Making Cells “Greener:” Research Progress of Natural Green Plant Extracts in Perovskite Solar Cells

Abstract Perovskite solar cells (PSCs) have great potential as a third‐generation emerging photovoltaic technology. Nevertheless, the perovskite films prepared by conventional solution methods are plagued by a large number of defects, which not only serve as nonradiative recombination centers, but also are more susceptible to the influence of water/oxygen/light in the environment, further degrading the film quality. To address this challenge, additive engineering has been widely applied to the PSCs. This review summarizes the research progress of low‐cost, natural, environmentally friendly, and nontoxic plant extracts improving device performance. Specifically, the advantages and limitations of different kinds of extracts applied to PSCs, and the analysis of different plant extracts in each layer and adjacent interface of PSCs. Furthermore, the effects and applications of plant extracts on the PSCs are discussed from four aspects, namely, regulating the crystallinity of perovskite crystals, improving device stability, adjusting energy levels, and innovative applications. Finally, this review summarizes and prospects the role of plant extracts in the PSCs and the development of large‐scale industrialization.