Facile synthesis of TiO 2 and Sn‐TiO 2 heterostructures based photoanodes for dye sensitized solar cells

Abstract

In the present study, nanorods of TiO2, Sn-doped TiO2 (Sn-TiO2), TiO2@Sn-TiO2 and Sn-TiO2@TiO2 were prepared by sol-gel method. Dye-sensitized solar cells (DSSCs) photoanodes were synthesized by depositing films on fluorine doped tin oxide (FTO) glass substrate using doctor blade method. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and UV-Vis spectroscopy. XRD results indicated the formation of tetragonal anatase structure of TiO2 in pristine TiO2 and Sn-TiO2 films. It was observed that formation of heterostructure particles spured the conversion of TiO2 from anatase to rutile phase. SEM analysis indicated the formation heterostructures of rod like morphology with increased diameter. Optical parameters of films (absorbance, transmittance, refractive index, dielectric constants and band gap) were measured using UV-Vis spectroscopy data. The results confirmed that Sn doping decrease the bandgap. Amongst the four prepared films, band gap of Sn-TiO2@TiO2 heterosturcture based film was smallest (3.09 eV). The efficiency of Sn-TiO2@TiO2 heterostructure based DSSC was found to be 54.3% better compared with DSSC based on Sn-TiO2 and 96.37% better compared with the DSSC based on pristine TiO2.