Photoconductivity of solid fullerene C60 film modified by laser irradiation

An improvement on photoconductivity of fullerene C60 film has been observed after modification of laser irradiation at room temperature or at about 100°C because some dimer, trimer and polymer of C60 have been formed under the laser irradiation. This leads to some change of charge transfer (CT) states and reduction on resistance to transport of photocarriers. Another important reason for the great increase on photoconductivity of C60 modified by laser irradiation at about 100°C (373 K) is thermal effect. Thermal treatment of the laser modified C60 thin film at above 100°C (373 K) for a few hours makes a great improvement on its photoconductivity because this treatment reduces trap centers for photocarriers resulted from an increase on its crystallinity and some change on its morphology. Oxygen has a great effect on photoconductivity reduction of the laser modified C60 thin film.