Significant THz-wave absorption property in mixed δ- and α-FAPbl_3 hybrid perovskite flexible thin film formed by sequential vacuum evaporation

摘要

The flexible and mixed delta- and alpha-formamidinium lead iodide (FAPbI(3)) hybrid perovskite thin films fabricated by the sequential vacuum evaporation method (SVE) were studied using the THz-wave absorption property. The formed FAPbI(3) using SVE showed the typical delta-phase. After annealing for 10 min, we confirmed a mixed state with delta- and alpha-phases and observed THz-wave absorption at 1.62 THz with 40% absorptance. In the C 1s core-level spectra, we found two different chemical states originated from delta- and alpha-FAPbI(3). The origin of the THz-wave absorption property is assumed from a significant Pb-I vibration mode from the mixed phases in FAPbI(3). (C) 2019 The Japan Society of Applied Physics