Enhanced current efficiency of organic light-emitting devices due to a broad localized surface plasmonic resonance of Au-ZnO nanocomposites

Organic light-emitting devices (OLEDs) were fabricated with Au-ZnO nanocomposites (NCs) synthesized by using a sol-gel process in order to enhance their current efficiency. Photoluminescence (PL) and time-resolved PL spectra showed an enhanced fluorescence emission due to the localized surface plasmonic resonance (LSPR) of the Au-ZnO NCs. The electroluminescence intensity of the OLEDs with Au-ZnO NCs at a wavelength of 523 nm was significantly increased by a factor of 0.84 in comparison with that of the OLEDs with ZnO nanoparticles (NPs). The current efficiency of the OLEDs with Au-ZnO NCs at 50 mA/cm2 was 0.46 cd/A higher than that of the OLEDs with ZnO NPs. The enhanced current efficiency in the OLEDs with Au-ZnO NCs was dominantly attributed to the existence of the LSPR due to the presence of the Au NPs in the ZnO layer.