Thermal stability and electrical studies on hybrid and composite sol–gel quasi-solid-state electrolytes for dye-sensitized solar cells

Nanocomposite organic/inorganic materials made through sol–gel method can be applied as quasi-solid-state electrolytes aiming to overcome the common issues of evaporation, leaking and stability in dye-sensitized solar cells. Two different kinds of quasi-solid-state electrolytes, depending on the different interactions between silica as inorganic phase and organic substances such as polyethylene/or polypropylene oxide derivatives, are prepared by the sol–gel technique in room temperature. Release dynamics of volatile components from two types of quasi-solid-state electrolytes are studied by thermogravimetry (TG) in order to predict the stability or changes in composites during their application in dye-sensitized solar cells. Two online coupled evolved gas analytical tools (TG-EGA-FTIR and TG/DTA-EGA-MS) are applied to test the gel electrolytes for accelerated thermal vaporization, degradation and decomposition processes as a function of temperature during dynamic heating in air. Stable solar cells based on the different quasi-solid-state electrolytes are constructed and characterized with current density curves exhibiting overall efficiencies varying from 2.9 to 4.2 % for thin TiO 2 films sensitized with standard commercial dye.