Improving stability of chlorophyll as natural dye for dye-sensitized solar cells

Natural dyes have attracted much researcher’s attention due to their low-cost production, simple synthesis processes and high natural abundance. However the dye-sensitized solar cells (DSSCs) based natural dyes have higher tendency to degradation. This article reports on the enhancement of performance and stability of dye-sensitized solar cells (DSSCs) using natural dyes. The natural dyes were extracted from papaya leaves by ethanol solvent at a temperature of 50 °C. Then the extracted dyes were isolated and modified into Mg-chlorophyll using column chromatography. Mg-chlorophyll was then synthesized into Fe-chlorophyll to improve stability. The natural dyes were characterized using ultraviolet-visible spectrometry, Fourier transform infrared spectroscopy, and cyclic voltammetry. The performance of DSSCs was tested using a solar simulator. The results showed the open-circuit voltage, the short-circuit current density, and the efficiency of the extracted papaya leaves-based DSSCs to be 325 mV, 0.36 mA/cm2, and 0.07%, respectively. Furthermore, the DSSCs with purified chlorophyll provide high open-circuit voltage of 425 mV and short-circuit current density of 0.45 mA/cm². The use of Fe-chlorophyll for sensitizing the DSSCs increases the efficiency up to 2.5 times and the stability up to two times. The DSSCs with Fe-chlorophyll dyes provide open-circuit voltage, short-circuit current density, and efficiency of 500 mV, 0.62 mA/cm2, and 0.16%, respectively. Further studies to improve the current density and stability of natural dye-based DSSCs along with an improvement in the anchor between dyes and semiconducting layers are required.