Temperature dependence of photoluminescence spectra of C60 films and a luminescence related to oxygen molecules

The photoluminescence intensity has a maximum at 50 K and decreases as temperature increases rather rapidly above 90 K. The decrease of photoluminescence at main and at 0.968 eV bands on a C60 film is observed when it is exposed to air and irradiated by a laser. This phenomenon is explained by relating to the intercalation of O2.