A comparative study of charge transport in quasi-solid state dye-sensitized solar cells using polymer or nanocomposite gel electrolytes

To improve the photovoltaic and durability performance of quasi-solid dye-sensitized solar cells (DSCs), we added selected gelators to the liquid electrolyte. Metal-oxide nanoparticles or fluorine polymers were employed to solidify 3-methoxypropionitrile-based liquid electrolytes containing an ionic liquid, 1,2-dimethyl-3-propyl imidazolium iodide, as a source of iodide. The electrochemical impedance spectroscopy and cyclic voltammetry were employed to study the kinetics of electrochemical and photoelectrochemical processes, including the elucidation of the electronic and ionic processes occurring in the various quasi-solid-state solar cells. Among tested gelators, a cell with TiO2 solidified electrolyte (P25, 17.5 wt%) exhibited the best photovoltaic performance with power conversion efficiency 7.65% under simulated sunlight (100 mWcm−2). The DSCs with a TiO2 solidified electrolyte showed endurance of stability superior to that of a pure liquid electrolyte.