Excited State Relaxation in Cationic Pentamethine Cyanines Studied by Time-Resolved Spectroscopy


In this work, we examined the nature and pathways of electronic excitation relaxation at low temperature in cationic pentamethine pyrylocyanine dye, which in the ground state is characterized by symmetric and non-symmetric localization of cationic charge on the carbon chain between the terminal groups. The carbon chain in such symmetric and non-symmetric charge localizations is close to polymethine and polyene conformations, respectively. The effect of symmetry breaking during the two-way transition polymethine – polyene in the optically excited state on the electronic properties of dyes is considered. Combined quantum-chemical calculations and time-resolved spectral measurements allowed us to characterize the symmetric and non-symmetric structures in the ground and excited states with specific peaks of transitions and lifetimes. The features of the polymethine structure of the dye are attributed to large-radius polaron formation, whereas for the polyene structures the model of excitons formed on the double bonds of the carbon chain can be used to analyze the relaxation pathways. The energy diagram model for relaxation pathways of optically excited electronic states has been proposed. The proposed model can be characteristic for pentamethine cyanine dyes with the symmetric and non-symmetric distribution of cationic charge at the carbon chain between the terminal groups in the ground and excited states.

Publication DOI: https://doi.org/10.1016/j.dyepig.2021.109539
Divisions: College of Engineering & Physical Sciences > Aston Institute of Photonics Technology (AIPT)
College of Engineering & Physical Sciences
Additional Information: © 2021, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Uncontrolled Keywords: pentamethine pyrylocyanine dye,polymethine and polyene conformations,photoluminescence,time-resolved emission spectra,pump-probe spectroscopy
Publication ISSN: 0143-7208
Last Modified: 27 Jun 2024 10:47
Date Deposited: 07 Jun 2021 14:14
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Related URLs: https://www.sci ... 143720821004058 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2021-09-01
Published Online Date: 2021-06-06
Accepted Date: 2021-06-03
Authors: Piryatinski, Yuri P.
Verbitsky, Anatoli B.
Dmytruk, Andriy
Malynovskyi, Markiian
Lutsyk, Petro (ORCID Profile 0000-0002-7004-1946)
Rozhin, Alex (ORCID Profile 0000-0003-2271-8227)
Kachkovsky, Oleksiy
Prostota, Yaroslav
Kurdyukov, Vladimir

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