Abstract
Organic electrophosphorescent devices using several small molecules as a host and Ir(ppy)3 as a green emitting guest have been fabricated by spin coating. We used new host materials in which a cyclohexanyl or adamatyl group was inserted between two phenyl rings of CBP (named Cy-Cz, Ad-cz). The device with Cy-Cz host material and a guest concentration of 24wt% showed an external quantum efficiency of 11% and a power efficiency of 27lm/W at 100cd/m2. These results suggest that small molecule-based organic electrophosphorescent devices fabricated by spin coating can be highly efficient.