KR100676966B1 - Deuterated organic electroluminescence material, preparation method thereof and organic light emitting diode using the same - Google Patents

Abstract

The present invention relates to a material of a deuterated organic electroluminescent device, a manufacturing method thereof and an organic electroluminescent device using the same. The organic EL device using the material of the deuterated organic EL device according to the present invention is excellent in luminous efficiency, brightness, power efficiency, thermal stability and the like.

Description

Deuterated organic electroluminescent compound, preparation method thereof, and organic electroluminescent device using the same TECHNICAL FIELD

1 shows the results of efficiency evaluation of devices using Compound A and Compound B (■: Compound A, ●: Compound B).

Figure 2 shows the results of evaluating the efficiency of the device using the compound C and compound (■: Compound C, ●: Compound D).

Figure 3 shows the results of evaluating the efficiency of the device using the compound E and compound F (■: Compound E, ●: Compound F).

The present invention relates to a deuterated organic electroluminescent material, a method of manufacturing the same, and an organic electroluminescent device using the same.

US Pat. No. 6,699,599 discloses a phosphorescent material in which some or all of the hydrogen atoms of Ir (ppy) ₃ are replaced with deuterium. In general, when hydrogen in the compound is substituted with deuterium, it is possible to exhibit higher photoluminescence efficiency since the exciton is better formed. This is because the bond strength between carbon and deuterium is stronger than the bond strength between carbon and hydrogen, so that when deuterium is substituted, the bond length between carbon and deuterium is short, and thus the van der Waals forces are smaller, resulting in higher fluorescence efficiency. For losing.

However, the US Patent No. 6,699, 599 does not give a numerical value of how much the efficiency is improved compared to the case of unsubstituted hydrogen in Ir (ppy) ₃ , and only a slight improvement effect I can only guess.

An object of the present invention is to provide a deuterated low molecular weight organic electroluminescent compound which can be applied to a light emitting layer, a hole transporting layer and / or an electron transporting layer of an organic light emitting device, a manufacturing method thereof and an organic light emitting device using the same.

Another object of the present invention is to provide an organic electroluminescent compound, a method for manufacturing the same, and an organic light emitting device using the same, which can remarkably improve the luminous efficiency, thermal stability, and the like of the device, as compared with the conventional organic electroluminescent compound.

Another object of the present invention is to provide an organic electroluminescent compound which is operated at a low voltage, can realize various colors, and has a fast response speed, a method of manufacturing the same, and an organic light emitting device using the same.

An object of the present invention as described above is a substituted or unsubstituted carbazole, aryl, aromatic amine, aliphatic amine, phenoxazine and phenocazine in the stilbene or biphenyl ring is substituted with a heteroaromatic ring selected from the group By providing a compound having a structure and in which at least one hydrogen atom present in the molecule is substituted with deuterium.

Therefore, the organic electroluminescent compound according to the present invention has a structure represented by the following Chemical Formula 1.

Wherein m and n are each independently 0 or 1,

when n = 0 B is N, when n = 1 A is carbon, B is CH,

Ar and Ar 'are the same or different substituted or unsubstituted aromatic groups selected from the group consisting of phenyl, toluyl, biphenyl, naphthyl, carbazole, anthracenyl and fluorenyl,

Ar and Ar 'may be connected to each other or directly connected without a connector by a connector selected from the group consisting of O, S, N-Ar, NR, CH ₂ and SiR ₂ ,

In the case of a substituted aromatic group the substituent is deuterium, CN, F, Cl or Br,

R and R 'are each independently selected from the group consisting of hydrogen, deuterium, CN, F and CH ₃ ,

The compound of formula 1 necessarily has one or more deuterium per molecule.

In Chemical Formula 1, the compound having m is 1 may be prepared by reacting a secondary amine compound represented by Chemical Formula 2 with a stilbene compound represented by Chemical Formula 3 by an Ulman reaction or a CN bonding reaction using a palladium catalyst. have.

The compound of Formula 1 wherein n is 1 may be obtained by reacting the compound of Formula 2 with a benzaldehyde compound represented by Formula 4 to obtain a compound represented by Formula 5, and coupling two molecules of Compound 5 to each other.

Meanwhile, the compound of Formula 1 where n = 0 may be obtained by converting a biphenyl compound represented by the following Formula 6 into a phosphonate compound and activating it to react with benzophenone.

In the above Chemical Formulas 2 to 6, Ar, Ar ', R and R' are the same as those defined for Chemical Formula 1, and X and Y are each a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine atoms.

In preparing the compound of Formula 1 of the present invention, deuterium may be introduced by adding a compound to be introduced into deuterium in an aqueous solution in which boron trifluoride is dissolved in heavy water and stirring for 48 hours or more. In this case, deuterium may be obtained by obtaining a compound of Formula 1 that is not deuterated using a starting material that is not deuterated, or deuteration of the starting material, or a compound of Formula 1 that is deuterated using the starting material first. have.

The present invention also relates to an electroluminescent device using the compound of Formula 1 above. The compound of formula 1 according to the present invention has a positive electrode for injecting holes made of indium tin oxide (ITO) having a large work function, and various work functions such as aluminum, lithium fluoride / aluminum, copper, silver, calcium, gold, or magnesium. It is applied between cathodes injecting electrons made of metal or alloys thereof, and may be applied to a light emitting layer, a hole transporting layer and / or an electron transporting layer of a light emitting device.

Example

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. However, the examples are only illustrative of the present invention, and the scope of the present invention is not limited to the examples.

In the present invention, the structure of the compound prepared in Example was determined by ¹ H-NMR, elemental analysis, mass spectrometry, etc., and the compound was dissolved in dichloromethane to measure UV and PL spectra, and an organic light emitting device was fabricated and their Luminescent properties were evaluated.

Example 1: Preparation of 4,4'-di (9-carbazolyl) stilbene-d4 (Compound A) substituted with deuterium

50 ml of heavy water was added to a 100 ml flask, 12 g (0.07 mole) of carbazole was added thereto, and boron trifluoride gas was injected into the reaction mixture for 15 minutes with stirring, followed by stirring at room temperature for 48 hours. The reaction mixture was poured into 200 ml of distilled water, neutralized by addition of caustic soda until the pH of the solution reached 7, followed by filtration and drying. The dried reaction was dissolved in toluene and purified by silica gel chromatography to give 10.8 g (0.064 mole) of carbazole-d2 (yield: 89%).

Into a 100 ml flask, 10 g (60 mmol) of carbazole-d2 and 4-fluoro benzaldehyde (7.45 g, 60 mmol, manufactured by Aldrich) were added, 16.5 g of potassium carbonate was added, and dimethylformamide was used as a solvent. It was refluxed and stirred for 4 hours. After completion of the reaction, the reaction was confirmed by TLC, and after completion of the reaction, the reaction mixture was purified by column chromatography to obtain 4-carbazolylbenzaldehyde-d2 14 g (0.051 mole) (yield: 87%).

5 g (0.0182 mole) of 4-carbazolylbenzaldehyde-d2 was placed in a flask, dissolved in a dehydrated tetrahydrofuran solvent, followed by 3.0 g (0.0455 mole) of zinc powder, and 4.0 ml (0.0364 mole) of titanium tetrachloride. Was added slowly to the reaction mixture for 30 minutes. Titanium tetrachloride was added and stirred under reflux for 6 hours. The resulting reaction was purified by column chromatography and recrystallized from toluene to obtain 3.7 g (0.0071 mole) of the target compound (Compound A). The yield of the final product was 78.5%, showing a very stable form.

¹ H-NMR (CDCl ₃ , 300 MHz) δ (ppm) 8.16 (d), 7.8 (d), 7.6 (d), 7.5-7.4 (m), 7.3 (t)

In order to compare the luminescence properties of the compound obtained in Example 1, 4,4'-dicarbazolyl stilbene (Compound B) was prepared, and the organic field was After the light emitting device was constructed, their light emission characteristics were evaluated.

ITO / m-MTDATA (600nm) / NPB (200nm) / Compound A (300nm) / Alq3 (250nm) / LiF (10nm) / Al

ITO / m-MTDATA (600nm) / NPB (200nm) / Compound B (300nm) / Alq3 (250nm) / LiF (10nm) / Al

Table 1 below summarizes the brightness and current efficiency of Compound (A), and Table 2 summarizes the brightness and current efficiency of Compound (B). From Tables 1 and 2, it can be seen that the brightness and current efficiency of the compound according to Example 1 of the present invention are superior to that of Compound B.

Current density (mA / cm ² ) Voltage (V) Luminance (cd / m ² ) Color coordinates (CIE) Efficiency (cd / A) 10 6.0 231 (0.160, 0.124) 2.3 25 6.8 579 (0.169, 0.133) 2.3 50 7.7 1163 (0.170, 0.133) 2.3 100 8.7 2,437 (0.170, 0.133) 2.4

Current density (mA / cm ² ) Voltage (V) Luminance (cd / m ² ) Color coordinates (CIE) Efficiency (cd / A) 10 6.0 120 (0.170, 0.135) 1.2 25 6.8 308 (0.169, 0.133) 1.2 50 7.6 609 (0.170, 0.133) 1.2 100 8.5 1,200 (0.170, 0.133) 1.2

The efficiency according to the current of the above evaluation results is shown in FIG.

Example 2: Preparation of 4,4'-bis (2,2-diphenylethen-1-yl) biphenyl-d10 (Compound C)

In a 100 ml flask, 18 g (0.21 mole) of benzene-d6, 20 g (0.14 mole) of benzoyl chloride, and 6.8 g (0.05 mole) of aluminum trichloride were added and refluxed for 6 hours. Then, the reaction mixture was poured into 100 ml of water, extracted with toluene, and then the organic layer was purified by silica gel chromatography to obtain 24 g (0.128 mole) of benzophenone-d5 with a yield of 90%.

In a 100 ml flask, 20 g (0.057 mole) of 4,4'-bromomethylbiphenyl and 37 ml (0.22 mole) of triethylphosphite were added, refluxed for 2 hours, the reaction was cooled to room temperature, and then 50 ml. Was added thereto, stirred for 2 hours, and then filtered to obtain 21 g (0.0497 mole) of 4,4'-bis (diethoxyphosphorylmethyl) biphenyl in a solid state in a yield of 87%.

To a 100 ml flask, 2.4 g (0.013 mole) of benzophenone-d5 and 2.17 g (0.05 mole) of 4,4'-bis (diethylphosphonateyl) biphenyl were added, anhydrous tetrahydrofuran was added, followed by sodium hydride. 0.37 g (0.015 mole) was added and heated to reflux for 12 h. The reaction solution was poured into methanol, the precipitate was filtered off, the filtrate was concentrated and the concentrate was purified by silica gel column chromatography to give 4,4'-bis (2,2-diphenylethen-1-yl) biphenyl 1.1 g (0.0021 mole) of -d10 (Compound C) were obtained. The yield of the final product was 41% and showed a very stable form.

¹ H-NMR (CDCl ₃ , 300 MHz) δ (ppm) 7.35 to 7.32 (m), 7.26 (s), 7.25 to 7.2 (m), 7.4 (d), 6.98 (s)

4,4'-bis (2,2-diphenyl-ethen-1-yl) biphenyl (Compound D) was synthesized and the luminescent properties and fertilizer of the deuterated compound (Compound C) prepared in Example 2 To this end, organic electroluminescent devices were constructed using these as light emitting layers, respectively, and then their light emission characteristics were evaluated.

ITO / m-MTDATA (450nm) / NPB (150nm) / Compound C (300nm) / Alq3 (250nm) / LiF (10nm) / Al

ITO / m-MTDATA (450nm) / NPB (150nm) / Compound D (300nm) / Alq3 (250nm) / LiF (10nm) / Al

Table 3 below summarizes the brightness and current efficiency of Compound C, and Table 4 summarizes the brightness and current efficiency of Compound D, respectively. From Tables 3 and 4, it can be seen that the luminance and current efficiency of the compound of Example 2 of the present invention are superior to that of Compound D.

Current density (mA / cm ² ) Voltage (V) Luminance (cd / m ² ) Color coordinates (CIE) Efficiency (cd / A) 10 6.9 472 (0.156, 0.126) 4.7 25 7.9 1,130 (0.155, 0.123) 4.5 50 8.7 2,206 (0.155, 0.121) 4.4 100 9.6 4,203 (0.154, 0.118) 4.2

Current density (mA / cm ² ) Voltage (V) Luminance (cd / m ² ) Color coordinates (CIE) Efficiency (cd / A) 10 6.8 353 (0.156, 0.119) 3.5 25 7.7 845 (0.155, 0.117) 3.4 50 8.4 1,622 (0.155, 0.115) 3.2 100 9.2 3,097 (0.155, 0.112) 3.1

Figure 2 is a schematic of the current efficiency data of the evaluation results presented in Tables 3 and 4.

Example 3: Preparation of 4,4'-bis (1,2'-dinaphthylamino) stilbene-d4 (Compound E)

In a 100 ml flask, 10 g (0.069 mole) of 2-naphthol, 1-naphthylamine (10 g, 0.070 mole, product of Aldrich) and 0.8 g of phosphoric acid were added, and then 1,2-dichlorobenzene was used as a solvent. It was stirred at reflux for 12 hours. After completion of the reaction, the reaction was confirmed by TLC. After completion of the reaction, the reaction mixture was purified by column chromatography, obtaining 14 g (0.052 mole) of 1,2'-dinaphthylamine (yield: 75%).

1 g (2.96 mmol) of 4,4'-dibromostilbene and 1.8 g (6.79 mmol) of 1,2'-dinaphthylamine were dissolved in 20 mL of toluene. 0.14 g (0.15 mmol) of tris dibenzylidene acetone dipalladium was added under nitrogen, followed by 1.1 g (11.4 mmol) of NaOBu ^t , and 0.3 g (1.48 mmol) of (t-Bu) ₃ P was added to the reaction solvent. . The reaction mixture was stirred at reflux for 12 hours. The reaction was terminated by TLC and the reaction was cooled to room temperature when the reaction was complete. The reaction solution was poured onto a thin pad of silica, subjected to short column chromatography, and washed with dichloromethane. The filtrate was distilled under reduced pressure to remove the solvent, dried and placed in a 100 ml flask. 50 ml of heavy water was added to the flask, and boron trifluoride gas was injected into the reaction mixture for 15 minutes, and the mixture was stirred at room temperature for 48 hours. The reaction mixture was poured into 200 ml of distilled water, neutralized by addition of caustic soda until the pH of the solution reached 7, followed by filtration and drying. The dried reaction was dissolved in toluene and purified by silica gel chromatography to obtain 1.64 g (2.29 mmole) of 4,4'-bis (1,2'-dinaphthylamino) stilbene-d4 (Compound E). The yield of the final product was 78%, showing a very stable form.

¹ H-NMR (CDCl ₃ , 300 MHz) δ (ppm) 7.92 (q), 7.8 (d), 7.67 to 7.75 (m), 7.4 to 7.73 (m), 7.23 to 7.38 (m), 7.02 (d), 6.9 (s)

In order to synthesize 4,4'-bis (1,2'-dinaphthylamino) stilbene (Compound F) and to fertilize it with the luminescent properties of the deuterated compound (Compound E) prepared in Example 3, Each of these was used as a dopant for the light emitting layer to form an organic electroluminescent device as follows, and their luminescence properties were evaluated.

ITO / m-MTDATA (450nm) / NPB (150nm) / DPVBi (275nm) + Compound E (25nm) / Alq3 (250nm) / LiF (10nm) / Al

ITO / m-MTDATA (450nm) / NPB (150nm) / DPVBi (275nm) + Compound F (25nm) / Alq3 (250nm) / LiF (10nm) / Al

Table 5 summarizes the brightness and current efficiency of Compound E, and Table 6 summarizes the brightness and current efficiency of Compound F, respectively. From Tables 5 and 6, it can be seen that the brightness and current efficiency of the compound of Example 3 of the present invention are superior to that of Compound F and the color purity is improved.

Current density (mA / cm ² ) Voltage (V) Luminance (cd / m ² ) Color coordinates (CIE) Efficiency (cd / A) 10 6.0 553 (0.147, 0.164) 5.5 25 6.8 1,305 (0.146, 0.163) 5.2 50 7.9 2,423 (0.146, 0.163) 4.8 100 8.8 4,385 (0.146, 0.160) 4.4

Current density (mA / cm ² ) Voltage (V) Luminance (cd / m ² ) Color coordinates (CIE) Efficiency (cd / A) 10 6.0 468 (0.146, 0.167) 4.7 25 6.9 1,107 (0.146, 0.165) 4.4 50 7.7 2,028 (0.145, 0.163) 4.1 100 8.6 3,508 (0.145, 0.160) 3.5

3 is a diagram of current efficiency data among evaluation results shown in Tables 5 and 6. FIG.

From the above results, it can be seen that the deuterated compound according to the present invention exhibits a similar degree of luminescence properties as compared with the undeuterated compound, and is superior in brightness and current efficiency.

All simple modifications or changes of the present invention can be easily made by those skilled in the art, and it should be understood that all such modifications or changes are included in the scope of the present invention.

According to the present invention, a material of a deuterated organic EL device, a method of manufacturing the same, and an organic EL device using the same are provided. The organic EL device using the material of the deuterated organic EL device according to the present invention is excellent in luminous efficiency, brightness, power efficiency, thermal stability and the like.

Therefore, the compound of the present invention can be applied to the light emitting layer, the hole transporting layer and / or the electron transporting layer of the organic electroluminescent device.

Since the compound according to the present invention is a low molecular color compound, when applied to a light emitting device, blue light emission can be driven at a low voltage, and because it is an organic material having a conjugated double bond, it is possible to implement various colors by using another light emitting material as a dopant, Luminance and luminous efficiency are also excellent.

Claims (9)

Deuterated compounds represented by the following formula (1): [Formula 1]

Wherein m and n are each independently 0 or 1, when n = 0 B is N, when n = 1 A is carbon, B is CH, Ar and Ar 'are the same or different substituted or unsubstituted aromatic groups selected from the group consisting of phenyl, toluyl, biphenyl, naphthyl, carbazole, anthracenyl and fluorenyl, Ar and Ar 'may be connected to each other or directly connected without a connector by a connector selected from the group consisting of O, S, N-Ar, NR, CH ₂ and SiR ₂ , In the case of a substituted aromatic group the substituent is deuterium, CN, F, Cl or Br, R and R 'are each independently selected from the group consisting of hydrogen, deuterium, CN, F and CH ₃ , The compound of formula 1 necessarily has one or more deuterium per molecule. The compound of claim 1, wherein Ar and Ar ′ are linked to each other to form a carbazole ring. The compound of claim 1, wherein m = 1, n = 0 and Ar and Ar ′ are linked to each other to form a carbazole ring. The compound of claim 1, wherein m = 1, n = 0 and Ar and Ar ′ are each a naphthyl group. The compound of claim 1, wherein m = 0, n = 1 and Ar and Ar ′ are each a phenyl group. A method for preparing a compound of Formula 1 comprising reacting an amine compound represented by Formula 2 with a compound represented by Formula 3. [Formula 1]

[Formula 2]

[Formula 3]

Wherein m and n are each independently 0 or 1, when n = 0 B is N, when n = 1 A is carbon, B is CH, Ar and Ar 'are the same or different substituted or unsubstituted aromatic groups selected from the group consisting of phenyl, toluyl, biphenyl, naphthyl, carbazole, anthracenyl and fluorenyl, Ar and Ar 'may be connected to each other or directly connected without a connector by a connector selected from the group consisting of O, S, N-Ar, NR, CH ₂ and SiR ₂ , In the case of a substituted aromatic group the substituent is deuterium, CN, F, Cl or Br, R and R 'are each independently selected from the group consisting of hydrogen, deuterium, CN, F and CH ₃ , X is a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine atoms, The compound of formula 1 necessarily has one or more deuterium per molecule. (1) reacting an amine compound represented by Formula 2 with a compound represented by Formula 4 to obtain a compound represented by Formula 5; (2) coupling a compound of Formula 5 to obtain a compound of Formula 1; [Formula 1]

[Formula 2]

[Formula 4]

 [Formula 5]

Wherein m and n are each independently 0 or 1, when n = 0 B is N, when n = 1 A is carbon, B is CH, Ar and Ar 'are the same or different substituted or unsubstituted aromatic groups selected from the group consisting of phenyl, toluyl, biphenyl, naphthyl, carbazole, anthracenyl and fluorenyl, Ar and Ar 'may be connected to each other or directly connected without a connector by a connector selected from the group consisting of O, S, N-Ar, N-R, CH2 and SiR2, In the case of a substituted aromatic group the substituent is deuterium, CN, F, Cl or Br, R and R 'are each independently selected from the group consisting of hydrogen, deuterium, CN, F and CH3, Y is a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine atoms, The compound of formula 1 necessarily has one or more deuterium per molecule. A method for preparing a compound of Formula 1, comprising converting a compound represented by Formula 6 into a phosphonate compound and activating it to react with benzophenone to obtain a compound of Formula 1. [Formula 1]

[Formula 6]

Wherein m and n are each independently 0 or 1, when n = 0 B is N, when n = 1 A is carbon, B is CH, Ar and Ar 'are the same or different substituted or unsubstituted aromatic groups selected from the group consisting of phenyl, toluyl, biphenyl, naphthyl, carbazole, anthracenyl and fluorenyl, Ar and Ar 'may be connected to each other or directly connected without a connector by a connector selected from the group consisting of O, S, N-Ar, N-R, CH2 and SiR2, In the case of a substituted aromatic group the substituent is deuterium, CN, F, Cl or Br, R and R 'are each independently selected from the group consisting of hydrogen, deuterium, CN, F and CH3, X is a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine atoms, The compound of formula 1 necessarily has one or more deuterium per molecule. An organic electroluminescent device comprising the compound according to any one of claims 1 to 5.

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