Borophene gas sensor

High-performance gas sensing devices have been extensively studied in industrial production, clinical medicine and environmental monitoring. Among the materials used to fabricate gas sensors, two-dimensional (2D) materials are viewed as favorable candidate sensing materials because of their high surface-to-volume ratios, abundant surface activity, defect sites. However, gas sensors based on the previously reported 2D materials have some disadvantages such as poor air-stability and slow dynamic response. Recently, borophene, as a unique 2D material, has been theoretically predicted to have excellent gas sensing characteristic, especially for nitrogen dioxide (NO₂). However, the gas sensing property of borophene has not been still reported experimentally. Here, we report that a chemiresistive sensor device based on borophene shows high sensitivity, fast response, high selectivity, good flexibility and long-time stability. It is found that the sensor has a low experimental detection limit of around 200 ppb, a large detection range from 200 ppb to 100 ppm, and fast response time of 30 s and recovery time of 200 s at room temperature, which are remarkably superior to those of reported 2D materials. The underlying NO₂ sensing mechanism of borophene is revealed by first-principles calculations. In line with theoretical predication, it has also been confirmed experimentally that the borophene-based sensor has a unique selectivity to NO₂ compared with other common gases. Furthermore, the sensor also displays superior flexibility and stability under different bending angles. This study shows excellent electronic and sensing characteristic of borophene, which indicates that it has great potential application value in high-performance sensing and detection in the future.