Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Nanotechnology. 2010 Feb 5;21(5):055504. doi: 10.1088/0957-4484/21/5/055504. Epub 2009 Dec 24.
Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of approximately 1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.
基于单壁碳纳米管 (SWNT) 网络的纳米级传感器由于灵敏度差和信噪比小等几个基本限制，被认为不切实际。在此，我们提出了一种克服这些基本问题的策略，通过控制 SWNT 网络的结构来构建高灵敏度、低噪声的纳米级传感器。在该策略中，我们使用定向组装策略制备了基于排列 SWNT 网络的纳米级宽度通道。显著的是，具有更窄通道的排列网络基传感器的信噪比甚至优于具有更宽通道的传感器，这与传统的随机网络基传感器相反。作为概念验证，我们展示了 100nm 尺度的低噪声传感器，用于检测汞离子，其检测限约为 1pM，优于任何最先进的便携式检测系统，并且低于大多数政府环境保护机构设定的饮用水中汞离子的允许限值。这是首次展示基于 SWNT 网络的 100nm 尺度低噪声传感器。考虑到人们对医疗保健和环境保护中高密度传感器阵列的兴趣增加，我们的策略应该对各种工业应用产生重大影响。
