Surface acoustic wave gas Sensors: Recent developments and their role in sensing technology

• SAW gas sensors can detect ultra-low concentrations of gaseous compounds, benefiting environmental monitoring, industrial safety, and healthcare. • Recent progress in the incorporation of nanomaterials such as ZnO, graphene oxide, and metal–organic frameworks has been discussed. • The adoption of wireless technology has expanded the application of SAW sensors in remote and real-time monitoring. • SAW biosensors enable non-invasive diagnostics, playing a crucial role in medical and healthcare applications. Surface acoustic wave (SAW) sensors are widely used in sensing technology owing to their high sensitivity, stability and ability to detect various physical, chemical and biological properties. They operate by detecting changes in the velocity and amplitude of acoustic waves travelling along piezoelectric materials, which are influenced by environmental variations. This review focuses on the development of SAW sensors, particularly gas and biosensors. SAW gas sensors can detect gaseous compounds at very low concentrations, making them valuable for environmental monitoring, process safety and health applications. Recent advancements in nanomaterials, such as based on zinc oxide, graphene oxide and metal–organic frameworks, and in thin-film fabrication methods, have improved the sensitivity and selectivity of these sensors. The integration of wireless technology has further expanded the potential of SAW sensors for industrial and environmental monitoring. In biosensing, SAW sensors are critical for non-invasive diagnostics. Future trends include bio-diagnostic and micro-fluidic applications, which will enhance the usability and effectiveness of SAW sensors across various fields.