Emission frequency modulation by electronic confinement effect: Congo Red incorporated within a dendritic structure.

We have investigated the photophysical properties of an organic dye (Congo Red) incorporated within the internal cavities of a dendrimer (type polypropylenimine of fifth-generation modified with a dense shell of amino acids). In this paper we show that the luminescence properties of Congo Red encapsulated into the "dendritic box" can be modulated by the electronic confinement effect. The emission frequencies of this organic dye incorporated within the dendritic structure can be red shifted with respect to their emission in solution, and the magnitude of this shifting can be modulated under appropriate experimental conditions.