Biopolymers, Water, and Integrated Systems: the New Frontier of Dye-Sensitized Solar Cells

Photovoltaic (PV) technology has evolved rapidly in the past few decades and now encompasses a large variety of materials and device structures. A key aspect to be taken into account in any PV technology is the operational durability under real outdoor conditions, as well as the sustainability of materials/components and the facile integration with energy storage systems. In the last five years, dye-sensitized solar cells (DSSCs) with water-based electrolytes are considered as one of the possible breakthroughs towards DSSCs 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 can reduce the leakage outside the device, thus increasing the long-term stability. In this respect, bio-derived polymers appear promising candidates for electrolyte stabilization, being renewable and easy available at low cost. The investigation on bio-derived hydrogel electrolytes for dye-sensitized solar cells is proposed in this talk: cellulose- and alginate-derivatives, xanthan gum and other bio-matrices are investigated in terms of their electrochemical and physico-chemical properties. Moreover, paper-based flexible electrodes and electrolytes for third generation solar cells, useful to lower the oil-derived components and typical temperatures used during electrodes’ processing, are presented and thoroughly characterized in bendable configurations. As a last step, integrated energy harvesting and storage (HS) devices obtained by proper combination of a DSSC module with an electrical double layer capacitor also having non-conventional configurations are presented.