KR20130114377A - Blue phosphorescent compound and organic electroluminescent device using the same - Google Patents

Abstract

PURPOSE: A blue phosphorous compound has excellent power efficiency and excellent properties and improves the luminous efficiency of an organic electroluminescent device. CONSTITUTION: A blue phosphorous compound is represented by chemical formula 1. In chemical formula 1, X1, X2, and X3 are N or C; A is a heteroaromatic group which includes X1-X2-N and is formed of 5-6 elements; B is a heteroaromatic group which includes X3-C and is formed of 5-6 elements; X4-L1-X5 is a bidentate ligand; X4 and X5 are carbon, nitrogen atom, or oxygen atom; L1 is an atom group forming a bidentate; n is an integer from 1-3; a is an integer from 1-4; and b is an integer from 0-4.

Description

Blue phosphorescent compound and organic electroluminescent device using the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blue phosphorescent compound, and more particularly, to a blue phosphorescent compound having excellent properties in both power efficiency and color and an organic light emitting device having high efficiency capable of providing a high quality image 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. Not only can the device be formed on a flexible transparent substrate such as plastic, but it can also be driven at a lower voltage (less than 10V) compared to a plasma display panel or an inorganic electroluminescent (EL) display. In addition, the power consumption is relatively low, there is an advantage that the color purity is excellent. 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 phosphors, there is a need for the development of materials that meet both the efficiency and color requirements.

The present invention is to provide a high efficiency organic EL 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 comprising a blue phosphorescent compound represented by the formula and a light emitting material layer comprising the same.

(X1, X2, X3 each 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, and B is X3-C An aromatic or heteroaromatic group consisting of 5 to 6 elements,

X4-L1-X5 is a bidentate ligand, X4 and X5 are carbon atoms, nitrogen atoms or oxygen atoms, respectively, and L1 is a group of atoms forming a bidentate 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 hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Selected from a silyl group substituted with a heteroaromatic group,

Each R b is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted, C5 Selected from silyl groups substituted with at least heteroaromatic groups,

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, * represents a bonding site,

Each Rc is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Is selected from 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 the phenyl group substituted with the silyl group in the nitrogen of the imidazole is provided to provide a blue phosphorescent compound having excellent characteristics in both power efficiency and color, by using this high efficiency to provide a high quality image It is to provide an organic electroluminescent device of.

1A and 1B are ultraviolet-visible (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 light emitting display device according to an embodiment of the present invention.

Hereinafter, a structure of a blue phosphorescent compound according to the present invention, a synthesis example thereof, and an organic light emitting display 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)

In Formula 2, 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, and B is X3-C It is an aromatic or heteroaromatic group consisting of 5 to 6 elements, including. X4-L1-X5 is a bidentate ligand, X4 and X5 are carbon atoms, nitrogen atoms or oxygen atoms, respectively, and L1 is an atomic group forming a bidentate ligand. n is an integer of 1-3, a is an integer of 1-4, b is an integer of 0-4. Each Ra is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Each of Rb is independently hydrogen, D, F, Cl, Br, halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substitution, or Unsubstituted aromatic group, C5 or more substituted or unsubstituted heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to Or a silyl group substituted with an C18 alkyl group or a C6 or more aromatic group, or a silyl group substituted with a C5 or more heteroaromatic group.

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

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

(3)

In Formula 3, Z is an aromatic or heteroaromatic group consisting of 5 to 6 elements, c is an integer of 1 to 5, and * represents a bonding site. Each Rc is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more And a silyl group substituted with a heteroaromatic group, at least one of which is a silyl group.

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

Formula 4

In Chemical Formula 4, d is an integer of 0 to 3, e is an integer of 0 to 4, f is an integer of 1 to 5. Each Rd is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Each of Re is independently selected from hydrogen, D, F, Cl, Br, halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substitution or unsubstituted A substituted aromatic group, C5 or more substituted or unsubstituted heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to Or a silyl group substituted with a C18 alkyl group or a C6 or more aromatic group, a silyl group substituted with a C5 or more heteroaromatic group, and each Rf is independently hydrogen, D, F, Cl, Br halogen, cyano group, C1 C1 to C18 alkoxy group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic groups are selected from substituted amine groups, C1 to C18 alkyl groups, silyl groups substituted with C6 or more aromatic groups, and silyl groups substituted with C5 or more heteroaromatic groups. In addition, at least one of Rf is selected from the silyl group.

More specifically, the material of Formula 2 is any one of a plurality of materials shown in the following formula (5).

Formula 5

The blue phosphorescent compound represented by Chemical Formula 2 has excellent characteristics in power / current efficiency and color compared to the conventional blue phosphorescent compound, as described later.

Hereinafter, synthesis examples of the blue phosphorescent compound according to the present invention will be described. The blue phosphorescent compounds represented by Formulas B-17 and B-22 are imidazoles in which the heteroaromatic group A is X1 in nitrogen in Formula 2, and has a structure in which 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 Chemical Formula 5 is synthesized as follows.

(1) Synthesis of Compound A

Scheme 1

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 (8.85g, 76.30mmol) was added and stirred until all dissolved, 4-fluorobenzoyl chloride (14.82g, 93.47mmol) was added and stirred at 0 ℃ for 1 hour, then raised to room temperature 1 Stir for further time. Water was added to terminate the reaction and filtered. The residue was reprecipitated using methylene chloride and hexane to obtain Compound A (14.81g, 73.45mmol).

(2) Synthesis of compound B

Scheme 2

Put A (10.00g, 49.60mmol) in a 250 ml round bottom flask, dissolve in xylene (110ml), add pentachlorophosphine (15.49g, 74.38mmol) and reflux for 2 hours. After lowering the temperature to room temperature, 2-bromobenzenamine (9.39 g, 54.59 mmol) was added and refluxed for 20 hours. After the reaction was completed, the precipitate was filtered using toluene, dissolved in methylene chloride, and neutralized with aqueous ammonium chloride solution. Extraction and concentration of the solution were carried out by column chromatography 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) in 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 for 3 hours at room temperature, ethanol was added to terminate the reaction. Filter was performed using ethyl acetate in Celite, the solution was concentrated, and column chromatography was performed 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) in a 250 mL round bottom flask and cooled to -78 ° C. Slowly add 2.5 M butyl lithium (5.30 ml, 13.28 mmol) and stir for 1 hour. Then, chlorodimethyl (phenyl) silane (2.28g, 13.36mmol) was added, stirred for 1 hour, and maintained at room temperature for 3 hours. Water was added to terminate the reaction, the mixture was extracted with ethyl acetate, the solution was concentrated and column chromatography was performed 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 (2.50g, 6.71mmol) and Iridium (III) acetylacetonate (0.65g, 1.34mmol) were added to a 50mL round bottom flask, and the reaction mixture was vacuum dried for 30 minutes, and the reaction flask was filled with nitrogen gas. (Repeat 3 times) After adding ethylene glycol (25ml) to the reaction mixture and reacted for 48 hours at 200 ℃, lowered the temperature to room temperature, and filtered using methanol. The precipitate was dissolved in methylene chloride and column chromatography was performed using hexane. Thereafter, compound B-17 was synthesized by precipitation and vacuum filtration using methylene chloride and methanol. (0.42 g, 0.32 mmol)

Referring to FIG. 1A showing a photoluminescence spectra of the blue phosphor compound B-17, light emission characteristics are exhibited at the blue wavelength positions 464 and 489 nm.

1. Second Synthesis Example

The blue phosphorescent compound represented by B-22 in Chemical Formula 5 is synthesized as follows.

(1) Synthesis of Compound A

Scheme 6

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 (8.85g, 76.30mmol) was added and stirred until all dissolved, 4-fluorobenzoyl chloride (14.82g, 93.47mmol) was added and stirred at 0 ℃ for 1 hour, then raised to room temperature 1 Stir for further time. Water was added to terminate the reaction and filtered. The residue was reprecipitated using methylene chloride and hexane to obtain Compound A (14.81g, 73.45mmol).

(2) Synthesis of Compound E

Scheme 7

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

(3) Synthesis of Compound F

Scheme 8

Dissolve Compound E (10.00 g, 25.12 mmol) in acetonitrile (300 ml) in a 500 ml round bottom 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 for 3 hours at room temperature, ethanol was added to terminate the reaction. Filtration was carried out using ethyl acetate in Celite, the solution was concentrated, and column chromatography was performed 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) is dissolved in tetrahydrofuran (80 ml) in a 250 mL round bottom flask and cooled to -78 ° C. Add 2.5 M butyl lithium (9.52ml, 23.86mmol) slowly and stir for 1 hour. Then, chlorodimethyl (phenyl) silane (4.13g, 23.86mmol) was added, stirred for 1 hour, and maintained at room temperature for 3 hours. Water was added to terminate the reaction, the mixture was extracted with ethyl acetate, the solution was concentrated, and column chromatography was performed 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 (2.69g, 5.31mmol) and Iridium (III) acetylacetonate (0.64g, 1.31mmol) were added to a 50mL round bottom flask, and the reaction mixture was vacuum dried for 30 minutes, and the reaction flask was filled with nitrogen gas. (Repeat 3 times) After adding ethylene glycol (25ml) to the reaction mixture, the reaction was carried out for 48 hours at 200 ℃, lowered the temperature to room temperature, and filtered using methanol. The precipitate was dissolved in methylene chloride and column chromatography was performed using hexane. Thereafter, compound B-22 was synthesized by precipitation and filtration under reduced pressure using methylene chloride and methanol. (0.31g, 0.18mmol)

Referring to FIG. 1B showing a photoluminescence spectra of the blue phosphor compound B-22, light emission characteristics are shown at the blue wavelength positions 460 and 486 nm.

Hereinafter, the performance of the blue phosphorescent compound according to the present invention and the organic electroluminescent device using the same will be described through Experimental Example 1 and Experimental Example 2 for fabricating an 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. HAT-CN (hexaazatriphenylene-hexacarbonitirile, 50 kPa), NPB (550 kPa), TAPC (di- (4- (N, N'-ditolyl) on the ITO layer at a pressure of about 1 * 10 ^-6 torr in the vacuum chamber -amino) -phenyl) cyclohexane, 100Å), host mCP (9- (3- (9H-carbazol-9-yl) phenyl) -9H-carbazole, 300Å) + dopant B-17 (15%), TmPyPB (1 , 3,5-tri [(3-pyridyl) -phen-3-yl] benzene, 400 Pa), LiF (5 Pa) and Al (1000 Pa) were formed in this order.

At 10mA / cm ² , the driving voltage was 7.85V, the current efficiency was 15.45cd / A, the power efficiency was 6.18lm / W, and the quantum efficiency was 8.1%. In this case, CIE x = 0.181, 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. HAT-CN (50 kPa), NPB (550 kPa), TAPC (100 kPa), host mCP (300 kPa) + dopant B-22 (15%) on the ITO layer with a vacuum chamber pressure of about 1 * 10 ^-6 torr. ), TmPyPB (400 kV), LiF (5 kV), and Al (1000 kV) in this order.

At 10mA / cm ² , the driving voltage was 7.75V, the current efficiency was 17.60cd / A, the power efficiency was 7.13lm / W, and the quantum efficiency was 9.3%. In this case, CIE x = 0.169, 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. HAT-CN (50 kPa), NPB (550 kPa), TAPC (100 kPa), host mCP (300 kPa) + on the ITO layer with a pressure of about 1 * 10 ^-6 torr in the vacuum chamber It formed into a film in order of dopant (15%), TmPyPB (400 kPa), LiF (5 kPa), and Al (1000 kPa).

At 10mA / cm ² , the driving voltage is 7.86V, current efficiency is 12.75cd / A, power efficiency is 5.10lm / W, and quantum efficiency is 6.7%, and CIE x = 0.196, 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. HAT-CN (50 kPa), NPB (550 kPa), TAPC (100 kPa), host mCP (300 kPa) + host mCP (300 kPa) + on the ITO layer at a pressure of about 1 * 10 ^-6 torr in the vacuum chamber It formed into a film in order of dopant (15%), TmPyPB (400 kPa), LiF (5 kPa), and Al (1000 kPa).

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

Here, HAT-CN, TAPC, mCP, TmPyPB are represented by the formulas 6-3 to 6-6, respectively.

6 -One

6 -2

6 -3

6 -4

6 -5

6 -6

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

Voltage [V] electric current
[10mA / 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 (CIE (y)), but Experimental Examples 1 and 2 have excellent characteristics in current efficiency and power efficiency compared to Comparative Example 1. That is, Experimental Examples 1 and 2 have a power efficiency improved by 20 to 40% compared to Comparative Example 1.

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

An embodiment of an organic light emitting display device including the blue phosphorescent compound is shown in FIG. 2.

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, the organic light emitting device using the blue phosphorescent compound has a high efficiency advantage that can 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 (5)

A blue phosphorescent compound represented by the following formula:

(X1, X2, X3 each 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, and B is X3-C An aromatic or heteroaromatic group consisting of 5 to 6 elements,
X4-L1-X5 is a bidentate ligand, X4 and X5 are carbon atoms, nitrogen atoms or oxygen atoms, respectively, and L1 is a group of atoms forming a bidentate 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 hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Selected from a silyl group substituted with a heteroaromatic group,
Each R b is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted, C5 Selected from silyl groups substituted with at least heteroaromatic groups,
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, * represents a bonding site,
Each Rc is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Is selected from a silyl group substituted with a heteroaromatic group, and at least one of Rc is a silyl group.)
The method of claim 1,
And said heteroaromatic group A is an imidazole wherein X 1 is nitrogen.
The method of claim 1,
Blue phosphorescent compound which is any one of the substances represented by B-1 to B-92 in the following formula.

A first electrode;
A second electrode facing the first electrode;
A light emitting material layer positioned between the first and second electrodes,
The organic light emitting device is characterized in that the light emitting material layer comprises a blue phosphorescent compound represented by the following formula.

(X1, X2, X3 each 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, and B is X3-C An aromatic or heteroaromatic group consisting of 5 to 6 elements,
X4-L1-X5 is a bidentate ligand, X4 and X5 are carbon atoms, nitrogen atoms or oxygen atoms, respectively, and L1 is a group of atoms forming a bidentate 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 hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Selected from a silyl group substituted with a heteroaromatic group,
Each R b is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted, C5 Selected from silyl groups substituted with at least heteroaromatic groups,
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, * represents a bonding site,
Each Rc is independently hydrogen, D, F, Cl, halogen of halogen, cyano group, C1 to C18 alkyl group, C1 to C18 alkoxy group, C6 or more substituted or unsubstituted aromatic group, C5 or more substituted or unsubstituted Heteroaromatic group, C1 to C18 amine group, C6 or more aromatic group substituted amine group, C5 or more heteroaromatic group substituted amine group, C1 to C18 alkyl group or C6 or more aromatic group substituted by C6 or more aromatic group, C5 or more Is selected from a silyl group substituted with a heteroaromatic group, and at least one of Rc is a silyl group.)
5. The method of claim 4,
Wherein said heteroaromatic group A is imidazole wherein X 1 is nitrogen.

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