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.