Efficient preparation of La@C_(60), C_(60)Br_(24) and the electrical conductivity of sulfur-doped C_(60) films

摘要

La@C_(60) is prepared in gram quantities using anode-arc vaporization of graphite rod with 99.9% purity lanthanum powder wick in a 150-Torr atmosphere of helium. C_(60)Br_(24) is prepared by mixing 99.9% purity of C_(60) powder with neat bromine and iron powder catalyst at ambient temperature. The temperature-dependent conductivities of sulfur-doped C_(60) films are measured. The obvious semiconductive properties are confirmed in the temperature range from ambient temperature to 368 K. The activation energy decreases and the conductivity increases with an increase in the sulfur doping level. C_(60) and C_(70) are prepared in quantities by using anode-arc vaporization of graphite rod in an atmosphere of helium and the optimal conditions of preparation are contained in this paper.