Photoelectrochemical properties of nanoflake-like cadmium sulfide-sensitized Zn2SnO4 thin film electrodes prepared by chemical methods

Abstract

The photoelectrochemical (PEC) properties of nanoflake-like cadmium sulfide (CdS) sensitized zinc stannate (Zn2SnO4) heterostructure prepared by spray pyrolysis technique and chemical bath deposition (CBD) are investigated in detail. The crystallinity and surface morphology of the Zn2SnO4 and CdS films are evaluated by X-ray diffraction (XRD), and scanning electron microscope, whereas its optical properties are analyzed by UV-VIS spectroscopy. Zn2SnO4 exhibits uniform granular structure and it has well defined reflection along (311) plane revealing inverse-spinel cubic structure. Zn2SnO4 showed band gap of 3.8 eV, it is well agreeing with the literature. The CdS films fabricated by CBD exhibited nanoflake-like structures. The XRD pattern of the CdS-sensitized Zn2SnO4 heterostructure exhibits a mixed phases of the zinc stannate and CdS. The PEC properties of the Zn2SnO4-CdS heterojunction are studied by using a three-electrode electrochemical cell in a Na2S electrolyte. Zn2SnO4-CdS system has shown 0.8 mA/cm(2) photo-current density whereas with increasing CdS layer thickness it has shown marginal enhancement up to 2.2 mA/cm(2). The stability of the Zn2SnO4-CdS heterojunction is outstanding up to 300 s. The results demonstrate that Zn2SnO4-CdS heterojunction could be a potential material in PEC and solar cell applications.