High Carrier Mobility up to 1.4 cm2·V-1·s-1in Non-Peripheral Octahexyl Phthalocyanine

Carrier transport properties of a non-peripherally alkyl-substituted phthalocyanine, 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) have been investigated. The material is a low-molecular-weight organic semiconductor with high solubility for typical organic solvents and liquid crystallinity. The carrier mobility was measured in the crystal phase and the hexagonal disordered columnar (Colhd) mesophase by the time-of-flight technique. A strong negative temperature dependence was observed for the hole mobility in the crystal phase, and a maximum drift mobility of 1.4 cm2·V-1·s-1 was achieved at -15 °C. A maximum mobility of 0.5 cm2·V-1·s-1 was obtained for the electrons that had a smaller dependence.