A versatile triphenylamine/fluoranthene-based derivative as a nondoped green-emitting, hole-transporting interlayer for electroluminescent devices.

ABSTRACT

A new triphenylamine-bridged fluoranthene derivative, 4-(7,10-diphenylfluoranthen-8-yl)-N-[4-(7,10-diphenylfluoranthen-8-yl)phenyl]-N-phenylaniline (BDPFPA), with a high glass transition temperature of 220 °C has been synthesized and characterized. BDPFPA is a highly fluorescent and versatile material that can be used as a nondoped green emitter and as a hole transporter. BDPFPA was used in a standard trilayer device as the emitting layer, which showed a low turn-on voltage (<3 V) and a high efficiency of 11.6 cd A(-1). The device also shows little efficiency roll-off at high brightness. For example, the efficiency can still be maintained at 11.4 cd A(-1) (5.4 lm W(-1)) at a brightness of 10,000 cd m(-2). These results are among the best reported for nondoped fluorescent green organic light-emitting diodes. A simple bilayer device, in which BDPFPA serves as a hole-transporting layer, has a maximum power efficiency of 3.3 lm W(-1) and the performance is nearly 40 % higher than that of an N,N'-bis(1-naphthyl)-N,N'- diphenyl-1,1'-biphenyl-4,4'-diamine (NPB)-based standard device.