Modification of the luminescent characteristics belonging to the molecule that interacts with the exciton states of the J-aggregate

A quantum theory for the light absorption and photoluminescence of a molecule (luminophore) interacting with a J-aggregate linear molecular chain is constructed. It is shown that together with the band states of Frenkel excitons in the molecular chain the contribution to light absorption and luminescence comes from local levels that split off from the exciton band as a result of the interaction between the molecular chain and the luminophore. It is also demonstrated that the contribution to light absorption and photoluminescence from local levels is non-linearly dependent on the coupling parameter between the luminophore and the J-aggregate molecular chain. Published by AIP Publishing

Photocatalytic activity of ZnO nanopowders: The role of production techniques in the formation of structural defects

International audienc

Uniform exciton fluorescence from individual molecular nanotubes immobilized on solid substrates

Self-assembled quasi one-dimensional nanostructures of π-conjugated molecules may find a use in devices owing to their intriguing optoelectronic properties, which include sharp exciton transitions, strong circular dichroism, high exciton mobilities and photoconductivity. However, many applications require immobilization of these nanostructures on a solid substrate, which is a challenge to achieve without destroying their delicate supramolecular structure. Here, we use a drop-flow technique to immobilize double-walled tubular J-aggregates of amphiphilic cyanine dyes without affecting their morphological or optical properties. High-resolution images of the topography and exciton fluorescence of individual J-aggregates are obtained simultaneously with polarization-resolved near-field scanning optical microscopy. These images show remarkably uniform supramolecular structure, both along individual nanotubes and between nanotubes in an ensemble, demonstrating their potential for light harvesting and energy transport.