Oriented Perovskite Film from Laser Recrystallization in Magnetic Field.

The orientation of crystals on the substrate and the presence of defects are critical factors in electro-optic performance. However, technical approaches to guide the orientational crystallization of electro-optical thin films remains challenging. This article reports on a novel physical method called magnetic field assisted pulse laser annealing (MAPLA) for controlling the orientation of perovskite crystals on substrates. By inducing laser recrystallization of perovskite crystals under a magnetic field and with magnetic nanoparticles, the optical and magnetic fields w ere found to guide the orientational gathering of perovskite units into nanoclusters, resulting in perovskite crystals with preferred lattice orientation in (110) and (220) perpendicular to the substrate. The perovskite crystals obtained by MAPLA exhibited significantly larger grain size and fewer defects compared to those from pulsed laser annealing (PLA) and traditional thermal annealing, resulting in improved carrier lifetime and mobility. Furthermore, MAPLA demonstrated improved device performance, increasing responsivity and detectivity by two times, and photocurrent by nearly three orders compared with PLA. The introduction of Fe 2 O 3 nanoparticles during MAPLA not only improved crystal size and orientation but also significantly enhanced long-term stability by preventing Pb 2+ reduction. The MAPLA method has great potential for fabricating many electro-optical thin films with desired device properties and stability. This article is protected by copyright. All rights reserved.