Modulation of the photophysical properties of C60 by electronic confinement effect

This research work reports on the incorporation of fullerene C60 in diverse inorganic and organic matrixes and how these different environments induce changes on the photophysical properties of the molecule depending on the cavity dimensions of the host. Indeed the fluorescence emission band of C60 experiences a progressive bathochromic shift with respect to C60 in solution as the cavity dimensions of the host decrease in going from the mesoporous material MCM41 to UTD-1 and Na-Y zeolites. This experimental observation, which has been documentarily confirmed by theoretical predictions and recent experimental results, is a reflection of the confinement effect imposed by the host. However, the most striking result reported in this work is that the fluorescence range accessible to this occluded species can be extraordinarily extended by confinement inside the neutral cages of a "dendritic box". The ability of the dendritic shell to create a microenvironment, modifying the properties of its functional core, allows the emission bands of C60 incorporated into a dendrimer to be effectively red-shifted with respect to their emission in solution, and, contrarily to other confined spaces of considerable hardness such as zeolites or the high surface material MCM41, the magnitude of this shifting is maximum and can be modulated under appropriate experimental conditions. This phenomenon has an enormous relevance since it can be exploited in future technological applications.