Structural and optical properties of CdS thin films on organic substrates for flexible solar cell applications

Cadmium sulphide (CdS) films were chemically deposited on glass, polycarbonate (PC), and polyethylene terephthalate (PET). Effects of substrate types on the structural and optical properties of the films were investigated. There is a preferential orientation of the crystallites in the film grown on the glass along the c-axis (perpendicular to the plane of the substrate) producing a strong hexagonal (0 0 2) or cubic (1 1 1) peak, regardless of the presence of ITO coating. However, such preferential orientation decrease or disappear when the deposition was made onto PC or PET substrates. PC and PET substrates exhibited the larger roughness than that for the glass because of large particles adsorbed on the PC and PET substrate. The average transmittance of the films on PC and PET is about 50%, 55%, respectively, and increases up to 70% for glass substrate. The improvement of the transmittance was obtained from ITO-coated substrates.