<![CDATA[This study investigates the relationship between optical absorption, photovoltaic performance, and charge transfer properties of dye-sensitized solar cells (DSSCs) sensitized with natural dye extracted from water spinach (Ipomoea aquatica). The DSSC was fabricated with an FTO/TiO2/dye/Mosalyte/Pt/FTO configuration and evaluated on day 1 and day 5 to investigate short-term dye degradation. UV–Vis spectra exhibited a chlorophyll absorption peak at 665.04 nm on day 1, which slightly shifted to 663.13 nm on day 5 with a significant decrease in absorbance intensity, indicating pigment degradation. The bandgap energy remained nearly constant (1.799–1.805 eV), suggesting that the intrinsic electronic structure of the dye was preserved. In contrast, photovoltaic performance deteriorated, with the short-circuit current density (JSC) decreasing from 0.316 to 0.232 mA/cm2 and the power conversion efficiency dropping from 0.109% to 0.064%. Electrochemical impedance spectroscopy (EIS) showed an increase in series resistance (RS) and charge transfer resistance (RCT) at low bias, particularly at 0 V, suggesting hindered interfacial charge transfer. These findings demonstrate that dye degradation primarily reduces light harvesting and charge transfer rather than altering the dye energy levels, resulting in lower DSSC performance. This study highlights the importance of dye stability in improving the efficiency and durability of natural dye-based DSSCs.]]>
