Synthesis of a graphene–tungsten composite with improved dispersibility of graphene in an ethanol solution and its use as a counter electrode for dye-sensitised solar cells

Abstract

The article reports a nanocomposite (graphene and tungsten (GN–W)) successfully used as an alternative to a conventional Pt counter electrode in dye-sensitised solar cells (DSSCs). The dispersibility of the GN structure in ethanol was enhanced by acid oxidation and planetary ball milling. Raw, purified and purified and ground GN structures were spin coated onto fluorine-doped tin oxide (FTO) glass substrates and examined as catalytic films on the counter electrodes of DSSCs. Purified and ground GNs exhibited the best photovoltaic performance (4.55%) among these structures. The grinding method was found effective for upgrading the dispersibility of GNs in a base fluid and the photovoltaic efficiency results. Based on the photovoltaic efficiency results of the DSSCs with different GN structures, the purified and ground GN structure was selected and incorporated with tungsten. A composite film of GN–W was used as a catalytic film on the counter electrode of a DSSC. The DSSC fabricated with the GN–W composite counter electrode achieved a photovoltaic efficiency of 5.88%. This performance is comparable to that of a DSSC with a standard Pt counter electrode (5.92%).