Highly fluorescent organic nanoparticles of thiacyanine dye: A synergetic effect of intermolecular H-aggregation and restricted intramolecular rotation

Abstract

Highly fluorescent organic nanoparticles are synthesized via ion-association between 3,3′-diethylthiacyanine (TC) cation and tetrakis(4-fluorophenyl)borate anion in the presence of a neutral stabilizing polymer in water. The fluorescence shows a significant increase with a decrease in the nanoparticle size, resulting in a high fluorescence quantum yield of about 0.8–0.9. The observed fluorescence enhancement is due to a synergetic effect of both restriction of intramolecular rotation of TC and intermolecular H-aggregation in an inclined manner.