RADIATION-INDUCED CONDUCTIVITY IN POLYMERIZED AND NONPOLYMERIZED COLUMNAR AGGREGATES OF PHTHALOCYANINE

Upon pulsed irradiation, long-lived, highly mobile charge carriers have been found in columnar stacks of thermotropic liquid-crystalline monomer octakis(dodecyloxy)phthalocyanine, Pc12, and polymeric octakis(octyloxy)phthalocyanine, [Si(Pc8)O]n. The sum of the charge-carrier mobilities in the solid phase of Pc12 lies between 0.04 X 10(-4) and 1.3 X 10(-4) m2/(V s) at room temperature. At the transition from the solid phase to the mesophase, a decrease in the mobilities by a factor of 8 is found. The activation energies associated with the mobilities are very small, on the order of 0 +/- 0.05 eV, in both the solid phase and the mesophase. The conductive properties of the liquid-crystalline polymer change gradually over the temperature range studied, from -100 to +200-degrees-C, and coincide with those of the monomer in its mesophase.