pH-dependent conductance behaviors of layer-by-layer self-assembled carboxylated carbon nanotube multilayer thin-film sensors
pH-dependent conductance behaviors of layer-by-layer self-assembled carboxylated carbon nanotube multilayer thin-film sensors
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DOI：
10.1116/1.3002386
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发表时间：
2009-03-01
影响因子：
1.4
通讯作者：
Cui, Tianhong
中科院分区：
文献类型：
--
作者：
Lee, Dongjin;Cui, Tianhong
作者报道了单壁碳纳米管（SWCNT）多层薄膜传感器的pH依赖性电导行为。单壁碳纳米管被羧基官能化，并与聚阳离子、聚二烯丙基二甲基氯化铵在微加工金属电极上交替逐层组装。电流 - 电压（I - V）特性表明，单壁碳纳米管多层薄膜传感器的电导随pH值的升高而降低。另一方面，以聚甲基丙烯酸甲酯（PMMA）作为钝化层的多层电阻器表现出电导随pH值升高而增加，这与没有PMMA层的情况相反。没有PMMA时的电导变化归因于p型半导体单壁碳纳米管的分子质子化/去质子化对作为电荷载流子的空穴的掺杂/去掺杂。有PMMA层时，电介质上氢离子的浓度梯度形成栅极偏压，从而改变下面的半导体单壁碳纳米管层的电导。每种pH依赖性行为在化学和生物检测中都有多种应用。（C）2009美国真空学会。[DOI: 10.1116/1.3002386]
The authors report pH-dependent conductance behaviors of single-walled carbon nanotube (SWCNT) multilayer thin-film sensors. SWCNTs are functionalized with carboxylic groups, and layer-by-layer assembled alternatively with polycation, polydiallyldimethyammonium chloride on the microfabricated metal electrodes. Current-voltage (1-V) characteristics show that the conductance of SWCNT multilayer thin-film sensors decreases with increase of pH values. On the other hand, the multilayer resistors with polymethylmethacrylate (PMMA) as a passivation layer demonstrate the increasing conductance with pH, opposite to the case of the absence of PMMA layer. The conductance change in the absence of PMMA attributes to doping/undoping of holes as charge carriers by molecular protonation/deprotonation of p-type semiconducting SWCNTs. With PMMA layer, concentration gradient of hydrogen ions on the dielectric forms the gate bias voltage, which,changes the conductance of underlying semiconducting SWCNT layer. Each pH-dependent behavior has versatile applications for chemical and biological detections. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3002386]