Betalain Pigments as Natural Photosensitizers for Dye-Sensitized Solar Cells: The Effect of Dye pH on the Photoelectric Parameters

Abstract

Dye-sensitized solar cells (DSSC) were fabricated using red bougainvilleaglabra flower dye extracts as natural dye sensitizers at three dye pH values of 1.23, 3.0, and 5.7. Water was used as dye-extracting solvent. DSSCs from dye extract of pH 3.0 had the highest photocurrent density Jsc of 3.72 mA/cm2 and fill factor FF of 0.59. While the DSSCs from dye sensitizer pHs of 1.23 and 5.7 had Jsc of 1.13 and 2.27 mA/cm2, and fill factors of 0.43 and 0.61, respectively. The maximum powers Pmax of the DSSCs were 0.50, 1.64, and 0.94 mW/cm2 for dye sensitizer pH of 1.2, 3.0, and 5.7, respectively.