Open-Air Processing of Mechanically Robust Metal Halide Perovskites with Controllable Thicknesses above 10 µm

We report on the use of open-air blade-coating as a scalable method for producing metal halide perovskite films with >10× fracture energy for durability and mechanical stability through the addition of corn starch polymer additives. This results in a manufacturable and robust perovskite that has tunable thicknesses exceeding 10 µm, among the highest reported values for solution-processed polycrystalline films. We find that an increasing amount of starch causes more uniform carbon distribution within the perovskite thickness as quantified by cross-sectional elemental composition measurements. Further, the incorporation of starch introduces beneficial compressive film stresses. Importantly, the optoelectronic behavior is not compromised, as the photoluminescence spectrum becomes more homogenous with the addition of corn starch up to 20% by weight.