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

摘要

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 (η_c) of 48 cd/A and power efficiency (η_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 η_c of 50 cd/A and η_p of 22 lm/W were obtained.