Fast electron transport in discotic columnar phase of triphenylene derivative, hexabutyloxytriphenylene

We have re-investigated the charge carrier transport in a discotic columnar phase of triphenylene derivative, hexabutyloxytriphenylene (H4T) by time-of-flight experiments. We observed two transits for negative charge carriers in a different time range that corresponded to a fast mobility of 10(-2)cm(2)/Vs and a slow mobility of 10(-5) cm(2)/VS in the discotic hexagonal plastic phase of H4T, while a high mobility on the order of 10(-2)cm(2)/Vs as reported previously. These were attributed to the electronic conduction caused by fast electron transport along with the discotic columns and slow ionic conduction caused by drift of ionized impurity molecules hat accepted photo-generated electrons, respectively.