ZnO-nanorod arrays for solar cells with extremely thin sulfidic absorber

Solar cells with an extremely thin sulfidic absorber have been prepared by spray ion layer gas reaction (ILGAR) of In2S3 on ZnO-nanorod arrays. As transparent hole conductor, CuSCN was deposited on the coated ZnO nanorods by impregnation. Surface photovoltage spectroscopy was applied to characterize states contributing to excess carrier generation and charge separation. The charge-selective contact is formed at the In2S3/CuSCN interface region the states of which also contribute significantly to the photocurrent. The influence of annealing temperature and annealing time of the In2S3/CuSCN contact region on the open-circuit potential (VOC), short-circuit current (ISC) and fill factor (FF) was studied in detail. For solar cells based on ZnO-nanorod arrays (rod length 1.5 μm), efficiency of 2.8% is obtained at AM1.5.