Quasi-solid aqueous electrolytes based on bio-derived polymers

In recent years, with the idea of creating efficient, safe, and low-cost DSSCs, the research moved the attention towards alternative solvent-based electrolytes. Above all, DSSCs with water-based electrolytes have been proposed as one of the possible solution providing reduced costs, non-flammability and environmental compatibility. Recently we demonstrated that stability issues can be properly addressed by choosing the appropriate dye. Moreover, the possibility of gelling the liquid solvent into a polymeric matrix can reduce the electrolyte leakage outside the device, increasing the long-term stability. In this contribution, the investigation on a series of iodine and cobalt-based 100% aqueous electrolytes is presented. Thanks to our previous experience and to a multivariate approach (Design of Experiment), the effects of the change in redox mediator concentrations and in photoanode preparation on DSSCs performances have been evaluated. Finally, the gelation of the best aqueous electrolytes with bio-derived polymers has been performed. Photovoltaic performances and stabilities will be discussed by comparing liquid and gel electrolytes. In lab-scale solar cells interesting photovoltaic performances superior to 4% were achieved.