Crystal structure and photo-physical properties in a perovskite–type semiconducting hybrid phase: {(m-C6H7N2O2)2CdCl4}n

Abstract

A new intercalation crystalline polymer compound of bis m-nitroanilinium tetrachlorocadmate (II) {(m-C6H7N2O2)2CdCl4}n was synthesized and analyzed using single crystal SXRD, differential scanning calorimetry (DSC), DFT analysis, thermal gravimetric analysis (TGA) and FT-IR, Raman, UV–Vis, fluorescence spectroscopy techniques. X-ray diffraction analyses (SXRD, PXRD) show a layered structure consisting of alternating organic bilayers and two-dimensional inorganic sheets in which each CdCl6 octahedron shares four corners with adjacent octahedra. The crystal packing is consolidated by means of classic and non-classic hydrogen bonds and π-π interactions. At room temperature photoluminescence spectra of {(m-C6H7N2O2)2CdCl4}n yield broad peaks in the 469–770 nm range with full width at half maximum (FWHM) values up to 153 nm. Besides, this compound exhibits a semiconducting behavior with bright red-light under 360 nm ultraviolet photoexcitation and possesses a large Stokes shift and direct band gap of 2.69 eV which overlaps well with solar spectrum. The CIE chromaticity coordinates of {(m-C6H7N2O2)2CdCl4}n are (x = 0.4704 and y = 0.4523). The color rendering index CRI and the low correlated color temperature CCT are 84 and 2861 K, respectively. Electronic structure (BS, DOS and PDOS), and optical properties (dielectric constant ε(ω), refractive index n(ω), reflectivity R(ω), absorption coefficient α(ω), optical conductivity σ(ω) and energy loss function L(ω) with the incident photon energy) were determined using (DFT) calculations by CASTEP code.