Transition‐Metal‐Doped p‐Type ZnO Nanoparticle‐Based Sensory Array for Instant Discrimination of Explosive Vapors

Abstract

The development of portable, real-time, and cheap platforms to monitor ultratrace levels of explosives is of great urgence and importance due to the threat of terrorism attacks and the need for homeland security. However, most of the previous chemiresistor sensors for explosive detection are suffering from limited responses and long response time. Here, a transition-metal-doping method is presented to remarkably promote the quantity of the surface defect states and to significantly reduce the charge transfer distance by creating a local charge reservoir layer. Thus, the sensor response is greatly enhanced and the response time is remarkably shortened. The resulting sensory array can not only detect military explosives, such as, TNT, DNT, PNT, PA, and RDX with high response, but also can fully distinguish some of the improvised explosive vapors, such as AN and urea, due to the huge response reaching to 100%. Furthermore, this sensory array can discriminate ppb-level TNT and ppt-level RDX from structurally similar and high-concentration interfering aromatic gases in less than 12 s. Through comparison with the previously reported chemiresistor or Schottky sensors for explosive detection, the present transition-metal-doping method resulting ZnO sensor stands out and undoubtedly challenges the best.

Investigation of Gas-Sensitive Properties of Thin-Film Thermovoltaic Sensor Elements Based on Zinc Oxide

“…ZnO-based composites doped with transition metals are increasingly being studied as promising nanomaterials [8]. For example, the authors of [9] considered that Fе 3+ ions replace Zn 2+ ions, forcing them into the internodes.…”

Semiconducting Metal Oxides Nanocomposites for Enhanced Detection of Explosive Vapors

“…Promising results with regards to explosives detection are described in ref. [9] where ZnO nanopowders doped with Fe, Co, and Ni were prepared. In this work, 50 mL of a solution of Zn(NO 3 ) 2 0.1 M in ethanol and 0.005 M of iron nitrate nonahidrate, cobalt nitrate tetrahydrate, or nickel acetate tetrahydrate were mixed with 50 mL of a 0.15 M solution in ethanol of LiOH.H 2 O.…”

“…Ammonium nitrate-fuel oil (ANFO) and urea nitrate (UNi) are two main kinds of IEs [9]. UNi can be transformed into nitro-urea (NH 2 CONH-NO 2 ), a more powerful explosive, through a dehydration process [9]. The detection of IEs (ANFO, UNi, and nitro-urea) can be achieved by the indirect detection of their raw materials, for example, AN and urea [9].…”

“…Apart from nitro-based explosives, usually indicated as military explosives, homemade explosives, also referred to as improvised explosives (IEs), are produced widely by many terrorist groups throughout the world. Ammonium nitrate-fuel oil (ANFO) and urea nitrate (UNi) are two main kinds of IEs [9]. UNi can be transformed into nitro-urea (NH2CONH-NO2), a more powerful explosive, through a dehydration process [9].…”

“…Ammonium nitrate-fuel oil (ANFO) and urea nitrate (UNi) are two main kinds of IEs [9]. UNi can be transformed into nitro-urea (NH 2 CONH-NO 2 ), a more powerful explosive, through a dehydration process [9].…”