Solvent selection for anthrocyanin dye extraction from Kigelia Africana and Hibiscus sabdariffa for dye sensitized solar cells

Abstract

The main flavonoid pigment in the petals of Kigelia Africana and the calyx of Hibiscus sabdariffa is anthocyanin, responsible for the vibrant red, maroon, and purple hues in flowers. This pigment can modulate incident light on flowers, prompting its selection for detailed investigation. TiO₂ nanostructures were synthesized using a one-step hydrothermal method, revealing the formation of nanorods and a single-phase rutile structure through FESEM and XRD analyses, respectively. The study aimed to assess the impact of various solvents on the extraction of natural dyes, which were subsequently sensitized on TiO₂ photoanodes for DSSC applications. Four solvents-water, water with HCl, ethanol, and citric acid were employed to extract natural dyes from Kigelia Africana's petals and Hibiscus sabdariffa's calyx. Notably, dyes extracted with citric acid demonstrated promising results. The conversion efficiency of DSSCs fabricated with Kigelia Africana dye and Hibiscus sabdariffa dye, extracted using citric acid as the solvent, was found to be 0.87 % and 0.92 %, respectively. The implications of these findings are discussed.