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

MAPbBr3 perovskite crystals have attracted significant attention due to their outstanding performance in various optoelectronic applications. However, further understanding for the growth mechanism of MAPbBr3 and its temperature-dependent variations of MA+ should be addressed. In this study, MAPbBr3 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 MAPbBr3. 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 MAPbBr3 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.