Betalain pigments as natural photosensitizers for dye-sensitized solar cells: the effect of dye pH on the photoelectric parameters

Dye-sensitized solar cells (DSSC) were fabri- cated using red bougainvillea glabra 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/cm 2 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/cm 2 , 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/cm 2 for dye sensi- tizer pH of 1.2, 3.0, and 5.7, respectively.