Structural, vibrational, photoelectrochemical, and optical properties of two-dimensional Ruddlesden-Popper perovskite BAPbI crystals.

Two-dimensional organic-inorganic hybrid Ruddlesden-Popper perovskites have attracted a lot of attention due to their unique photochemical properties and enhanced stability towards photoluminescence devices. Compared with three-dimensional materials, two-dimensional perovskites show great potential for photoelectric applications due to their tunable band gap, great excitation binding energy, and large crystal anisotropy. Although the synthesis and optical properties of BAPbI crystals have been extensively studied, the role of their microstructure in photoelectric applications, their electronic structure, and their electron-phonon interaction are still poorly understood. In this paper, based on the preparation of BAPbI crystals, the electronic structure, phonon dispersion, and vibrational properties of BAPbI crystals were revealed in detail with the help of density functional theory. The BAPbI stability diagram of formation enthalpy was calculated. The crystal structure of the BAPbI crystals was characterized and calculated with the aid of Rietveld refinement. A contactless fixed-point lighting device was designed based on the principle of an electromagnetic induction coil, and the points with different thicknesses of BAPbI crystal were tested. It is proved that the excitation peak of the bulk is 564 nm, and the surface luminescence peak is 520 nm. Phonon dispersion curves and the total and partial phonon densities of states have been calculated for the BAPbI crystals. The calculated results are in good agreement with the experimental Fourier infrared spectra. Besides the basic characterization of the BAPbI crystals, the photoelectrochemical properties of the materials were also studied, which further proves the excellent photoelectric properties of the BAPbI crystals and the broad application prospect.