Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China.
School of Aerospace Engineering, Xiamen University, Xiamen 361102, China.
ACS Appl Mater Interfaces. 2024 Aug 28;16(34):45252-45264. doi: 10.1021/acsami.4c07731. Epub 2024 Aug 14.
Humidity-sensor-based fully contactless respiratory monitoring can eliminate the discomfort and infection risks associated with any wearable device. However, challenges in the facile fabrication of highly sensitive humidity sensors continue to hinder their widespread application for fully contactless respiratory monitoring. In this study, we introduce a simple method to fabricate highly sensitive humidity sensors. Our method employs laser-induced graphene (LIG) on an ethanol-soaked polyimide (PI) film as the electrode of the humidity sensor. The ethanol-soaked PI between adjacent LIG electrodes functions as the sensing material, enabling ion-conductive humidity sensing. Compared to the LIG humidity sensors fabricated on untreated PI films, LIG humidity sensors fabricated on ethanol-soaked PI films exhibit superior performance with higher linearity ( = 0.9936), reduced hysteresis (Δ = 5.1% RH), and increased sensitivity (0.65%/RH). Notably, the LIG humidity sensor fabricated on the ethanol-soaked PI film can detect a person's breathing from a distance of 30 cm, a capability not achieved by sensors fabricated on untreated PI films. Moreover, incorporating these LIG humidity sensors into an array further enhances both the detection distance and the sensitivity for respiratory monitoring. Experimental results demonstrate that the LIG humidity sensor array can be employed for fully contactless on-bed respiration monitoring and for continuous, fully contactless monitoring of the respiratory rate during treadmill exercise. These results highlight the great potential of our LIG humidity sensors for various practical applications in medicine and sports.
基于湿度传感器的全非接触式呼吸监测可以消除与任何可穿戴设备相关的不适和感染风险。然而，制造高灵敏度湿度传感器的简便方法仍然存在挑战，这阻碍了它们在全非接触式呼吸监测中的广泛应用。在本研究中，我们介绍了一种制造高灵敏度湿度传感器的简单方法。我们的方法采用激光诱导石墨烯（LIG）在乙醇浸泡聚酰亚胺（PI）薄膜上作为湿度传感器的电极。相邻 LIG 电极之间的乙醇浸泡 PI 用作传感材料，实现了离子导电湿度传感。与在未经处理的 PI 薄膜上制造的 LIG 湿度传感器相比，在乙醇浸泡 PI 薄膜上制造的 LIG 湿度传感器具有更高的线性度（=0.9936）、更小的滞后（Δ=5.1% RH）和更高的灵敏度（0.65%/RH）。值得注意的是，在乙醇浸泡 PI 薄膜上制造的 LIG 湿度传感器可以从 30 厘米的距离检测到人的呼吸，而未经处理的 PI 薄膜上制造的传感器则无法实现这一功能。此外，将这些 LIG 湿度传感器集成到阵列中可以进一步提高呼吸监测的检测距离和灵敏度。实验结果表明，LIG 湿度传感器阵列可用于完全非接触式床上呼吸监测以及在跑步机运动期间进行连续、完全非接触式呼吸率监测。这些结果突出了我们的 LIG 湿度传感器在医学和运动等各个实际应用中的巨大潜力。
