Advanced flexible humidity sensors: structures, techniques, mechanisms and performances
Yuzhe Zhang1, Yuxi Liu1, Lifei Lin2,4, Man Zhou1,3, Wang Zhang2, Liwei Lin2,3(), Zhongyu Li1,3(), Yuanzhe Piao2,6(), Sun Ha Paek5,6
1. School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China 2. Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea 3. Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China 4. College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China 5. Department of Neurosurgery, Movement Disorder Center, Seoul National University Hospital, Seoul 03080, Republic of Korea 6. Advanced Institutes of Convergence Technology, Suwon-si, Gyeonggi-do 16229, Republic of Korea
Flexible humidity sensors are widely used in many fields, such as environmental monitoring, agricultural soil moisture content determination, food quality monitoring and healthcare services. Therefore, it is essential to measure humidity accurately and reliably in different conditions. Flexible materials have been the focusing substrates of humidity sensors because of their rich surface chemical properties and structural designability. In addition, flexible materials have superior ductility for different conditions. In this review, we have summarized several sensing mechanisms, processing techniques, sensing layers and substrates for specific humidity sensing requirements. Aadditionally, we have sorted out some cases of flexible humidity sensors based on different functional materials. We hope this paper can contribute to the development of flexible humidity sensors in the future.
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