Nanoscale stability behavior of the CH3NH3PbI3 perovskite via scanning thermal chemical microscopy

Abstract

High resolution scanning thermal chemical microscopy (STCM), developed on the basis of commercial atomic force microscopy-based infrared (AFM-IR) spectroscopy and custom-developed AFM-tip heating techniques, was carried out using a home-built set up to perform studies of the nanoscale stability behavior of CH₃NH₃PbI₃ perovskite crystals in response to local cooperative stimulation of IR light and thermal fields. Nanoscale temperature dependent infrared spectra gave direct evidence that the chemical bond vibration dynamics change of the methylammonium (MA⁺) cations was closely related to the structural stability, and nanoscale thermal chemical imaging demonstrated the effect of MA⁺ cation movement caused by the tip's heating temperature on the ferroelastic domain configuration. The present new findings provide new insights into the nanoscale stability behavior of CH₃NH₃PbI₃ perovskite crystals under external conditions.