Aqueous electrolytes: a possible breakthrough toward DSSCs widespread commercialization

Dye sensitized solar cells (DSSCs) with high performances (PCE > 14%) have been fabricated mainly with organic solvent-based liquid electrolytes, i.e. acetonitrile and methoxypropionitrile. However, these solvents have high vapor pressure and are often toxic and flammable. In recent years, the idea of creating an efficient, inexpensive and safe system moved the attention of scientific community towards alternative solvent-based systems. Above all, DSSCs fabricated with water-based electrolytes may offer reduced costs, non-flammability and environmental compatibility, but the same water present in the cell may reduce the long term stability as well as the photovoltaic performances. In order to reduce these drawbacks, an increasing number of research articles has been published in this direction and several sensitizers, electrodes and electrolyte components are continuously proposed and investigated. In this contribution, the study of iodine-based 100% aqueous electrolytes and their interaction with different selected dyes are presented. Moreover, a chemometric approach, useful to perform a multivariate investigation (DoE) and to optimize DSSCS efficiency and stability, is effectively demonstrated. Finally, the development of a series of novel aqueous gel electrolytes based on bio-derived polymers is also discussed as well as their interesting photovoltaic characteristics.