Optimization of a Quasi‐Solid‐State Dye‐Sensitized Photoelectrochemical Solar Cell Employing a Ureasil/Sulfolane Gel Electrolyte

Abstract A quasi‐solid‐state, dye‐sensitized photoelectrochemical solar cell employing a gel electrolyte obtained by sol–gel chemistry is described. The gel electrolyte is based on a ureasil precursor (i.e., a poly(propylene oxide) oligomer end‐capped by triethoxysilane groups through urea bridges) and sulfolane and it incorporates the I₃^–/I^– redox couple. It is shown that the combination of these two reagents prevents crystallization of KI, thus ensuring a long life for the cell and a satisfactory overall efficiency that surpasses 5 %. Cell efficiency increases with temperature. Optimization of gel‐electrolyte performance has been obtained by studying mobility with fluorescence‐quenching techniques complemented by direct‐current conductivity measurements.