Spatial photon confinement and super-radiation from dye cored dendrimer

This paper describes the preparation of a dendritic macromolecule having a rhodamine B chromophore, called Rh-dendrimer, and the emission properties f rom the neat films due to the spontaneous emission and super-radiative emis sion. An important concept to be investigated for material preparation, is the surrounding of a fluorescent chromophore by the dendritic branches. The refore, a dendrimer becomes a core-shell structure, achieving a high effici ency of fluorescence with little energy transfer and self-quenching. The. o ptical properties from dendrimer were very different from that of a bare ch romophore. The Rh-dendrimer showed a high efficiency of fluorescence, while a bared rhodamine chromophore formed a charge transferred complex and exhi bited less fluorescence. Under optical excitation with sufficient intensity (I-0), the emission intensity was non-linearly increased as a function of the square of the number of molecules (N), giving relation of I alpha (NI0) -I-2. This property cannot be adequately explained within the simple pictur e of spontaneous emission. Results were discussed in terms of cooperative e mission. (C) 2001 Elsevier Science B.V. All rights reserved.