Polymer electrolyte membranes for dye-sensitized solar cells prepared by an elegant and rapid UV-curing process

As a feasible option for photovoltaic technology to meet the growing energy demand, dye-sensitized solar cells (DSSCs) have attracted much attention due to their low cost, ease of fabrication and good performance. Standard DSSCs use a liquid electrolyte, which leads to relevant technological drawbacks associated with poor long-term stability, difficulty in robust and hermetic sealing, electrolyte evaporation/leakage. In this context, a very promising and common skill used to solve these problems is the attempt to replace the liquid electrolyte with a quasi-solid or solid electrolyte. We report on the preparation and characterization of novel polymer electrolyte membranes for quasi-solid DSSCs. New methacrylic-acrylic gel-polymer electrolytes were prepared by photo-polymerization of multifunctional monomers. The crosslinked films were self-standing, transparent and flexible. They were swelled by an iodine-iodide solution, obtaining a stable gel, where the polymeric network acts as a cage to retain the liquid, preventing its evaporation. The evaluation of the structural and physicochemical characteristics of the polymer, combined with the electrical characterization of the membranes by means of the electrochemical impedance spectroscopy, allowed us to investigate the structure/property relationship of the material. The electric characterizations of the solar harvester based on the quasi-solid electrolyte showed high photovoltaic conversion efficiencies (more than 5%). Moreover, a significant improvement in the durability of the devices was demonstrated with respect to the liquid electrolyte-based counterparts. In order to further optimize the photovoltaic performance, a chemometric approach (at the best of our knowledge for the first time in the DSSC area) was selected.