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°C using the pulse-radiolysis time-resolved microwave conductivity (PR-TRMC) technique. The one-dimensional, intracolumnar mobility, σμc, of charge carriers in the various phases is estimated and compared with values obtained using the time-of-flight technique. Temperature independent values of σμc, of 0.4×10−4 and 0.08×10−4 m2/Vs are found for the K (crystalline solid) and H (helical columnar mesophase) of HHTT respectively. A much lower value of σμc ≈ 0.01×10−4m2/Vs is found for the K phase of HHOT.