Deterministic Nucleation for Halide Perovskite Thin Films with Large and Uniform Grains

Halide perovskite materials have come to the forefront of optoelectronics recently owing to their excellent light absorbing and emitting properties. Despite their excellent properties there are still problems that need to be overcome such as short operating lifetimes, and an observed hysteresis behavior in their current–voltage characteristics. It is found that these challenges could be overcome by developing a deterministic nucleation process using gold as a nucleation promoter to control the grain size of the perovskite layer. It is shown that this deterministic nucleation process can be expanded across multiple perovskite systems and can be used to achieve extremely uniform and large grain sizes within the perovskite layer. These large perovskite grains exhibit enhanced stability compared to current state‐of‐the‐art nanocrystalline films, and exhibit no hysteresis in their I–V characteristics which is key if commercialization of perovskites is to be realized.