Proceedings of nanoGe Fall Meeting 2021 (NFM21)
Publication date: 23rd September 2021
Preparation of high-quality perovskite thin-films with a low concentration of defects has recently been achieved through cation engineering using Cs halide salts. However, an obstacle in the development of Cs-based perovskites is that cesium iodide (CsI) is the only sufficiently soluble cesium halide in common solvents, while other salts, such as CsBr and CsCl, have poor solubility. The solubility challenge has limited the progress in compositional engineering especially when pure Br-based compounds are aimed for. It is thus necessary to develop a technique for bringing insoluble additives into play.
Mechanosynthetic strategy is a green, rapid and solvent-free method for incorporation of insoluble dopants to perovskites, providing a promising strategy for the formation of high-quality films. With this approach, a triple Cs/FA/MA cation wide band-gap perovskite can be fabricated that could not be realized through a conventional solution processing.
The use of mechanosynthesis perovskites for thin film formation allows for the growth of relatively large crystalline grains. The champion device achieved a maximum PCE of 7.3% (7.03% stabilized), with JSC of 7.08 mA cm−2, VOC of 1.48 V, and a fill factor (FF) of 70%. This performance and voltage are among the highest reported for wide band-gap PSCs devices incorporating triple cation Csx(FAyMA(1-y))(1-x)PbBr3 perovskite.