A study of mixed vegetable dyes with different extraction concentrations for use as a sensitizer for dye-sensitized solar cells

Abstract

Two vegetable dyes are used for the study: chlorophyll dye from sweet potato leaf extract and anthocyanin dye from extracts of blueberry, purple cabbage, and grape. The chlorophyll and anthocyanin dyes are blended in a cocktail in equal proportions, by volume. This study determines the effect of different extraction concentrations and different vegetable dyes on the photoelectric conversion efficiency of dye-sensitized solar cells. In order to make the electrode for the experiments, P25 TiO2 powder was coated on the ITO conducting surface, using a medical blade, to form a thin film with a thickness of around 35 m. The experimental results show that the cocktail dye blended using extracts of sweet potato leaf and blueberries, in the volumetric proportion 1: 1, at a weight concentration of 40%, using an extraction temperature of 50°C and an extraction heating time of 10 min produces the greatest photoelectric conversion efficiency (η) of up to 1.57%, an open-circuit voltage (VOC) of 0.61 V, and a short-circuit current density (JSC) of 4.75 mA/cm2. © 2014 Kun-Ching Cho et al.