From seaweeds to biopolymeric electrolytes for third generation solar cells: An intriguing approach

•Products derived from algae are chemically modified for applied energy purposes.•A new smart activation process by sublimation is proposed.•The prepared materials are used as green solid electrolytes in photovoltaic cells.•The highest ever obtained ionic conductivity for a biopolymeric electrolyte was measured.

Renewable energy systems represent a milestone of third millennium applied scientific research. As a viable, economic and environmentally friendly alternative to the solid electrolytes currently used in dye-sensitized solar cells (DSSCs), here we propose a biopolymer derived from seaweeds, which undergoes a process of selective carboxylation to improve its transport properties. Subsequently, a chemometric approach is used to tune the amount of salts and additives, and the highest ever measured ionic conductivity for a biopolymeric solid electrolyte has been reached (5.53 ∙ 10−2 S  cm−1). To make this material suitable for DSSC application, an innovative sublimation process has been developed to allow a molecule-by-molecule activation of the electrolyte, and an efficiency of 2.06% (stable in aging tests) was measured in a first device prototype. Green chemistry, low cost materials, multivariate-based preparation methods and activation via spontaneous sublimation make this investigation a concrete starting point for the new generation of solid electrolytes for DSSCs.

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