Reduced graphene oxide layer on nanostructured SnS thin films for improved visible light photoelectrochemical activity

Abstract

The deposition of reduced graphene oxide over layer on the SnS thin films had been shown to be an effective tool to improve its photoelectrochemical response. Pure phase SnS thin films were prepared using simple and inexpensive thermal evaporation method on ITO glass substrate followed by the deposition of reduced graphene oxide (rGO) layer by drop cast method. Samples were characterized using X-ray diffraction, Raman, scanning electron microscopy, UV–Visible absorption spectroscopy and their photoelectrochemical activity has been investigated. The results show the formation of pure phase SnS having orthorhombic crystal structure with optical band gap of 2.0 eV, rGO layer enhances the absorption in visible region. Maximum photocurrent density exhibited by SnS/0.1 wt% rGO was observed to be 1.1 mA/cm2 as compared to pristine SnS (0.3 mA/cm2) at 0.95V Ag/AgCl with enhanced photostability up to 1 h. Graphene oxide over layer acts as protecting layer for SnS in the electrolyte and plays a promising role in enhancing the charge carriers separation at the interface on account of being an electron reservoir to accept the photoexcited electrons. This work highlights the role of rGO and SnS interface on the photoelectrochemical water splitting.