Excited-state dynamics of the mixed J-aggregate of two kinds of cyanine dyes in layer-by-layer alternate assemblies

Layer-by-layer alternate assemblies, which incorporate two kinds of cyanine dyes in the form of mixed J-aggregates, were fabricated by means of the alternate adsorption method. The excited-state dynamics of the mixed J-aggregates were examined by steady-state fluorescence spectroscopy and picosecond lifetime measurements. In these assemblies, the behavior of excitation energy transfer between the donor and acceptor J-aggregates obeyed Stern–Volmer kinetics in the low concentration region of the acceptor molecules. It was found that both the fluorescence lifetime and quantum yield of the acceptor aggregates decrease with increasing concentration of the acceptor molecules, which indicates that fluorescence self-quenching occurred in the acceptor aggregates.