Dark Resistivity of Anthracene Measured by Potentiometric Method

Using a potentiometric method, the electrical dark resistivity of anthracene crystals, together with the voltage distributions in the crystals was measured in a range from 80°C up to about 150°C. The activation energy for dark conduction and ρ0 were found to 0.87 ±0.3 eV independent of the crystal orientation, and to be 2.8×103 Ω-cm in the direction perpendicular to the ab-plane and 6.7×102 Ω-cm in the direction parallel to the abplane, respectively. When the present results are considered together with previous measurements, the presently available data for the activation energy of anthracene fall into two distinct groups, viz, Group A, with activation energy near 0.9 eV, and Group B, with activation energy near 1.4 eV. A possible interpretation of these values is discussed.