Solution-processable cyclometalated gold(III) complexes for high-brightness phosphorescent white organic light-emitting devices

Abstract

We report two yellow-emitting cyclometalated gold(III) complexes serving as phosphorescent dopants for high-brightness solution-processed white organic light-emitting devices (WOLEDs). Dichromatic WOLEDs consisting of our newly synthesized Au–Y or Au–wY for yellow emission in combination with FIrpic for blue emission have been studied. Notably, white emissions in terms of Commission Internationale de L’Eclairage coordinates of (0.31, 0.39) and (0.40, 0.47) and color rendering indices of 66 and 69 have been accomplished with Au–Y- and Au–wY-based WOLEDs. In addition, current efficiencies of 26.0 and 25.7 cd/A corresponding to external quantum efficiencies of 11.0% and 10.5% are achieved and can be maintained at 19.8 and 25.3 cd/A at a high brightness level of 10,000 cd/m2 for these devices. Such high-performance WOLEDs in terms of small efficiency roll-offs over a wide brightness range are believed to be due to the use of gold(III) complexes with very short-lived emission lifetimes of ~ 1 μs, high photoluminescence quantum yields of up to 86% and broad yellow emission bandwidths of up to 107 nm. This study opens up the possibility of using solution-processable cyclometalated organogold(III) complexes with short-lived emissive excited states for the fabrication of WOLEDs, especially for high-brightness applications.