Temperature Dependence of the Mössbauer Spectra of CsSnCl3

Room-Temperature Stable Inorganic Halide Perovskite as Potential Solid Electrolyte for Chloride Ion Batteries

“…Figure shows the XRD patterns of the cubic MM-1 h-HT materials stored in inert atmosphere at different temperatures. The cubic structure was maintained after three months at 298 K, indicating that the as-prepared cubic CsSnCl 3 material possessed notably enhanced structural stability compared to the previously reported cubic CsSnCl 3 materials, which transformed to the white monoclinic CsSnCl 3 materials after 1 day. ,, One possible explanation may be related to the nanograins in the as-prepared cubic CsSnCl 3 material. It has been reported for many cubic perovskites that the small grains could increase the surface energy (surface to volume ratio) and thus stabilize the cubic structure. , Moreover, the lattice strain in the as-prepared cubic CsSnCl 3 material could induce a lattice distortion, which was also regarded as an effect that improved the stability of the cubic structure. − Another reason for the enhancement in this structural stability was that the tin vacancy in the as-prepared cubic phase could not only produce a lattice distortion, but also create the locations with strengthened Cs–Cl bonds (Figure S3), thereby increasing the energy barrier for the octahedral titling of the cubic structure. , The as-prepared cubic phase can be kept at a lower temperature of 283 K for 1 day.…”

“…The cubic structure was maintained after three months at 298 K, indicating that the as-prepared cubic CsSnCl 3 material possessed notably enhanced structural stability compared to the previously reported cubic CsSnCl 3 materials, which transformed to the white monoclinic CsSnCl 3 materials after 1 day. 27,37,38 One possible explanation may be related to the nanograins in the as-prepared cubic CsSnCl 3 material. It has been reported for many cubic perovskites that the small grains could increase the surface energy (surface to volume ratio) and thus stabilize the cubic structure.…”

A Mössbauer Study of the Phase Transitions in CsSnBr3

“…The values of (6E/E + 3kT/2mc2) were found to decrease linearly with 1/T. With the temperature coefficient a set to zero and using the value of the slope of the (6E/E + 3kT/2mcZ) versus 1/T plot, the Debye temperature OD for CsSnBr, was estimated to be 260 K. A similar temperature dependence was observed for the (6E/E + 3kT/2mc2) values of CsSnC1, for which the Debye temperature was found to be 399 K [6].…”

“…1 shows the variation of isomer shifts with temperature. These values, calculated relative to cl-tin, are typical of the trihalogenostannates [4,9]; an earlier Mossbauer work by'us revealed isomer shift values of around 1.60 mm/s for CsSnC1, [6]. For CsSnBr,, the isomer shift decreases linearly with temperature from 2.05 mm/s at 82 K to 1.91 mm/s at 280 K. However, at around 285 K, it increases on heating the absorber to 327 K. Scaife and co-workers [2] found that the lattice symmetry changes from a cubic perovskite, with a = 0.580 nm, to a tetragonally distorted perovskite, with a = 1.159 nm and c = 1.161 nm, at 292 K. In view of this, the anomaly observed in the temperature dependence of the isomer shift is indicative of a structural transformation at around 285 K.…”

“…The Mossbauer set-up employed, with lI9Sn in a calcium stannate matrix as the source, has been described elsewhere [6]. The CsSnBr, concentration in the absorbers used was 0.08 g/cm3, an optimum value calculated from a formula given by Long et al [8].…”