Exciton-phonon coupling in the lead-free double-perovskite Cs<sub>2</sub>InAgCl<sub>6</sub>
ORAL
Abstract
The lead-free halide double perovskite Cs2InAgCl6 possesses a wide direct band-gap exceeding 3 eV, and exhibits very broad and strong photoluminescence (PL) in the visible region [G. Volonakis, et al., J. Phys. Chem. Lett. 8, 772 (2017)]. This property has been employed to realize white-light-emitting diodes with near-unity PL quantum yield [J. Luo, et al., Nature 563, 541 (2018); S. Li et al., ACS Appl. Mater. Interfaces 12, 46330 (2020)]. The atomic scale mechanisms of light emission in this compound remain a subject of debate, with proposals ranging from self-trapped excitons to defect-assisted luminescence. To shed light on this debate, in previous work [V.-A Ha, et al., J. Phys. Chem. C 125, 21689 (2021)] we investigated the electronic band structure of Cs2InAgCl6 using GW method, and the temperature-dependent band gap renormalization via electron-phonon interactions within special displacement method. Here, we extend this study to include excitonic effect via the Bethe-Salpeter equation, and their coupling to phonons via the special displacement method. We will discuss our results in relation to the observed PL signal.
*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award DE-SC0020129. Computational resources were provided by the Texas Advanced Computing Center (TACC) at The University of Texas at Austin, the National Energy Research Scientific Computing Center (a DOE Office of Science User Facility supported under Contract No. DE-AC02-05CH11231), and the Argonne Leadership Computing Facility (a DOE Office of Science User Facility supported under Contract DE-AC02-06CH11357).
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Presenters
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Viet-Anh Ha
- University of Texas at Austin