Cathodoluminescence of fullerene C-60

Fullerenes are not automatic candidates for luminescence analyses due to th eir highly absorptive nature. Consequently, very few luminescence experimen ts have been performed on fullerenes. This paper focuses on the luminescenc e properties of commercially available C-60 when bombarded by electrons (ca thodoluminescence) and, to a lesser extent, x-rays (radio-thermoluminescenc e) between 20 and 270 K. Wavelength resolved luminescence signals have been recorded as a function of temperature. CL experiments reveal pronounced an omalies that truncate the emission spectrum between 155 and 170 K. Other le ss pronounced anomalous features are detected at 70 and 245 K. These dramat ic changes in the luminescence spectra are cautiously interpreted to be man ifestations of phase transitions and support the view that cathodoluminesce nce (CL) can be used to monitor for phase transitions in fullerenes. The lu minescence signals offer information on the mechanisms of the relaxation pr ocesses, including changes in charge trapping energies and emission spectra .