Highly stable and sensitive humidity sensors based on quartz crystal microbalance coated with hexagonal lamelliform monodisperse mesoporous silica SBA-15 thin film

A novel mesoporous silica SBA-15 with monodisperse hexagonal lamelliform was prepared, and deposited on the quartz crystal microbalances (QCMs) to construct highly stable and sensitive humidity sensors. The humidity sensing characteristics of the sensors were investigated by measuring the resonant frequency shift of QCMs due to the additional mass loading caused by adsorption of water. X-ray diffraction, nitrogen adsorption/desorption, transmission electron microscopy and field emission scanning electron microscopy were employed to characterize these sensing materials. The results showed that the sensors had high sensitivity, good stability, short response/recovery time, well reproducibility and narrow hysteresis. Herein, not only a novel and low-cost humidity sensor material was exploited, but also a new application area for mesoporous materials was opened up.