Low-cost hydrogen sensors, designed for ultrasensitive, reliable, and rapid identification of hydrogen gas (H₂), are extremely desired in almost all hydrogen-related applications in the forthcoming hydrogen economy, including crude oil refinement, hydrogen-fueled vehicles, and molecular hydrogen therapy. Here, we first report on the experimental realization of an ultrasensitive optical hydrogen sensor based on a new type of flexible palladium (Pd) nanogroove array. Each groove can be driven synchronously by absorbed hydrogen, with the assistance of the underneath elastic substrate, to mechanically reconfigure itself and thus amplify the spectral shift of plasmon resonance for hydrogen sensing. Our experimental results show a plasmon resonance with a narrow line width of 74 nm, which has a wavelength shift of 18 nm after exposed to 4% H₂ in nitrogen gas (N₂). In addition, the extremely high relative reflectance change of 400% was achieved, giving rise to an ultralow H₂ (in N₂) detection limit of 0.1% and sensing resolution of 0.013% in the low H₂ volume concentration regime. Meantime, exposure to H₂ causes a rapid and reversible change in reflectance on a time scale of seconds. This pronounced performance suggests that our flexible Pd nanogroove array provides a promising optical hydrogen detection scheme for practical applications.

中文翻译：

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机械可重构的Pd纳米槽阵列：超灵敏的光学氢检测器

低成本氢气传感器，专为超灵敏，可靠，快速识别氢气（H ₂在即将到来的氢经济中，几乎所有与氢有关的应用都非常需要）），包括原油精制，氢燃料汽车和分子氢疗法。在这里，我们首先报告基于新型柔性钯（Pd）纳米沟槽阵列的超灵敏光学氢传感器的实验实现。每个凹槽都可以在弹性底盘的帮助下被吸收的氢同步驱动，从而机械地重新配置自身，从而放大用于氢感测的等离激元共振的光谱位移。我们的实验结果表明以74纳米的窄线宽度，其具有暴露于4％H之后的18纳米的波长偏移的等离子体共振₂氮气中（N ₂）。另外，实现了400％的极高的相对反射率变化，从而在低H ₂体积浓度方案中产生了0.1％的超低H ₂（在N _2中）检测极限和0.013％的感测分辨率。同时，暴露于H ₂会在几秒钟的时间尺度上导致反射率的快速且可逆的变化。这种显着的性能表明我们的柔性Pd纳米槽阵列为实际应用提供了有希望的光学氢检测方案。