Transition metal oxides as Pt-free counter electrodes for liquid-junction photovoltaic devices

Abstract

This work presents the synthesis of the transition metal oxides (micro-wheels composed of self-assembled WO3 nanorods, SnO2 nanosheets, and Fe2O3 nanoparticles) by hydrothermal method. The synthesized catalysts are then applied for the regeneration of iodide ions from triiodide ions at counter electrodes (CEs) of dye-sensitized solar cells (DSCs). As the results, the DSCs with low-cost catalysts as WO3, SnO2, and Fe2O3 provided an efficiency of 4.36, 4.37 and 1.54 %, respectively, under 1 sun irradiation that is slightly lower than that of a cell with Pt electrode (5.86 %). This behavior is elucidated by electrochemical impedance measurements. These findings provide a strategy to develop low-cost materials for DSC application.