Strategies to design electrodes and electrolytes for aqueous solar cells: performances, sustainability and scenarios

Dye-sensitized solar cells (DSSCs) with water-based electrolytes have recently been considered as one of the possible breakthroughs towards DSSC large-scale diffusion. If opportunely developed and optimized, aqueous solar cells can be truly considered a zero-impact photovoltaic device with no toxic components. Moreover, the possibility of gellyfing the electrolyte into a solid matrix and the replacement of Pt cathodes with conductive polymers or biosourced carbon platforms could increase the long-term stability and lower fabrication costs. In this contribution, the investigation on a series of iodine/cobalt-based 100% aqueous electrolytes is presented and coupled with the investigation of several polymeric matrices for hydrogels formulation. In parallel, photoanodes preparation strategies are discussed, and the possibilities behind the use of Pt-alternative counter electrodes will be mentioned. As a final proof of the whole aqueous DSSC concept, we will show a scenario of water-based cells integrated in buildings and offices.