Elaborately designed intelligent responsive sensing materials for development of flexible gas sensors

Abstract

With the development of artificial intelligence and Internet of Things, flexible gas sensors have emerged as vital functional devices by integrating with smart wearable electronics, which exhibit irreplaceable advantages in medical diagnosis, aerospace, environmental remediation, robotics, and electronic skin. The elaborately designed sensing materials are critical to developing high-performance gas sensors in terms of sensitivity, selectivity, stability, and response/recovery dynamics. In addition, to achieve the reliable and consistent operation of the flexible sensing devices, it is essential to ensure an effective and stable integration between sensing materials and device substrates. Consequently, it is distinctly meaningful to comprehensively summarize the design principles and surface properties of gas-sensitive materials in flexible gas sensors. This review originates from the precise synthesis, regulation and structure optimization of sensing materials for flexible gas sensors, and the new concept of “chemical microenvironment” is proposed to elucidate the sensing mechanism from molecular-atomic level. Specifically, various carrier migration models (e.g., electron, proton, ion) and surface/interfacial interaction are highlighted. Finally, the emerging opportunities and challenges in flexible gas sensors are proposed and predicted, aiming to provide insight about the development of flexible gas sensors into the next-generation sensing applications and further satisfy the growing requirements of smart sensors for long-life, biocompatibility, and real-time communication capabilities.