Electric properties on iodine doped pentacene

Electric conductivity and NMR properties on iodine doped pentacene have been studied below room temperature. It was found that the electric conductivity parallel to the pentacene molecular layer becomes 10(7) times larger than 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 the electric resistivity is observed at 46 K with a thermal hysteresis of about 5 K. This anomaly was also observed in the spin-lattice relaxation time.