High Resolution Nanostructuring of Perovskites With Tunable Morphologies by Ultrafast Laser Direct Writing

Abstract Metal halide perovskites (MHPs) have attracted increasing attention in various optoelectronic devices due to their exceptional optical and electrical properties. The high precision patterning of MHPs is crucial adjective for device fabrication, while it is severely hindered by the active and sensitive chemistry of MHPs. In this work, high resolution and tunable nanostructuring of 2D MHP films are achieved by ultrafast laser direct writing (ULDW). The feature size of the created structure is down to 47 nm (λ/21), which is far beyond the diffraction limit of the optical system. The study proves the critical influence of the thermodynamic properties of materials on structure morphologies and establish a new mechanism of molten phase self‐evolution (MPSE) for the formation of super‐solution convex structures, which provides a new understanding for ultrafast laser‐matter interaction and high‐resolution patterning with ULDW. Different structure morphologies bring tunable optical properties. The applications are demonstrated in multimode information storage and encryption. The findings open new approaches to achieve hyperfine multi‐morphological structures on MHPs, which can boost many MHPs integration applications in nanophotonics, on‐chip electronics, and information encryption.