Solution Fabrication and Photoelectrical Properties of CuInS2 Nanocrystals on TiO2 Nanorod Array

One-dimensional semiconductor architectures are receiving attention in preparing photovoltaic solar cells because of its superior charge transport as well as excellent light-harvesting efficiency. In this study, vertically aligned single-crystalline TiO2 nanorods array was grown directly on transparent conductive glass (FTO), and then CuInS2 nanocrystals were deposited on nanorods array by spin coating method to form TiO2/CuInS2 heterostructure films. The resulting nanostructure assembly and composition was confirmed by field-emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), high-resolution TEM, and X-ray diffraction(XRD). Ultraviolet-visible absorption spectroscopy (UV-vis) data indicates that the absorbance of the nanocomposite film extended into the visible region compared with bare TiO2 nanorod arrays. The surface photovoltage spectra (SPS) also showed a new and enhanced response region corresponding to the absorption spectrum. These results suggest that the novel CuInS2 nanocrystals sensitized TiO2 nanorod array on FTO photoelectrodes has a potential application in photovoltaic devices.