A highly sensitive quartz crystal microbalance sensor assisted with ZnO nanosheets for nerve agent detection

Abstract

ZnO is known as a promising material for surface acoustic wave (SAW) sensor devices because of its piezoelectric property. Recently, quartz crystal microbalances (QCMs) have been promising as a sensor platform due to their high sensitivity and ease of measurement. In particular, the alignment of ZnO nanosheets (NSs) into ordered nanoarrays is expected to improve the device sensitivity and stability due to large specific surface area, which allows the captured significant quantities of gas molecules. In this study, we fabricated a quartz crystal microbalance sensor with ZnO NSs structures using polyvinylidene fluoride as a receptor for nerve agent detection. We synthesized two-dimensional NSs by chemical bath deposition (CBD) via the potassium hydroxide etching method. CBD is an excellent method that can easily form uniform structures at low cost. We fabricated ZnO NSs modified with polyvinylidene fluoride and used it for detection of dimethyl methylphosphonate (DMMP) gas. The NSs structure indicated that, when a similar functional group material is coated, the specific surface area increased compared to the nanorods (NRs) structure. As a result, the sensitivity of the quartz crystal microbalance sensor to DMMP gas was improved.