Photophysical and photochemical properties of bis-silylated C60 derivatives

Abstract

Photophysical and photochemical properties of bis-silylated C60 derivatives have been examined using steady-state and time-resolved spectroscopies. Absorption band edges of 1,2- and 1,4-bis-silylated C60 derivatives ranged to about 800 nm. Fluorescence quantum yields of 1,2- and 1,16-adducts were slightly larger than that of C60, while 1,4-adducts did not show fluorescence. By laser irradiation to the bis-silylated C60 derivatives, transient absorption bands due to their triplet excited states were confirmed in the visible and near-IR regions. Photoinduced electron transfer from electron donor to excited triplet states of bis-silylated C60 derivatives was also confirmed in transient absorption spectra. The acceptor-abilities of the excited triplet states changed with the position of the C60-silicon bonds, which can be explained mainly on the basis of reduction potentials and triplet energies of the bis-silylated C60 derivatives.