title: Lévy Defects in Matrix-Immobilized J Aggregates: Tracing Intra-and Intersegmental Exciton Relaxation.
abstract: 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.
authors.affiliation: IMDEA Nanociencia , C/Faraday 9, 28049 Cantoblanco, Madrid, Spain.
authors.forename: Larry
authors.identifier: http://orcid.org/0000-0001-9952-4207
authors.initials: L
authors.lastname: Lüer
authors.affiliation: Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy.|School of Physics and Astronomy, University of St. Andrews , St. Andrews, Fife KY16 9SS, United Kingdom.
authors.forename: Sai Kiran
authors.initials: SK
authors.lastname: Rajendran
authors.affiliation: Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Stoll
authors.affiliation: Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Ganzer
authors.affiliation: Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy.|Paul Scherrer Institut , 5232 Villigen PSI, Switzerland.
authors.forename: Julien
authors.initials: J
authors.lastname: Rehault
authors.affiliation: Department of Physics and Astronomy, University of Sheffield , Sheffield S3 7RH, United Kingdom.
authors.forename: David M
authors.initials: DM
authors.lastname: Coles
authors.affiliation: Department of Physics and Astronomy, University of Sheffield , Sheffield S3 7RH, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Lidzey
authors.affiliation: Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Tersilla
authors.initials: T
authors.lastname: Virgili
authors.affiliation: Dipartimento di Fisica, IFN-CNR , Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Cerullo