Synergistic effect and enhanced electrical properties of TiO2/SnO2/ZnO nanostructures as electron extraction layer for solar cell application

Abstract

The present work rationalizes the significance of smart combination of the metal oxide semiconductor (MOS) as electron extraction layer for photovoltaic applications. A synergistic effect of multi-metal oxides, at the nanoscale domain can yield an improved optical and electrical property when compared to their individual phases. In this paper, we report the preparation of a new ternary metal oxide composed of TiO2, SnO2 and ZnO by solvothermal method. The physicochemical properties of the samples were determined by an array of spectroscopic and microscopic techniques. XRD analysis showed the formation of the SnO2 and ZnO in the TiO2 sample. This was further confirmed by Raman and XPS analysis. Optical studies (PL and TRPL) revealed lower charge recombination of the ternary metal oxides. TEM images show the presence of SnO2 and ZnO in the TiO2 lattice. Intergrowth of SnO2 and ZnO in the TiO2 increased the surface area thereby reducing the electron – hole recombination in the ternary metal oxide. Hall measurements display higher carrier concentration and lower resistivity of the metal oxide when compared with pure TiO2. The results suggest that the blend of TiO2, SnO2 and ZnO can serve as a better electron extraction layer to promote charge separation and suppress charge recombination. The ternary metal oxide exhibits promising properties and can enhance the performance when used as an electron extraction layer for solar cell applications.