ABSTRACT
Three natural dyes, i.e., yellow, red, and blue, were extracted from gardenia and used as sensitizers in the assembly of rainbow dye-sensitized solar cells (DSSCs) to harvest light over a wide range of wavelengths. The adsorption characteristics, photovoltaic efficiencies, and electrochemical properties of the rainbow DSSCs were investigated. Adsorption kinetic data for the dyes were obtained in a small adsorption, chamber. The data fitted a pseudo-second-order model. The photovoltaic performance of a photo-electrode with an adsorbed mixture of the three dyes was evaluated from current-voltage measurements.
ABSTRACT
Two natural dyes extracted from gardenia yellow (Gardenia jasminoides) and cochineal (Dactylopius coccus) were used as sensitizers in the assembly of dye-sensitized solar cells (DSSCs) to harvest light over a wide range of wavelengths. The adsorption characteristics, electrochemical properties and photovoltaic efficiencies of the natural DSSCs were investigated. The adsorption kinetics data of the dyes were obtained in a small adsorption chamber and fitted with a pseudo-second-order model. The photovoltaic performance of a photo-electrode adsorbed with single-dye (gardenia or cochineal) or the mixture or successive adsorption of the two dyes, was evaluated from current-voltage measurements. The energy conversion efficiency of the TiO2 electrode with the successive adsorption of cochineal and gardenia dyes was 0.48%, which was enhanced compared to single-dye adsorption. Overall, a double layer of the two natural dyes as sensitizers was successfully formulated on the nanoporous TiO2 surface based on the differences in their adsorption affinities of gardenia and cochineal.
