Photoluminescence of C60-doped matrixes

Four matrixes were doped with C60: nano-ZrO2; nano-Al2O3; nano-SnO2; and polystyrene. Under Ar+ laser (476.5 nm) excitation, pure C60 and the above matrixes had only weak photoluminescence (PL) in the visible region. However, when the above matrixes were doped with C60, the PL intensities increased strongly. The PL spectra of C60-doped matrixes are similar. All spectra show a wide band covering the visible region with intensities from three to ten times stronger than those of the pure matrixes, respectively. The intensities and peak positions of the spectra varied for different matrixes and different crystallite sizes. It is probable that the photoluminescence is caused by the optically activated forbidden tlu⇒hu transition of C60 due to the interaction of C60 with the matrixes.