Enhancing the efficiency of dye-sensitized solar cells by hydrothermal post-treatment in acidic environment

Dye-sensitized solar cell (DSSC) have been extensively studied due to its low production cost and simple production process. In this research, DSSC with improved performance is acquired by modification of TiO₂ layer through hydrothermal post-treatment with different hydrochloric acid (HCl) concentrations to obtain various particles and pore sizes. Qualitative and quantitative characterizations of the TiO₂ film were conducted using thickness measurement, scanning electron microscope (SEM), and X-ray diffraction (XRD), while the solar cell performances were characterized using current-voltage (I-V) measurement under 0.5 Sun. When hydrothermally treated with 1 mol/L HCl at 180 °C for 3 h, the DSSC showed the most optimum photo-electricity conversion performance of 3.60%, which improved the efficiency of the non-treated DSSC by a factor of 1.2. As the HCl concentration increased, the treated TiO₂ film became thinner with smaller particle size and denser structure. It was suspected that the modification in the TiO2 film morphology has led to better light absorption, which consequently resulted in the improvement of DSSC performance. (paper)