Scientific Results

Photobehavior and Nonlinear Optical Properties of Push-Pull, Symmetrical, and Highly Fluorescent Benzothiadiazole Derivatives

Year: 2016

Authors: Ricci F., Elisei F., Foggi P., Marrocchi A., Spalletti A., Carlotti B.

Autors Affiliation: Department of Chemistry, Biology and Biotechnology, Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), University of Perugia, via Elce di Sotto 8, Perugia, 06123, Italy; LENS (European Laboratory for Non-Linear Spectroscopy), via Nello Carrara 1, Sesto Fiorentino, Firenze, 50019, Italy; INO-CNR, Istituto Nazionale di Ottica-Consiglio Nazionale Delle Ricerche, Largo Fermi 6, Firenze, 50125, Italy

Abstract: Three quadrupolar D-pi-A-pi-D compounds, bearing alkoxy phenyls as mild electron donors and a benzothiadiazole (A), two benzothiadiazoles (B), or a benzothiadiazole linked to two thiophenes (C) as the acceptor units, are collectively the object of this study. They proved to be efficient yellow/orange/red fluorophores, respectively, with fluorescence being their preferred deactivation pathway. These systems exhibited positive fluorosolvatochromism and a noticeable decrease of the fluorescence quantum yield in the most polar solvent (with the quenching following the trend B > A > C). These findings point to an intramolecular charge transfer (ICT) nature of the emitting state, whose photoinduced dynamics was investigated by femtosecond-resolved transient absorption and fluorescence upconversion. Remarkable values of hyperpolarizability were estimated by the solvatochromic method. The significant two-photon absorption cross sections measured for A-C (whose trend nicely parallels that of ICT efficiency), coupled. with the intense emission, make them promising for applications as environment-sensitive probes in two-photon excited fluorescence imaging.

Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY C

Volume: 120 (41)      Pages from: 23726  to: 23739

KeyWords: Charge transfer; Fluorescence; Fluorophores; Nonlinear optics; Optical properties; Photons; Two photon processes, Benzothiadiazole derivatives; Fluorescence quantum yield; Fluorescence upconversion; Intramolecular charge transfers; Non-linear optical properties; Solvatochromic methods; Two-photon absorption cross section; Two-photon excited fluorescence, C (programming language)
DOI: 10.1021/acs.jpcc.6b07290

Citations: 26
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2020-08-02
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