Undoped, red organic light-emitting diodes based on a N,N,N', N'-tetraphenylbenzidine (TPD) derivative as red emitter with a triphenylamine derivative as hole-transporting layer

摘要

A novel dicyanovinyl-functionalized N,N,N',N'-tetraphenylbenzidine (TPD) derivative, N,N'-bis[4-(1,1-dicyanovinyl)phenyl]-N,N-bis(4-fluorophenyl)benzidine and a novel triphenylamine-based derivative, 4,4',4"-tris{[di(p-tolyl)amino]phenyl}triphenylamine were synthesized and employed as red molecular emitter and hole-transporting layer, respectively, in an undoped organic light-emitting diode devices. The device based on the TPD-FCN emitter and DBTPA hole-transporting material, which was fabricated in a facile non-doped configuration, achieved maximum luminance of 3400 cd m~(-2) at a driven voltage of 17.5 V and maximum luminous efficiency of 3.04 cd A~(-1). Interestingly, the device reached a brightness of 1399 cd m~(-2) and luminous efficiency of 2.85 cd A~(-1) at the low current density of 20 mA cm~(-2).