Opuntia spp. in Dye-sensitized solar cells

Abstract

Solar energy is one of the most important renewable and sustainable forms of energy. Different technologies have been developed to harness this free energy and contribute to the world economy, especially in countries with no seasonal variations in solar radiation. Dye-sensitized solar cells (DSSCs) are simply used to collect solar energy and convert that visible light into electricity. This depends on the photosensitization of wide band-gap metal oxide semiconductors. The photoelectrode spectral sensitivity needs specific chemical dyes for the lower energy photons collection. Significant research efforts for identifying new organic dyes from natural sources have been carried out. Higher plants contain many natural pigments well-known to interact with solar radiation. The fruit of the Opuntia spe-cies contains a particular type and unique pigment called betalain. This type of compound has an interesting conjugation system with nitrogen atoms forming an unusual natural dye. Betalain has a potential interest in the photosensitization process when added to the DSSCs system. This chapter provides a review on the structural features and potential applications of the betalain pigments in the photosensitization solar cells.