Abstract:
Composite films based on CH$_{3}$NH$_{3}$PbI$_{3}$ organometallic perovskite and mixed cellulose ester (CE) were studied using terahertz (THz) spectroscopy in the time domain. It is established that the introduction of CE into CH$_{3}$NH$_{3}$PbI$_{3}$ precursor significantly modifies the parameters of perovskite in the THz range and improves stability of the composite films. In particular, CE addition to the perovskite composite film leads to significant weakening of absorption bands in the region of 1–2 THz related to the excitation of low-frequency oscillatory modes in CH$_{3}$NH$_{3}$PbI$_{3}$ molecules. This can be explained by damping of these modes on CE molecules enveloping the perovskite molecules.
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