Comparative study of Sb2S3, Bi2S3 and In2S3 thin film deposition on TiO2 by successive ionic layer adsorption and reaction (SILAR) method

Sensitization of nanoporous TiO2 with Sb2S3, Bi2S3, and In2S3 thin films deposited at the room temperature by using the simple and inexpensive SILAR method is presented. Structural, morphological, and optical characterization of thin films prepared by this method were conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS). The photocurrent response of the thin films was studied with a three electrode photoelectrochemical cell. The influence of the number of deposition cycles on the optical properties of the thin films was investigated, and the structural and morphological studies revealed the formation of polycrystalline thin films with an orthorhombic structure for Sb2S3 and Bi2S3 system, whereas a cubic structure was found for the In2S3, which had a cluster-like surface morphology and uniform distribution. Optical studies showed that enhancing TiO2 light absorption in the visible range is possible by the incorporation of antimony, bismuth, and indium sulfides. Photocurrent measurements showed that photons are absorbed by metal sulfide and electrons injected to TiO2.