Regensburg 2022 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Perovskite and Photovoltaics 4 (joint session HL/CPP/KFM)
CPP 32.7: Vortrag
Mittwoch, 7. September 2022, 17:00–17:15, H34
Calculating the temperature-dependent band gap of the halide perovskite CsPbBr3 — •Stefan Seidl, Christian Gehrmann, Xiangzhou Zhu, Sebastian Caicedo Davila, and David A. Egger — Department of Physics, Technical University of Munich, Garching, Germany
Theoretical calculations based on density functional theory (DFT) can predict thermal effects in the electronic structure by considering important phenomena, such as thermal lattice expansion and electron-phonon coupling. The latter can be calculated using a Monte-Carlo (MC) sampling approach that is formally rooted within the harmonic approximation, which has recently been shown to yield accurate temperature-dependent band gaps for inorganic semiconductors [1]. A complementary approach to predict thermal effects in the electronic structure is first-principles molecular dynamics (MD), which can account for vibrational anharmonicity that is an important effect for certain technologically relevant materials. Here, we assess the temperature-dependent band gap of the halide perovskite CsPbBr3 in the cubic and orthorhombic phases employing the two different methods, MC and MD, and compare our findings with experimental results. This includes a discussion about the role of anharmonicity and the contributions from spin-orbit coupling and thermal lattice expansion.
[1] F. Karsai et al, New J. Phys. 20, 123008 (2018)