一种基于电子隧穿机制的柔性氢气传感器

氢气传感器在涉氢安全领域扮演着重要角色,随着可穿戴设备大量应用,柔性氢气传感器的发展日益受到重视。纳米粒子薄膜以其离散的纳米颗粒状结构和独特的电学响应性质成为了理想的柔性氢气敏感材料。通过在聚对苯二甲酸乙二醇酯(PET)柔性衬底上沉积钯(Pd)纳米粒子薄膜构筑了一种柔性氢气传感器。通过上百次反复弯折,该传感器体现了较好的机械性能和电学稳定性,气敏性能在弯折循环前后无衰减。通过系统研究应变状态下的氢气响应性质,发现拉应变使Pd纳米粒子薄膜的氢气响应度增大,而压应变效应则相反。其原因主要归结为应变导致的纳米颗粒间距变化,拉应变产生的较大的纳米颗粒间距会使得传感器电流基线降低,且足够大的纳米粒子间距更能容纳Pd纳米粒子吸氢导致的晶格膨胀,反之亦然。此外,拉应变使Pd纳米粒子薄膜对氢气的响应时间显著缩短,而压应变产生的效果则相反。该氢气传感器探测范围达到0~10%,响应时间可达数秒量级,探测下限为25×10^-6。在低氢气浓度范围内,响应度ΔI/I0与P1/2H2呈现线性关系,对4%浓度氢气的响应度可达600%,灵敏度可达3.28% Pa-1/2。这些结果表明,该传感器具备优异的传感性能,在柔性气体传感器领域具有极大应用潜力。

A Flexible Hydrogen Sensor Based on Electron Tunneling Mechanism

This result was attributed to the change of interparticle space caused by strain. The larger interparticle space caused by tensile strain reduced current baseline of the sensor and can accommodate the lattice expansion caused by hydrogen absorption of Pd nanoparticles,and vice versa. In addition,tensile strain shortens the response time,while compressive strain has the opposite effect. The dynamic response range as wide as 0~10%. A response time of several seconds and a detection limit of 25×10^-6 were also observed. In the range of low hydrogen concentration,a linear relationship between responsiveness ΔI/I0 and P1/2H2 was observed. The response amplitude to 4% hydrogen can reach 600%,and the sensitivity can reach 3.28% Pa-1/2. These results indicate that the sensor has excellent sensing performance and has great potential in the field of flexible gas sensors.