Detection of Nitroaromatic Explosives in Air by Amino-Functionalized Carbon Nanotubes

Robust nanotube-based nanosensor designed for the detection of explosive molecules

The adequate determination and detection of explosive molecules is key to introducing improvements in areas related to safety, whose progress depends on an adequate and rapid determination of dangerous substances. To detect explosives down to the molecular level and accurately discriminate between different but somehow similar substances, it is necessary to design sensors that can differentiate them uniquely and efficiently. In this study, we present a new generation nanoscale sensor based on carbon nanotubes with an adapted nanopore shape that is capable of effectively discriminating between five types of explosive compounds (TATP, RDX, PENT, HMX and DNT). We show that the interaction of each compound with the walls of the nanotubes induces changes in transmission and current that allows clear differentiation of each type of molecule. Interestingly, the transport properties do not depend on the orientation of the molecules within the nanopore in most cases, making it a robust device with high reproducibility and stability. The results also show that these systems can lead to relatively high thermoelectric performances and, furthermore, the Seebeck coefficient can be used to discriminate between them.

Electrical properties and chemiresistive response to 2,4,6 trinitrotoluene vapours of large area arrays of Ge nanowires

We study the electrical and morphological properties of random arrays of Ge nanowires (NW) deposited on sapphire substrates. NW-based devices were fabricated with the aim of developing chemiresistive-type sensors for the detection of explosive vapours. We present the results obtained on pristine and annealed NWs and, focusing on the different phenomenology observed, we discuss the critical role played by NW-NW junctions on the electrical conduction and sensing performances. A mechanism is proposed to explain the high efficiency of the annealed arrays of NWs in detecting 2,4,6 trinitrotoluene vapours. This study shows the promising potential of Ge NW-based sensors in the field of civil security.