To investigate opulence of graphene in ZnO/graphene nanocomposites based dye sensitized solar cells

Abstract

The study reports the application of ZnO–graphene (ZGR) nanocomposite films for Dye-sensitized solar cells (DSSCs) as photoanodes. These nanocomposites were prepared by incorporating different amount of graphene (0–1 wt%) in sol–gel routed ZnO nanoparticles. The presence of graphene in nanocomposite films was revealed by X-ray diffraction (XRD) that was further supported by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX). The surface roughness value of these ZGR nanocomposite films was examined by Atomic Force Microscopy (AFM). The UV–Visible spectrum of the synthesized ZGR nanocomposite films was found to be shifted towards a longer wavelength region as compared to bare ZnO that ensured the formation of interfacial contact between ZnO and graphene. The enhanced absorption in the visible region of spectra is observed on incorporation of graphene in these ZGR nanocomposites. Significant increments in room temperature Photoluminescence (PL) intensity was attributed to the plasmonic effect of graphene. DSSCs were assembled with these ZGR nanocomposite photoanode films after tethering with N749 (black dye) and the effect of graphene concentration on their performance was investigated. The maximum power conversion efficiency obtained from these ZGR nanocomposites based DSSC has reached 3.17% that is 53% higher than that of bare ZnO based DSSC (2.07%).