The Formation of J-Aggregates of Mixed Merocyanines in Langmuir-Blodgett Films

Langmuir-Blodgett (LB) films of mutual mixtures of two alkylated merocyanine dyes, so called DO and DS, have been deposited on CaF 2 plates from the surface of a water solution of Cd 2+ . From the UV-visible absorption spectra observed for these films, it has been concluded that DO is included in the J-aggregates when the molar ratio of DO/DS is less than 1, while no J-band is observed when DO/DS is much larger than 1. Comparison of the IR absorption spectra of these LB films has suggested that the formation of the J-aggregates enhances the intramolecular charge transfer along the conjugated system of the merocyanine dye chromophore.