Humidity sensors were widely used in Internet of Things (IoT) applications. According to medical respiration monitoring, noncontact sensing, and human–computer interface requirements, fast response and high repeatability are important for efficient and precise signal acquisition. Previous research works mainly focus on sensitivity improvement with the scarification of response time, stability, and repeatability. In this paper, we proposed the surface acoustic wave (SAW) humidity sensors with comprehensive performance using the uniform multiwrinkled graphene oxide (GO) films as the sensing material obtained by vacuum filtration and liquid phase transfer method. The multiwrinkled GO films offered controllable thickness (thin to 29 nm), uniform wafer-level fabrication (2 in.), and abundant wrinkle, making them become effective sensitive films for SAW humidity sensors due to numerous adsorption sites and transfer channels for water molecules. The experimental results showed that the sensors can obtain high sensitivity (10.5 kHz/RH%@60 nm thick film), ultrafast response (∼45 ms), good stability (variation amplitude ∼0.1%), repeatability (variation amplitude ∼1%), and wafer-level fabrication capability demonstrating their practical applications for medical respiration monitoring, noncontact sensing, and human–computer interface.

中文翻译：

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一种具有均匀多褶皱氧化石墨烯薄膜的高性能表面声波湿度传感器


湿度传感器广泛用于物联网 （IoT） 应用。根据医疗呼吸监测、非接触式传感和人机界面要求，快速响应和高可重复性对于高效和精确的信号采集非常重要。以前的研究工作主要集中在通过缩短响应时间、稳定性和可重复性来提高灵敏度。在本文中，我们提出了具有综合性能的表面声波 （SAW） 湿度传感器，以均匀多皱氧化石墨烯 （GO） 薄膜为传感材料，通过真空过滤和液相转移法获得。多褶皱 GO 薄膜具有可控的厚度（薄至 29 nm）、均匀的晶圆级制造（2 英寸）和丰富的皱纹，由于水分子的众多吸附位点和转移通道，使其成为 SAW 湿度传感器的有效敏感薄膜。实验结果表明，传感器可以获得高灵敏度 （10.5 kHz/RH%@60 nm 厚膜）、超快响应 （∼45 ms）、良好的稳定性 （变化幅度 ∼0.1%）、可重复性 （变化幅度 ∼1%） 和晶圆级制造能力，证明了它们在医疗呼吸监测、非接触式传感和人机界面方面的实际应用。