LAUSR

Abstract In this article, we discuss the effect of the polysiloxane-based poly(ionic liquid) (PIL) electrolytes viscosity on the infiltration into mesoporous and bimodal TiO2 thin films with different thickness, and consequently on the DSSC performance. The mesoporous films contain small mesopores of 8–10 nm, resulted from the use of Pluronic P123 surfactant (SOFT), resulting in high surface area. The DUAL (soft/hard) templated films have unique bimodal porous structures comprising 8–10 nm mesopores and 60–70 nm macropores resulted from the use of P123 and 130 nm polystyrene beads, which encouraged the electrolyte pore infiltration and light harvesting. Electrochemical impedance spectroscopy confirms the lower charge transfer resistance of the DUAL templated TiO2 films as opposed to SOFT TiO2 electrodes which corresponds to higher DSSC efficiency, despite having lower dye adsorption thanks to the improved PIL electrolyte infiltration within larger pores. The addition of ionic liquids to PIL significantly lowers the viscosity, increases the ionic conductivity and I3− diffusion rate, resulting in noticeable improvement in photovoltaic performance in both SOFT and DUAL templated photoanodes for all the observed thickness.