出版社：The Society of Photographic Science and Technolgy of Japan
摘要：Various methods of determining the size of J-aggregates of cyanine dyes are reviewed, with emphasis on two methods, one utilizing the mass action relation between the concentrations of free and J-aggregated dye molecules in solution, and the other utilizing a relation between aggregate size and spectral absorption linewidth based on the theory of exchange narrowing. These methods have been used by the authors for estimating the association numbers n for J-aggregate particles of anionic oxa- and thiacarbocyanine dyes of similar structures, potassium 3, 3'-bis (sulfopropyl)-5, 5'-dipheny1-9-ethyloxacarbocyanine (Dye I) and sodium 3, 3'-bis (sulfopropyl)-5, 5'-dichloro-9-ethylthiacarbocyanine (Dye II). For both dyes, n increased with increasing temperature and tended to decrease with increasing dye concentration. The temperature dependence is explained as a Gibbs-Thomson effect characteristic of polydisperse J-aggregate particles. Concentration dependent n is expected from classical nucleation rate equation, regarding the J-aggregate particles as crystal nuclei.
