Aqueous Electrogenerated Chemiluminescence of Self-Assembled Double-Walled Tubular J-Aggregates of Amphiphilic Cyanine Dyes

This study investigates superradiant organic dye J-aggregates as a potential new class of aqueous luminophores for electrogenerated chemiluminescence (ECL). Simultaneous cyclic voltammograms (CVs) and ECL transients are obtained from the self-assembled double-walled tubular J-aggregates formed from the amphiphilic cyanine dye 3,3′-bis(2-sulfopropyl)-5,5′,6,6′-tetrachloro-1,1′-dioctylbenzimidacarbocyanine (C8S3) immobilized on glassy carbon electrodes in the presence of the oxidative−reductive coreactant 2-(dibutylamino)ethanol (DBAE). ECL is produced by both the direct oxidation of DBAE at the electrode and the catalytic oxidation of DBAE by the C8S3 J-aggregates. Optimization studies of the DBAE concentration and pH of the electrolyte show the most intense ECL signal was obtained with ∼17 mM DBAE as coreactant (saturated solution in 1 M KNO 3 ) at pH 12.85, an effect of DBAE solubility and p K a . The overlaid ECL spectrum and the fluorescence spectrum were in good agreement, confirming that the ECL emission is associated with the singlet exciton delocalized on the tubular C8S3 J-aggregates. Amphiphilic J-aggregates are promising new systems for ECL applications because of their unique characteristics such as accessible redox chemistry in the aqueous potential window, increased fluorescence emission, and narrow emission lines.