Gold nanoparticles (GNPs) on the performance of the phosphorescent organic light-emitting devices
(OLEDs) were investigated. The green phosphorescent OLEDs with GNPs incorporated in hole transporting
layer (HTL) or hole blocking layer (HBL) were fabricated using thermal evaporation technique.
The results indicated that the performance of the OLEDs with GNPs were dependent on the position
of the GNPs. The optimized device with GNPs in HBL shows enhanced current efficiency and reduced
efficiency roll-off. However, the efficiency of the device with GNPs in HTL was decreased. The detailed
physical mechanism is investigated in order to unveil such difference.