Dye-sensitized solar cells based on natural photosensitizers: A green view from Iran

Due to population growth and subsequent growing energy demand, clean energy generation is one of the major challenges today and in the future. Dye-sensitized solar cells (DSSCs) is one of the new approaches to producing clean, endless energy. In this review, the primary function, structure, performance parameters, and key elements of DSSCs are analyzed first, with a focus on the photosensitizer as the crucial part due to electron production. Photosensitizers based on natural resources recently attracted attention because of their economic and environmental advantages, but there are substantial challenges such as low conversion efficiency and long term stability. Also, diverse and, in some cases, contradictory results presented in the literature make conclusions difficult. Here, different challenges about DSSCs based on natural dyes are categorized and discussed according to the published papers, and possible solutions are presented, which could shed light on future investigations. Furthermore, according to different factors, such as average solar radiation and economic/technological aspects, DSSCs based on natural dyes are proposed to be the most promising renewable energy technology for arid to semi-arid, sunny countries like Iran in the future. Accordingly, the performance of DSSCs based on natural dyes manufactured using dye extract of different plants grow in Iranian is summarized then. In recent years, many DSSCs based on natural dyes have been manufactured using different plants grown in different parts of the country. Interestingly, it is possible to extract many natural dyes for DSSCs based on natural dyes from agricultural wastes such as saffron petals and walnut shells, of which thousand tons them are disposed every year.