Surface Acoustic Wave Sensors for the Detection of Hazardous Compounds in Indoor Air

Abstract : In this work, the authors show the capabilities of Surface Acoustic Wave (SAW) devices coupled with various absorbents to probe the properties of gas sensitive materials for the manufacturing of hazardous gas sensors. The great capabilities of cobalt corroles for the trapping of carbon monoxide (CO) were exploited to produce selective sensors. These corroles were deposited on SAW delay lines surfaces and then exposed to carbon monoxide (CO) in standard conditions. Concentrations of a few hundreds of ppb were measured emphasizing the interest of such sensors for the detection of CO. Another type of sensitive layers exhibiting specific porosity adapted to the trapping of formaldehyde (CH$_2$O) were deposited on similar delay lines. A detection threshold of 140 ppb was shown. These encouraging results pave the way for the development of a functionalized SAW sensors network for multi-gas detection in indoor air.