[DESCRIPTION]

[invention Title]

AROMATIC AMINE DERIVATIVES AND ORGANIC LIGHT EMITTING LAYER AND DIODE COMPRISING THE SAME [Technical Field]

The present invention relates to aromatic amine derivatives that can significantly improve material lifetime and luminous efficiency by introducing substituted or unsubstituted, saturated or unsaturated, hexagonal or more polygonal hydrocarbon rings into positions 2, 3, 6 and 7 of anthracene to thereby preventing the crystallization of anthracene, and an organic light emitting layer/diode comprising the same. [Background Art] An organic electroluminescence (hereinafter, referred to as "EL") device is a self-emitting device, and herein, when voltage is applied, a fluorescent material emits light by recombination energy of a hole injected from an anode, and an electron injected from a cathode. It is known that the device structure of an organic EL device includes a two-layered type having a hole transport (injection) layer and an electron transport/light emitting layer, or a three-layered type having a hole transport (injection) layer, a light emitting layer, and an electron transport (injection) layer, etc. In the field of a device including such a layered structure, research on a device structure for improving the recombination efficiency of an injected hole and an injected electron, and a method of manufacturing the same has been performed. Such a layered structure has an advantage in that it is possible to improve the efficiency of injecting a hole to a light emitting layer, to improve the efficiency of generating an exciton (which is generated through recombination) by blocking an electron

injected from a cathode, to keep the generated exciton within a light emitting layer, etc.

Since a low-voltage driven organic EL device using a layered device based on vacuum deposition was reported by CW. Tang, et al. of the Eastman Kodak Company in 1987, research on an organic EL device using an organic material as a constituent material has been actively performed. Tang et al. used tris(8- hydroxyquinolinol aluminum) for a light emitting layer, and triphenyldiamine derivative for a hole transport layer. Compounds that have been developed as the green light emitting material of an OLED up to now include tris(8- quinolinolato) aluminum, cumarin derivatives, quinacridone derivatives, anthracene derivatives, and others, and Korean Laid-open Patent No. 10-2006-0006803, Korean Laid-open Patent No. 2002-0062940, and Japanese Laid-open Patent No. 2001-207167 of the Idemistu Kosan Co. belong to the relevant prior art.

Typical anthracene-based green light emitting materials (dopants) disclosed in these patent laid-open gazettes are compounds represented by the fo Llowing formulas 1 to 3, characterized in that substituenbs are introduced into positions 2 and 6 of a conventional anthracene core: Tormula 1]

[Formula 3]

However, since anthracene-based aromatic amine derivative compounds disclosed in the prior art, including the above compounds, fail to solve the crystallization problem of anthracene, they still leave much to be improved in terms of material lifetime and luminous efficiency. In particular, there is a need for a way to improve insufficient luminance and durability caused by deterioration after long-term use. [Disclosure] [Technical Problem]

Therefore, the present invention has been made in view of the above-mentioned problems, and the present invention provides aromatic amine derivatives that can significantly improve material lifetime and luminous efficiency by introducing substituted or unsubstituted, saturated or unsaturated, hexagonal or more polygonal hydrocarbon rings into positions 2, 3, β and 7 of anthracene to thereby preventing the crystallization of anthracene, and an organic light emitting layer and an organic light emitting diode comprising the same.

[Technical Solution]

In accordance with an aspect of the present invention, there are provided aromatic amine derivatives represented by the following Formulas 4, 5 and 6, characterized in that substituted or unsubstituted, saturated or unsaturated, hexagonal or more polygonal hydrocarbon rings are introduced into positions 2, 3, 6 and 7 of anthracene:

[Formula 4]

[ Formula 5 ]

In Formulas 4 to 6, Ri to R ₅ are the same or different, and are each independently selected from the group consisting of hydrogen, a substituted or unsubstituted Ci-C ₃₀ alkyl group, a substituted or unsubstituted Ci-C ₃₀ alkenyl group, a substituted

or unsubstituted C ₅ -C ₃₀ aryl group, a substituted or unsubstituted C ₅ -C ₃₀ arylalkyl group, a substituted or unsubstituted C ₅ -C ₃₀ aryloxy group, a substituted or unsubstituted C ₅ -C ₃₀ heteroaryl group, a substituted or unsubstituted C ₅ -Ci ₀ cycloalkyl group, a substituted or unsubstituted C ₅ -Ci _O heterocycloalkyi group ),, or may each independently form a condensed ring group between adjacent substituents; R represents a substituted or unsubstituted, saturated or unsaturated, hexagonal or more polygonal hydrocarbon ring; and Ari and Ar ₂ are the same or different, and are each independently an aromatic ring group selected from the group consisting of benzene, naphthalene, biphenyl, anthracene, and triphenylamine.

In the present invention, typical examples of the substituted or unsubstituted Ci-C ₃₀ al kyl group include, but are limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, etc. In the present invention, typical examples of the substituted or unsubstituted Ci-C ₃₀ alkenyl group include, but are not limited to, a vinyl group, an acetyl group, a butadiene group, an isoprene group, etc.

In the present invention, typical examples of the substituted or unsubstituted C ₅ -C ₃₀ aryl group include, but are not limited to, a phenyl group, a 2-methylphenyl group, a 3- methylphenyl group, a 4-methylphenyl group, a 4-ethylphenyl group, a biphenyl group, a 4-methylbiphenyl group, a 4- ethylbiphenyl group, a 4-cyclohexylbiphenyl group, a terphenyl group, a 3, 5-dichlorophenyl group, a naphthyl group, a 5- methylnaphthyl group, an anthryl group, a pyrenyl group, etc.

In the present invention, typical examples of the substituted or unsubstituted C ₅ -C ₃₀ arylalkyl group include, but

are not limited to, a benzyl group, an α-methylbenzyl group, an α-ethylbenzyl group, an α,α-dimethyl benzyl group, a 4- methylbenzyl group, a 4-ethylbenzyl group, a 2-tert- buthylbenzyl group, a 4-n-octylbenzyl group, a naphthylmethyl group, a diphenylmethyl group, etc.

In the present invention, typical examples of the substituted or unsubstituted Cs-C _3O aryloxy group include, but are not limited to, a phenoxyl group, a naphthyloxyl group, an anthryloxyl group, a pyrenyloxyl group, a fluorantenyloxyl group, a chrysenyloxyl group, a perylenyloxyl group, etc.

In the present invention, typical examples of the substituted or unsubstituted C ₅ -C ₃₀ heteroaryl group include, but are not limited to, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, etc. In the present invention, typical examples of the substituted or unsubstituted C ₅ -Ci _O cycloalkyl group include, but are not limited to, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornenyl group, an adamantyl group, etc. In the present invention, typical examples of the substituted or unsubstituted C ₅ -Ci _O heterocycloalkyl group include, but are not limited to, a pyridyl group, a tiethyl group, a furyl group, a quinolyl group, a carbazolyl group, etc. The R may also be substituted by a hexagonal or more polygonal hydrocarbon ring, the carbon-to-carbon bond of which may consist only of a single bond, include an unsaturated bond, such as a double bond, and be conjugated with an adjacent π- bond of anthracene. The Ari and Ar ₂ are the same or different, and are each independently an aromatic ring. Typical examples thereof include, but are not limited to, benzene, naphthalene, biphenyl, anthracene, triphenylamine, etc.

In the present invention, typical examples of the substituted functional group include, but are not limited to, a halogen atom, such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; an alkyl group, such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group; an alkoxyl group, such as a methoxyl group and an ethoxyl group; an aryloxy group, such as a phenoxyl group; an arylalkyl group, such as a benzyl group, a phenethyl group, and a phenylpropyl group; a nitro group; a cyano group; a substituted amino group, such as a dimethylamino group, a dibenzylamino group, a diphenylamino group, and a porpholino group; an aryl group, such as a phenyl group, a tolyl group, a biphenyl group, a naphthyl group, an anthryl group, and a pyrenyl group; a heterocyclic group, such as a pyridyl group, a tiethyl group, a furyl group, a quinolyl group, and a carbazolyl group; and so forth.

According to a preferred embodiment, the present invention relates to an aromatic amine derivative selected from the group consisting of compounds represented by the following Formulas 7 to 15: [Formula 7]

[Formula 8;

[Formula 10]

[Formula 11]

[Formula 12]

In accordance with another aspect of the present invention, there is an organic light emitting layer comprising the aromatic amine derivative according to the present invention. In accordance with yet another aspect of the present

invention, there is an organic light emitting diode comprising the aromatic amine derivative according to the present invention.

In Examples to be described below, synthesis and experimental examples of the aromatic amine compounds represented by Formulas 7 and 8 are presented merely, but it is apparent to those skilled in the art that not only the inventive aromatic amine compounds other than those represented by Formulas 7 and 8 can be easily prepared, but also devices comprising such compounds can be fabricated, based on the following description of Examples of the present invention and basic knowledge in the art.

In addition, the gist of the present invention is to prevent the crystallization of anthracene from being caused by the planar stereo structure of anthracene, and thus improve device lifetime and luminous efficiency by using the compounds represented by Formulas 4 to 6, characterized in that substituted or unsubstituted, saturated or unsaturated, hexagonal or more polygonal hydrocarbon rings are formed in carbon positions 2, 3, 6 and 7 of anthracene.

Accordingly, although experimental examples regarding device lifetime and luminous efficiency are not presented for all the inventive compounds in Examples of the present invention, in view of results of the following experimental examples, it is apparent to the those skilled in the art that device lifetime and luminous efficiency may be improved over conventional light emitting materials, so long as they use the compounds represented by Formulas 4 to 6, characterized in that substituted or unsubstituted, saturated or unsaturated, hexagonal or more polygonal hydrocarbon rings are introduced into carbon positions 2, 3, 6 and 7 of anthracene. [Description of Drawings]

FIG. 1 is a graphical view illustrating a result of

measuring the UV absorbance of an aromatic amine derivative compound according to an exemplary embodiment of the present invention; and

FIG. 2 is a graphical view illustrating a result of measuring the UV absorbance of an aromatic amine derivative compound according to another exemplary embodiment of the present invention. [Best Mode]

Reference will now be made in detail to exemplary embodiments of the present invention. However, the following examples are illustrative merely, and the scope of the present invention is not limited thereto.

Preparation Example 1-1: Preparation of 4-t-butyl-N- (4- isopropylphenyl ) benzenamine As represented below in Reaction Scheme 1, 25g of 3-t- butylaniline (0.125mol) and 37.3g of 3-bromoisopropylbenzene

(0.25mol) were dissolved in 25OmL of toluene, and 3.43g of

Pd ₂ (dba) ₃ (0.0037mol) was added thereto under a nitrogen atmosphere. Then, 14.4g of NaOBu ^fc (0.15mol) and 1.157g of (t- Bu) ₃ P (0.0075mol) were added to the reaction solvent, and the reaction mixture was refluxed and stirred for 12 hours. The reaction mixture was checked for the completion of the reaction by means of TLC, and if the reaction was completed, the reaction product was cooled down to room temperature. The reacted solution was poured onto a thin silica pad to perform short chromatography, and then was washed with methylene chloride (MC) . The washed solution was subjected to distillation under reduced pressure to thereby remove the solvent, and was chromatographed using n-hexane to thereby obtain a desired white solid product (29.4g, 88%). [Reaction Scheme 1]

Preparation Example 1-2 : Preparation of l,l,4,4,8,8,ll,ll-octamethyl-l,2,3,4,8,9,10,ll- octahydropentacene

As represented below in Reaction Scheme 2, 7.Og of 9,10- dibromoanthracene (0.02mol) and 9.53g of 2, 5-dichloro-2, 5- dimethylhexane (0.052mol) were dissolved in 15OmL of MC, and then temperature was reduced down to 0 ^° C. 13.3g of aluminum chloride (O.lmol) was slowly added little by little to the reaction solution while the reaction solution was maintained at a temperature of 0 ^° C, and then the reaction mixture was stirred for 8 hours. The reaction mixture was poured onto 80OmL of water, stirred for 30 minutes, extracted with MC, dewatered with MgSO ₄ , and then filtered. The filtered solution was subjected to distillation under reduced pressure, and then was chromatographed with n-hexane to thereby obtain a dark yellow solid (5.3g, 67%) .

[Reaction Scheme 2]

Preparation Example 1-3: Preparation of 6, 13-dibromo- l,l,4,4,8,8,ll,ll-octamethyl~l,2,3,4,8,9,10,ll- octahydropentacene

As represented below in Reaction Scheme 3, 1.3g of l,l,4,4,8,8,ll,ll-octamethyl-l,2,3,4,8,9,10,ll-

octahydropentacene (3.26mmol) prepared in Preparation Example 1-2 and tetrabromocarbon were dissolved in 3OmL of carbon tetrachloride, and then temperature was reduced down to 0 ^° C. 0.57g of bromine (6.52mL) was slowly added to the reaction solution while temperature is maintained at 0 ^° C, temperature was slowly elevated to room temperature again, and then the reaction mixture was stirred for 2 hours. After the reaction was over, a saturated sodium thiosulfate solution was added to the reaction product, and then the reaction product was stirred for 30 minutes. The resultant product was extracted with MC, dewatered with MgSO ₄ , and then filtered. The filtered solution was subjected to distillation under reduced pressure to thereby obtain a solid, and the obtained solid was washed with n-hexane to finally obtain a bright yellow solid (l.βg, 2.96mol). [Reaction Scheme 3]

Example 1: Preparation of Compound Dl According to the Invention

As represented below in Reaction Scheme 4, 8.7g of 6,13- dibromo-1, 1, 4, 4, 8, 8, 11, 11-octamethyl-l, 2, 3,4,8,9, 10, 11- octahydropentacene (0.0157mol) prepared in Preparation Example 1-3 and 9.23g of 4-t-butyl-N- (4-isopropylphenyl) benzenamine (0.0345mol) prepared in Preparation Example 1-1 were dissolved in 25OmL of toluene, and then 0.43g of Pd ₂ (dba)3 (0.471mmol) was added thereto under a nitrogen atmosphere. 3.3g of NaOBu ^t (0.0345mol) and 0.19g of (t-bu) ₃ P (0.94mmol) were added to the reaction solvent, and then the reaction mixture was refluxed and stirred for 12 hours. The reaction mixture was checked for the completion of the reaction by means of TLC, and if the

reaction was completed, the reaction product was cooled down to room temperature. The reacted solution was poured onto a thin silica pad to perform short chromatography, and then was washed with MC several times. All solids existing on the silica pad were put into a flask, 50OmL of tetrahydrofurane (THF) was added thereto, and then the resultant solution was heated and stirred. After the solution was stirred for about 1 hour, it was subjected to hot filtration. The filtered solution was subjected to distillation under reduced pressure to thereby obtain a solid, and then the obtained solid was washed with n- hexane and was filtered to finally obtain an orange-colored solid (8.5g, 58.5%) .

¹ H NMR: 1.20 (d 4H), 1.33 (s 9H), 1.55 (s 12H), 5.98(s 4H), 6.38(d 4H), 7.01 (m 4H), 7.6 (s 4H). In a state where Compound Dl was dissolved in THF, the UV absorbance thereof was measured. As a result of the UV absorbance measurement, a maximum absorption wavelength of 474nm and a maximum emission wavelength of 536nm were confirmed (FIG. 1), and a HOMO energy level of 5.3IeV and a LUMO energy level of 2.95eV were also confirmed. [Reaction Scheme 4]

Preparation Example 2-1: Preparation of 4-bromo-N- (4-t- butylphenyl ) -N- ( 4-isopropylphenyl ) benzenamine

As represented below in Reaction Scheme 5, 9.23g of 4-t- butyl-N- (4-isopropylphenyl) benzenamine (0.0345mol) prepared in Preparation Example 1-1 and 8.1g of dibromobenzene (0.0345mol) were dissolved in 25OmL of toluene, and 0.43g of Pd ₂ (dba) ₃

(0.471mmol) was added thereto under a nitrogen atmosphere. Then, 3.3g of NaOBu* (0.0345mol) and 0.19g of (t-bu) ₃ P

(0.94mmol) were added to the reaction solvent, and the reaction mixture was refluxed and stirred for 12 hours. The reaction mixture was checked for the completion of the reaction by means of TLC, and if the reaction was completed, the reaction product was cooled down to room temperature. The reacted solution was poured onto a thin Celite pad to perform short chromatography, and then was washed with MC several times. The washed solution was chromatographed using n-hexane to thereby obtain a white solid compound (1Og, 70.4%). [Reaction Scheme 5]

Preparation Example 2-2: Preparation of 4-bromo-N- (4-t- bytylphenyl ) -N- (4-isopropylphenyl ) phenylboronic acid

As represented below in Reaction Scheme 6, Ig of 4-bromo- N- (4-t-butylphenyl) -N- (4-isopropylphenyl) benzenamine (0.0023βmol) prepared in Preparation Example 2-1 was dissolved in 25OmL of THF. 0.15g of n-butyllithium (0.0028mol) was slowly added thereto at -78 ^° C, and then the reaction mixture was stirred for 1 hour. Then, 0.16g of methylborate (0.0028mol) was slowly added thereto, and then the reaction mixture was stirred for 2 hour. After the reaction was over, water was added to the reacted solution, and then the reacted solution was extracted

with MC. The reacted solution was dewatered with MgSO ₄ , and then was filtered. The filtered solution was subjected to distillation under reduced pressure to thereby obtain a solid, and the obtained solid was washed with n-hexane to finally obtain a white solid (0.7g, 82.4%). [Reaction Scheme 6]

Preparation Example 2-3: Preparation of 4- (13-bromo- l,l,4,4,,8,8,ll,ll-octamethyl-l,2,3,4,8,9,10,ll- octahydropentacene-6-yl) -N- (4-t-bytylphenyl) -N- (4- isopropylphenyl ) benzylamine

As represented below in Reaction Scheme 7, 8.7g of 6,13- dibromo-1, 1, 4, 4, 8, 8, 11, 11-octamethyl-l, 2, 3,4,8,9, 10, 11- octahydropentacene (0.0157moL) prepared in Preparation Example 1-3 and 13.3g of 4-bromo-N- (4-t-bytylphenyl) -N- (4- isopropylphenyl)phenylboronic acid (0.034mol) prepared in Preparation Example 2-2 were dissolved in 5OmL of toluene, and then 25mL of a 2M sodium carbonate solution was added thereto. 0.36g of tetrakis (triphenylphosphine) palladium (0.3mmol) was added the reaction mixture, and then the reaction mixture was refluxed and stirred for 12 hours. After the reaction was over, the reacted solution was filtered on a Celite pad. The filtered solution was washed with distilled water, and was extracted with MC. A yellow solid was obtained through chromatography (1Og, 74.2%).

[Reaction Scheme 7]

Example 2 : Preparation of Compound D2 According to the Invention

8g of 4-(13-bromo-l, 1,4,4, , 8, 8, 11, 11-octamethyl- 1,2,3,4,8,9, 10, ll-octahydropentacene-6-yl) -N- (4-t-bytylphenyl) - N- (4-isopropylphenyl) benzylamine (0.0097mol) prepared in Preparation Example 2-3 and 2.59g of 4-t-butyl-N- (4- isopropylphenyl)benzenamine (0.0097mol) prepared in Preparation Example 1-1 were dissolved in 250ml, of toluene. And then O.lβg of Pd ₂ (dba) ₃ (0.24mmol) was added thereto under a nitrogen atmosphere. 1.8g of NaOBu* ¹ (0.0103mol) and 0.19g of (t-bu) ₃ P (0.48mmol) were added to the reaction solvent, and then the reaction mixture was refluxed and stirred for 12 hours. The reaction mixture was checked for the completion of the reaction by means of TLC, and if the reaction was completed, the reaction product was cooled down to room temperature. The reacted solution was poured onto a thin silica pad to perform short chromatography, and then was washed with MC several times. All solids existing on the silica pad were put into a flask, 50OmL of tetrahydrofurane (THF) was added thereto, and then the resultant solution was heated and stirred. After the solution was stirred for about 1 hour, it was subjected to hot filtration. The filtered solution was subjected to distillation under reduced pressure to thereby obtain a solid, and then the obtained solid was washed with n-hexane and was filtered to finally obtain a dark orange-colored solid (8.5g, 58.5%).

¹ H NMR: 1.20 (d 4H), 1.33 (s 9H), 1.55 (s 12H), 5.98(s

4H), 6.38(d 4H), β.52(d 2H), 7.01 (m 4H), 7.4β(d 2H), 7.6 (s 4H) .

In a state where Compound D2 was dissolved in THF, the UV absorbance thereof was measured. As a result of the UV absorbance measurement, a maximum absorption wavelength of 424nm and a maximum emission wavelength of 527nm were confirmed (FIG. 2), and a HOMO energy level of 5.32eV and a LUMO energy level of 2.66eV were also confirmed.

[Reaction Scheme 8]

mol%), 12h

Comparative Example 1: Preparation of Compound According to Korean Laid-open Patent No. 10-2006-0006803

A compound represented by the following Formula 16 was prepared according to a method disclosed in Korean Laid-open Patent No. 10-2006-0006803: [Formula 16]

Example 3: Fabrication of Organic LE Device According to the Invention Using Compound Dl prepared in Example 1 and Compound D2

prepared in Example 2, an organic LE device was fabricated as specified below in Tables 1 and 2. Here, DS-205 according to Korean patent Application No. 2005-38221 of the present applicant was used as the material of an HIL (Hole Injecting Layer) , and a compound represented by the following Formula 17 or 18 was used as the host material. [Table l]

[Table 2]

[Formula 17]

[Formula 18]

Comparative Example 2: Fabrication of Organic LE Device According to Korean Laid-open Patent No. 10-2006-0006803

An organic LE device was fabricated using the compound represented by Formula 16, which had been obtained in Comparative Example 1.

Experimental Example 1: Evaluation of Characteristics of Organic LE Device According to the Invention

The characteristics oi the organic LE device fabricated in Example 3 were evaluated to obtain the following results shown in Tables 3 to 6: [Table 3]

[Table 4]

characteristics of device fabricated using Dl and TH2 lifetime: half lifetime is 3200 hours at initial luminance of

5000cd/m ²

[Table 5]

[Table β]

Comparative Experimental Example 1: Evaluation of Characteristics of Organic LE Device According to Korean Laid- open Patent No. 10-2006-0006803

The characteristics of the organic LE device fabricated in Comparative Example 2 were evaluated to obtain the following results shown in Table 7: [Table 7]

[industrial Applicability]

As can be seen from the foregoing, it can be noted that the device fabricated using the compound according to the present invention can be driven at a lower voltage than that of the device fabricated in Comparative Example 2 by using the compound prepared in Comparative Example 1, and are excellent in luminous efficiency and device lifetime over the device of Comparative Example 2.

The present invention can prevent the crystallization of a conventional light emitting material, and thus improve its stability, lifetime and luminous efficiency by using aromatic amine derivatives represented by Formulas 4 to 6, where substituted or unsubstituted, saturated or unsaturated, hexagonal or more polygonal hydrocarbon rings are introduced into positions 2, 3, 6 and 7 of anthracene. Ultimately, the compound according to the present invention can significantly contribute to an improvement in the EL performance of an organic LE device, and particularly can maximize the performance of a full-color organic EL panel through an improvement in the performance of a green fluorescence emitting material.