Photophysical and nonlinear optical properties of [60]fullerene derivatives

A systematic spectroscopic study of a series of C-60 derivatives with different cage functionalizations is reported. The absorption spectra and absorptivities of the derivatives in solution were measured and compared. By recording the fluorescence spectra using a near-infrared-sensitive emission spectrometer (extending to 1200 nm), fluorescence quantum yields of the derivatives were determined quantitatively, Fluorescence lifetimes of the derivatives were obtained using the time-correlated single photon counting technique. The results show that both fluorescence quantum yields and lifetimes are rather similar for the different classes of C60 derivatives. The nonlinear absorptive properties of the derivatives were evaluated by optical limiting measurements in solution and in polymer film using the second harmonic of a Q-switched Nd:Yag laser at 532 nm, Effects of different fullerene cage functionalizations on the photophysical properties and optical limiting responses of the C-60 derivatives are discussed.