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arXiv · 2401.13468

Revisiting the pressure-induced phase transitions of Methylammonium Lead Bromide Perovskite

Akun Liang·Javier Gonzalez-Platas·Robin Turnbull·Catalin Popescu·Ismael Fernandez-Guillen·Rafael Abargues·Pablo P. Boix·Lan-Ting Shi·Daniel Errandonea
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Abstract

The high-pressure crystal structure evolution of CH3NH3PbBr3 (MAPbBr3) perovskite has been investigated by single-crystal X-ray diffraction and synchrotron-based powder X-ray diffraction. Single-crystal X-ray diffraction reveals that the crystal structure of MAPbBr3 undergoes two phase transitions following the space-group sequence: Pm-3m-to-Im3-to-Pmn21. The transitions take place at around 0.8 and 1.8 GPa, respectively. This result is contradicting the previously reported phase transition sequence: Pm-3m-to-Im3-to-Pnma. In this work the crystal structures of each of the three phases are determined from single-crystal X-ray diffraction analysis which is later supported by Rietveld refinement of powder X-ray diffraction patterns. The pressure dependence of the crystal lattice parameters and unit-cell volumes are determined from the two aforementioned techniques, as well as the bulk moduli for each phase. The bandgap behaviour of MAPbBr3 has been studied up to around 4 GPa, by the means of single-crystal optical-absorption experiments. The evolution of the bandgap has been well explained using the pressure dependence of the Pb-Br bond distance and Pb-Br-Pb angles as determined from single-crystal X-ray diffraction experiments.

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Akun Liang, Javier Gonzalez-Platas, Robin Turnbull, Catalin Popescu, Ismael Fernandez-Guillen, Rafael Abargues, Pablo P. Boix, Lan-Ting Shi, Daniel Errandonea. 2024-01-24. Revisiting the pressure-induced phase transitions of Methylammonium Lead Bromide Perovskite. https://doi.org/10.1021/jacs.2c09457

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