Strong Coupling of Chiral Frenkel Exciton for Intense, Bisignate Circularly Polarized Luminescence

Li, M and Nizar, S and Saha, S and Thomas, A and Azzini, S and Ebbesen, TW and Genet, C (2022) Strong Coupling of Chiral Frenkel Exciton for Intense, Bisignate Circularly Polarized Luminescence. In: Angewandte Chemie - International Edition .

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Abstract

We show that chiral Frenkel excitons yield intense circularly polarized luminescence with an intrinsic dissymmetry factor in emission glum as high as 0.08. This outstanding value is measured through thin films of cyanine J-aggregates that form twisted bundles. Our measurements, obtained by a Mueller polarization analysis, are artifact-free and reveal a quasi-perfect correlation between the dissymmetry factors in absorption, gabs, and in emission glum. We interpret the bisignate dissymmetry factors as the signature of a strong coupling between chiral Frenkel excitons longitudinally excited along the bundles. We further resolve by polarimetry analysis the split in energy between the excited states with a Davydov splitting as small as 28 meV. We finally show the anti-Kasha nature of the chiral emission bands with opposite optical chirality. These mirror-imaged emissive chiroptical features emerge from the structural rigidity of the bundles that preserves the ground- and excited-state chirality. © 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

Item Type:	Journal Article
Publication:	Angewandte Chemie - International Edition
Publisher:	John Wiley and Sons Inc
Additional Information:	The copyright for this article belongs to John Wiley and Sons Inc.
Keywords:	Chirality; Circular polarization; Dichroism; Ellipsometry; Excitons; Luminescence; Polarimeters; Self assembly, Circularly polarized emission; Circularly polarized luminescence; Circularly-polarized; Excited-states; Exciton coupling; Frenkel excitons; Mueller polarimetry; Polarized emissions; Strong-coupling; Thin-films, Excited states
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	31 Jan 2023 04:44
Last Modified:	31 Jan 2023 04:44
URI:	https://eprints.iisc.ac.in/id/eprint/79582

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