SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 45: Functional semiconductors for renewable energy solutions II
HL 45.2: Vortrag
Donnerstag, 30. März 2023, 15:15–15:30, POT 6
Discovery of multi-anion antiperovskite as promising thermoelectric materials by computational screening — •Dan Han1, Bonan Zhu2, Kieran B. Spooner2, Stefan S Rudel1, Wolfgang Schnick1, Thomas Bein1, David O. Scanlon2, and Hubert Ebert1 — 1Department of Chemistry, University of Munich, Germany — 2Department of Chemistry, University College London, United Kingdom
The thermoelectric performance of existing perovskites lags far behind the state-of-the-art thermoelectric materials such as SnSe, PbTe and Bi2Te3. Despite halide perovskites showing promising thermoelectric properties, namely, high Seebeck coefficients and ultralow thermal conductivities, their thermoelectric performance is significantly restricted by low electrical conductivities. Here, we explore new multi-anion antiperovskites by global structure searches, and demonstrate their phase stability by first-principles calculations. Ca6NFSn2 and Sr6NFSn2 exhibit decent Seebeck coefficients and ultralow lattice thermal conductivities (< 1 W m-1 K-1). The weak chemical bonding between the heavy-atom cage-rattler Sn and alkaline-earth metal (Ca and Sr) inducing low-frequency optical modes coupling with heat carrying acoustic phonons in combination with strong bond anharmonicity give rise to ultralow lattice thermal conductivities. Notably, Ca6NFSn2 and Sr6NFSn2 show remarkably larger electrical conductivities compared to halide perovskite CsSnI3. Our exploration of multi-anion antiperovskites X6NFSn2 (X = Ca, Sr) realizes the "phonon-glass, electron-crystal" concept within perovskite structures.