Intrinsic phonon-limited carrier mobilities and electron-phonon dynamics at finite temperature in lead-free halide double perovskite Cs<sub>2</sub>AgBi(X=Br,Cl)<sub>6</sub>
ORAL
Abstract
The lead-free halide double perovskite Cs2AgBiBr6 has emerged as a promising candidate for applications in tandem perovskite solar cells. The measured low carrier mobility, under 11 cm2/Vs, poses a challenge in developing efficient devices. Furthermore, the relative importance of defects and phonons in the scattering of the charge carriers remains unclear. In this first-principles investigation, we employ density functional perturbation theory (DFPT), Wannier-Fourier interpolation, and the Boltzmann transport equation (BTE) to calculate the electronic and phonon band structures, electron-phonon vertices, and intrinsic mobilities of electrons and holes in Cs2AgBiX6 (X=Br,Cl) at finite temperature. We find that phonon scattering accounts for the measured mobility at room temperature, and we identify the dominant electron-phonon scattering process in Cs2AgBiX6 (X=Br,Cl). Our findings provide an atomic-scale explanation for the low intrinsic carrier mobilities in these important solar cell candidate materials.
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Presenters
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Joshua Leveillee
University of Texas at Austin
Authors
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Joshua Leveillee
University of Texas at Austin
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Feliciano Giustino
Physics, University of Texas at Austin, University of Texas at Austin, Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Department of Physic, The University of Texas at Austin, Austin, Texas 78712, USA, Oden Institute for Computational Engineering and Sciences, Oden Institute, University of Texas at Austin, Department of Materials, University of Oxford, Department of Physics, University of Texas at Austin, ODEN Institute for Computational Engineering and Sciences, University of Texas at Austin