Cargando…
Unraveling the Ordered Phase of the Quintessential Hybrid Perovskite MAPbI(3)—Thermophysics to the Rescue
[Image: see text] Hybrid perovskites continue to attract an enormous amount of attention, yet a robust microscopic picture of their different phases as well as the extent and nature of the disorder present remains elusive. Using specific-heat data along with high-resolution inelastic neutron scatter...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2022
|
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9486940/ https://www.ncbi.nlm.nih.gov/pubmed/36069450 http://dx.doi.org/10.1021/acs.jpclett.2c02208 |
Sumario: | [Image: see text] Hybrid perovskites continue to attract an enormous amount of attention, yet a robust microscopic picture of their different phases as well as the extent and nature of the disorder present remains elusive. Using specific-heat data along with high-resolution inelastic neutron scattering and ab initio modeling, we address this ongoing challenge for the case of the ordered phase of the quintessential hybrid-perovskite MAPbI(3). At low temperatures, the specific heat of MAPbI(3) reveals strong deviations from the Debye limit, a common feature of pure hybrid perovskites and their mixtures. Our thermophysical analysis demonstrates that the (otherwise ordered) structure around the organic moiety is characterized by a substantial lowering of the local symmetry relative to what can be inferred from crystallographic studies. The physical origin of the observed thermophysical anomalies is unequivocally linked to excitations of sub-terahertz optical phonons responsible for translational–librational distortions of the octahedral units. |
---|