Chlorobenzene-Mediated Control of Crystallization in Perovskite Films for High-Performance Solar Cells

Uncontrollable crystallization is a huge problem for the fabrication of perovskite films with desired properties and performance. Recently, antisolvent precipitation has been widely used during spin-coating perovskite precursors to improve the crystallization rate and device performance. Herein, we demonstrate a method to enhance the photovoltaic performance of perovskite films by directly mixing an antisolvent, chlorobenzene (CB), into the perovskite precursor. By adding 30% CB to the precursor, the power conversion efficiency of the champion device was improved from 15.24 to 18.48% due to the improvement in the thickness and grain size of the films. In addition, the device showed ca. 8 times less degradation in normalized power conversion efficiency after 120 h of storage in the ambient air without encapsulation. By mixing the precursor solvent with the antisolvent, we improved the perovskite film thickness and reduced the material waste, which can benefit the commercialization of perovskite devices.