KR101984188B1 - Blue phosphorescent compound and Organic electroluminescent device using the same - Google Patents

Abstract

위와 같은 청색 인광 화합물은 전력효율 및 색감 모두에서 우수한 특성을 갖는다.The present invention provides a blue phosphorescent compound represented by the following formula.

The above-mentioned blue phosphorescent compound has excellent characteristics in both power efficiency and color.

Description

TECHNICAL FIELD The present invention relates to a blue phosphorescent compound and an organic electroluminescent device using the blue phosphorescent compound.

The present invention relates to a blue phosphorescent compound, and more particularly to a blue phosphorescent compound having excellent characteristics in both power efficiency and color, and a high efficiency organic electroluminescent device capable of providing high quality images using the same.

In recent years, the demand for a flat display device having a small space occupancy has been increased due to the enlargement of the display device. The technology of the organic electroluminescent device, which is also called an organic light emitting diode (OLED) And several prototypes have already been announced.

An organic electroluminescent device is a device that injects electric charge into a light emitting material layer formed between an electron injecting electrode (cathode) and a hole injecting electrode (anode) to form an electron and a hole. The device can be formed on a flexible transparent substrate such as a plastic substrate and can be driven at a lower voltage (10 V or less) than a plasma display panel or an inorganic electroluminescence (EL) It also has a relatively low power consumption and excellent color purity. In addition, organic electroluminescence (EL) devices can display three colors of green, blue, and red, making them a next-generation rich color display device and attracting a lot of interest from many people. Here, the process of fabricating the organic electroluminescent device will be briefly described.

(1) First, a material such as indium-tin-oxide (ITO) is deposited on a transparent substrate to form an anode.

(2) A hole injecting layer (HIL) is formed on the anode. The hole injection layer mainly comprises 4,4'-bis [N- (4- {N, N-bis (3-methylphenyl) amino} phenyl] -N- phenylamino] biphenyl To a thickness of 10 nm to 30 nm.

(3) Next, a hole transport layer (HTL) is formed on the hole injection layer. This hole transporting layer is formed by depositing 4,4'-bis [N- (1-naphtyl) -N-phenylamino] -biphenyl (NPB)

(4) Next, an emitting material layer (EML) is formed on the hole transport layer. At this time, a dopant is added as needed. For example, a phosphorescent red Dopant Bis (2-phenylquinoline) (acetylacetonate) iridium (III) (Ir (III)) represented by the following Formula 1-4 is added to bis (N-carbazolyl) biphenyl phq) 2acac) is doped to form a red light emitting material layer.

(5) Next, an electron transport layer (ETL) and an electron injecting layer (EIL) are successively formed on the light emitting material layer.

(6) Next, a cathode is formed on the electron injection layer, and finally, a protective film is formed on the cathode.

Formula 1 -One

Formula 1 -2

Formula 1 -3

Formula 1 -4

In recent years, a phosphorescent material is used more frequently than a fluorescent material in a luminescent material layer. In the case of a fluorescent material, only about 25% of the single excitons formed in the emitter layer are used to make light, and 75% of the triplet is mostly lost to heat, while the phosphors convert both singlet and triplet to light It has a luminescent mechanism. Phosphorescent compounds generally contain a heavy atom such as iridium (Ir) at the center of an organic material and have a high probability of electron transfer from triplet to singlet.

In such a phosphorescent material, there is a need to develop a material that satisfies both efficiency and color requirements.

An object of the present invention is to provide a high efficiency organic electroluminescent device capable of providing a high-quality image by providing a blue phosphorescent compound having excellent characteristics in both power efficiency and color.

In order to solve the above problems, the present invention includes an organic electroluminescent device including a blue phosphorescent compound represented by the following formula and a light emitting material layer comprising the same.

(Wherein each of X1, X2 and X3 is a nitrogen atom (N) or a carbon atom (C), A is a heteroaromatic group consisting of 5 to 6 elements including X1-X2-N, B is X3- An aromatic or heteroaromatic group consisting of 5 to 6 elements,

X4-L1-X5 is a bidentate ligand, X4 and X5 are each a carbon atom, a nitrogen atom or an oxygen atom, L1 is a group of atoms forming a 2-position ligand,

n is an integer of 1 to 3, a is an integer of 1 to 4, b is an integer of 0 to 4,

Each Ra is independently selected from the group consisting of hydrogen, halogen, cyano, C1 to C18 alkyl, C1 to C18 alkoxy, substituted or unsubstituted aromatic groups of C6 or more, substituted or unsubstituted C5 or more An aromatic group, a C1 to C18 amine group, an amine group substituted with an aromatic group of C6 or more, an amine group substituted with a heteroaromatic group of C5 or more, a silyl group substituted by C1 to C18 alkyl group or C6 or more aromatic group, A silyl group substituted with a heteroaromatic group,

Each Rb is independently selected from the group consisting of hydrogen, halogen, cyano, C1 to C18 alkyl, C1 to C18 alkoxy, substituted or unsubstituted aromatic groups of C6 or more, substituted or unsubstituted C5 or more, An amine group substituted with an aromatic group of C6 or higher, an amine group substituted with a heteroaromatic group of C5 or higher, a silyl group substituted with a C1 to C18 alkyl group or an aromatic group of C6 or higher, C5 Lt; / RTI > or more heteroaromatic group,

Wherein at least one of Ra is represented by the following formula,

Z is an aromatic or heteroaromatic group consisting of 5 to 6 elements, c is an integer of 1 to 5, * indicates a bonding site,

Each of Rc is independently selected from the group consisting of hydrogen, a halogen of D, F, Cl, Br, a cyano group, a C1 to C18 alkyl group, a C1 to C18 alkoxy group, a substituted or unsubstituted aromatic group of C6 or more, An aromatic group, a C1 to C18 amine group, an amine group substituted with an aromatic group of C6 or more, an amine group substituted with a heteroaromatic group of C5 or more, a silyl group substituted by C1 to C18 alkyl group or C6 or more aromatic group, A silyl group substituted with a heteroaromatic group, and at least one of Rc is a silyl group.

The blue phosphorescent compound of the present invention has an effect of having excellent characteristics in both power efficiency and color.

In particular, by having a structure in which a phenyl group substituted with a silyl group is substituted for nitrogen in imidazole, a blue phosphorescent compound having excellent characteristics in both power efficiency and color tone is provided. By using the blue phosphorescent compound, high efficiency Of the organic electroluminescent device.

1A and 1B are UV-vis spectra and PL spectra of a blue phosphorescent compound according to an embodiment of the present invention.
2 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present invention.

Hereinafter, the structure of the blue phosphorescent compound according to the present invention and its synthesis example and the organic electroluminescent device using the same will be described.

The blue phosphorescent compound of the present invention is an iridium (Ir) compound represented by the following formula (2).

(2)

Wherein X1, X2 and X3 are each a nitrogen atom (N) or a carbon atom (C), A is a heteroaromatic group containing 5 to 6 elements including X1-X2-N, B is X3-C And an aromatic or heteroaromatic group consisting of 5 to 6 elements. X4-L1-X5 is a bidentate ligand, X4 and X5 are each a carbon atom, a nitrogen atom or an oxygen atom, and L1 is an atom group forming a two-terminal ligand. n is an integer of 1 to 3, a is an integer of 1 to 4, and b is an integer of 0 to 4. Each Ra is independently selected from the group consisting of hydrogen, halogen, cyano, C1 to C18 alkyl, C1 to C18 alkoxy, substituted or unsubstituted aromatic groups of C6 or more, substituted or unsubstituted C5 or more An aromatic group, a C1 to C18 amine group, an amine group substituted with an aromatic group of C6 or more, an amine group substituted with a heteroaromatic group of C5 or more, a silyl group substituted by C1 to C18 alkyl group or C6 or more aromatic group, And each Rb is independently selected from the group consisting of hydrogen, halogen, cyano, C1 to C18 alkyl, C1 to C18 alkoxy, C6 or more substituted or unsubstituted groups of D, F, Cl, Br, An unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group of C5 or more, an amine group of C1 to C18, an amine group substituted by an aromatic group of C6 or more, an amine group substituted by a heteroaromatic group of C5 or more, A silyl group substituted with an alkyl group of C18 or an aromatic group of C6 or more, and a silyl group substituted by a heteroaromatic group of C5 or higher.

Herein, " independent of each other " means that when two or more substituents are included, the substituents may be the same or different from each other. For example, when three substituents (Ra) are introduced into A as the heteroaromatic group, they may be the same or different.

Also, at least one of Ra has a structure represented by the following formula (3).

(3)

In the formula (3), Z is an aromatic or heteroaromatic group having 5 to 6 atoms, c is an integer of 1 to 5, and * indicates a bonding site. Each of Rc is independently selected from the group consisting of hydrogen, a halogen of D, F, Cl, Br, a cyano group, a C1 to C18 alkyl group, a C1 to C18 alkoxy group, a substituted or unsubstituted aromatic group of C6 or more, An aromatic group, a C1 to C18 amine group, an amine group substituted with an aromatic group of C6 or more, an amine group substituted with a heteroaromatic group of C5 or more, a silyl group substituted by C1 to C18 alkyl group or C6 or more aromatic group, A silyl group substituted with a heteroaromatic group, and at least one is a silyl group.

For example, the material of Formula 2 may be represented by any one of a plurality of materials represented by Formula 4 below.

Formula 4

In Formula 4, d is an integer of 0 to 3, e is an integer of 0 to 4, and f is an integer of 1 to 5. Each of Rd is independently selected from the group consisting of hydrogen, a halogen of D, F, Cl, Br, a cyano group, a C1 to C18 alkyl group, a C1 to C18 alkoxy group, a substituted or unsubstituted aromatic group of C6 or more, An aromatic group, a C1 to C18 amine group, an amine group substituted with an aromatic group of C6 or more, an amine group substituted with a heteroaromatic group of C5 or more, a silyl group substituted by C1 to C18 alkyl group or C6 or more aromatic group, And each of R e is independently selected from the group consisting of hydrogen, halogen, cyano, C 1 to C 18 alkyl, C 1 to C 18 alkoxy, substituted or not more than C6, A substituted aromatic group, a substituted or unsubstituted heteroaromatic group of C5 or more, an amine group of C1 to C18, an amine group substituted by an aromatic group of C6 or more, an amine group substituted by a heteroaromatic group of C5 or more, A silyl group substituted by an alkyl group of C18 or an aromatic group of C6 or a silyl group substituted by a heteroaromatic group of C5 or more, each of Rf is independently selected from the group consisting of hydrogen, halogen, cyano, C1 C18 alkyl group, C1 to C18 alkoxy group, C6 or higher substituted or unsubstituted aromatic group, C5 or higher substituted or unsubstituted heteroaromatic group, C1 to C18 amine group, C6 or higher aromatic group substituted amine group, C5 or higher heteroaromatic group, a C1 to C18 alkyl group, a silyl group substituted with an aromatic group of C6 or higher, or a silyl group substituted with a heteroaromatic group of C5 or higher. Also, at least one of Rf is selected from a silyl group.

More specifically, the material of Formula 2 is any one of a plurality of materials represented by Formula 5 below.

Formula 5

As described later, the blue phosphorescent compound represented by Formula 2 has superior characteristics in terms of power / current efficiency and color tone as compared with the conventional blue phosphorescent compound.

Hereinafter, synthesis examples of the blue phosphorescent compound according to the present invention will be described. The blue phosphorescent compounds represented by the formulas B-17 and B-22 have a structure in which the heteroaromatic group A in the above formula (2) is an imidazole in which X1 is nitrogen and a phenyl group substituted with a silyl group is introduced into X1.

1. First synthetic example

The blue phosphorescent compound represented by B-17 in the above formula (5) is synthesized as follows.

(1) Synthesis of Compound A

Scheme 1

A 10% aqueous sodium hydroxide (6.71 g, 167.75 mmol) was added to a 250 ml round bottom flask and stirred at 0 ° C. Then, 2-chloroethanamine hydrochloride (8.85 g, 76.30 mmol) was added and stirred until all the solution was dissolved. Then, 4-fluorobenzoyl chloride (14.82 g, 93.47 mmol) was added thereto and stirred at 0 ° C for 1 hour. Stir for a further hour. The reaction was terminated by adding water, followed by filtration. The residue was reprecipitated with methylene chloride and hexane to obtain Compound A (14.81 g, 73.45 mmol).

(2) Synthesis of compound B

Scheme 2

Add A (10.00 g, 49.60 mmol) into a 250 ml round bottom flask, dissolve in xylene (110 ml), add pentachlorophosphine (15.49 g, 74.38 mmol) and reflux for 2 hours. After the temperature was lowered to room temperature, 2-bromobenzenamine (9.39 g, 54.59 mmol) was added and refluxed for 20 hours. After completion of the reaction, the precipitate is filtered using toluene, dissolved in methylene chloride, and then neutralized with an aqueous solution of ammonium chloride. The solution was concentrated, and column chromatography was performed using ethylacetate and hexane to obtain Compound B (9.72 g, 30.45 mmol).

(3) Synthesis of Compound C

Scheme 3

Dissolve compound B (9.72 g, 30.45 mmol) in acetonitrile (300 ml) into a 500-ml round bottom flask and slowly add a mixture of potassium permanganate (12.38 g, 78.33 mmol) and K-10 (24.76 g) at room temperature. After stirring at room temperature for 3 hours, ethanol was added to terminate the reaction. Celite was filtered with ethyl acetate, and the solution was concentrated and subjected to column chromatography using ethyl acetate and hexane to obtain Compound C (3.90 g, 12.30 mmol).

(4) Synthesis of Compound D

Scheme 4

Compound C (3.90 g, 12.30 mmol) was dissolved in tetrahydrofuran (80 mL) into a 250 mL round bottom flask and then cooled to -78 ° C. 2.5 M butyl lithium (5.30 ml, 13.28 mmol) was slowly added thereto and stirred for 1 hour. Then, chlorodimethyl (phenyl) silane (2.28 g, 13.36 mmol) was added thereto, stirred for 1 hour and then kept at room temperature for 3 hours. The reaction was terminated by adding water and extracted with ethyl acetate. The solution was concentrated and subjected to column chromatography using ethyl acetate and hexane to obtain Compound D (2.50 g, 6.71 mmol)

(5) Synthesis of blue phosphorescent compound B-17

Scheme 5

Compound D (2.50 g, 6.71 mmol) and Iridium (III) acetylacetonate (0.65 g, 1.34 mmol) were added to a 50 mL round-bottomed flask and the reaction mixture was vacuum dried for 30 minutes and then the reaction flask was filled with nitrogen gas. (3 times) Ethylene glycol (25 ml) was added to the reaction mixture, and the mixture was reacted at 200 ° C for 48 hours. The temperature was lowered to room temperature and then filtered using methanol. The precipitate was dissolved in methylene chloride, and column chromatography was performed using hexane. Then, the compound B-17 was synthesized by precipitation and filtration under reduced pressure using methylene chloride and methanol. (0.42 g, 0.32 mmol)

Referring to FIG. 1A showing the photoluminescence spectra of the blue phosphorescent compound B-17, the luminescent characteristics are shown at 464 and 489 nm, which are blue wavelength positions.

1. Second synthetic example

The blue phosphorescent compound represented by B-22 in the above formula (5) is synthesized as follows.

(1) Synthesis of Compound A

Scheme 6

A 10% aqueous sodium hydroxide (6.71 g, 167.75 mmol) was added to a 250 ml round bottom flask and stirred at 0 ° C. Then, 2-chloroethanamine hydrochloride (8.85 g, 76.30 mmol) was added and stirred until all the solution was dissolved. Then, 4-fluorobenzoyl chloride (14.82 g, 93.47 mmol) was added thereto and stirred at 0 ° C for 1 hour. Stir for a further hour. The reaction was terminated by adding water, followed by filtration. The residue was reprecipitated with methylene chloride and hexane to obtain Compound A (14.81 g, 73.45 mmol).

(2) Synthesis of Compound E

Scheme 7

Add A (14.81 g, 73.45 mmol) in a 250 ml round bottom flask, dissolve in xylene (110 ml), add pentachlorophosphine (PCL5, 15.49 g, 74.38 mmol) and reflux for 2 hours. After the temperature was lowered to room temperature, 2,4-dibromobenzenamine (13.69 g, 54.55 mmol) was added thereto and refluxed for 20 hours. After completion of the reaction, the precipitate is filtered using toluene, dissolved in methylene chloride, and then neutralized with an aqueous solution of ammonium chloride. After extraction, the solution was concentrated and subjected to column chromatography using ethyl acetate and hexane to obtain Compound E (12.05 g, 30.27 mmol).

(3) Synthesis of Compound F

Scheme 8

Dissolve compound E (10.00 g, 25.12 mmol) in acetonitrile (300 ml) into a 500 ml round-bottomed flask and slowly add a mixture of potassium permanganate (11.91 g, 75.36 mmol) and K-10 (23.81 g) at room temperature. After stirring at room temperature for 3 hours, ethanol was added to terminate the reaction. Celite was filtered with ethyl acetate, and the solution was concentrated and subjected to column chromatography using ethyl acetate and hexane to obtain Compound F (4.50 g, 11.36 mmol).

(4) Synthesis of Compound G

Scheme 9

Compound F (4.50 g, 11.36 mmol) was dissolved in tetrahydrofuran (80 mL) into a 250 mL round bottom flask and cooled to -78 ° C. 2.5 M butyl lithium (9.52 ml, 23.86 mmol) is added slowly and stirred for 1 hour. Then, chlorodimethyl (phenyl) silane (4.13 g, 23.86 mmol) was added thereto, stirred for 1 hour, and kept at room temperature for 3 hours. The reaction was terminated by adding water and extracted with ethyl acetate. The solution was concentrated and subjected to column chromatography using ethyl acetate and hexane to obtain Compound G (2.69 g, 5.31 mmol).

(5) Synthesis of blue phosphorescent compound B-22

Scheme 10

Compound G (2.69 g, 5.31 mmol) and Iridium (III) acetylacetonate (0.64 g, 1.31 mmol) were placed in a 50 mL round-bottomed flask and the reaction mixture was vacuum dried for 30 minutes and then the reaction flask was filled with nitrogen gas. (3 times) Ethylene glycol (25 ml) was added to the reaction mixture, reacted at 200 ° C for 48 hours, cooled to room temperature, and then filtered using methanol. The precipitate was dissolved in methylene chloride, and column chromatography was performed using hexane. Then, the compound B-22 was synthesized by precipitation using methylene chloride and methanol and filtration under reduced pressure. (0.31 g, 0.18 mmol)

Referring to FIG. 1B showing the photoluminescence spectra of the blue phosphorescent compound B-22, the luminescence characteristics are shown at 460 and 486 nm, which are blue wavelength positions.

Hereinafter, the performance of the blue phosphorescent compound according to the present invention and the organic electroluminescent device using the blue phosphorescent compound according to the present invention will be described with reference to Experimental Example 1 and Experimental Example 2 for fabricating the organic electroluminescent device using the blue phosphorescent compound of the present invention .

Experimental Example 1

The ITO layer was patterned to have a light emitting area of 3 mm x 3 mm on the substrate and then cleaned. The pressure in the vacuum chamber of about 1 * 10 HAT-CN ^-6 torr in the state on the ITO layer (hexaazatriphenylene-hexacarbonitirile, 50Å), NPB (550Å), TAPC (di- (4- (N, N'-ditolyl -amino) -phenyl) cyclohexane, 100 Å), host mCP (9- (9H-carbazol-9-yl) phenyl) -9H-carbazole, 300 Å + dopant B-17 (15%), TmPyPB , 3,5-tri [(3-pyridyl) -phen-3-yl] benzene, 400 Å), LiF (5 Å) and Al (1000 Å).

At 10 mA / cm ² , the driving voltage was 7.85 V, the current efficiency was 15.45 cd / A, the power efficiency was 6.18 lm / W, and the quantum efficiency was 8.1%, where CIE x = 0.181 and y = 0.339.

Experimental Example 2

The ITO layer was patterned to have a light emitting area of 3 mm x 3 mm on the substrate and then cleaned. The pressure in the vacuum chamber of about 1 * 10 ^-6 torr of HAT-CN (50Å) on the ITO layer in the state, NPB (550Å), TAPC ( 100Å), the host mCP (300Å) + dopant B-22 (15% ), TmPyPB (400 Å), LiF (5 Å), and Al (1000 Å).

At 10 mA / cm ² , the driving voltage was 7.75 V, the current efficiency was 17.60 cd / A, the power efficiency was 7.13 lm / W and the quantum efficiency was 9.3%, which was CIE x = 0.169 and y = 0.328.

Comparative Example 1

The ITO layer was patterned to have a light emitting area of 3 mm x 3 mm on the substrate and then cleaned. (50 ANGSTROM), NPB (550 ANGSTROM), TAPC (100 ANGSTROM), and host mCP (300 ANGSTROM) on the ITO layer at a pressure of about 1 × 10 ^-6 torr + Dopant (15%), TmPyPB (400 Å), LiF (5 Å), and Al (1000 Å).

At 10 mA / cm ² , the driving voltage was 7.86 V, the current efficiency was 12.75 cd / A, the power efficiency was 5.10 lm / W and the quantum efficiency was 6.7%, which was CIE x = 0.196 and y = 0.333.

Comparative Example 2

The ITO layer was patterned to have a light emitting area of 3 mm x 3 mm on the substrate and then cleaned. (50 ANGSTROM), NPB (550 ANGSTROM), TAPC (100 ANGSTROM), and host mCP (300 ANGSTROM) on the ITO layer at a pressure of about 1 × 10 ^-6 torr + Dopant (15%), TmPyPB (400 Å), LiF (5 Å), and Al (1000 Å).

At 10 mA / cm ² , the driving voltage was 7.93 V, the current efficiency was 15.38 cd / A, the power efficiency was 6.09 lm / W and the quantum efficiency was 7.2%, which was CIE x = 0.182 and y = 0.395.

Herein, HAT-CN, TAPC, mCP and TmPyPB are represented by the following formulas (6-3) to (6-6), respectively.

6 -One

6 -2

6 -3

6 -4

6 -5

6 -6

The experimental results of the above-described Experimental Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 below.

Voltage [V] electric current
[10 mA / cm ² ] Current efficiency [cd / A] Power Efficiency [lm / W] Quantum efficiency [%] CIE (x) CIE (y) Experimental Example 1 7.85 10 15.45 6.18 8.1 0.181 0.339 Experimental Example 2 7.75 10 17.60 7.13 9.3 0.169 0.328 Comparative Example 1 7.86 10 12.75 5.10 6.7 0.195 0.333 Comparative Example 2 7.93 10 15.38 6.09 7.2 0.182 0.395

As shown in Table 1, Experimental Examples 1 and 2 and Comparative Example 1 have a similar color tone (CIE (y)), but Experimental Examples 1 and 2 have superior characteristics in current efficiency and power efficiency as compared with Comparative Example 1. In other words, the experimental examples 1 and 2 have a power efficiency improved by about 20 to 40% as compared with the comparative example 1.

On the other hand, Experimental Examples 1 and 2 have a significantly different color feeling with improved current efficiency and power efficiency as compared with Comparative Example 2. That is, the blue phosphors of Experimental Examples 1 and 2 have light emission characteristics different from those of Comparative Example 2.

An embodiment of an organic electroluminescent device comprising the above-mentioned blue phosphorescent compound is shown in Fig.

As shown, the organic electroluminescent device includes first and second substrates (not shown) facing each other, and an organic light emitting diode 130 formed between the first and second substrates (not shown) .

The organic light emitting diode 130 includes a first electrode 132 serving as an anode, a second electrode 138 serving as a cathode, and an organic light emitting layer formed between the first and second electrodes 132 and 138 .

The first electrode 132 is made of a relatively high work function material such as indium-tin-oxide (ITO), and the second electrode 138 is made of a material having a relatively low work function value, For example, aluminum (Al) or an aluminum alloy.

In order to maximize luminous efficiency, the organic light emitting layer has a multilayer structure, that is, a hole injection layer (HTL) 133, a hole transporting layer (HIL) 134 Emitting material layer (EML) 135, an electron transporting layer (ETL) 136, and an electron injection layer (EIL) 137.

Herein, the organic light emitting layer includes a blue phosphorescent compound represented by Formula 2. [ That is, the blue phosphorescent compound is doped in the host material in an amount of 0.1 to 50%, preferably 1 to 20%, to form an organic light emitting layer. As described above, these blue phosphorescent compounds have excellent characteristics in both power efficiency and color. Therefore, when the blue phosphorescent compound of the present invention is applied to a light emitting device, the luminous efficiency of the device can be increased. Therefore, an organic electroluminescent device using such a blue phosphorescent compound has a high efficiency advantage of being able to provide a high quality image.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that

132: first electrode 133: hole injection layer
134: hole transport layer 135: light emitting material layer
136: electron transport layer 136: electron injection layer
138: Second electrode

Claims (8)

A blue phosphorescent compound represented by the following formula:

(Wherein each of X1, X2 and X3 is a nitrogen atom (N) or a carbon atom (C), at least one of X1 and X2 is nitrogen and A is a heteroaromatic group containing 5 to 6 elements including X1- B is an aromatic or heteroaromatic group containing 5 to 6 elements including X 3 -C,
X4-L1-X5 is a bidentate ligand, X4 and X5 are each a carbon atom, a nitrogen atom or an oxygen atom, L1 is a group of atoms forming a 2-position ligand,
n is an integer of 1 to 3, a is an integer of 1 to 4, b is an integer of 0 to 4,
Each Ra is independently selected from the group consisting of hydrogen, halogen, cyano, C1 to C18 alkyl, C1 to C18 alkoxy, substituted or unsubstituted aromatic groups of C6 or more, substituted or unsubstituted C5 or more An aromatic group, a C1 to C18 amine group, an amine group substituted with an aromatic group of C6 or more, an amine group substituted with a heteroaromatic group of C5 or more, a silyl group substituted by C1 to C18 alkyl group or C6 or more aromatic group, A silyl group substituted with a heteroaromatic group,
Each Rb is independently selected from the group consisting of hydrogen, halogen, cyano, C1 to C18 alkyl, C1 to C18 alkoxy, substituted or unsubstituted aromatic groups of C6 or more, substituted or unsubstituted C5 or more, An amine group substituted with an aromatic group of C6 or higher, an amine group substituted with a heteroaromatic group of C5 or higher, a silyl group substituted with a C1 to C18 alkyl group or an aromatic group of C6 or higher, C5 Lt; / RTI > or more heteroaromatic group,
Wherein at least one of Ra is represented by the following formula,

Z is an aromatic or heteroaromatic group consisting of 5 to 6 elements, c is an integer of 1 to 5, * indicates a bonding site,
Each of Rc is independently selected from the group consisting of hydrogen, a halogen of D, F, Cl, Br, a cyano group, a C1 to C18 alkyl group, a C1 to C18 alkoxy group, a substituted or unsubstituted aromatic group of C6 or more, An aromatic group, a C1 to C18 amine group, an amine group substituted with an aromatic group of C6 or more, an amine group substituted with a heteroaromatic group of C5 or more, a silyl group substituted by C1 to C18 alkyl group or C6 or more aromatic group, A silyl group substituted with a heteroaromatic group, and at least one of Rc is a silyl group.
The method according to claim 1,
Wherein said heteroaromatic group A is imidazole wherein X < 1 > is nitrogen.
The method according to claim 1,
A blue phosphorescent compound which is any one of the materials represented by the following formulas B-1 to B-92.

A first electrode;
A second electrode facing the first electrode;
And a light emitting material layer disposed between the first and second electrodes,
Wherein the light emitting material layer comprises the blue phosphorescent compound of any one of claims 1 to 3.
delete 5. The method of claim 4,
Wherein the blue phosphorescent compound is used as a dopant, and the light emitting material layer further comprises a host.
The method according to claim 6,
Wherein the blue phosphorescent compound is doped with 0.1 to 50% of the host.
5. The method of claim 4,
A hole transporting layer and a hole transporting layer sequentially stacked between the first electrode and the light emitting material layer, and an electron transporting layer and an electron injecting layer sequentially deposited between the light emitting material layer and the second electrode, .

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