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.

*This work is supported by the Computational Materials Sciences Program funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-SC0020129, and by the Robert A. Welch Foundation under award number F-1990-20190330.

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Presenters

  • Joshua Leveillee

    • University of Texas at Austin

Authors

  • Joshua Leveillee

    • University of Texas at Austin

  • 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