Charge carrier lifetimes in a smectic liquid crystalline photoconductor of a 2-phenylnaphthalene derivative


We have investigated the charge carrier lifetimes for electrons and holes in smectic mesophases of a 2-phenylnaphthalene derivative, 6-(4’-octylphenyl)-2-dodecyloxynaphthalene (8-PNP-O12) by time-of-flight (TOF) measurement. For the negative charge carriers, we found two transits in different time range, which are attributed to electronic and ionic conduction. With the aid of liquid-like fluidity of the material, we could prepare very thick samples over 500μm, and it enables us to determine the carrier lifetimes, which are governed by different regimes: the hole lifetime is governed by recombination of charge carriers and estimated to be 10–2 sec; on the other hand, the electron lifetime is dominated by trapping at deep states and estimated to be on the order of 10–5 sec for both SmA and SmB phases.

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Correspondence to Hiroaki Iino.

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Iino, H., Hanna, JI. Charge carrier lifetimes in a smectic liquid crystalline photoconductor of a 2-phenylnaphthalene derivative. MRS Online Proceedings Library 771, 747 (2003).

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