Bipolar blue phosphorescent host material based on carbazole and 1,2,4-triazole

A technology of blue phosphorescence and host materials, which is applied in the direction of luminescent materials, electric solid-state devices, semiconductor devices, etc., can solve the problem of not being able to meet the requirements of deep blue phosphorescent OLED devices, the triplet energy level is not very high, and reduce the triplet energy of the host material. Level and other issues, to achieve good double carrier transport characteristics, prevent energy return, and improve solubility

Active Publication Date: 2016-10-26
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
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  • Claims
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Problems solved by technology

[0006] The triplet energy levels of bipolar host materials based on carbazole and triazole as donor and acceptor groups reported in the above literature are not very high, which cannot meet the

Method used

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  • Bipolar blue phosphorescent host material based on carbazole and 1,2,4-triazole
  • Bipolar blue phosphorescent host material based on carbazole and 1,2,4-triazole
  • Bipolar blue phosphorescent host material based on carbazole and 1,2,4-triazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] 2-cyanopyridine (5.21g, 50mmol), hydrazine hydrate (2.50g, 50mmol), and 25mL of ethanol were sequentially added to a 250mL two-necked round-bottomed flask, and reacted at a low temperature of 0°C for 8 hours to form a viscous light yellow paste. The excess ethanol was removed under vacuum at room temperature, the solid was washed with a small amount of ether, filtered, and dried under vacuum at room temperature for 3 hours to obtain white crystals of (2-pyridine)aminohydrazone.

[0034] (2-pyridine)aminohydrazone (4.08g, 30mmol), Na 2 CO 3 (3.15g, 30mmol), benzoyl chloride (4.20g, 30mmol), and 30mL tetrahydrofuran were added to a 250mL two-neck round bottom flask, reacted at room temperature for 6h, and filtered. The filtrate was refluxed in 30ml of ethylene glycol for 30min to dehydrate and ring-closed, filtered, dried in vacuo for 8h, and recrystallized from ethanol to obtain 2-(3-phenyl-1H-1,2,4-triazol-5-yl) Pyridine is white needle crystal, the yield is 92%.

[...

Embodiment 2

[0053] Carbazole (5.0g, 30mmol), 1,6-dibromobutane (31.9g, 150mmol), TBAB (1.0g, 3mmol), 40mL toluene, 50% KOH solution (25mL), were added to a 250mL two-necked round-bottomed flask in turn , reflux reaction under nitrogen protection for 12h. Cool to room temperature, add 50mL deionized water, extract with dichloromethane (50×3mL), wash the organic layer several times with deionized water, dry over anhydrous magnesium sulfate, filter, distill under reduced pressure, and separate and purify the crude product by column chromatography (Petroleum ether: dichloromethane = 8:1), 9-(6-bromobutyl)-9H-carbazole (L3) was obtained as white crystals with a yield of 80%.

[0054] 1 H NMR δ: 8.13(dt, 2H, J=7.8 Hz, 1.2 Hz), 7.48-7.47(m, 2H), 7.42(d, 2H, J=8.4 Hz), 7.26-7.24m, 2H), 4.35( d, 2H, J =7.2 Hz), 3.36(d, 1H, J =7.2 Hz), 1.96-1.80 (m, 1H), 1.52-1.39(m, 1H).

[0055] 2-(3-Phenyl-1H-1,2,4-triazol-5-yl)pyridine (2.21g, 10mmol), 9-(6-bromobutyl)-9H-carbazole (3.61g, 12mmol ), TBAB (0...

Embodiment 3

[0062] Carbazole (5.0g, 30mmol), 1,6-dibromoethane (27.8g, 150mmol), TBAB (1.0g, 3mmol), 40mL toluene, 50% KOH solution (25mL), were added to a 250mL two-necked round-bottomed flask in sequence , reflux reaction under nitrogen protection for 12h. Cool to room temperature, add 50mL deionized water, extract with dichloromethane (50×3mL), wash the organic layer several times with deionized water, dry over anhydrous magnesium sulfate, filter, distill under reduced pressure, and separate and purify the crude product by column chromatography (Petroleum ether: dichloromethane = 8:1), 9-(6-bromoethyl)-9H-carbazole was obtained as white crystals with a yield of 85%.

[0063] 2-(3-Phenyl-1H-1,2,4-triazol-5-yl)pyridine (2.21g, 10mmol), 9-(6-bromoethyl)-9H-carbazole (2.22g, 12mmol ), TBAB (0.32g, 1mmol), 30mL toluene, 50% KOH solution (15mL), were successively added to a 250mL two-necked round bottom flask, protected by nitrogen, stirred at room temperature for 30min, and heated to reflu...

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Abstract

The invention discloses a bipolar blue phosphorescent host material which is as shown in a structural general formula (I) and takes carbazole and 1,2,4-triazole as a donor and a receptor respectively. The triplet-state energy level of the host material is improved by introducing an alkyl chain into the portion between carbazole and 1,2,4-triazole to prevent a conjugated structure between the donor and the receptor. When the bipolar blue phosphorescent host material is applied to dark blue phosphorescent organic electroluminescence devices, energy return between a host and a guest in the blue phosphorescent devices can be effectively prevented, and the luminous efficiency of the devices is improved. Please see the formula in the description.

Description

technical field [0001] The invention relates to a phosphorescent host material, in particular to a phosphorescent host material capable of emitting blue light with carbazole and triazole as donor and acceptor groups. Background technique [0002] Phosphorescent organic electroluminescent devices (PhOLED: Phosphorescent organic-light emitting devices) have great application prospects in the fields of display and solid-state lighting. However, compared with other materials, the lack of blue phosphorescent host materials has seriously restricted the development of its industrialization. The main reasons for this situation are: on the one hand, the triplet energy level of the blue phosphorescent host material is not high enough, and the energy return from the guest to the host reduces the efficiency of the device; on the other hand, the carrier transport of the blue phosphorescent host material The performance is poor, the probability of electron and hole recombination is low, ...

Claims

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Application Information

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IPC IPC(8): C07D401/14C09K11/06H01L51/54
CPCC09K11/06C07D401/14C09K2211/1059C09K2211/1029C09K2211/1007H10K85/654H10K85/6572H10K50/00
Inventor 许慧侠孙鹏王科翔杨婷婷苗艳勤王华许并社
Owner TAIYUAN UNIV OF TECH
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