Low-Temperature Flexible Photoanode and Net-Like Pt Counter Electrode for Improving the Performance of Dye-Sensitized Solar Cells

Back-illuminated dye-sensitized solar cell (DSSC) based on a flexible TiO 2 /Ti foil photoanode and a high transparent platinum counter electrode (Pt-CE) has been developed by using a net-like Pt-CE and a relatively low annealing temperature (120 °C) for the preparation of a binder-free TiO 2 paste. The TiO 2 /Ti foil photoanode was annealed at various temperatures (120, 250, 350, and 450 °C). Solar-to-electricity efficiencies (η) of 4.34, 3.72, and 3.40% were obtained for the DSSCs with TiO 2 /Ti photoanodes annealed at 350, 250, and 120 °C, respectively, which are comparable to the value of 4.33% obtained at 450 °C. The DSSC with Ti foil as working substrate shows better performance (η = 3.40%) than that of a DSSC with indium tin oxide (ITO)/polyethylene naphthalate (PEN) as the substrate (2.08%), both prepared through a low-temperature fabrication process (120 °C). The η is further improved to 4.77% at 350 °C by using a net-like Pt-CE. Explanations are substantiated through scanning electron microscopy (SEM), X-ray diffraction analysis, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and transmission spectral studies.