Cubic or Not Cubic? Combined Experimental and Computational Investigation of the Short-Range Order of Tin Halide Perovskites

Abstract

Tin-based metal halide perovskites with a composition of ASnX3 (where A= MA or FA and X = I or Br) have been investigated by means of X-ray total scattering techniques coupled to pair distribution function (PDF) analysis. These studies revealed that that none of the four perovskites has a cubic symmetry at the local scale and that a degree of increasing distortion is always present, in particular when the cation size is increased, i.e., from MA to FA, and the hardness of the anion is increased, i.e., from Br– to I–. Electronic structure calculations provided good agreement with experimental band gaps for the four perovskites when local dynamical distortions were included in the calculations. The averaged structure obtained from molecular dynamics simulations was consistent with experimental local structures determined via X-ray PDF, thus highlighting the robustness of computational modeling and strengthening the correlation between experimental and computational results.

Structural Features Governing the Near-Edge X-ray Absorption Spectra of Lead Halide Perovskites

“…On the contrary, the near-edge portion of the spectrum is much less affected by static and dynamic disorder, and its sensitivity to symmetry and overall geometry (whether or not multiple scattering contributions play a role, as seen in this case) provide an idea complement to diffraction analysis …”

“…32−34 On the contrary, the near-edge portion of the spectrum is much less affected by static and dynamic disorder, and its sensitivity to symmetry and overall geometry (whether or not multiple scattering contributions play a role, as seen in this case) provide an idea complement to diffraction analysis. 35 The understanding of structure−property relations is of pivotal importance for the future development of halide perovskites for solar cells with improved power conversion efficiency, one of the many fields of prospected application.…”

Morphological, structural, optical and dielectric analysis of Cs2TiBr6 perovskite nanoparticles

“…A significant challenge hindering the practical use and advancement of metal halide perovskites pertains to the harmful nature of their primary component, lead (Pb). 1–3 The adverse impacts of lead on the environment and human well-being have raised substantial concerns, underscored by prevailing regulations in various countries that restrict the use of heavy metals. 4 Consequently, there exists a continually increasing fascination with innovative lead-free halide perovskite configurations, encompassing both bulk films and nanocrystals (NCs).…”

Quantifying Dynamic Tilting in Halide Perovskites: Chemical Trends and Local Correlations

“…Several previous studies have highlighted the crucial role played by the dynamic local structure and octahedral tilting in halide perovskites . For example, some investigations have revealed that ignoring the local structure can lead to inaccurate interpretation of various experimental techniques, including X-ray absorption near edge structure spectroscopy, high-energy resolution inelastic X-ray scattering, and pair distribution function analysis. − Moreover, electronic structure calculations performed for simulation cells corresponding to the average perovskite structure have been shown to result in poor estimates of band gaps, − emphasizing that it is critical to account for transient local distortions. These findings underscore the importance of understanding the dynamic nature of halide perovskites and its implications for a wide range of applications.…”