Enhancing the electron transfer process of TiO2-based DSSC using DC magnetron sputtered ZnO as an efficient alternative for blocking layer

Abstract

Abstract Developing dye sensitized solar cell (DSSC) technology by exploiting different alternative semiconductors has attracted research attentions. Among all types of semiconductors, ZnO nanostructures due to their unique electrical properties and the facile preparation of various morphologies, have considered as the promising materials for application in DSSCs. In the present study, DC magnetron sputtering method was utilized to prepare a ZnO thin film as an efficient alternative for TiCl4 pre-treatment to suppress the charge recombination process occurring at a conventional TiO2-based DSSC. Different thicknesses of ZnO seed layers on fluorine tin oxide conductive glass substrates (FTO) were prepared via various sputtering deposition times. Field emission-scanning electron microscopy (FE-SEM) and x-ray diffraction (XRD) analyses were utilized to study the surface uniformity and crystallinity of the ZnO nanostructures. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were employed to investigate the photoanode interface properties via determination of the electron lifetime and density of electron in conduction band. The results demonstrated that the thickness of ZnO compact layer which either acts as electron trapping states or blocking layer has the important role in cell performance. Finally, by the optimum thickness of ZnO thin film, the highest efficiency was achieved at 5.1%.