Effect of Chlorine Addition on the Performance and Stability of Electrodeposited Mixed Perovskite Solar Cells

In this work, electrodeposition was explored as an alternative technique for elaborating large-scale and homogeneous perovskite layers for photovoltaic application. This method was used to elaborate simple MAPbI3 and mixed halide perovskites MAPbI3–xClx. PbO2 was first electrodeposited in a controlled manner. Next, the conversion into perovskite was conducted with various iodine/chlorine ratios. This produced different compositions of perovskites combining an interesting range of microstructural and functional properties. These perovskites, obtained for the first time using electrodeposition, were then tested in solar cell devices. The performances obtained with these innovative electrodeposited mixed perovskites are excellent, better than those obtained with most of the common forms of MAPbI3 published so far. In addition, the stability of these electrodeposited perovskites has been evaluated under mild aging conditions (40 °C, under vacuum or an ambient atmosphere) for 500 h. For the treatment under vacuum, a maturation process was evidenced inducing an improvement of PCE close to 40%, to reach 7%. These results are of great interest, especially considering the active area tested close to 0.2 cm2. The addition of Cl in the lattice not only limits the formation of by-products (PbI2, MAPbCl3, etc.) and enhances the efficiency of the solar cells but also largely increases the stability.