In this study, we investigated the possibility of nanocomposite formation between polyvinylidene fluoride (PVDF) and perovskite Cs2SnF3I3 using density functional theory (DFT). The Gibbs free energy changes of about - 23 kcal/mol observed during the formation of the complexes indicates that this process is thermodynamically feasible. The NBO and AIM results also confirmed that the interactions of a physical nature at several points between PVDF and this perovskite cause this favorable interaction. The gap energy value of Cs2SnF3I3 3.629 eV and its composites were obtained 3.255 eV, which indicates that their optical excitation occurs at short wavelengths of light, namely near ultraviolet and violet-blue. The study of UV-vis spectra of this perovskite and its complexes with PVDF showed that the creation of composites, in addition to changing the wavelength of absorption peaks towards visible light, can also increase the absorption intensity. The polarity study also showed that due to the composite of Cs2SnF3I3 with PVDF, its dipole moment increased from 10.28 to 14.71 Debye. In addition, the polarizability coefficient and the first hyperpolarizability coefficient also increased with the increase in the number of perovskite units in the composites, improving their optical properties.
Magham et al. (Tue,) studied this question.