Ultrasound assisted low-concentration VOC sensing

This paper reports a new method to ultrasonically enhance the metal oxide gas sensor's sensitivity to low-concentration volatile organic compound (VOC) gases. The system uses an ultrasonic transducer to produce an ultrasonic standing wave field above the sensing layer. Ultrasonic field near the sensing layer drives the VOC molecules to the sensing layer, and promotes the oxidation-reduction reaction between the VOC molecules and reactive oxygen species on the surface of the sensing layer, which increases the resistance change of the sensing resistor. The experiments show that this method can greatly enhance the gas sensor's sensitivity to low-concentration VOC gases. With the assistance of ultrasound, the sensitivity can be increased up to 30 times.