Lévy defects in matrix-immobilized J aggregates : tracing intra-and intersegmental exciton relaxation
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One-dimensional J aggregates present narrow and intense absorption and emission spectra that are interesting for photonics applications. Matrix immobilization of the aggregates, as required for most device architectures, has recently been shown to induce a non-Gaussian (Lévy type) defect distribution with heavy tails, expected to influence exciton relaxation. Here we perform two-dimensional electronic spectroscopy (2DES) in one-dimensional J aggregates of the cyanine dye TDBC, immobilized in a gel matrix, and we quantitatively model 2DES maps by nonlinear optimization coupled to quantum mechanical calculations of the transient excitonic response. We find that immobilization causes strong non-Gaussian off-diagonal disorder, leading to a segmentation of the chains. Intersegmental exciton transfer is found to proceed on the picosecond time scale, causing a long-lasting excitation memory. These findings can be used to inform the design of optoelectronic devices based on J aggregates as they allow for control of exciton properties by disorder management.
Lüer , L , Rajendran , S K , Stoll , T , Ganzer , L , Rehault , J , Coles , D M , Lidzey , D , Virgili , T & Cerullo , G 2017 , ' Lévy defects in matrix-immobilized J aggregates : tracing intra-and intersegmental exciton relaxation ' , Journal of Physical Chemistry Letters , vol. 8 , no. 3 , pp. 547-552 . https://doi.org/10.1021/acs.jpclett.6b02704
Journal of Physical Chemistry Letters
Copyright © 2017 American Chemical Society. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1021/acs.jpclett.6b02704
DescriptionL.L. thanks the EC for financial support by the cofunded Amarout program and the Spanish Ministry for economy and competitiveness (plan nacional, Project MultiCrom (CTQ2014-58801)). G.C. acknowledges financial support by the European Research Council (ERC-2011-AdG No. 291198). D.G.L. and D.C. thank the UK EPSRC for funding via research grant EP/M025330/1 “Hybrid Polaritonics”
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