Enhanced electrochemical performance of the counterelectrode of dye sensitized solar cells by sandblasting

Abstract Counterelectrode plays an important role in dye sensitized solar cells. It helps the regeneration of the redox couples in electrolyte and makes the cell a complete circuit. In order to improve the electrochemical performance of counterelectrode, a strategy of sandblasting has been utilized to pre-treat the surface of glass substrate. Counterelectrodes were fabricated by sputtering Pt/Ti bilayers films onto the treated substrates. Morphological, electrical, electrochemical and optical properties of the counterelectrode were characterized by scanning electronic microscopy, four-probe measurement, electrochemical impedance spectroscopy, cyclic voltammetry and UV–vis reflection spectroscopy, respectively. Effect of the treatment on these properties was evaluated. It was found that counterelectrode made from sandblasted substrates showed increased roughness of surface and sheet resistance, along with the enhanced catalysis efficiency and improved light scattering. The enhanced catalysis efficiency toward reduction of tri-iodide was found to be due to smaller Pt crystallite grown on the sandblasted substrate, since the electrochemical active surface area changed little. And scattering was caused by increased roughness of the substrate. Typical solar cells were assembled with the counterelectrode made of the sandblasted substrates. Effect of the treatment on current–voltage curves and performance parameters of the solar cells was checked and discussed.