Unravelling the spectral enigma with enhanced extraction of algal dyes: A sustainable energy tactic

Natural microalgal dyes as a photosensitizer in dye-sensitized solar cells (DSSCs) have the potential to challenge the slender spectral response in DSSCs. This paper analyses the extraction efficiency of these dyes obtained via the hot and cold solvent methods in the finest solvent concentration. The dye from six indigenous microalgal species i.e., Scenedesmus sp., Asterarcys quadricellulare, Coelastrella sp., Desmodesmus pseudocommunis, Coelastrum proboscideum, and Pediludiela daitoensis utilizing solvents of acetone, ethanol, and methanol in various concentrations of 80%, 90%, and 100%, were further plotted for UV-Vis spectra and analyzed via MATLAB. Species were continuously shortlisted based on the accepted method of hot solvent extraction using more efficient solvent ethanol. The UV-Vis spectra showed peaks at wavelengths 421, 435, 467, 618, 652, and 665 nm to conclude the presence of pigments like Chlorophyll a and b, pheophytin a and b in it alongside some shifts. The most promising results are found in the Asterarcys quadricellulare and Scenedesmus sp. species extracted in ethanol at 80% concentration. Ethanol (80%) and methanol (90%) hot solvent extracted dyes were compared for characterization analysis like FTIR, Cyclic Voltammetry, and stability testing via UV-Vis to support their po-tential to be efficient dyes for DSSC fabrication. It was also observed that the Scenedesmus sp. dye is compara-tively less stable than Asterarcys quadricellulare dye in ethanol solvent whereas Scenedesmus sp. dye seems to be more stable in methanol.