Edy Supriyanto, Firman Wahidi, Novita Andarini, Henry Ayu Kartikasari, Nova Alviati, Ahmad Taufiq, Agus Subekti
Biological pigments are under investigation for dye-sensitized solar cells (DSSC) to increase their performance and affordability. Optical properties, including the absorbance and range of absorption spectrum, are among the characteristics that determine the suitability of a dye for DSSC. This study compares the use of pH conditions in the preparation of new bio-pigments that may improve DSSC performance. Optical analysis was carried out on Moringa Oleifera Lam, Ipomea reptans Poir, Averrhoa bilimbi Linn, and Tamarindus Indica fruit extracts at acidified to a pH range of 1–6 (Moringa Oleifera Lam dyes and Ipomea reptans Poir) and 1–2.6 (Averrhoa bilimbi Linn and Tamarindus Indica fruit) using sulfuric and formic acid. Absorbance data and light absorption spectra were characterized using UV-Vis spectroscopy. We observed that extracts of Moringa oleifera Lam and Ipomea reptans Poir, which contain chlorophyll-b, have the same absorbance spectra (range, 400–500 nm). Tannins are the light-major absorbing compounds in Averrhoa bilimbi Linn, and chalcone is the major light-absorbing compound in Tamarindus Indica. Adding sulfuric acid to these extracts causes a decrease in absorbance without changing the absorption range. In contrast, adding formic acid changes the absorbance and widens the absorption range to the near-infrared region due to chemical changes in the solvent. © 2025 American Institute of Physics Inc.. All rights reserved.
Department of Physics, Faculty of Mathematics and Natural Sciences, Jember University, Kalimantan Street 37, Jember, 68121, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember, Kalimantan Street 37, Jember, 68121, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Malang State University, Semarang Street 5, Malang, 65145, Indonesia
