The effect of fullerenes C60 and C70 on the photo- and triboluminescence of terbium sulphate crystallohydrate in the solid phase

Abstract

It was found that the addition of C60 and C70 fullerenes to Tb2(SO4)3·8H2O crystals led to a decrease in the photo- and triboluminescence intensities of the Tb3+ ion, without affecting the positions of its luminescence maxima. An increase in the intensity of the emission band ascribed to fullerene at 630-850 nm, relative to that without terbium sulphate, was also observed in the photoluminescence spectra. The phosphor luminescence was quenched in a mechanical mixture with the quenchers and luminescence sensitization of the quenchers occurred, indicating that quenching took place in the solid phase by a mechanism similar to that observed in solution; this is due to radiationless energy transfer from the excited Tb3+ ion to the C60 and C70 molecules. The excitation energy is probably transferred through the contacting crystal surfaces of the phosphor and quencher.