In-situ Optical Control of Local Periodical Ferroelastic Domain Evolution in CH₃NH₃PbI₃ Perovskites

Local pulse mid-infrared (IR) light at 1468 cm(-1) corresponding to the C-N dipoles within the CH3NH3+ rock was incorporated into the present study to explore ferroic domain dynamics of the methylammonium lead triiodide (MAPbI(3)) crystal. The pulsed IR illumination was found to induce the CH3 asymmetric deformation, rotation of the MA(+) ion, and inorganic PbI6 octahedra framework deformation, resulting in a remarkable strain as a driving force for domain wall movement, local ions migration, and properties tailoring of the MAPbI(3) system. Local chemical mapping, nanoscale IR spectrum, and local thermal ionic imaging demonstrated that the strain plays an important role in the redistribution of mobile CH3NH3+ ions, contributing to local triangle- or spindle-shaped nucleation and growth kinetic behavior of periodical, stripe twin domains. The results offer insights into the interplay of the strain level, ferroic properties, and chemical ion migration on the optoelectronic performance of metal halide perovskites-based solar cells and suggest a promising optical modulation approach for periodical ferroelastic domain configurations to enhance the optoelectronic performance of metal halide perovskites-based solar cells.