Long-range energy transfer between the J-aggregates of cyanine dyes capable of forming the amalgamation-type mixed aggregate

Sandwich-type monolayer assemblies, [donor/spacer/acceptor], consisting of the J-aggregates of two kinds of cyanine dyes, donor aggregate and acceptor aggregate, as well as inert spacer layers have been fabricated. A combination of cyanine dyes, 5,5′-dichloro-3,3′-diethyl-9-phenyl-thiacarbocyanine chloride (Thia()) + 3,3′-dimethyl-9-phenyl-4, 5,4′,5′-naphthothiacarbocyanine chloride (Nap()), has been focused on because this combination is capable of forming the homogeneous aggregate of the amalgamation-type (HA-aggregate) in the mixed assembly. Sensitization of resonance fluorescence of the acceptor aggregate (Nap()) occurs at the expense of quenching of the resonance fluorescence of the donor aggregate (Thia()) in the sandwich assembly. The critical distance of energy transfer, d0, in the exponential decay law is fairly large (d0 = 170 A).