KR20150062241A - Compound and organic light emitting device comprising the same - Google Patents

Abstract

A compound according to an embodiment of the present invention is represented by Chemical Formula 1. In the Chemical Formula 1, G_1 and G_2 are independently aromatic ring compounds composed of substituted or unsubstituted C4 to C24 in which N1 to N3 or S1 and S2 may be respectively or together included.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a compound and an organic electroluminescent device including the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compound used in an organic electroluminescent device, and more particularly, to a compound capable of improving light emission efficiency and lowering a driving voltage and an organic electroluminescent device including the same.

The image display device that realizes various information on the screen is a core technology of the information communication age and it is becoming thinner, lighter, more portable and higher performance. (LCD), a plasma display panel (PDP), an electro luminescent display (ELD), a field emission display (FED), and an organic light emitting diode (OLED) display device, Organic Light Emitting Diode) have been actively studied.

Among these organic electroluminescent devices, electrons and holes are paired when an electric charge is injected into the organic light emitting layer formed between the anode and the cathode, and then the light is emitted while disappearing. The organic electroluminescent device can be formed not only on a flexible transparent substrate such as a plastic but also can be driven at a lower voltage than a plasma display panel (plasma display panel) or an inorganic electroluminescence (EL) display, It has the advantage of being excellent in color.

In the organic electroluminescent device, the holes injected from the anode pass through the hole transport layer and form an exciton in the light emitting region. The excitons formed are transferred to the dopant by a physical method of energy transfer. In order to improve the efficiency of such a transfer process, the energy level of the host is sufficiently larger than the energy level of the dopant, so that the reverse energy transfer does not occur. The quantum efficiency of the organic electroluminescent device can be maximized only if the generation of the reverse energy transition is inhibited. Further, a double emission layer may be laminated in the organic electroluminescent device to improve the luminous efficiency. In order to form a double luminescent layer, a host having a hole-transporting property and a host having an electron-transporting property are used in the same dopant.

Another technique is to use a physical phenomenon called a thermally activated delayed fluorescence (TADF) proposed by Adachi, and it has been difficult to improve the lifetime of the organic electroluminescent display device. . Therefore, a new method for improving the efficiency of an organic electroluminescent device is required.

The present invention provides a compound capable of improving the luminous efficiency and lowering the driving voltage of an organic electroluminescent device and an organic electroluminescent device including the same.

In order to accomplish the above object, the compound according to one embodiment of the present invention is represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1, G ₁ and G ₂ each independently represent a substituted or unsubstituted aromatic cyclic compound composed of C4 to C24, N1 to N3, or substituted and unsubstituted C4 to C24, or S1 and S2, .

The G ₁ or G ₂ substituent may be an alkyl group such as methyl, ethyl, propyl, i-propyl, octyl, t- Alkoxy groups such as methoxy, ethoxy and buthoxy, trimethylsilyl, fluorine, and chlorine. The term " alkoxy group "

Wherein G ₁ and G ₂ are any one selected from the following compounds.

The compound is characterized in that it is any one selected from the following compounds.

An organic electroluminescent device according to an embodiment of the present invention includes at least two light emitting layers between an anode and a cathode, and includes an intermediate layer disposed between the light emitting layers, And the intermediate layer comprises the compound.

And the two or more light emitting layers emit light of the same or different colors.

Wherein the two or more light emitting layers and the intermediate layer each have a thickness of 1 to 30 nm.

And a charge generation layer disposed between the anode and the cathode.

By applying the compound of the present invention to the first intermediate layer and the second intermediate layer, the excitons formed in the light emitting layers are clogged to prevent the excitons from emitting in other places than the light emitting layer. Accordingly, there is an advantage that the luminous efficiency of the organic electroluminescent device can be improved and the driving voltage can be lowered.

1 is a view illustrating an organic electroluminescent device according to an embodiment of the present invention.
2 is a view illustrating an organic electroluminescent device according to a second embodiment of the present invention.
3 is a graph showing the relationship between the wavelength and the light emission intensity of the organic electroluminescent device manufactured according to Examples 1 to 4 and Comparative Example of the present invention.
4 is a graph showing the relationship between voltage and current of an organic electroluminescent device manufactured according to Examples 1 to 4 and Comparative Example of the present invention.
5 is a graph showing the relationship between luminance and current efficiency of an organic electroluminescent device manufactured according to Examples 1 to 4 and Comparative Example of the present invention.

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

1 is a view illustrating an organic electroluminescent device according to an embodiment of the present invention.

1, an organic electroluminescent device 100 according to an embodiment of the present invention includes an anode 110, a hole injection layer 120, a hole transport layer 130, a first emission layer 140, an intermediate layer 150 A second light emitting layer 160, an electron transport layer 170, an electron injection layer 180, and a cathode 190.

The anode 110 may be any one of indium tin oxide (ITO), indium zinc oxide (IZO), and zinc oxide (ZnO). When the anode 110 is a reflective electrode, the anode 110 may have a reflective layer made of any one of aluminum (Al), silver (Ag), and nickel (Ni) under the layer made of any one of ITO, IZO, .

The hole injection layer 120 may function to smoothly inject holes from the anode 110 into the light emitting layer 140. The hole injection layer 120 may be formed of cupper phthalocyanine (CuPc), poly (3,4) -ethylenedioxythiophene (PEDOT) polyaniline and NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), but the present invention is not limited thereto. The thickness of the hole injection layer 120 may be 1 to 150 nm. If the thickness of the hole injection layer 120 is 1 nm or more, the hole injection characteristics can be prevented from being degraded. If the thickness is 150 nm or less, the thickness of the hole injection layer 120 is too thick, There is an advantage that it is possible to prevent the drive voltage from rising.

The hole transport layer 130 plays a role of facilitating the transport of holes and may be formed by using NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'- N, N'-bis- (phenyl) -benzidine), s-TAD, and MTDATA (4,4 ', 4 "-tris (N-3-methylphenyl-N-phenylamino) -triphenylamine) The thickness of the hole transport layer 130 may be 1 to 150 nm. If the thickness of the hole transport layer 130 is 5 nm or more, the hole transport property may be deteriorated When the thickness is 150 nm or less, the thickness of the hole transport layer 130 is too thick, which is advantageous in preventing the driving voltage from rising to improve the movement of holes.

The first light emitting layer 140 and the second light emitting layer 160 may be formed of materials emitting red, green, and blue light, respectively, and may be formed using phosphorescent or fluorescent materials.

When the first light emitting layer 140 or the second light emitting layer 160 is red, a host material including CBP (carbazole biphenyl) or mCP (1,3-bis (carbazol-9-yl) (1-phenylquinoline) acetylacetonate iridium), PQIr (acac) (bis (1-phenylquinoline) acetylacetonate iridium), PQIr (t-phenylquinoline) iridium) and PtOEP (octaethylporphyrin platinum) (DBM) ₃ (Phen) or perylene, but the present invention is not limited thereto.

A dopant including a host material including CBP or mCP and containing Ir (ppy) 3 (fac tris (2-phenylpyridine) iridium) when the first light emitting layer 140 or the second light emitting layer 160 is green And a phosphorescent material including Alq3 (tris (8-hydroxyquinolino) aluminum). However, the present invention is not limited thereto.

(4,6-F ₂ ppy) ₂ Irpic, when the first light emitting layer 140 or the second light emitting layer 160 is blue, the host material including CBP or mCP, And may be made of a phosphorescent material, and alternatively may be any one selected from the group consisting of spiro-DPVBi, spiro-6P, distyrylbenzene (DSB), distyrylarylene (DSA), PFO- But it is not limited thereto.

An intermediate layer 150 is positioned between the first emission layer 140 and the second emission layer 160. The intermediate layer 150 serves to cause light emission in the light emitting region by cladding an exciton formed by combining holes and electrons between the first light emitting layer 140 and the second light emitting layer 160, ≪ / RTI >

[Chemical Formula 1]

In Formula 1, G ₁ and G ₂ each independently represent a substituted or unsubstituted aromatic cyclic compound composed of C4 to C24, substituted or unsubstituted C4 to C24, N1 to N3, or S1 and S2, .

The G ₁ or G ₂ substituent may be alkyl (alkyl) such as methyl, ethyl, propyl, i-propyl, octyl, ) Group, an alkoxy group such as methoxy, ethoxy and buthoxy, trimethylsilyl, fluorine and chlorine.

Here, G ₁ and G ₂ are each selected from the following compounds.

The compound of the present invention is composed of any one selected from the compounds shown below.

The compound used in the intermediate layer 150 of the present invention is made of a material having a wide energy band gap and excites the excitons formed in the first and second light emitting layers 140 and 160, Thereby preventing light emission. Accordingly, there is an advantage that the luminous efficiency of the organic electroluminescent device can be improved and the driving voltage can be lowered.

The electron transport layer 170 serves to smooth the transport of electrons and is made of at least one selected from the group consisting of Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq and SAlq But is not limited thereto. The thickness of the electron transport layer 170 may be 1 to 50 nm. If the thickness of the electron transporting layer 170 is 1 nm or more, there is an advantage that the electron transporting property can be prevented from being degraded. If the thickness is 50 nm or less, the thickness of the electron transporting layer 170 is too thick, There is an advantage that the driving voltage can be prevented from rising.

The electron injecting layer 180 serves to smooth the injection of electrons and may include Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq or SAlq. The thickness of the electron injection layer 180 may be 1 to 50 nm. If the thickness of the electron injection layer 180 is 1 nm or more, there is an advantage that the electron injection characteristics can be prevented from being degraded. If the thickness is 50 nm or less, the thickness of the electron injection layer 180 is too thick, There is an advantage that it is possible to prevent the drive voltage from rising.

The cathode 190 is an electron injection electrode and may be made of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof having a low work function. Here, the cathode 190 may be formed to have a thickness thin enough to transmit light when the organic electroluminescent device has a front or both-side emission structure, and when the organic electroluminescent device has a back light emitting structure, It can be formed thick enough.

2 is a view illustrating an organic electroluminescent device according to a second embodiment of the present invention. In the following, description of the same components as those of the first embodiment will be omitted.

2, the organic electroluminescent device 200 according to the present invention includes stacks ST1 and ST2 located between an anode 210 and a cathode 310 and a charge located between the stacks ST1 and ST2. Generation layer (260).

In more detail, the first stack ST1 constitutes one light emitting device unit and includes a first light emitting layer 240a and a second light emitting layer 240b. The first light emitting layer 240a and the second light emitting layer 240b may emit light of the same color or different colors. For example, when the first light emitting layer 240a and the second light emitting layer 240b emit blue light, the blue light emitting materials described in the first embodiment may be used.

In the first stack ST1 of the present invention, the first intermediate layer 245 is positioned between the first light emitting layer 240a and the second light emitting layer 240b. The first intermediate layer 245 interposes the exciton formed by the combination of holes and electrons between the first light emitting layer 240a and the second light emitting layer 240b to cause light emission in the light emitting region. Is made of the same material as the compound described in the embodiment. Since the compound has been described in detail above, the description thereof will be omitted here.

The first stack ST1 further includes a hole injection layer 220 and a first hole transport layer 230 between the anode 210 and the first light emitting layer 240a. The hole injection layer 220 and the first hole transport layer 230 have the same structure as the hole injection layer and the hole transport layer of the first embodiment. The first stack ST1 further includes a first electron transport layer 250 on the second light emitting layer 240. [ The first electron transporting layer 250 has the same structure as the electron transporting layer of the first embodiment described above. Accordingly, a hole injecting layer 220, a first hole transporting layer 230, a first light emitting layer 240a, a first intermediate layer 245, a second light emitting layer 240b, and a first electron transporting layer 250 (ST1).

A charge generation layer (CGL) 260 is disposed on the first stack ST1. The charge generation layer 260 may be a PN junction charge generation layer in which an N-type charge generation layer 260N and a P-type charge generation layer 260P are bonded. At this time, the PN junction charge generation layer 260 generates charges or separates them into holes and electrons, and injects charges into the respective light emitting layers. That is, the N-type charge generation layer 260N supplies electrons to the first light emitting layer 240a and the second light emitting layer 240b adjacent to the anode, and the P-type charge generation layer 260P supplies electrons to the second light emitting layer 240B of the second stack ST2 By supplying holes to the light emitting layer, the luminous efficiency of the organic electroluminescent device having a plurality of light emitting layers can be further increased, and the driving voltage can be lowered.

The P-type charge generation layer 260P may be formed of a metal or a P-type doped organic material. The metal may be one or two or more alloys selected from the group consisting of Al, Cu, Fe, Pb, Zn, Au, Pt, W, In, Mo, Ni and Ti. The P-type dopant and the host material used for the organic material doped with P-type may be a conventionally used material. For example, the P-type dopant may be 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), derivatives of tetracyanoquinodimethane, iodine , FeCl ₃ , FeF _3, and SbCl ₅ . In addition, the host may be selected from the group consisting of N, N'-di (naphthalene-1-yl) -N, N-diphenyl-benzidine (NPB), N, N'- -1,1-biphenyl-4,4'-diamine (TPD) and N, N ', N'-tetranaphthyl-benzidine (TNB).

The N-type charge generation layer 260N may be formed of a metal or an N-type doped organic material. The metal may be one selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy and Yb. The N-type dopant used for the organic material doped with the N-type material and the host material may be a commonly used material. For example, the N-type dopant may be an alkali metal, an alkali metal compound, an alkaline earth metal, or an alkaline earth metal compound. In detail, the N-type dopant may be selected from the group consisting of Cs, K, Rb, Mg, Na, Ca, Sr, Eu and Yb. The host material may be a material selected from the group consisting of tris (8-hydroxyquinoline) aluminum, triazine, hydroxyquinoline derivatives, and benzazole derivatives and silole derivatives.

On the other hand, a second stack ST2 including a third emission layer 280a and a fourth emission layer 280b is positioned on the charge generation layer 260. The third light emitting layer 280a and the fourth light emitting layer 280b may emit light of the same color or different colors. For example, when the third light emitting layer 280a and the fourth light emitting layer 280b emit yellow light, the third light emitting layer 280a and the fourth light emitting layer 280b may be CBP (4,4'-N, N'-dicarbazolebiphenyl ) Or Balq (bis (2-methyl-8-quinlinolato-N1, O8) - (1,1'-Biphenyl-4-olato) aluminum) as a phosphorescent yellow green dopant Lt; / RTI >

In the second stack ST2 of the present invention, the second intermediate layer 285 is positioned between the third emission layer 280a and the fourth emission layer 280b. The second intermediate layer 285 serves to emit light in the light emitting region by interposing an exciton formed by the combination of holes and electrons between the third light emitting layer 280a and the fourth light emitting layer 280b. And is made of the same material as the intermediate layer 285. The second stack ST2 further includes a second hole transport layer 270 between the charge generation layer 260 and the third emission layer 280a. The second hole transport layer 270 has the same structure as the first hole transport layer 230 described above.

The second stack ST2 further includes a second electron transport layer 300 on the fourth emission layer 280b and the second electron transport layer 300 includes the first electron transport layer 300 of the first stack ST1, (250). Therefore, the second hole transport layer 270, the third emission layer 280a, the second intermediate layer 285, the fourth emission layer 280b, and the second electron transport layer 300 are formed on the charge generation layer 260 2 stack (ST2). A cathode 310 is provided on the second stack ST2 to constitute an organic electroluminescent device according to the second embodiment of the present invention.

As described above, by applying the compound of the present invention to the first intermediate layer and the second intermediate layer, the excitons formed in the light emitting layers are shielded to prevent the excitons from emitting in other places than the light emitting layer. Accordingly, there is an advantage that the luminous efficiency of the organic electroluminescent device can be improved and the driving voltage can be lowered.

Hereinafter, synthesis examples of the compound of the present invention and an organic electroluminescent device including the same will be described in the following Synthesis Examples and Examples. However, the following examples are illustrative of the present invention, but the present invention is not limited to the following examples.

Synthetic example

1) Preparation of Compound A

Bromo-4- (1-bromonaphthalen-4-yl) naphthalene (2 g, 4.85 mmol) and 1-bromo-4- Phenanthren-9-yl-9-boronic acid (2.37 g, 10.7 mmol) was added to 80 mL of anhydrous tetrahydrofuran and stirred. Tetrakis (triphenylphosphine) palladium (0.28 g, 5 mol%), potassium carbonate (K ₂ CO ₃ , 20 g) and distilled water (80 mL) were added and refluxed at 100 ° C. for 24 hours. At the end of the reaction, tetrahydrofuran is removed and the resulting solid is filtered. Recrystallization was performed using dichloromethane and methanol to obtain Compound A (2.30 g, 78%).

2) Preparation of compound B

1-bromo-4- (1-bromonaphthalene-4-yl) naphthalene (2g, 4.85mmol) and Carbazole (1.79g, 10.7mmo) were added to a 2-necked round bottom flask with 5mol% CuI, 10mol 1,4-Diaminocyclohexane and K ₃ PO ₄ (2.06 g, 9.70 mmol) were dissolved in 80 ml of dimethylformamide (DMF) and refluxed at 100 ° C. for 24 hours. When the reaction is complete, the purified water is placed in a flask and the resulting solids are filtered. Recrystallization was performed using dichloromethane and methanol to obtain Compound B (2.21 g, 78%).

3) Preparation of compound C

To a 2 necked round bottom flask were added 1-bromo-4- (1-bromonaphthalene-4-yl) naphthalene (2 g, 4.85 mmol) and 2-dibenzothiophenboronic acid , 10.7 mmol) were dissolved in 80 mL of anhydrous tetrahydrofuran and stirred. Tetrakis (triphenylphosphine) palladium (0.28 g, 5 mol%), potassium carbonate (20 g) and distilled water (80 mL) were added and refluxed at 100 ° C for 24 hours. At the end of the reaction, tetrahydrofuran is removed and the resulting solid is filtered. Recrystallization was performed using dichloromethane and methanol to obtain Compound C (2.04 g, 68%).

4) Preparation of compound D

To a 2-neck round bottom flask was added 1-bromo-4- (1-bromonaphthalene-4-yl) naphthalene (2g, 4.85mmol) and N-phenyl- carbazolylboronic acid (3.07 g, 10.7 mmol) were dissolved in 80 mL of anhydrous tetrahydrofuran and stirred. Tetrakis (triphenylphosphine) palladium (0.28 g, 5 mol%), potassium carbonate (20 g) and distilled water (80 mL) were added and refluxed at 100 ° C for 24 hours. At the end of the reaction, tetrahydrofuran is removed and the resulting solid is filtered. Recrystallization was performed using dichloromethane and methanol to obtain Compound D (2.61 g, 73%).

Hereinafter, embodiments in which an organic electroluminescent device is manufactured using the compounds A, B, C, and D of the present invention prepared in the above-mentioned synthesis examples as an intermediate layer are disclosed.

≪ Example 1 >

The ITO glass was patterned to have a light emitting area of 3 mm x 3 mm and then cleaned. After the substrate was mounted in a vacuum chamber, the base pressure was adjusted to ¹ × 10 ^-6 torr. Then, DNTPD was formed to a thickness of 700 Å as a hole injection layer on the anode ITO, α-NPD was formed to a thickness of 300 Å as a hole transport layer Doped BD-1 was doped with a doping concentration of 4% to form a 50 Å thick layer, a compound A was formed to a thickness of 50 Å as an intermediate layer, and MADN as a host to the second light emitting layer the Al as the cathode by doping a dopant BD-1 with a doping concentration of 4% and formed to a thickness of 50Å, to form a Alq ₃ as the electron transport layer to a thickness of 125Å to form a LiF electron injection layer to a thickness of 5Å, Lt; RTI ID = 0.0 > 1000A < / RTI > to form an organic electroluminescent device.

≪ Example 2 >

An organic electroluminescent device was fabricated under the same process conditions as in Example 1 except that the intermediate layer was formed of Compound B only.

≪ Example 3 >

An organic electroluminescent device was fabricated under the same process conditions as in Example 1 except that the intermediate layer was formed of the compound C.

<Example 4>

An organic electroluminescent device was fabricated under the same process conditions as in Example 1 except that the intermediate layer was formed of Compound D.

<Comparative Example>

Except that the host MADN was doped with a doping concentration of BD-1 at a doping concentration of 4% and formed to a thickness of 300 ANGSTROM under the same process conditions as in Example 1, except that an intermediate layer was not formed. Respectively.

The driving voltage, the luminous efficiency, the quantum efficiency, the luminance and the color coordinates of the organic electroluminescent device manufactured according to Examples 1 to 4 and Comparative Example were measured and shown in Table 1 below. The relationship between the wavelength and the luminous intensity is shown in FIG. 3 FIG. 4 shows the relationship between the voltage and the current, and FIG. 5 shows the relationship between the luminance and the current efficiency. (The current of the organic electroluminescent device was 10 mA / cm 2 at this time).

# Driving voltage
(V) Luminous efficiency Quantum efficiency
(%) Luminance
(Cd / m 2) Color coordinates Cd / A lm / W CIE_x CIE_y Comparative Example 5.41 4.29 2.49 3.68 428.5 0.138 0.156 Example 1 4.80 5.53 3.62 5.83 552.6 0.137 0.115 Example 2 4.63 4.51 3.06 4.69 450.7 0.139 0.117 Example 3 4.37 5.83 4.19 6.03 582.9 0.137 0.119 Example 4 4.58 5.84 4.00 5.64 584.3 0.135 0.132

Referring to Table 1 and FIGS. 3 to 5, Examples 1 to 4 of the present invention show the same color coordinates as those of the comparative example, and the driving voltage is decreased and the luminous efficiency, quantum efficiency and brightness are improved compared with the comparative example .

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100: organic electroluminescent device 110: anode
120: Hole injection layer 130: Hole transport layer
140: First light emitting layer 150:
160: second light emitting layer 170: electron transporting layer
180: electron injection layer 190: cathode

Claims (8)

Lt; RTI ID = 0.0 &gt; (1) &lt; / RTI &gt;
[Chemical Formula 1]

In Formula 1,
G ₁ and G ₂ each independently may be substituted or unsubstituted aromatic cyclic compound composed of C4 to C24, N1 to N3, or substituted and unsubstituted C4 to C24, or S1 and S2, respectively.
The method according to claim 1,
The G ₁ or G ₂ substituent may be an alkyl group such as methyl, ethyl, propyl, i-propyl, octyl, t- An alkoxy group such as methoxy, ethoxy, buthoxy and the like, trimethylsilyl, fluorine and chlorine, and the like.
The method according to claim 1,
Wherein G &lt; _{1 &gt;} and G &lt; ₂ &gt; are any one selected from the compounds shown below.

The method according to claim 1,
Wherein said compound is any one selected from the compounds shown below.

An organic electroluminescent device comprising at least two light emitting layers between an anode and a cathode,
And an intermediate layer disposed between the light emitting layers and in contact with the light emitting layers, wherein the intermediate layer comprises the compound according to any one of claims 1 to 4.
6. The method of claim 5,
Wherein the two or more light emitting layers emit light of the same or different colors.
6. The method of claim 5,
Wherein the two or more light emitting layers and the intermediate layer each have a thickness of 1 to 30 nm.
6. The method of claim 5,
And a charge generation layer disposed between the anode and the cathode.

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