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|Title:||Calculation of two-photon absorption by nanocrystals of CsPbBr3||Authors:||Blundell, S. A.
Nguyen, T. P. T.
|Keywords:||Science::Physics||Issue Date:||2021||Source:||Blundell, S. A., Nguyen, T. P. T. & Guet, C. (2021). Calculation of two-photon absorption by nanocrystals of CsPbBr3. Physical Review B, 103(4), 045415-. https://dx.doi.org/10.1103/PhysRevB.103.045415||Project:||NRF-CRP14-2014-03||Journal:||Physical Review B||Abstract:||We present calculations of the two-photon absorption cross section σ(2)(ω) for nanocrystals (NCs) of the inorganic perovskite CsPbBr3 for photon energies ω ranging from the absorption threshold at 2ω≈2.3eV up to 2ω=3.1eV. The calculations employ a 4×4k⋅p envelope-function model, with final-state excitons described in a self-consistent Hartree-Fock approximation. The k⋅p corrections to σ(2)(ω) are found to be rather large, giving a reduction of about 30% in the cross section at the largest energies considered. The cross section is shown to be independent of polarization in the effective-mass approximation (EMA), but including k⋅p corrections leads to a small difference in σ(2)(ω) between circular and linear polarization, which rises to about 16% at 2ω=3.1eV. The theoretical cross section follows closely a power-law dependence on NC size, σ(2)(ω)∝Lα, with theoretical exponents α=3.4 (EMA) or α=3.2 (4×4k⋅p model), in excellent agreement with experiment. The dominant contribution to the exponent α is shown to be the number of final-state excitons per unit energy. Measured values of the absolute (normalized) cross section σ(2)(ω) show a large spread of values, differing by as much as a factor of 25 for some NC sizes. Our calculations strongly favor a group of measurements at the lower end of the reported range of σ(2)(ω).||URI:||https://hdl.handle.net/10356/151090||ISSN:||2469-9950||DOI:||10.1103/PhysRevB.103.045415||Rights:||© 2021 American Physical Society (APS). All rights reserved. This paper was published in Physical Review B and is made available with permission of American Physical Society (APS).||Fulltext Permission:||open||Fulltext Availability:||With Fulltext|
|Appears in Collections:||ERI@N Journal Articles|
Updated on Oct 20, 2021
Updated on Oct 20, 2021
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