This paper demonstrates the potential of a new photoanode material Zn-doped SnO 2 nanoflower for efficient dyesensitized solar cells. The nanoflower structure is synthesized using a hydrothermal method and is shown to have electron mobility higher than that of the conventional titania photoanode. The overall power conversion efficiency for the Zn-doped SnO 2 nanoflower dye-sensitized solar cell reaches 3.00% with a V oc of 0.78 V and increases to 6.78% after TiCl 4 treatment. Electrochemical impedance spectroscopy measurement showed that the Zn-doped SnO 2 nanoflower film has a large intrinsic electron mobility that favors the fast charge transport. This work shows that Zn-doped SnO 2 nanoflower material is a most interesting material and has good potential for application in solar cells.

Semiconductor ZnO nanotube arrays have been synthesized by direct electrochemical deposition from aqueous solutions into porous anodic alumina membranes. Scanning electron microscopy and transmission electron microscopy indicate that large-area and highly ordered nanotube arrays have been obtained. X-ray diffraction and selected-area electron diffraction analyses show that the as-synthesized nanotubes are polycrystalline. Photoluminescence spectra of the ZnO nanotube arrays show that a violet peak and a blue peak are centered at 414 and 464 nm, respectively. The ordered polycrystalline ZnO nanotube arrays may find potential applications in optoelectronic and sensor devices. The growth mechanism and the electrochemical deposition process are discussed.

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Uniform CdS/ZnO core/shell nanowires are hydrothermally synthesized using a two‐step process and assembled into a photodetector and a NO2 optoelectronic sensor for the first time. The corresponding photodetector exhibits a fast, reversible, and stable optoelectronic response with a rise time of ∼26 ms, a decay time of ∼2.1 ms and a stability of over 5 months. The remarkable photosensitivity and fast photoresponse are attributed to the formation of a heterojunction structure between CdS and ZnO, which greatly inhibits the recombination of photoinduced electrons and holes. The CdS/ZnO core/shell nanowires also show an excellent visible‐light‐activated gas sensing performance towards ppb‐level NO2 at room temperature. The responses range from 6.7% to 337% toward NO2 concentrations of 5 to 1000 ppb. It is found that the sensitivity of the NO2 sensor is dependent on the illuminated light intensity with a maximum value at 0.68 mW/cm2. The sensing mechanisms of the CdS/ZnO nanowires under visible‐light irradiation and the influence of light intensity are also discussed. The present CdS/ZnO core/shell nanowire not only benefits the fabrication of efficient photodetectors, but also makes the instant, optically controlled sensing of ppb‐level NO2 gas possible.

The growth mechanism of the electrodeposited single crystalline nanowires is generally considered to follow a three-dimensional to two-dimensional (2D) transition mode, and as for the 2D growth, it is ordinarily considered as a plane growth mode (layer-by-layer growth mechanism). We report in this Letter the growth of Bi/BiSb superlattice nanowires by adopting a charge-controlled pulse electrodeposition technique, and to our best knowledge, different growth modes of the nanowires, the 2D plane growth mode, the tilted plane growth mode, and the curved plane growth mode, were first observed. These growth modes were gathered and analyzed from the perspectives of crystal growth as well as kinetics and thermodynamics. It is shown that the superlattice nanowires are good structures for studying the growth mechanism of electrodeposited nanowires. This work will deeply benefit the understanding of the growth process of the electrodeposited nanowires and provide important experiment data to crystal growth theory.

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.

The detection of ultralow or nonvolatile target analytes remains a significant challenge for artificial olfactory systems even after decades of development, which severely limits their widespread application. To overcome this challenge, an artificial olfactory system based on a colorimetric hydrogel array is constructed for the first time as a universal representative. As an effective extension of conventional artificial olfactory systems that integrates the merits of its predecessors, the proposed system accurately mimics olfactory mucosa and specific odorant binding proteins using hydrogels endowed with specific colorimetric reagents for the detection of hypochlorite, chlorate, perchlorate, urea, and nitrate. Therefore, the proposed system is capable of detecting and discriminating between these five airborne improvised explosive microparticulates with a detection limit as low as 39.4 pg. Additionally, the system demonstrates good reusability over ten cycles, rapid response time of ≈0.2 s, and excellent discrimination properties, despite significant variation. This proof‐of‐concept study on colorimetric artificial olfactory systems yields a novel strategy for the direct and discriminative detection of nonvolatile airborne microparticulates.

A rapid, ultrasensitive artificial olfactory system based on an individual optoelectronic Schottky junction is demonstrated for the discriminative detection of explosive vapors, including military explosives and improvised explosives.