Humidity Sensor Based-on Quartz Crystal Microbalance of Sprayed Silver Nanoparticles Films

Abstract

Abstract The silver nanoparticles (Ag NPs) film was prepared in this work by the electrostatic spray deposition technique. The Ag NPs film properties were characterized by X-ray diffraction, UV-visible spectrophotometer, Raman spectroscopy, and scanning electron microscope. Then, the Ag NPs film was prepared on a 2 MHz crystal microbalance to fabricate the humidity sensor. The measurement systems are composed of a fabricated sensor, oscillator circuit, and frequency counter. The sensor performances were obtained in terms of the frequency shift of the device at various humidity levels. The conditions of saturated salt solutions following NIST standard were used as humidity values for measurement. It was found that the fabricated device exhibited approximately a frequency shift of 25 Hz in the humidity range of 11-93 %RH. Moreover, the device demonstrated low hysteresis at a value of about 1%RH with a humidity level of 43 %RH.