We synthesized gold (Au) nanoparticles via a rapid chemical route by reducing chloroauric acid by trisodium citrate. TEM micrographs revealed that particles were spherical with well-defined lattice structures and most of them were within the size range of 8–12 nm. A single surface plasmon resonance peak observed at 525 nm indicated the uniformness of the spherical morphology of the particles. XRD analysis showed that the particles were well crystalline. An impedance-based humidity sensor device was fabricated for depositing these gold nanoparticles in their non-functionalized state and the sensor revealed fast response time of 54 s, high stability and repeatability, and an impressive average sensitivity of 7.57 MΩ/% RH within the humidity range of 10–95%. SEM micrographs revealed the presence of cracks on the film surface and our analysis of the sensing mechanism correlated the sensitivity and the surface cracks along with smaller particle sizes. Our results show that gold nanoparticles without further functionalization are able to perform as a well-performing humidity sensor.

我们通过快速化学路线通过用柠檬酸三钠还原氯金酸来合成金（Au）纳米粒子。TEM显微照片显示，颗粒是球形的，具有明确的晶格结构，并且大多数在8-12 nm的尺寸范围内。在525nm处观察到的单个表面等离子体共振峰表明了颗粒的球形形态的均匀性。XRD分析表明颗粒是良好的结晶。制造了一种基于阻抗的湿度传感器设备，用于以非功能状态沉积这些金纳米颗粒，该传感器显示出54 s的快速响应时间，高稳定性和可重复性，以及在湿度范围内令人印象深刻的平均灵敏度为7.57MΩ/％RH范围为10–95％。SEM显微照片揭示了膜表面上存在裂纹，并且我们对感测机理的分析将灵敏度和表面裂纹与较小的粒径相关联。我们的结果表明，未经进一步功能化处理的金纳米颗粒能够用作性能良好的湿度传感器。