Combined effect of in-situ grown p-type CuSbS2 / n-type CdS coupled with hierarchical ZnO nano disks for improved photovoltaic light harvesting efficiency

Abstract

In this report, we have synthesized porous two dimensional zinc oxide disk structures, using a biomass derived templating agent i.e., Xanthan gum. This templating agent is mainly accountable to control the growth kinetics of high energy facets of wurtzite zinc oxide crystal structure, to obtain these disk structures. A comparative photovoltaic study of as-synthesized two dimensional porous zinc oxide structures with respect to one dimensional zinc oxide structures (in absence of xanthan gum) is carried out by co-sensitizing with in-situ grown one dimensional cadmium sulfide nanowires array and ternary metal chalcogenide viz. copper antimony sulfide. Superior photovoltaic performance (∼45% enhancement in efficiency) is obtained for co-sensitized device with porous two dimensional zinc oxide disk as compared to one dimensional zinc oxide structures, owing to improved current density and fill factors. This enrichment is mainly attributed to large exposed surface active sites for optimum loading of light absorbing materials, better light scattering and improved hole recovery rate of sensitizers with the better penetration of redox shuttle. Moreover, crystal phase purity of copper antimony sulfide and p-n junction formed between copper antimony sulfide and cadmium sulfide also support the enhanced efficiency by facilitating the electron-hole separation and electron transportation.