High-efficiency yellow double-doped organic light-emitting devices based on phosphor-sensitized fluorescence

摘要

We demonstrate high-efficiency yellow organic light-emitting devices (OLEDs) employing 2-methyl-6-2,3,6,7-tetrahydro-1H,5H-benzoijquinolizin-9-yl)ethenyl-4H-pyran-4-ylidene propane-dinitrile (DCM2) as a fluorescent lumophore, with a green electrophosphorescent sensitizer, fac tris(2-phenylpyridine) iridium Ir(ppy)_(3) co-doped into a 4,4′-N,N′-dicarbazole-biphenyl host. The devices exhibit peak external fluorescent quantum and power efficiencies of 9±1 (25 cd/A) and 17±2 lm/W at 0.01 mA/cm~(2), respectively. At 10 mA/cm~(2), the efficiencies are 4.1±0.5 (11 cd/A) and 3.1±0.3 lm/W. We show that this exceptionally high performance for a fluorescent dye is due to the ～100 efficient transfer of both singlet and triplet excited states in the doubly doped host to the fluorescent material using Ir(ppy)_(3) as a sensitizing agent. These results suggest that 100 internal quantum efficiency fluorescent OLEDs employing this sensitization process are within reach.