Giant thermally induced band-gap renormalization in anharmonic silver chalcohalide antiperovskites
Silver chalcohalide antiperovskites (CAP), Ag3XY (X = S, Se; Y = Br, I), are a family of highly anharmonic inorganic compounds with great potential for energy applications. However, a substantial and unresolved discrepancy exists between the optoelectronic properties predicted by theoretical first-p...
| Autores: | , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/429440 |
| Acceso en línea: | https://hdl.handle.net/2117/429440 https://dx.doi.org/10.1039/d5tc00863h |
| Access Level: | acceso abierto |
| Palabra clave: | Chalcogenides -- Optical properties Electronic structure Calcogènids -- Propietats òptiques Estructura electrònica Àrees temàtiques de la UPC::Enginyeria dels materials::Materials funcionals |
| Sumario: | Silver chalcohalide antiperovskites (CAP), Ag3XY (X = S, Se; Y = Br, I), are a family of highly anharmonic inorganic compounds with great potential for energy applications. However, a substantial and unresolved discrepancy exists between the optoelectronic properties predicted by theoretical first-principles methods and those measured experimentally at room temperature, hindering the fundamental understanding and rational engineering of CAP. In this work, we employ density functional theory, tight-binding calculations, and anharmonic Fröhlich theory to investigate the optoelectronic properties of CAP at finite temperatures. Near room temperature, we observe a giant band-gap (Eg) reduction of approximately 20–60% relative to the value calculated at T = 0 K, bringing the estimated Eg into excellent agreement with experimental measurements. This relative T-induced band-gap renormalization is roughly twice the largest value previously reported in the literature for similar temperature ranges. Low-energy optical polar phonon modes, which break inversion symmetry and enhance the overlap between silver and chalcogen s electronic orbitals in the conduction band, are identified as the primary drivers of this significant Eg reduction. Furthermore, when temperature effects are considered, the optical absorption coefficient of CAP increases by nearly an order of magnitude in the visible light spectrum. These findings not only bridge a critical gap between theory and experiment but also pave the way for future technologies where temperature, electric fields, and light dynamically modulate optoelectronic properties, establishing CAP as a versatile platform for energy and photonic applications. |
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