Two-dimensional (2D) metal oxide lamellar membranes provide high-aspect-ratio interlayer nanochannels and yield continuous interstitial space and a nanoconfined length scale comparable to the size of charged ions, which opens up the platform to fabricate channels at this dimension to study charge transport and storage for chemical sensing. Here, we demonstrate a versatile approach to construct the wafer-scale nanoconfined membrane from 2D metal oxide nanosheets through a layer-by-layer assembly process. Such a layered nanochannel by arranging 2D MoO_3–x nanosheets into a dense network can be percolated by molecular conducting polyaniline and further protonic acid doping, and consequently, its conductivity shows improvements of 1797 and 354 times, respectively. The nanoconfined membrane further shows an electrochemical response to the presence of heavy metal ions (lead), enabling a successful demonstration of an electrochemical sensor. The nanoconfined 2D channels with light-tunable capacitance show a promising application in heavy metal detection with high sensitivities of 1.12 × 10^–4 and 2.81 × 10^–4 mA μM^–1 cm^–2 under dark and light conditions, respectively. Our results suggest that nanoconfined 2D metal oxide channels represent an efficient approach to study charge transport and storage for heavy metal sensing at this dimension.

中文翻译：

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用于重金属传感器的二维纳米限制通道

二维（2D）金属氧化物层状膜可提供高纵横比的层间纳米通道，并产生连续的间隙空间和纳米带限的长度尺度，可与带电离子的大小相媲美，这为在此尺寸下制造通道以研究电荷的平台打开了平台用于化学传感的运输和存储。在这里，我们展示了一种通用的方法，可以通过逐层组装过程从2D金属氧化物纳米片构建晶圆级纳米约束膜。通过排列2D MoO _{3– x形成}这样的分层纳米通道通过分子导电聚苯胺和进一步的质子酸掺杂，可以渗透成紧密网络的纳米片，因此，其电导率分别提高了1797和354倍。纳米约束膜还显示出对重金属离子（铅）的电化学响应，从而成功展示了电化学传感器。具有光可调电容的纳米限制二维通道在重金属检测中显示出有希望的应用，其高灵敏度为1.12×10 ^–4和2.81×10 ^–4 mAμM ^–1 cm ^–2分别在黑暗和明亮的条件下。我们的结果表明，纳米约束的二维金属氧化物通道代表了一种有效的方法来研究此尺寸下重金属感测的电荷传输和存储。