Abstract
The stability and efficiency of dye-sensitized solar cells (DSSCs) are often limited by the degradation of key components, including dyes, electrolytes, and electrodes. This study investigates the effect of gum Arabic as a biopolymeric binder on TiO₂ photoanode fabrication and the photovoltaic performance of DSSCs sensitized with a natural dye extracted from Sorghum bicolor grains. TiO₂ films were prepared using the doctor-blade technique with gum Arabic concentrations of 0.56 g (Sample A) and 1.25 g (Sample B). Fourier transform infrared (FTIR) spectroscopy revealed O–H and C–O–C functional groups that promote dye adsorption and film stability, while UV–Visible spectroscopy confirmed strong absorption in the ultraviolet–visible region, extending the spectral response of TiO₂. Photovoltaic performance was evaluated using current–voltage (I–V) measurements under dark and illuminated conditions. Sample B exhibited the best performance under illumination, with Voc = 0.60 V, Jsc = 1.50 mA/cm², Vmax = 0.46 V, Imax = 1.15 mA, Pmax = 5.3 × 10⁻⁴ W, FF = 0.59, and η = 0.53%. The improved performance is attributed to enhanced visible-light absorption by anthocyanin dye molecules, reduced charge recombination, and improved electron transport. These findings demonstrate the potential of gum Arabic-modified TiO₂ photoanodes and sorghum-derived natural dyes as low-cost and environmentally sustainable materials for DSSC applications.