Excitation localization in a trimeric perylenediimide macrocycle: Synthesis, theory, and single molecule spectroscopy

Hauschildt SJ, Wu Z, Uersfeld D, Schmid P, Goetz C, Engel V, Engels B, Muellen K, Basche T (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Journal of Chemical Physics AIP Publishing

Book Volume: 156

Article Number: 044304

Journal Issue: 4

DOI: 10.1063/5.0077676

Abstract

A novel trimeric perylenediimide (PDI) macrocycle was synthesized, and its intramolecular electronic couplings were investigated by bulk and single-molecule optical spectroscopy and by various theoretical approaches. In polarization-resolved excitation spectroscopy at 1.2 K in a PMMA matrix, the appearance and disappearance of the three zero-phonon lines (ZPLs) of an individual trimer by changing the polarization in steps of 60° nicely reflect an approximate triangular geometry of the macrocycle and indicate localized excitations that are transferred by incoherent hopping processes at time scales of around 1 ps as inferred from the ZPL linewidths. The electronic coupling strength deduced from the low temperature data is found to be in good agreement with theoretical estimates. Bulk spectroscopy in toluene at room temperature indicates that the excitations are also localized under these conditions. Theory reveals that the reasons for the localized nature of the excitations at room and low temperatures are different. For a rigid macrocycle, the excitations are predicted to be delocalized, but molecular dynamics simulations point to considerable structural flexibility at ambient temperatures, which counteracts excitation delocalization. At 1.2 K in a PMMA matrix, this effect is too small to lead to localization. Yet, supported by simple model calculations, the disorder in the PMMA host induces sufficient differences between the PDI chromophores, which again result in localized excitations. By addressing crucial aspects of excitation energy transfer, our combined approach provides a detailed and quantitative account of the interchromophore communication in a trimeric macrocycle.

Additional Organisation(s)

Sonderforschungsbereich/Transregio 306/1: Quantenkooperativität von Licht und Materie - QuCoLiMa

Related research project(s)

Mechanical and chemical control of single and multiphoton emission (C03) TRR 306: Quantenkooperativität von Licht und Materie – QuCoLiMa Jan. 1, 2021 - Dec. 31, 2024

Involved external institutions

Johannes Gutenberg-Universität Mainz (JGU) DE Germany (DE) Julius-Maximilians-Universität Würzburg DE Germany (DE)

How to cite

APA:

Hauschildt, S.J., Wu, Z., Uersfeld, D., Schmid, P., Goetz, C., Engel, V.,... Basche, T. (2022). Excitation localization in a trimeric perylenediimide macrocycle: Synthesis, theory, and single molecule spectroscopy. Journal of Chemical Physics, 156(4). https://dx.doi.org/10.1063/5.0077676

MLA:

Hauschildt, Simon J., et al. "Excitation localization in a trimeric perylenediimide macrocycle: Synthesis, theory, and single molecule spectroscopy." Journal of Chemical Physics 156.4 (2022).

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