Vibrational mode of low-dimensional ionic liquid bismuth hybrid perovskite probed by FTIR and Raman Spectroscopy

Bismuth-based hybrid organic-inorganic perovskites (Bi-HOIPs) are developed as lead-free halide perovskites due to their low toxicity and good stability. In this study, the incorporation of ionic liquid (IL) cations in the Bi-HOIPs structure, namely 1-butyl-1-methylpyrrolidinium (BMP) and 1-(3-aminopropyl) imidazole (API), are investigated. Bi-based HOIPs are kept in ambient conditions (20–25 °C) to compare the structural differences in FTIR and Raman spectra between pristine and aged samples. The FTIR and Raman spectra of all aged samples are slightly shifted after being retrieved at the ambient conditions for four months (∼below 45 cm−1). Our work paves the way in developing Bi-based HOIPs for solar cells and photodetectors applications.