Impurity effects on charge carrier transport in various mesophases of smectic liquid crystals
Impurity effects on charge carrier transport in various mesophases of smectic liquid crystals
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DOI：
10.1063/1.2812574
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发表时间：
2007-11
影响因子：
3.2
通讯作者：
H. Ahn;A. Ohno;J. Hanna
中科院分区：
文献类型：
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作者：
H. Ahn;A. Ohno;J. Hanna
由于窄分布的态密度，即使是少量的化学杂质也可以引起相对明显的中间带隙态，并显着降低液晶中的电荷载流子输运。然而，化学杂质对电荷载流子输运的影响尚未得到充分解释，因为液晶中电子传导的发现相对较新。在这份报告中，我们研究了掺杂三噻吩的模型近晶液晶（2-苯基萘衍生物）的各种中间相的杂质效应，通过瞬态光电流测量。我们讨论了化学杂质对载流子迁移率的影响，在各种中间相作为温度和杂质浓度的函数。本研究为有机半导体液晶的纯度评估提供了指导。
Owing to the narrowly distributed density of states, even small amounts of chemical impurities can cause relatively distinct midgap states and significantly reduce the charge carrier transport in liquid crystals. However, the effects of chemical impurities on charge carrier transport have not yet been explained sufficiently because the discovery of electronic conduction in liquid crystals is relatively recent. In this report, we investigate impurity effects in various mesophases of model smectic liquid crystals (2-phenylnaphthalene derivatives) doped with a terthiophene through transient photocurrent measurements. We discuss the effects of chemical impurities on the carrier mobility in various mesophases as a function of temperature and impurity concentration. This study provides guidelines for purity assessment of liquid crystals as organic semiconductors.