A bipolar emitting material for high efficient non-doped fluorescent organic light-emitting diode approaching standard deep blue

A deep blue emitting compound 9-(4′-(1,4,5-triphenyl-1H-imidazol-2-yl)-[1,1′-biphenyl] -4-yl)-9H-carbazole was designed and synthesized. The emitting compound characters as donor-π-acceptor structure with carbazole as the electron-donor and imidazole as the electron-acceptor. The emitting compound shows high quantum yield (0.87) in solution and good thermal stability. The emitting compound exhibits bipolar transporting characteristics identified by single-carrier devices. The non-doped fluorescent organic light-emitting diode with the emitting compound as emitting layer exhibits emission peak at 420 nm and full width at half maximum of 54 nm, maximum current efficiency of 2.30 cd/A, and maximum power efficiency of 1.52 lm/W, which are higher than most reported deep blue emitters with a y coordinate ≤0.064. The chromaticity coordinate is stable at (0.166, 0.064) with increasing operation voltage.