基于新型三取代苯衍生物的双极性主体材料及其高效蓝色电致磷光

New trisubstituted benzene derivatives bipolar host material for efficient blue electrophosphorescence

高性能蓝光磷光主体材料是实现高性能电致发光器件的重要因素之一。本文选取咔唑和二苯并[b,d]呋喃作为空穴传输基团和氰基苯基作为电子传输基团,通过合理的分子设计,制备了两例基于三取代苯衍生物的具有高三重态能级的新型双极性主体材料(材料1和2)。材料1和2在非极性或弱极性溶剂中具有强烈的蓝紫色荧光发射。研究发现,将氰基基团引入到苯环的不同位置可以有效地调节双极性主体材料的三重态能级(T1),特别是对于具有更高三重态能级的材料1,该化合物适用于制备高效蓝色磷光有机发光二极管(OLED)。此外,三取代分子设计策略还为双极性主体材料提供了有利于实现高性能有机电致发光的空间位阻效应。以材料1为主体的蓝色磷光OLED的峰值电流效率、功率效率和外量子效率分别达到31.53 cd/A、26.93 lm/W和16.17%。初步结果表明,三取代分子设计策略在设计用于蓝色电致发光的高性能主体材料方面具有巨大潜力。

High-performance blue phosphorescent host materials are one of the important factors for realizing high-efficiency electroluminescent devices.A pair of trisubstituted benzene isomers(material 1 and 2)as new bipolar host material with tunable triplet energy levels are well designed and prepared by incorporating carbazole and dibenzo[b,d]furan as the hole transport moieties and cyanophenyl as the electron transport moiety.Material 1 and 2 show intense violet fluorescence in the non-polar or less polar solvents.The introduction of cyano unit into the different position on phenyl moiety could effectively tune the triplet energy level(T1)of the bipolar host materials,especially for material 1 with much higher T1,which is suitable for efficient blue phosphorescent organic light-emitting diodes(OLEDs).Moreover,the trisubstitution molecular design strategy also provides the bipolar host materials with the steric hindrance in favor of OLEDs.The peak current efficiency,power efficiency,and external quantum efficiency of the blue phosphorescent OLED using materiat 1 as host reach 31.53 cd/A,26.93 lm/W,and 16.17%,respectively.The preliminary results suggest that the trisubstitution molecular design strategy has great potential in designing new host materials for high-performance blue electroluminescence in the future.