Functionalized semiconducting carbon nanotube arrays for gas phase explosives detection

•Experiments on explosive sensing are complicated by safety concerns and handling constraints.•Functionalized semiconducting CNT arrays can add selectivity to chemiresistive sensors.•Selective discrimination among background gases and various explosive types can be achieved. [Display omitted] Single molecule detection systems are of considerable practical interest in sensing applications, such as disease detection or transient kinetics monitoring, where ultra-sensitive measurements are needed. Trace detection of explosives is an application where the mere presence, not necessarily the concentration, of an analyte is cause for concern. As in many other sensing applications, carbon nanotube (CNT) based devices are under study for single molecule detection systems, motivated by interest in reducing the size, cost, and power requirements of current sensing systems. Although CNT sensors have been shown to be highly sensitive to some analytes, a longstanding obstacle to the development of ultra-sensitve CNT sensors has been their lack of selectivity. Ab initio modeling of functionalized semiconducting CNT arrays suggests that they offer sensitive and selective explosives detection, capable of distinguishing explosives from common background gases, distinguishing nitroaromatic from nitramine explosives, and discriminating among distinct nitramine explosives with very similar structures.