Photovoltaic property dependence of dye-sensitized solar cells on sheet resistance of FTO substrate deposited via spray pyrolysis

F-doped SnO2 (FTO) glass substrate was successfully fabricated via spray-pyrolysis deposition for use as a transparent conducting substrate in dye-sensitized solar cells (DSSCs). To investigate the performance dependence of DSSCs on the sheet resistance of the FTO films, three types of FTO films with sheet resistance values of 2 Ω/□, 4 Ω/□, and 10 Ω/□ were fabricated. Commercial FTO films having a sheet resistance of 15 Ω/□ were prepared for comparison. The structural, electrical, and optical properties of FTO films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), the four-point probe method, and UV–vis spectrometry. The photocurrent–voltage data show that DSSCs fabricated with a sheet resistance of 2 Ω/□ exhibit the best photoconversion effciency (∼5.5%) among the four samples. The performance improvement of DSSCs is due to improved short-circuit current density (∼13.7 mA/cm2) and fill factor (∼62.3%).