Ultrafast and coherent dynamics in a solvent switchable “pink box” perylene diimide dimer

Bressan, Giovanni ORCID: https://orcid.org/0000-0001-7801-8495, Penty, Samuel E., Green, Dale ORCID: https://orcid.org/0000-0002-2549-0486, Heisler, Ismael A., Jones, Garth A., Barendt, Timothy A. and Meech, Stephen R. ORCID: https://orcid.org/0000-0001-5561-2782 (2024) Ultrafast and coherent dynamics in a solvent switchable “pink box” perylene diimide dimer. Angewandte Chemie-International Edition, 63 (39). ISSN 1433-7851

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Abstract

Perylene diimide (PDI) dimers and higher aggregates are key components in organic molecular photonics and photovoltaic devices, supporting singlet fission and symmetry breaking charge separation. Detailed understanding of their excited states is thus important. This has proven challenging because interchromophoric coupling is a strong function of dimer architecture. Recently, a macrocyclic PDI dimer was reported in which excitonic coupling could be turned on and off simply by changing the solvent. This presents a useful case where coupling is modified without synthetic changes to tune supramolecular structure. Here we present a detailed study of solvent dependent excited state dynamics in this dimer by means of coherent multidimensional spectroscopy. Spectral analysis resolves the different coupling strengths, which are consistent with solvent dependent changes in dimer conformation. The strongly coupled conformer forms an excimer within 300 fs. The low-frequency Raman active modes recovered from two-dimensional electronic spectra reveal frequencies characteristic of exciton coupling. These are assigned to modes modulating the coupling from the corresponding DFT calculations. Further analysis reveals a time dependent frequency during excimer formation. Analysis of two-dimensional “beatmaps” reveals features in the coupled dimer which are not predicted by the displaced harmonic oscillator model and are assigned to vibronic coupling

Item Type:	Article
Additional Information:	Funding information: The quantum chemical calculations presented in this work were carried out on the High Performance Computing Cluster supported by the Research and Specialist Computing Support service at the University of East Anglia. We acknowledge support from the Engineering and Physical Sciences Research Council under Award No. EP/V00817X/1 and EP/W037661/1 and the Royal Society (RGS\R2\222164). G.B. is grateful to the Leverhulme Trust for funding him through an Early Career Fellowship (Grant No. ECF-2023-195). We would like to thank Dr James Bull and Ms Eleanor Ashworth for helpful discussions.
Uncontrolled Keywords:	excitonic coupling,perylene diimide,structural dynamics,ultrafast spectroscopy,vibrational coherence,chemistry(all),catalysis,sdg 7 - affordable and clean energy,3*,nice work, hot area, good journal ,/dk/atira/pure/subjectarea/asjc/1600
Faculty \ School:	Faculty of Science > School of Chemistry (former - to 2024) Faculty of Science > School of Physics (former - to 2024)
UEA Research Groups:	Faculty of Science > Research Groups > Centre for Photonics and Quantum Science Faculty of Science > Research Groups > Chemistry of Light and Energy Faculty of Science > Research Groups > Quantum Matter Faculty of Science > Research Groups > Numerical Simulation, Statistics & Data Science
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	22 Jul 2024 16:31
Last Modified:	07 Nov 2024 12:48
URI:	https://ueaeprints.uea.ac.uk/id/eprint/95999
DOI:	10.1002/anie.202407242

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