Impact of Ion-Pairing Effects on Linear and Nonlinear Photophysical Properties of Polymethine Dyes** |
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| Authors: | Dr Simon Pascal Dr San-Hui Chi Prof Joseph W Perry Dr Chantal Andraud Dr Olivier Maury |
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| Institution: | 1. Laboratoire de Chimie, Univ. Lyon, ENS Lyon, CNRS, Université Lyon 1, 46 Allée d'Italie, 69364 Lyon, France;2. School of Chemistry and Biochemistry, Center for Organic Photonics and Electronics, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia, 30332-0400 United States |
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| Abstract: | The two-photon absorption (2PA) and photophysics of heptamethine dyes featuring cyanine or dipolar electronic structures have been compared for the first time. The perfectly delocalized cyanine system is classically characterized by a two-photon transition matching the vibronic component of its lower energy absorption band. The dipolar species is generated by ion-pairing with a hard counterion in a non-dissociating solvent and displays significant modifications oft he optical properties, including a significant hypochromic shift of absorption, weaker emission and 2PA matching the lower energy transition, thus revealing symmetry breaking within the polymethine electronic structure. |
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| Keywords: | cyanines near-infrared dyes non-linear optical properties polymethines two-photon absorption |
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