Highly Sensitive, Selective, Stable, and Flexible NO₂ Sensor Based on GaSe

Abstract

Air pollution is a global problem, which poses serious environmental concerns and health risks. In light of this, a key aspect of the challenge of managing air pollution is effective monitoring, which requires reliable high‐sensitivity sensors with strong selectivity and long‐term stability. Layered materials represent an emergent class of materials with extraordinary electronic properties and physicochemical properties, and, therefore, are a highly attractive prospect for this field. Here, such a sensor for NO2 based on GaSe is presented. An ultrahigh sensitivity of 0.5 part per billion (p.p.b.) is achieved at room temperature, and the NO2 selectivity ratios with respect to other likely interfering environmental gases are larger than 100. Moreover, no great degradation is observed after 10 days of air exposure. As a practical demonstration, the GaSe‐based sensors are also used to detect vehicle exhaust emission, and wearable GaSe‐based NO2 sensors are presented and tested. Based on the results obtained in this work, it is believed that GaSe‐based sensors can be used for the detection of NO2 in real‐world applications.

High-Performance Atomically-Thin Room-Temperature NO2 Sensor

“…Two-dimensional (2D) materials − offer an extremely high surface-to-volume ratio, a layer-dependent electronic structure, and tunable active sites for redox reactions, making them attractive candidates for gas sensing applications. ,− While they have been widely used for gas sensing applications with an excellent sensitivity for toxic gases such as NO 2 , the reported ultrathin NO 2 sensors usually suffer from slow recovery kinetics at room temperature, inferior selectivity, and/or poor stability. For example, graphene and MoS 2 , have shown excellent sensitivities toward NO 2 , but they are not selective and suffer from slow recovery kinetics.…”

A Photovoltaic Self‐Powered Gas Sensor Based on All‐Dry Transferred MoS2/GaSe Heterojunction for ppb‐Level NO2 Sensing at Room Temperature

“…It is noteworthy that the LOD toward NO 2 of our devices is the lowest among the reported self‐powered gas sensors, which might be owing to the excellent intrinsic gas sensing properties of MoS 2 and GaSe. [ 16 , 47 ]…”

“…In 2020, Wu et al reported a GaSe-based NO 2 gas sensor at room temperature with the LOD of 0.5 ppb. [16] Wang et al fabricated a self-powered photodetector based on GaSe/WS 2 heterojunction which showed high photoresponsivity and quite short response time. [17] To the best of our knowledge, the heterojunction combining GaSe with other 2D materials as gas sensor has not been reported so far.…”

Recent progress on Schottky sensors based on two-dimensional transition metal dichalcogenides

“…A GaSe-based sensor with strong selectivity and long-term stability was fabricated to detect NO 2 . 118 The sensitivity of this sensor was 0.5 ppb at room temperature and its NO 2 selectivity ratio was 100 times that of other interfering environmental gases. In practical terms, GaSe-based sensors can detect vehicle exhaust emissions and act as wearable NO 2 sensors.…”