Valorization of Caesalpinia sappan L. Anthocyanin as a Natural Sensitizer for Dye-Sensitized Solar Cells: Optical, Morphological, and Photovoltaic Insights

Solar energy is one of the renewable energy sources with great potential for development through environmentally friendly solar cell technologies such as dye-sensitized solar cells (DSSC). This study aims to explore the potential of anthocyanins from secang wood (Caesalpinia sappan L.) as a natural dye in DSSCs. The dye extract was tested using UV-Vis to determine its light absorption capacity, while structural and morphological characterization was performed using XRD and SEM-EDS mapping. The UV-vis test results showed that the secang wood dye was able to absorb light in the wavelength range suitable for the photosensitization process. SEM-EDS analysis confirmed the distribution of O, Si, Ca, and Ti elements that supported dye binding to the TiO₂ layer. Solar cell performance tests produced an open circuit voltage (Voc) of 0.303 V, a short circuit current (Isc) of 0.000007 A, a fill factor (FF) of 4.1 × 10⁻², and an energy conversion efficiency of 0.105%. Although the obtained power conversion efficiency (0.105%) remains relatively low, the findings demonstrate the feasibility of utilizing anthocyanin extracted from Caesalpinia sappan L. as a natural sensitizer for DSSC applications. The low efficiency is attributed to limited light absorption, weak dye-TiO₂ interaction, and charge recombination losses, indicating the need for further optimization of dye extraction and device fabrication parameters.