Electric properties on iodine doped pentacene

Electric conductivity and NMR properties on iodine doped pentacene have bee n studied below room temperature. It was found that the electric conductivi ty parallel to the pentacene molecular layer becomes 10(7) times larger tha n that perpendicular to the molecular layer at room temperature. Moreover, NMR results show that the frequency f dependence of spin-lattice relaxation lime T-1 at room temperature obeys the relation (1/T-1 = In f) indicating two-dimensional nature. It was also found that the anomalous behaviour of t he electric resistivity is observed at 46 K with a thermal hysteresis of ab out 5 K. This anomaly was also observed in the spin-lattice relaxation time .