Ambipolar Carrier Transport in Terphenyl Derivative

Abstract

We have investigated the liquid crystalline behavior and charge carrier transport properties in the semectic phases of a terphenyl derivative, 4-4″-bis(dodecyloxy)-3-methyl-p-terphenyl (12O-TPMe-O12) having methyl side chain in the terphenyl core part. In its samples highly purified by recrystallization several times, we observed the transient photocurrents indicating electronic conduction not only for holes but also electrons and determined their mobilities to be 5 × 10⁻⁴ and 0.9 × 10⁻² cm²/Vs in SmC and SmG phases, respectively. Thus, we concluded that the intrinsic nature of charge carrier transport in the terphenyl derivatives is electronic and ambipolar, where electrons and holes can be transported.

Keywords:

• ambipolar
• calamitic liquid crystal
• electronic transport
• ionic transport
• mobility
• terphenyl derivative

Acknowledgments

We thank Honshu Chemical Industry Co., LTD. for providing a source material for 12O-TPMe-O12. This study was partly supported by Grants-in-Aid for Scientific Research sponsored by the Ministry of Education, Culture, Sports, Science and Technology, and by NEDO international joint research grant.