There has been long-standing interest in developing metal oxide-based sensors with high sensitivity, selectivity, fast response and low material consumption. Here we report for the first time the utilization of Cu₂O@PNIPAM core–shell microgels with a nanocube-shaped core structure for construction of novel CuO gas sensing layers. The hybrid microgels show significant improvement in colloidal stability as compared to native Cu₂O nanocubes. Consequently, a homogeneous thin film of Cu₂O@PNIPAM nanoparticles can be engineered in a quite low solid content (1.5 wt%) by inkjet printing of the dispersion at an optimized viscosity and surface tension. Most importantly, thermal treatment of the Cu₂O@PNIPAM microgels forms porous CuO nanocubes, which show much faster response to relevant trace NO₂ gases than sensors produced from bare Cu₂O nanocubes. This outcome is due to the fact that the PNIPAM shell can successfully hinder the aggregation of CuO nanoparticles during pyrolysis, which enables full utilization of the sensor layers and better access of the gas to active sites. These results point out great potential of such an innovative system as gas sensors with low cost, fast response and high sensitivity.

中文翻译：

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Cu ₂ O @ PNIPAM核壳微凝胶作为新型喷墨材料，用于制备CuO中空多孔纳米立方体气体传感层†

长期以来，人们一直在开发具有高灵敏度，选择性，快速响应和低材料消耗的基于金属氧化物的传感器。在这里，我们首次报道了具有纳米立方体形核结构的Cu ₂ O @ PNIPAM核壳微凝胶用于新型CuO气体传感层的构建。与天然Cu ₂ O纳米立方体相比，杂化微凝胶在胶体稳定性方面显示出显着改善。因此，通过以最佳的粘度和表面张力对分散体进行喷墨印刷，可以将Cu ₂ O @ PNIPAM纳米粒子的均质薄膜工程化为相当低的固体含量（1.5重量％）。最重要的是，Cu _2的热处理O @ PNIPAM微凝胶形成多孔CuO纳米立方体，与从裸露的Cu ₂ O纳米立方体生产的传感器相比，它们对相关的痕量NO ₂气体显示出更快的响应。该结果归因于以下事实：PNIPAM外壳可以成功地阻止热解过程中CuO纳米粒子的聚集，从而可以充分利用传感器层，并使气体更好地进入活性位点。这些结果表明，低成本，快速响应和高灵敏度的气体传感器这样的创新系统具有巨大的潜力。