Pomegranate leaves and mulberry fruit as natural sensitizers for dye-sensitized solar cells

This study employs chlorophyll extract from pomegranate leaf and anthocyanin extract from mulberry fruit as the natural dyes for a dye-sensitized solar cell (DSSC). A self-developed nanofluid synthesis system is employed to prepare TiO2 nanofluid with an average particle size of 25 nm. Electrophoresis deposition was performed to deposit TiO2 nanoparticles on the indium tin oxide (ITO) conductive glass, forming a TiO2 thin film with the thickness of 11 μm. Furthermore, this TiO2 thin film was sintered at 450 °C to enhance the thin film compactness. Sputtering was used to prepare counter electrode by depositing Pt thin film on FTO glass at a thickness of 20 nm. The electrodes, electrolyte (I3-), and dyes were assembled into a cell module and illuminated by a light source simulating AM 1.5 with a light strength of 100 mW/cm2 to measure the photoelectric conversion efficiency of the prepared DSSCs. According to experimental results, the conversion efficiency of the DSSCs prepared by chlorophyll dyes from pomegranate leaf extract is 0.597%, with open-circuit voltage (VOC) of 0.56 V, short-circuit current density (JSC) of 2.05 mA/cm2, and fill factor (FF) of 0.52. The conversion efficiency of the DSSCs prepared by anthocyanin dyes from mulberry extract is 0.548%, with VOC of 0.555 V and JSC of 1.89 mA/cm2 and FF of 0.53. The conversion efficiency is 0.722% for chlorophyll and anthocyanin as the dye mixture, with VOC of 0.53 V, JSC of 2.8 mA/cm2, and FF of 0.49.