Recent advances in graphene-based materials for dye-sensitized solar cell fabrication

In the past few years, dye-sensitized solar cells (DSSCs) have received considerable research attention, as potential alternatives to the commonly used, but expensive, silicon-based solar cells owing to the low-cost, facile fabrication procedures, less impact on the environment, capability of working even under low incoming light levels, and flexibility of DSSCs. However, the relatively low power conversion efficiencies (PCEs) and poor long-term operational stability of DSSCs still limit their large-scale and commercial applications. As a consequence, this has prompted tremendous research effort towards the realization of high performance and sustainable devices, through tailoring of the properties of the various DSSC components, via approaches such as introducing novel materials and new synthesis techniques. Among these, the application of novel materials, especially carbon-based materials, such as graphene and its derivatives, is more appealing due to their excellent optoelectronic, mechanical, thermal and chemical properties, which give them ample potential to replace or modify the traditional materials that are commonly used in the fabrication of the various DSSC components. In addition, the low-cost, abundance, non-toxicity, large specific surface area, flexibility and superior stability of graphene-based materials have enabled their recent use as photoanodes, i.e., transparent conducting electrodes, semiconducting layers and dye-sensitizers, electrolytes and counter electrodes in DSSCs. Recently, the introduction of graphene-based materials into DSSCs resulted in a pronounced increase in PCE from similar to 0.13 to above 12.00%. Thus, employing the recent breakthroughs can further improve the optoelectronic properties of the various DSSC components and, hence, close the gap between DSSCs and their silicon-based counterparts that are currently exhibiting desirable PCEs of above 26%. Therefore, this review focuses on the recent applications of graphene-based materials as photoanodes, electrolytes and counter electrodes, for the possible fabrication of all-carbon-based DSSCs. The limitations, merits and future prospects of graphene-based DSSCs are discussed, so as to improve their photovoltaic performance, sustainability and cost-effectiveness.