MoS₂/Graphene Oxide/C₆₀-OH Nanostructures Deposited on a Quartz Crystal Microbalance Transducer for Humidity Sensing

Abstract

In this work, MoS 2 /graphene oxide (GO)/C 60 -OH nanocomposites are synthesized by a hydrothermal method and deposited on a quartz crystal microbalance (QCM) transducer for humidity detection. Microscopic characterization shows that the nanocomposites are composed of GO/C 60 -OH composite encapsulated MoS 2 nanoflowers. The QCM humidity sensor with MoS 2 /GO/C 60 -OH nanocomposites as the sensing film demonstrates an excellent response and recovery times (1.3/1.2 s), which are shorter than most QCM humidity sensors proposed at present. Meanwhile, the QCM humidity sensor has a high sensitivity (31.8 Hz/% RH), which is approximately 3 times that of the QCM humidity sensor based on pure GO. It is possible that the support of MoS 2 nanoflowers significantly weakens the stacking effect of GO films and accelerates the diffusion rate of water molecules in the composites. Besides this, the addition of C 60 -OHs can also greatly increase water absorption sites in the composites, thus improving the sensor's humidity-sensitive response. Owing to its fast response/recovery rate, the proposed MoS 2 /GO/C 60 -OH-based QCM humidity sensor can be used for human respiratory status detection with digital frequency output signals.

Quartz Crystal Microbalance Humidity Sensors Based on Structured Graphene Oxide Membranes with Magnesium Ions: Design, Mechanism and Performance

“…It can be observed that the amount of hydroxyl/epoxy in GO is lower than that in HGO, which is consistent with the FTIR results. It is easily understood that the interlayer spacing of GOMs may have a direct influence on their ability to adsorb water molecules [10]. As shown in Figure 5a, the interlayer spacing of GO (~8.3 Å) is greater than that of HGO (~7.5 Å) at ambient humidity, while that of HGO&GO (~7.8 Å) is between those of HGO and GO.…”

“…The materials coating a QCM are the key to determining the detection performance of QCM-based humidity sensors [10,11]. Various materials, such as two-dimensional (2D) materials [11,12], polyelectrolytes [13] and metal oxides [14], have been researched.…”

Photoacid-Loaded Nanopores of Hollow Mesoporous Organosilica Capsules for Fluorescent Humidity Sensing

“…Besides the performance evaluation under static RHs, we further examined the humidity sensors for human respiration. ,,− We first quantitatively examined the response and recovery time of sensors 1 and 2 with a single breath. As illustrated in Figure a,b, color change response times of sensors 1 and 2 are estimated to be 0.8 and 1.3 s, respectively.…”

Guar Gum/Ethyl Cellulose-Polyvinyl Pyrrolidone Composite-Based Quartz Crystal Microbalance Humidity Sensor for Human Respiration Monitoring

“…The sensor can sensitively detect the subtle changes in breathing signals caused by coughing and speaking . Tang et al reported a MoS 2 /GO/C 60 -OH-based QCM humidity sensor detecting respiratory rate at different breathing states correctly . Liu et al reported a high-sensitivity CS/PPy QCM sensor that can detect respiratory features of rhythm-type and frequency-type abnormal breathing in the disease diagnosis .…”

“…11 Tang et al reported a MoS 2 /GO/C 60 -OH-based QCM humidity sensor detecting respiratory rate at different breathing states correctly. 12 Liu et al reported a highsensitivity CS/PPy QCM sensor that can detect respiratory features of rhythm-type and frequency-type abnormal breathing in the disease diagnosis. 13 Therefore, the development of a high-performance QCM humidity sensor for respiratory monitoring and health analyzation is of great research value.…”