Ultrasensitive, Real-time and Discriminative Detection of Improvised Explosives by Chemiresistive Thin-film Sensory Array of Mn2+ Tailored Hierarchical ZnS

Abstract

A simple method combing Mn2+ doping with a hierarchical structure was developed for the improvement of thin-film sensors and efficient detection of the explosives relevant to improvised explosive devices (IEDs). ZnS hierarchical nanospheres (HNs) were prepared via a solution-based route and their sensing performances were manipulated by Mn2+ doping. The responses of the sensors based on ZnS HNs towards 8 explosives generally increase firstly and then decrease with the increase of the doped Mn2+ concentration, reaching the climate at 5% Mn2+. Furthermore, the sensory array based on ZnS HNs with different doping levels achieved the sensitive and discriminative detection of 6 analytes relevant to IEDs and 2 military explosives in less than 5 s at room temperature. Importantly, the superior sensing performances make ZnS HNs material interesting in the field of chemiresistive sensors, and this simple method could be a very promising strategy to put the sensors based on thin-films of one-dimensional (1D) nanostructures into practical IEDs detection.

Semiconductor surface spectroscopy using transverse acousto-electric effect: Role of surface charge in photo-processes at the ZnS/Si interface

“…This charge can be both of the biographical origin, and induced in the bulk by the surface states of the opposite sign. The latter, as it is well known, is associated with the oxygen centers of adsorption origin, the negative charge of which is related with the capture of electrons from the near-surface region of the material [30][31][32].…”

Rational Design of Semiconductor‐Based Chemiresistors and their Libraries for Next‐Generation Artificial Olfaction

“…[2] To date, numerous e-nose systems using sensor arrays have been explored to find new functionalities. [3][4][5][6] These systems demonstrate promising potential in a wide range of applications, including medical diagnosis, [7][8][9][10][11][12] environmental monitoring, [13,14] food quality assessment, [15,16] smart farming, [17,18] identifying harmful chemicals, [19][20][21][22][23][24] and discriminating among different incomplete but partial specificity toward different individual or complex airborne chemicals were proposed for odor identification via pattern recognition in the 1980s. These were called an "electronic nose" or "artificial olfaction."…”

Fast-Response Metal–Semiconductor–Metal Junction Ultraviolet Photodetector Based on ZnS:Mn Nanorod Networks via a Cost-Effective Method

“…Therefore, the adsorbed oxygen molecules can easily draw electrons from the ZnS:Mn NRs, which in turn contribute to increase of the charge-depletion layer depth and improve the photoconductivity. In addition, it has been observed that doped semiconductor nanocrystals exhibit a “self-purification effect, , implying that the Mn impurities at the optimal concentration tend to be repelled and move to the surface layer of NRs, contributing to increase the oxygen adsorption . The schematic illustration of the possible mechanisms is shown in Figure S7.…”

“…However, in the pure form, ZnS exhibits highly insulating behavior due to its low donor–accepter defect level and high crystal quality, and without doping, it is not suitable for device applications . The intentional incorporation of doped impurities is considered as a fundamental approach for tailoring the physical and chemical properties of a semiconductor material, leading to the design and fabrication of photodetector, electronic, optoelectronic, and spintronic devices of desired features and characteristics. − 1D fluorescent nanomaterials with large surface-to-volume ratios exhibit enhanced light sensitivity, photoluminescence (PL), and fast response due to quantum confinement effects, , which can be efficiently improved and tuned with impurity concentration levels. Intentional doping of transition metals can generate midgap states in the II–VI compound semiconductors, which are involved in the band gap tuning and photoionization transitions through radiative or nonradiative decay and can contribute to the improvement of the photoconduction process. − Particularly, Mn 2+ -doped ZnS nanomaterials are considered as important luminescent materials due to their ability to modify the energy band and generate luminescent centers of different energy levels, giving rise to various interesting properties and applications. , …”

“…However, in the pure form, ZnS exhibits highly insulating behavior due to its low donor−accepter defect level and high crystal quality, and without doping, it is not suitable for device applications. 7 The intentional incorporation of doped impurities is considered as a fundamental approach for tailoring the physical and chemical properties of a semiconductor material, 45 and fabrication of photodetector, electronic, optoelectronic, and spintronic devices of desired features and characteristics. 8−10 1D fluorescent nanomaterials with large surface-tovolume ratios exhibit enhanced light sensitivity, photoluminescence (PL), and fast response due to quantum confinement effects, 11,59 which can be efficiently improved and tuned with impurity concentration levels.…”