Synthesis and pressure-induced structural phase transition of energetic molecular perovskite DAI-1

We synthesized the energetic molecular perovskite DAI-1 (C 48 H 112 I 24 N 16 Na 8 O 96 ) and investigated its behavior under high pressure using high-pressure Raman spectroscopy. DAI-1 exhibits an ABX 3 cubic perovskite structure, with significant changes in its Raman spectrum occurring between 4.3 and 7.1 GPa, signaling a phase transition. Releasing the pressure after applying it up to 12.3 GPa showed that the Raman spectrum did not return to its original state, indicating an irreversible phase transition. Furthermore, we conducted simulations to analyze the trend of changes in the crystal structure under pressure. This study serves as a reference for in-depth research on the high-pressure behavior of DAI-1 and other related substances.