Strategies and challenges for improving the performance of two-dimensional materials-based gas sensors

ABSTRACTTwo-dimensional (2D) materials emerged in the last decade have been considered as an attractive class of gas sensing materials due to their large surface-to-volume ratio, high surface reaction activity and good gas adsorption performance provided by the atomically thickness and flat surface. The development of high-performance micro-nano gas sensors places higher demands on sensing materials, thus 2D materials must satisfy good sensing performance requirements such as excellent gas selectivity, reproducibility, long-term stability, and fast response/recovery time to achieve high sensitivity detection at low concentrations. Herein, we overview the recent literature on the sensor structure, sensing mechanisms and improved gas sensing performance of 2D materials-based gas sensors. In particular, we discuss how the sensing properties of 2D materials can be modulated through defect and doping engineering, modification with noble metal, constructing heterostructure, as well as external energy assistance, e.g. by light illumination. Besides reviewing the achievements of gas sensors based on 2D materials, we provide an outlook on their future developments. Understanding the relationship between structure and sensing mechanisms of 2D materials-based sensors provides vast opportunities for designing advanced gas sensors, making it promising for a wide range of practical applications.