Optical Behaviors of a Microsized Single-Crystal MAPbI3 Plate under High Pressure

Abstract

The correlation between the crystal structure and the optoelectrical property of methylammonium lead iodide (MAPbI3) is investigated by measuring the optical absorption and the photoluminescence spectra of a microsized single-crystal MAPbI3 plate (MSCMP) up to 20.43 GPa with confocal μ-spectroscopy. The pressure-induced phase transitions of an MSCMP are identified by the absorption edges of the absorption spectrum and the fluorescence peaks of the PL spectrum. A tetragonal–cubic phase transition is confirmed under a pressure within the range of 0.23 to 0.46 GPa. The optical property of the cubic phase is dominated by the competition between Pb–I bond contraction and PbI6 octahedron tilt up to 2.72 GPa. Furthermore, the MAPbI3 plate experiences an isostructural cubic phase transition with a unique optical behavior below 3.90 GPa. Little amount of nonradiative high-pressure phase presents a radiative emission mixed with a radiative low-pressure phase, which originates from the diffusion and recombination of...