Surface modification of fluorine-doped tin oxide films using electrochemical etching for dye-sensitized solar cells

We modified the surface of fluorine-doped tin oxide (FTO) films using electrochemical etching in order to improve the photovoltiac performance of dye-sensitized solar cells (DSSCs). For the electrochemical etching, a mixture of HCl and zinc precursor was used as the electrolyte, which generated the H⁺ needed for activating the SnO₂ etching reaction. This led to the formation of surface-modified FTO films that resulted in an increase in surface roughness and a high level of haze without changing the sheet resistance and optical transmittance of the FTO films. The open circuit voltage, fill factor, and short-circuit current density of the DSSCs assembled using the surface-modified FTO films were 0.73 V, 60.53%, and 15.67 mA/cm², respectively. The surface-modified FTO films created using electrochemical etching showed an improved photoconversion efficiency (~6.95%) when compared to bare FTO films (~6.33%). This improvement in performance was caused by an improved ability to trap light by increasing haze, which resulted in an enhancement in the surface roughness of the FTO films.