Luminescent materials containing pyrene and carbazole for organic light-emitting diode

Abstract

Three N-substituted 3,6-dipyrenylcarbazole derivatives (2PCT, 4P2C and 2PCP) were synthesized and applied as blue light-emitting or hole-transporting materials in organic light-emitting diode (OLED). In CH2Cl2 solution, the 4- (diphenylamino)phenyl substituent increases electronic-vibration coupling in the excited state whereas the substituents have no effect on the photophysical properties of the compounds in solid state thin film. Toluyl and 4-(diphenylamino)phenyl substitutents promote electro-oxidative coupling of 2PCT and 2PCP in solution. All derivatives show high thermal stability and can be used as both emitting and holetransporting materials in OLED. 2PCP exhibits the most promising optoelectronic properties as it gives the highest maximum luminance of 1,600 cd/m2 at 8.8 V with the lowest turn-on voltage of 3.8 V