School of Electronics and Information Engineering, Guangdong Ocean University, Zhanjiang 524088, China.
College of Mechanical Engineering, Guangdong Ocean University, Zhanjiang 524088, China.
Sensors (Basel). 2023 Jul 29;23(15):6784. doi: 10.3390/s23156784.
Respiratory rate and skin humidity are important physiological signals and have become an important basis for disease diagnosis, and they can be monitored by humidity sensors. However, it is difficult to employ high-quality humidity sensors on a broad scale due to their high cost and complex fabrication. Here, we propose a reliable, convenient, and efficient method to mass-produce humidity sensors. A capacitive humidity sensor is obtained by ablating a polyimide (PI) film with a picosecond laser to produce an interdigital electrode (IDE), followed by drop-casting graphene oxide (GO) as a moisture-sensitive material on the electrode. The sensor has long-time stability, a wide relative humidity (RH) detection range from 10% to 90%, and high sensitivity (3862 pF/%RH). In comparison to previous methods, the technology avoids the complex procedures and expensive costs of conventional interdigital electrode preparation. Furthermore, we discuss the effects of the electrode gap size and the amount of graphene oxide on humidity sensor performance, analyze the humidity sensing mechanism by impedance spectrum, and finally perform the monitoring of human respiratory rate and skin humidity change in a non-contact manner.
呼吸频率和皮肤湿度是重要的生理信号，已成为疾病诊断的重要依据，可以通过湿度传感器进行监测。然而，由于高质量湿度传感器成本高、制造工艺复杂，因此很难大规模使用。在这里，我们提出了一种可靠、方便、高效的批量生产湿度传感器的方法。通过皮秒激光烧蚀聚酰亚胺（PI）薄膜来制作叉指电极（IDE），然后将氧化石墨烯（GO）滴铸在电极上作为湿敏材料，从而获得电容式湿度传感器。该传感器具有长时间稳定性，相对湿度（RH）检测范围从 10%到 90%，且灵敏度高（3862 pF/%RH）。与以往的方法相比，该技术避免了传统叉指电极制备的复杂程序和昂贵成本。此外，我们还讨论了电极间隙大小和氧化石墨烯用量对湿度传感器性能的影响，通过阻抗谱分析湿度传感机制，最后以非接触的方式监测人体呼吸频率和皮肤湿度的变化。
