Step-controlled growth of MAPbBr3 single crystal and temperature-dependent variations of MA+ cations during nonphase transition

MAPbBr 3 perovskite crystals have attracted significant attention due to their outstanding performance in various optoelectronic applications . However, further understanding for the growth mechanism of MAPbBr 3 and its temperature-dependent variations of MA + should be addressed. In this study, MAPbBr 3 single crystal was grown using the inverse temperature crystallization method with a crystallization temperature of approximately 60 °C. Optical microscopy and atomic force microscopy were used to illustrate the surface structure of the resultant MAPbBr 3 . The results show that there is a layered growth mode with concave grooves and 2D nuclei on its surface. In situ variable-temperature Raman measurements were performed on the MAPbBr 3 crystal at a temperature range of 80–300 K. The narrowing of Raman bands unrelated to the phase transition of the crystal was observed around 100 K. By combining the variable-temperature X-ray diffractometry results from 80 to 105 K, the reason can be attributed to the lattice distortion and vibration within the crystals.