PERSISTENT PHOTOELECTRIC PHENOMENA IN OXYGENATED C-60 THIN-FILMS

We report on a persistent internal photopolarization effect observed i n C-60 thin films at room temperature. This differs from the similar ' 'photoelectret'' state previously seen in some other materials by an a bsence of fast photodepolarization. Our oxygenated C-60 thin films als b exhibit persistent photoconductivity. Both phenomena are discussed w ithin the framework of a model of photogenerated carrier trapping at d eep level centers and an inhibition of their recombination due to stro ng distortion of the C-60 molecule which is known to occur in the pres ence of localized charge. Copyright (C) 1996 Elsevier Science Ltd