Biophotovoltaics: Natural pigments in dye-sensitized solar cells

TLDR

Dye‑sensitized solar cells (DSSCs) are low‑cost, flexible photovoltaic devices that use a wide‑bandgap semiconductor such as TiO₂ for charge separation and can incorporate a wide variety of dyes—including natural pigments—making them attractive for sustainable, low‑energy‑payback solar energy generation. The authors aim to review the current knowledge of natural dyes used in DSSCs to evaluate their light‑harvesting efficiency, sustainability, cost, and waste‑management potential. They conduct a literature review summarizing the use of natural dyes in DSSCs. Carotenoids, polyphenols, and chlorophylls emerge as promising natural dyes for DSSCs.

Abstract

Dye-sensitized solar cells (DSSCs) which are also called Graetzel cells are a novel type of solar cells. Their advantages are mainly low cost production, low energy payback time, flexibility, performance also at diffuse light and multicolor options. DSSCs become more and more interesting since a huge variety of dyes including also natural dyes can be used as light harvesting elements which provide the charge carriers. A wide band gap semiconductor like TiO2 is used for charge separation and transport. Such a DSSC contains similarities to the photosynthetic apparatus. Therefore, we summarize current available knowledge on natural dyes that have been used in DSSCs which should provide reasonable light harvesting efficiency, sustainability, low cost and easy waste management. Promising natural compounds are carotenoids, polyphenols and chlorophylls.