Excitation energy transfer between J-aggregates in layer-by-layer alternate assemblies

Abstract

The layer-by-layer alternate assemblies incorporating two kinds of cyanine dyes have been fabricated by the alternate adsorption technique. In order to examine excitation energy transfer between J-aggregates, a thiacyanine dye has been employed as the donor and thiacarbocyanine dyes as the acceptor. It is confirmed that these dye combinations form the mixed J-aggregate in the alternate assemblies. From steady-state fluorescence spectra of the molecular assemblies, the occurrence of efficient energy transfer from the donor J-aggregate to the acceptor J-aggregate has been demonstrated. The experimentally obtained rate constant of energy transfer kET in the Stern–Volmer kinetics of the order of 1013nm2molecules−1s−1 is interpreted in terms of exciton migration and trapping in the mixed J-aggregate. The difference in kET between various combinations of cyanine dyes is not inconsistent with an exponential energy gap law.