A facile green solvent engineering for up-scaling perovskite solar cell modules

Organic-inorganic hybrid halide perovskite solar cells (PSCs) have shown the potential for the commercialization due to its high efficiency and low cost. How to scale up the module nowadays becomes a great challenge. Anti solvent assisted crystallization is one of the most widely used methods to obtain pinhole-free homogeneous perovskite films owing to its advantage of low cost and simple process. The commonly used anti-solvents are toxic, such as chlorobenzene and toluene. Herein, we have made an effort to find a green solvent engineering by the anti-solvent bath to produce large area uniform perovskite films. Compared to the traditional solvent processed perovskite films, the films produced by n-butyl alcohol soaking exhibit smoother surface and superior performance. A moderate concentration of FAI/MABr has been added in the n-butyl alcohol solution to compensate for the loss of FAI/MABr during the soaking step. By this means, it alleviates the phenomenon of cracks on the perovskite surface, which exhibited a champion efficiency of 17.67% for PSCs with small area of 0.16 cm(2) and a PCE of 13.85% for 10 cm x 10 cm perovskite solar modules.