Slow Cooling of Hot Polarons in Halide Perovskite Solar Cells

Frost, Jarvist Moore, Whalley, Lucy and Walsh, Aron (2017) Slow Cooling of Hot Polarons in Halide Perovskite Solar Cells. ACS Energy Letters, 2 (12). pp. 2647-2652. ISSN 2380-8195

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Official URL: https://doi.org/10.1021/acsenergylett.7b00862

Abstract

Halide perovskites show unusual thermalization kinetics for above-bandgap photoexcitation. We explain this as a consequence of excess energy being deposited into discrete large polaron states. The crossover between low-fluence and high-fluence “phonon bottleneck” cooling is due to a Mott transition where the polarons overlap (n ≥ 1018 cm–3) and the phonon subpopulations are shared. We calculate the initial rate of cooling (thermalization) from the scattering time in the Fröhlich polaron model to be 78 meV ps–1 for CH3NH3PbI3. This rapid initial thermalization involves heat transfer into optical phonon modes coupled by a polar dielectric interaction. Further cooling to equilibrium over hundreds of picoseconds is limited by the ultralow thermal conductivity of the perovskite lattice.

Item Type: Article
Subjects: F100 Chemistry
F200 Materials Science
F300 Physics
H800 Chemical, Process and Energy Engineering
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Elena Carlaw
Date Deposited: 23 Jun 2020 11:34
Last Modified: 23 Jun 2020 11:45
URI: http://nrl.northumbria.ac.uk/id/eprint/43553

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