Highly efficient green phosphorescent single-layered organic light-emitting devices

The authors studied the highly efficient green electrophosphorescent light-emission from single-layered organic light-emitting devices made by a simple wet process with a composite solution. The solution was prepared by predissolving organic charge transport, host compounds with green phosphorescent guest iridium complex, and a copolymer of oxadiazole units. The fabricated devices show excellent performances, i.e., operation at relatively low voltages, resulting in a high peak current efficiency (eta(c)) of 48 cd/A and power efficiency (eta(p)) of 45 lm/W at a current density of 0.02 mA/cm(2). Even at 1000 cd/m(2) (2 mA/cm(2)), high eta(c) of 50 cd/A and eta(p) of 22 lm/W were obtained. (c) 2006 American Institute of Physics.