Organic Light-Emitting Devices with High External Quantum Efficiency and Operational Stability Based on Highly Phosphorescent Cyclometalating Rhodium(III) Complexes

A series of orange–red-emitting cyclometalating rhodium(III) complexes have been synthesized, characterized, and applied as phosphorescent dopants to fabricate solution-processed and vacuum-deposited organic light-emitting devices (OLEDs). Various substituents on different positions of 2,3-diphenylquinoxaline (dpqx) cyclometalating ligands were introduced. High external quantum efficiencies of 9.40% and good operational half-lifetimes of up to 17 322 h at 100 cd m–2 were achieved. The results revealed that the fluorine atoms might improve the electroluminescence performance in terms of device lifetime, demonstrating the potential suitable phosphorescent materials for OLED application.