A Fascinating Trip into Iron and Copper Dyes for DSSCs

The production of electricity in a greener and more sustainable way by employing renew‐ able sources is a great challenge in modern times. Photovoltaic systems represent an important pos‐ sibility because sunlight is the most abundant renewable source. In this review article, recent studies (from 2018 to the present) involving novel iron and copper complexes employed as dyes in Dye‐ Sensitized Solar Cells (DSSCs) are reported; mono‐ and bimetallic Fe complexes, Cu‐based dyes, and devices presenting both metals are discussed, together with the performances of the DSSCs reported in the papers and the corresponding values of the main parameters employed to charac‐ terize such solar cells. The feasibility of DSSCs employing copper and iron dyes, alone or in combi‐ nation with other earth‐abundant metals, is demonstrated. The proper optimization of the sensitiz‐ ers, together with that of the electrolyte and of the semiconducting layer, will likely lead to the de‐ velopment of highly performing and cheap photovoltaic devices for future applications on a much larger scale.