Spectroelectrochemical investigation of double-walled tubular J-aggregates of amphiphilic cyanine dyes

Jennifer L. Lyon, Dörthe M. Eisele, Stefan Kirstein, Jürgen P. Rabe, David A. Vanden Bout, Keith J. Stevenson

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41 Citations (Scopus)

Abstract

The amphiphilic cyanine dye 3,3′-bis(2-sulfopropyl)-5,5′,6, 6′-tetrachloro-1,1′-dioctylbenzimidacarbocyanine (C8S3) self-assembles in aqueous solution to form double-walled, tubular J-aggregates with ∼13 nm diameters and lengths up to several hundred nanometers. The redox and light absorption properties of immobilized J-aggregates on transparent, conductive indium tin oxide (ITO) electrodes have been studied directly using cyclic voltammetry (CV) in conjunction with UV-vis spectroscopy to elucidate unique mechanistic features of J-aggregate oxidation. Morphological properties were examined using in situ atomic force microscopy (AFM). Irreversible J-aggregate oxidation appears to occur primarily along the outer wall of the tubular structure as evidenced by the potential-induced irreversible bleaching of J-band absorption. Voltammetric studies as a function of scan rate and pH indicate that J-aggregate oxidation involves both electrochemical and chemical steps in which dimerization and subsequent dehydrogenation of the J-aggregate leads to the formation of a new dehydrogenated dimer oxidation product. This dehydrogenated dimer exhibits an absorbance band near 560 nm along with a reversible reduction peak characteristic of a surface-confined, redox-active species. Excellent correlation of J-aggregate redox potentials with spectroelectrochemical data is obtained that allows us to understand energetic thresholds for electron transfer in C8S3 tubular J-aggregates.

Original languageEnglish
Pages (from-to)1260-1268
Number of pages9
JournalJournal of Physical Chemistry C
Volume112
Issue number4
DOIs
Publication statusPublished - 31 Jan 2008
Externally publishedYes

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