Charge carrier mobilities in the crystalline solid and discotic mesophases of hexakis-hexylthio and hexakis-hexyloxy triphenylene

The radiation-induced conductivities of bulk samples of hexakis-hexylthio and hexakis-hexyloxy triphenylene, HHTT and HHOT, have been studied from 0 to +100 degrees C using the pulse-radiolysis time-resolved microwave conductivity (PR-TRMC) technique. The one-dimensional, intracolumnar mobility, Sigma mu(C), of charge carriers in the various phases is estimated and compared with values obtained using the time-of-night technique. Temperature independent values of Sigma mu(C), of 0.4x10(-4) and 0.08x10(-4) m(2)/Vs are found for the K (crystalline solid) and H (helical columnar mesophase) of HHTT respectively. A much lower value of Sigma mu(C), approximate to 0.01x10(-4) m(2)/Vs is found for the K phase of HHOT.