Impact of anharmonicity on the carrier mobility of the Pb-free CsSnBr$_3$ perovskite

Fuente: arXiv
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Main Authors: Yin, Junwen, Hellman, Olle, Poncé, Samuel
Format: Preprint
Published: 2025
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author Yin, Junwen
Hellman, Olle
Poncé, Samuel
author_facet Yin, Junwen
Hellman, Olle
Poncé, Samuel
contents Charge carrier mobilities are critical parameters in halide perovskite solar cells, governing their average carrier velocity under an applied electric field and overall efficiency. Recent advances in first-principles calculations of electron-phonon interactions and carrier mobilities have enabled predictive computations for perovskite solar cells. However, the flexible octahedral frameworks and cationic displacements in these materials challenge the harmonic approximation, leading to significant difficulties in accurately calculating transport properties. To address these issues, we combine temperature-dependent effective potentials with the ab initio Boltzmann transport equations to compute carrier mobilities in a representative lead-free perovskite, CsSnBr$_3$. At room temperature, the electron/hole Hall mobilities in CsSnBr$_3$ are 106/256 cm$^2$/Vs when neglecting anharmonic effects and 59/145 cm$^2$/Vs when included. This overestimation of the harmonic approximation arises from the neglect of scattering coming from soft modes. We provide a workflow for performing first-principles carrier mobility calculations in anharmonic systems, advancing the predictive modeling of perovskite solar cells.
format Preprint
id arxiv_https___arxiv_org_abs_2505_20092
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Impact of anharmonicity on the carrier mobility of the Pb-free CsSnBr$_3$ perovskite
Yin, Junwen
Hellman, Olle
Poncé, Samuel
Materials Science
Charge carrier mobilities are critical parameters in halide perovskite solar cells, governing their average carrier velocity under an applied electric field and overall efficiency. Recent advances in first-principles calculations of electron-phonon interactions and carrier mobilities have enabled predictive computations for perovskite solar cells. However, the flexible octahedral frameworks and cationic displacements in these materials challenge the harmonic approximation, leading to significant difficulties in accurately calculating transport properties. To address these issues, we combine temperature-dependent effective potentials with the ab initio Boltzmann transport equations to compute carrier mobilities in a representative lead-free perovskite, CsSnBr$_3$. At room temperature, the electron/hole Hall mobilities in CsSnBr$_3$ are 106/256 cm$^2$/Vs when neglecting anharmonic effects and 59/145 cm$^2$/Vs when included. This overestimation of the harmonic approximation arises from the neglect of scattering coming from soft modes. We provide a workflow for performing first-principles carrier mobility calculations in anharmonic systems, advancing the predictive modeling of perovskite solar cells.
title Impact of anharmonicity on the carrier mobility of the Pb-free CsSnBr$_3$ perovskite
topic Materials Science
url https://arxiv.org/abs/2505.20092