Integrated sensor based on acoustics-electricity-mechanics coupling effect for wireless passive gas detection

Integrated sensor combines multiple sensor functions into a single unit, which has the advantages of miniaturization and better application potential. However, limited by the sensing platforms of the sensor and the selectivity of the sensitive film, there are still challenges to realize multi-component gas detection in one unit. Herein, a principle integration method is proposed to achieve the multi-component gas detection based on the acoustics-electricity-mechanics coupling effect. The electrical and mechanical properties of the Bi₂S₃ nanobelts materials in different atmospheres indicate the possibility of realizing the principle integration. At the same time, the surface acoustic wave (SAW) sensor as a multivariable physical transducer can sense both electrical and mechanical properties. Upon exposure to 10 ppm NO₂, NH₃, and their mixtures, the integrated SAW gas sensor shows a 4.5 kHz positive frequency shift (acoustoelectric effect), an 11 kHz negative frequency shift (mechanics effects), and a reduced 4 kHz negative frequency shift (acoustics-electricity-mechanics coupling effect), respectively. Moreover, we realize wireless passive detection of NO₂ and NH₃ based on the SAW sensor. Our work provides valuable insights that can serve as a guide to the design and fabrication of single sensors offering multi-component gas detection via different gas sensing mechanisms.