Optimising microalgal dyes extraction design for stable dye-sensitized solar cells: Chromatographic insights on bio-deterioration and longevity

Background: The demand for sustainable energy solutions has increased interest in natural microalgal dyes as photosensitizers in dye-sensitized solar cells (DSSCs). This study addresses the critical issue of maximizing dye integrity and yield during extraction, particularly the degradation that occurs at temperatures above 60 degrees C. Our investigation of dye extraction from Asterarcys quadricellulare and Scenedesmus sp. using hot solvent methods revealed significant findings. High-Performance Liquid Chromatography (HPLC) analysis identified essential pigments, including Chlorophyllide a and beta-carotene. Results: Our research found that temperatures above 60 degrees C reduce chlorophyll (Chl) stability and extraction efficiency. Using multiple wavelengths in a photodiode array (PDA) detector improves Chl identification by targeting distinct absorption peaks, resolving overlap with other compounds, and confirming purity. This approach also helps validate extraction methods and ensures accurate quantification. Since high temperatures are detrimental to Chl stability, this method is crucial for reliable analysis and longer dye storage. Ethanol outperformed methanol in extraction efficiency, while the stability of the dyes was tied to specific derivatives. Notably, Scenedesmus sp. showed better preservation of chlorophyll compounds, influenced by extraction temperature and solvent characteristics. Significance: This research underscores the potential for optimising natural dye extraction methods, offering a pathway to enhance the sustainability and cost-effectiveness of DSSC production, thus contributing to greener energy technologies.