Structural, BFDH morphology, DSC, Infrared, and UV absorption studies of tetrachlorocobaltate and manganate NH3(CH2)nNH3MCl4 (M: Co, Mn, and n = 4, 5, 9) hybrid perovskite salts

Abstract

Hybrid perovskite crystals NH3(CH2)nNH3MCl4 (M: Co, Mn, and n = 4, 5, 9), abbreviated CnMCl studied elswhere are investigated in terms of structural analysis, DSC, Infrared, and UV–visible spectroscopy properties. The structures of these salts are compared in terms of parametrs and space groups relationship symmetry. BFDH (Bravais-Fridel, Donnay–Harker) crystals morphologies are simulated using the units cell parametres and Laue symmetries of NH3(CH2)nNH3CoCl4 (n = 4, 9) of space group P-1 (Z = 2), NH3(CH2)5NH3MnCl4 considered in I212121 (Z = 4) and Imma (Z = 4) space groups, and NH3(CH2)9NH3CoCl4 (P21/c, Z = 4). DSC analyses showed that C4CoCl salt presents two continuous phase transitions at heating/cooling (321/320 K) and (309/295 K), while the C9CoCl salt did not present any phase transition between 310 and 400 K. The C5MnCl salt undergoes two continuous reversible phase transitions at heating/cooling (287/285 K) and (295/325 K); the thermal behavior of this salt is discussed in respect to the phase transition observed elswhere at 298 K. Infrared spectra of C4CoCl and C5MnCl compounds are discussed at different temperatures (80–352 K) regarding their DSC thermal behaviors. Far-Infrared spectra are discussed for CoCl42- and MnCl42- vibrational anions in CnCoCl (n = 4, 9) and CnMnCl (n = 5, 9) crystals based on theoretical group analyses. The UV–visible optical absorptions (300–1500 nm) revealed low bands gap for C4CoCl (1.80 eV) and C9CoCl (1.77 eV), suggesting these cobalt salts as good conductors for photovoltaic applications and solar cells, and good absorber materials with energies gap under 2 eV.