 g).

four. Synthesis of {9,9-dimethyl-7- [2- (4'-trimethylsilanyl-biphenyl-4-yl) -vinyl] -9H-fluorene-2-yl} -diphenylamine

As shown in Scheme 7 below, 2.88 g (5.3 mmol) of {7- [2- (4-bromophenyl) -vinyl] -9,9-dimethyl-9H-fluoren-2-yl} -diphenylamine And 2.2 g (7.96 mmol) of 4,4,5,5-tetramethyl-2- (4-trimethylsilanyl-phenyl)-[1,3,2] dioxaborolane in 50 ml of tetrahydrofuran, 0.21 g (0.26 mmol) of [1,1'-bis (diphenylphosphino) ferrocene] palladium (II) chloride (Pd (dppf) ₂ Cl ₂ ) and 2.58 g of sodium hydrogencarbonate (NaHCO ₃ ) in 49 ml of water Melted. After refluxing at 100 ° C. overnight, the reaction was terminated with water and the layers separated and the organic layer was purified by crude column, yielding {9,9-dimethyl-7- [2- (4′-trimethylsilanyl-biphenyl- 4-yl) -vinyl] -9H-fluoren-2-yl} -diphenylamine ({9,9-Dimethyl-7- [2- (4'-trimethylsilanyl-biphenyl-4-yl) -vinyl]- 9 H -fluorene-2-yl} -diphenyl-amine) was synthesized in a yield of 84% (2.7 g). In the TLC experiment using n-hexane and ethyl acetate of the synthesized material at 9: 1 (volume ratio), the Rf value was 0.43 and the m / e + value confirmed by the mass spectrometer was 610. The UV-Visible Spectrophotometer measurement results of the synthesized material are shown in FIG. 3.

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, HI-01 (HIL material made by LG-102: LG Chem.) Was vacuum deposited on the ITO electrode to form a hole injection layer at 600Å thickness, and NPB ((N, N ') was formed on the hole injection layer. -Diphenyl-N, N'-bis (1-naphthyl) -1,1'-biphenyl) -4,4'-diamine)) was vacuum deposited to a thickness of 200 kPa to form a hole transport layer. Blue light emitting organic compound ({9,9-dimethyl-7- [2- (4'-trimethylsilanyl-biphenyl-4-yl) -vinyl containing a fluorene group and a silicon group as a dopant on the hole transport layer ] -9H-fluoren-2-yl} -diphenylamine) and α-ADN (9,10-di-naphthalen-1-yl-anthracene, 9,10-Di-naphthalene-1 as host A mixture containing -yl-anthracene) was deposited to a thickness of 300 mm ₃ , and then Alq ₃ was deposited to 200 mm thickness as an electron transport layer. An electron injection layer was formed by vacuum depositing LiF to a thickness of 10 Å on the electron transport layer. Finally, an organic electroluminescent device was manufactured by depositing Al at a thickness of 1000 에 on the electron injection layer to form a cathode. The organic electroluminescent device is prepared, in the color coordinate was 1000cd / m ² was (0.15, 0.16), efficiency was 4.82cd / A.

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.

Figure 3 is a UV-Visible Spectrophotometer (UV-Visible Spectrophotometer) measurement graph of a blue light emitting organic compound containing a fluorene group and a silicon group according to an embodiment of the present invention.

Claims (4)

An organic compound having a structure represented by Chemical Formula 1 and including a fluorene group and a silicon group which emit blue light under the energy generated by recombination of electron-holes. [Formula 1]

Here, R ₁ and R ₂ are each independently a substituted or unsubstituted aryl or heteroaryl group having 4 to 24 carbon atoms, A each independently represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, R ₃ to R ₅ are each independently a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. The method according to claim 1, wherein R ₁ to R ₂ are simultaneously or independently of each other,

,

,

,

,

, Carbazole groups and fluorene groups. A is simultaneously or independently of each other,

,

,

,

,

,

And

Selected from R ₃ to R ₅ , simultaneously or independently of each other,

And

An organic compound containing a fluorene group and a silicone group selected from (* represents a bonding site). A first electrode having a high work function; A second electrode having a low work function; And At least one having a structure of Formula 1, including an organic compound containing a fluorene group and a silicon group that emits blue light by receiving energy generated by the recombination of electron-holes, and located between the first and second electrodes Organic compound layer, [Formula 1]

(Wherein R ₁ and R ₂ are each independently a substituted or unsubstituted aryl or heteroaryl group having 4 to 24 carbon atoms, and A each independently represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms , R ₃ to R ₅ are each independently a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms). The organic light emitting diode of claim 3, wherein the organic compound layer is selected from the group consisting of a light emitting layer, a hole injection layer, and a hole transport layer.

Images