Effect of doping concentration on device performances of triplet mixed host devices

Device performances of triplet mixed host devices were correlated with host composition and doping concentration. A mixed host of (4,4′-N,N′-dicarbazole)biphenyl (CBP) and spirobifluorene type host (PH1) was used and quantum efficiency of mixed host devices was optimized in CBP:PH1 (90:10) devices at all doping concentration. Quantum efficiency was not greatly affected by host composition at high doping concentration, while host composition was critical to quantum efficiency at low doping concentration. In addition, doping concentration had no influence on quantum efficiency of CBP:PH1 (90:10) devices.