Optical-thermally actuated graphene mechanical resonator for humidity sensing

• Published in: Sensors and actuators. B, Chemical Vol. 374; p. 132851
• Main Authors: Xiao, Xing, Li, Cheng, Fan, Shang-Chun, Liu, Yu-Jian, Liu, Yang
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.01.2023; Elsevier Science Ltd
• Subjects: Diameters; Graphene; Graphene resonator; Humidity sensing; Multilayers; Optical fibers; Opto-thermal actuation; Quartz crystals; Resonators; Temperature drift; Temperature effects; Temperature drift; Graphene resonator; Humidity sensing; Opto-thermal actuation
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2022.132851

This paper demonstrates an optical-thermally actuated multi-layer graphene resonator for humidity sensing. A ∼10-layered graphene resonator with a diameter of 125 µm peripherally clamped on the fiber ferrule end face was actuated to vibrate using the intensity-modulated laser, and the vibration was detected based on the optical fiber Fabry-Perot interference method. The humidity sensing experiment exhibited an up to 350 Hz/%RH humidity sensitivity in the range of 0–100 % RH at 25 °C, which was 10 times higher than those of the previously reported Quartz Crystal Microbalance (QCM)-based humidity sensors. Also, a good repeatability of the frequency-humidity response was observed for the presented graphene resonator. Moreover, in view of the coupling effect of temperature on the graphene resonator, the temperature drift of 0.942 kHz/°C was measured in the range of 25–50 °C, thereby inducing an absolute humidity error of about 0.6 g/(m3·°C). •Micro fiber-optic graphene resonators are fabricated and used for humidity sensing innovatively.•Graphene resonators exhibit a much higher humidity sensitivity of 350 Hz/%RH compared with the Quartz Crystal Microbalance.•The humidity response of the graphene resonators shows the good linearity and stability at atmospheric pressure.