An Efficient Approach for Controlling the Crystallization, Strain, and Defects of the Perovskite Films in Hybrid Perovskite Solar Cells Through Antisolvent Engineering

The efficiency and stability of perovskite solar cells are regulated by defects at the grain boundaries and at the surface of organic-inorganic halide perovskite films. Various methods have been proposed to improve the quality of the perovskite film, but most of these approaches complicate the fabrication procedure. Here, we show an efficient and simple engineering approach for regulating the crystallization, strain, and defects of the perovskite film by adding the organic salt octylammonium bromide (OABr) in the antisolvent solution. The proposed treatment improves the crystallization of the perovskite film, controls the strain in the film, and efficiently passivates defects of the hybrid quadruple cation perovskite, reducing the charge trap density and non-radiative recombination. Consequently, the non-radiative losses in the optimized OABr treated devices were considerably mitigated by 43.6%, allowing a V-oc of 1.16 V and efficiency up to 20.4% to be achieved. In addition, the stability of the OABr treated devices was improved, retaining 80% of their initial performance under ambient conditions for more than 1400 hours.