부산대학교 도서관

The structural stability and internal properties of hybrid organic–inorganic perovskites (HOIPs) have been widely investigated over the past few years. The interplay between organic cations and inorganic framework is one of the prominent features. Herein we report the evolution of Raman modes under pressure in the hybrid organic–inorganic perovskite MAPbI336-1-16-1-1-1-1 by combining the experimental approach with the first-principles calculations. A bulk MAPbI336-1-16-1-1-1-1 single crystal was synthesized via inverse temperature crystallization (ITC) technique and characterized by Raman spectroscopy, while the diamond anvil cells (DACs) was employed to compress the sample. The classification and behaviours of their Raman modes are presented. At ambient pressure, the vibrations of inorganic PbI336-1-16-1-1-1-1 octahedra and organic MA dominate at a low-frequency range (60–760 cm336-1-16-1-1-1-1) and a fingerprint range (900–1500 cm336-1-16-1-1-1-1), respectively. The applied pressure exhibits two significant changes in the Raman spectrum and indicates of phase transition. The results obtained from both experiment and calculations of the second phase at 3.26 GPa reveal that the internal vibration intensity of the PbI336-1-16-1-1-1-1 octahedra (< 110 cm336-1-16-1-1-1-1) reduces as absences of MA libration (150–270 cm336-1-16-1-1-1-1) and internal vibration of MA (450–750 cm336-1-16-1-1-1-1). Furthermore, the hydrogen interactions around 1300 cm336-1-16-1-1-1-1 remain strong high pressure up to 5.34 GPa.