Performance of dye-sensitized solar cells with natural dye from local tropical plants

Abstract

Dye-sensitized solar cell (DSSC) is a class of third generation solar cells that are formed by placing a semiconductor between a photosensitized anode and an electrolyte, which allows the light to pass through the cell. Synthetic dyes, usually ruthenium-based and commonly used in DSSCs, are environmentally toxic and expensive than natural dyes. The aim of the study was to investigate native and cheap sources of natural dyes as photosensitizers for DSSCs using tropical plants. Dyes from four different local plant sources were successfully extracted, prepared, and characterized and were used as alternative, non-toxic, natural photosensitizers. The visible spectra of the extracts with peaks between 430-440 nm suggest that they are dominated by chlorophyll a (430-662 nm) and chlorophyll b (453-642 nm). When observed under ambient conditions, the fabricated DSSCs demonstrated high outputs for OCVmax wherein 433, 397, 311, and 203 mV were obtained using dye-sensitizers from dried talisay leaves (Terminalla catappa), spent coffee grounds (Coffea spp.), fresh talisay leaves, and alugbati fruit (Basella alba), respectively. The observed open circuit potentials were comparable with other reported DSSCs. The output current, fill factor, and cell efficiency can be improved by co-sensitization and increasing the light-scattering capability, among other methods of constructing the DSSCs. Generally, with the limited impacts to the environment and cheap production cost, this research has opened opportunities for application of natural dye from local sources for renewable energy technologies.