Construction of light-harvesting reverse micelles in nanoscopic dimensions

Construction of light-harvesting reverse micelle system was achieved in nanoscopic dimensions via self-assembly of anthracene–perylene triad which could undergo efficient intramolecular energy transfer from the anthracene antennae to the perylene cores. Absorption spectra of the reverse micelles in toluene solutions exhibited broad, unstructured, and red-shifted bands attributed to interacting chromophores within molecular aggregates, while the emission spectra showed significant fluorescence quenching of both the excited anthracene and the perylene groups. The atomic force microscope (AFM) analysis revealed a number of small and medium-sized spherical objects that can be attributed to the individual reverse micelles and their assemblies. A cross-sectional view of the AFM image indicated that nearly 90% of these peak heights were less than 10 nm. Titration experiments of fluorescence properties of the reverse micelles allowed determination of its cmc value as 3 μM. Spectroscopic and microscopic behavior of a series of the reverse micelles at the W0 values (water/surfactant ratios) of 30, 50, 100, and 200 suggested that the reverse micelles should have a uniform aggregate size independent of the water/surfactant ratio, revealing a unique relation between specific geometrical configuration of the amphiphilic molecules and intrinsic size of the reverse micelles.