Solution-processed In2S3 nanosheet arrays for CuInS2 thin film solar cells

In2S3 is a promising electron transporting material for solar cells. In this paper, In2S3 nanosheet arrays are grown on TiO2 films by a facile molecular precursor solution method for the first time. The composition, morphology and chemical valance states of the In2S3 nanosheet arrays are investigated by XRD, SEM, TEM and XPS techniques. Upon the in situ growth of CuInS2 nanoparticles into the In2S3 nanosheet arrays, the novel CuInS2 bulk heterojunction solar cells are obtained with a peak power conversion efficiency of 2.58% depending on the In2S3 nanosheet array height.