A Way to Reach 10% Efficiency with Carbon‐Based Electrodeposited Mixed Perovskite Solar Cells

Electrodeposition is investigated in this work as an alternative method to develop a large‐area perovskite active layer for solar device application. In addition to the single perovskite MAPbI 3 , the deposition of mixed perovskites MAPbI x Cl 1− x and MA 1− y FA y PbI 3− x Br x is studied. This study is unique since these mixed perovskites have never been developed by electrodeposition before. It is noticed that depending on the ratios of FA, Br, and Cl infiltrated into the perovskite lattice, different microstructures and optical and chemical properties are obtained, having an impact on the photovoltaic performance of the perovskite layer. In fact, increasing the percentages of FA, Br, and Cl in the mixed perovskite improves the photovoltaic performance. Thanks to a maturation step carried out under vacuum at 40 °C for 500 h, the performances can be significantly improved, at best by 60%, to reach record efficiencies of 10%. An improvement of the stability under air at 40 °C is also observed. All the results obtained are compared with recent results in the literature, which makes it possible to appreciate the originality and innovation of the study proposed in this article. In summary, this work illustrates the importance of electrodeposition and its flexibility to develop different types of perovskites.