Khattak Zarak Jamal, Sajid Memoon, Javed Mazhar, Zeeshan Rizvi Hafiz Muhammad, Awan Faisal Saeed
Faculty of Electrical Engineering, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi, K.P. 23640, Pakistan.
ACS Omega. 2022 May 6;7(19):16605-16615. doi: 10.1021/acsomega.2c00850. eCollection 2022 May 17.
Relative humidity sensors are widely studied under the categories of both environmental and biosensors owing to their vast reaching applications. The research on humidity sensors is mainly divided into two concentration areas including novel material development and novel device structure. Another approach focuses on the development of printed sensors with performance comparable to the sensors fabricated via conventional techniques. The major challenges in the research on relative humidity sensors include the range of detection, sensitivity (especially at lower %RH), transient response time, and dependence on temperature. Temperature dependence is one of the least studied parameters in relative humidity sensor development. In this work, relative humidity sensors were fabricated using all-printed approaches that are also compatible with mass production, resulting in low cost and easy development. Laser-induced graphene (LIG)-based printed electrodes were used as the transducers, while the 2D MoS and graphene nanocomposite was used as the active layer material with the built-in property of temperature independence. The exfoliation process of 2D MoS was based on wet grinding, while graphene for the active layer was obtained by scratching the graphene grown on the polyimide (PI) surface via laser ablation. The resulting sensors showed an excellent output response for a full range of 0%RH to 100%RH, having no dependence on the surrounding temperature, and excellent response and recovery times of 4 and 2 s, respectively. The developed sensors can be confidently employed for a wide range of humidity sensing applications where the temperature of the surrounding environment is not constant.
由于相对湿度传感器的应用广泛，因此在环境传感器和生物传感器领域都得到了广泛研究。湿度传感器的研究主要分为两个集中领域，包括新型材料开发和新型器件结构。另一种方法则专注于开发性能与传统技术制造的传感器相当的印刷传感器。相对湿度传感器研究中的主要挑战包括检测范围、灵敏度（尤其是在较低相对湿度下）、瞬态响应时间以及对温度的依赖性。温度依赖性是相对湿度传感器开发中研究最少的参数之一。在这项工作中，采用全印刷方法制造相对湿度传感器，这种方法也与大规模生产兼容，从而实现了低成本和易于开发。基于激光诱导石墨烯（LIG）的印刷电极用作换能器，而二维MoS₂与石墨烯的纳米复合材料用作具有温度独立性内在特性的活性层材料。二维MoS₂的剥离过程基于湿磨，而活性层用的石墨烯则通过激光烧蚀刮擦生长在聚酰亚胺（PI）表面的石墨烯获得。所得传感器在0%RH至100%RH的全范围内表现出优异的输出响应，不依赖于周围温度，响应时间和恢复时间分别为4秒和2秒，性能出色。所开发的传感器可放心用于周围环境温度不恒定的广泛湿度传感应用中。
