Plasmonic Effects of ZnO-coated Ag Nanowire Top Electrodes on Photovoltaic Performance in NiO/ZnO-Heterojunctions

Transparent photovoltaic (TPV) devices with Ag nanowire top electrodes can be installed in windows, producing electricity from solar radiation while remaining invisible to human eyes. In this work, we pay special attention to the contributions of surface plasmon (SP) excitation in ZnO-coated Ag nanowires (AgNWs) to the photovoltaic performance of NiO/ZnO TPV devices. The optical measurements and calculations showed a localized SP excitation in AgNWs. The spatial redistribution and transport of photo-generated charge carriers were analyzed using Kelvin probe force microscopy and current-sensing atomic force microscopy. The results revealed a strong dependence on both the polarization and the wavelength of the incident light. The nanoscopic characterizations showed the beneficial roles of ZnO-AgNWs top electrodes in the collection and generation of photo-carriers in TPV devices.