Year: 2025
Type: article
Abstract: Metal halide perovskites (MHPs) have emerged as noteworthy candidates for photovoltaic applications in recent years. Their high power-conversion efficiency is largely attributed to the structure-function relationship, which is not well understood. In this study, we examine the low-frequency phonons of the double perovskite Cs 2 AgBiBr 6 using neutron inelastic scattering. We find that the acoustic phonon lifetimes decrease from 16 to 3 ps along Γ to X , which is indicative of significant anharmonicity that contributes to the ultralow thermal conductivity. Additionally, we observe a linear temperature dependence of the square of the zone-center soft optical phonon energy, which is consistent with a weakly first-order displacive cubic-tetragonal structural phase transition. These results provide a deeper understanding of the lattice dynamics and phase transitions in MHPs as well as the effects of anharmonicity by comparison with prototypical hybrid organic-inorganic MHPs, ( CH 3 NH 3 ) PbX 3 (X = Br, I).
Source: Newton
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,460
Funders: National Science Foundation, U.S. Department of Energy, Stanford University, Center for Hybrid Organic Inorganic Semiconductors for Energy, National Institute of Standards and Technology, Office of Science, Division of Materials Research, Basic Energy Sciences, Oak Ridge National Laboratory, Division of Materials Sciences and Engineering
Awards: G1229526393, G1286251239, G2371548206, G237429762, G2664202130, G303061748, The NIST/NSF Center for High Resolution Neutron Scattering, G3702897590, G3713408349, G495301720, G498139845, G507895560, Graduate Research Fellowship Program (GRFP), G5570207115, G5922085581, G6453377689, G6550344761, G7283024673, G7306200462, G8382000481, G8628718575, G911061179, G969889393
OpenAlex ID: W4410230582