Synthesis of mesoporous SnO2-SiO2 composites and their application as quartz crystal microbalance humidity sensor

Abstract In this paper, chemically derived mesoporous SnO 2 –SiO 2 composite was deposited on a transducer of quartz crystal microbalances (QCMs) to construct a humidity sensor for wide range humidity detection. The composite was synthesized through a facile one-pot sol–gel method and characterized by XRD, TEM, EDX, ICP and nitrogen adsorption–desorption test. The humidity sensing characteristics of the QCMs coated with SnO 2 –SiO 2 composites thin film were investigated by exposing the QCMs to various relative humidity (RH) environments at room temperature, including sensitivity and linearity, response and recovery, and humidity-hysteresis. The results exhibit that the sample with a atomic ratio of Sn/Si = 1:1 shows better humidity sensing properties than others within the range of 11–96.1% relative humidity (RH), and the sensor also displays rapid response and recovery about 14 s and 16 s, respectively. The nanocomposite also shows suitable sensitivity and low hysteresis, revealing its great potential in humidity sensors.