A Highly Sensitive Humidity Sensor Based on Ultrahigh-Frequency Microelectromechanical Resonator Coated with Nano-Assembled Polyelectrolyte Thin Films

Micromachines

Hemi Qu¹  Xuexin Duan¹  Wei Pang¹  Hao Zhang²  Wenpeng Liu²  Jizhou Hu² 

[1] Instruments, Tianjin University, Tianjin 300072, China;;State Key Laboratory of Precision Measuring Technology &

关键词: humidity sensor;    film bulk acoustic resonator (FBAR);    ultrahigh frequency;    microelectromechanical resonator;    nano-assembled polyelectrolyte (PET) thin films;    wireless sensor networks (WSNs);   

DOI  :  10.3390/mi8040116

来源: DOAJ

【 摘 要 】

We developed a highly sensitive humidity sensor based on the combination of ultrahigh-frequency film bulk acoustic resonator (FBAR) and nano-assembled polyelectrolyte (PET) thin films. The water molecule absorption efficiency was optimized by forming loosely-packed PET nanostructures. Then, the humidity sensing characteristics were analyzed in terms of sensitivity, linearity, reversibility, stability and detection limit. As a result, PET-coated FBAR exhibits excellent humidity sensitivity of 2202.20 Hz/ppm, which is five orders of magnitude higher than quartz crystal microbalance (QCM). Additionally, temperature dependence was investigated with the result that PET-coated FBAR possessed a higher sensitivity at low temperature. Furthermore, we realized the selective detection of water vapor from volatile organic compounds (VOCs) with respect to the polarity property. Owing to the high sensitivity, miniaturized size and ultrahigh operating frequency, PET-coated FBAR is uniquely favorable as a wireless humidity sensor node to integrate into wireless sensor networks (WSNs).

【 授权许可】

Unknown