Search

Long-lasting and highly efficient antibacterial fabrics play a key role in public health occurrences caused by bacterial and viral infections. However, the production of antibacterial fabrics with a large size, highly efficient, and broad-spectrum antibacterial performance remains a great challenge due to the complex processes. Herein, we demonstrate sizable and highly efficient antibacterial fabrics through hydrogen bonding interaction and electrostatic interaction between surface groups of ZnO nanoparticles and fabric fibers. The production process can be carried out at room temperature and achieve a production rate of 300 × 1 m 2 within 1 h. Under both visible light and dark conditions, the bactericidal rate against Gram-positive ( S. aureus ), Gram-negative ( E. coli ), and multidrug-resistant (MRSA) bacteria can reach an impressive 99.99%. Furthermore, the fabricated ZnO nanoparticle-decorated antibacterial fabrics (ZnO@fabric) show high stability and long-lasting antibacterial performance, making them easy to develop into variable antibacterial blocks for protection suits.

The microbial spoilage of soybeans during soaking process severely deteriorates the quality of soybean products and threatens human health. Herein, water-soluble aminated zinc oxide nanoparticles (ZnO NPs) were developed to effectively control the microbial spoilage in soybeans during soaking. ZnO NPs achieved significant inactivation of three dominant spoilage bacteria (bacillus cereus, bacillus megaterium and enterococcus faecium) isolated from the deteriorated soybeans, which could adhere to the bacterial surface and damage the cell wall/membrane, but also generate large amounts of reactive oxygen species (ROS). Compared to two commercial ZnO, water-soluble ZnO exhibited superior antibacterial properties due to producing more ROS and bacteria-adhered ability. After ZnO NPs treatment, the content of the residual Zn (51.1 mg/kg) in soybeans was the safety standards of Zn element in soybeans products for human). Therefore, the water-soluble ZnO NPs showed great potentials as efficient and safe antimicrobial agents for soybeans preservation during soaking process., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

An europium functionalized ZnO quantum dots (QDs) ratiometric fluorescent nanoprobe is designed to establish a real time, on-site visual, and highly sensitive probe method for tetracycline (TC). The yellow-emitting ZnO QDs serves as the internal reference, while the Eu 3+ chelated on the surface of ZnO QDs is used as the signal reporting unit. This nanoprobe exhibits rapid response, excellent selectivity, and high sensitivity with a detection limit of 4 nM in detecting the levels of TC. In addition, fluorescence of the nanoprobe can change from yellow to red as the concentration of TC increases. Thus, naked eye detection of TC was realized using the test paper processed by nanoprobe, followed by RGB value analysis function on the mobile phone APP., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

We propose a kind of hybrid plasmonic Fabry-Perot (F-P) microcavity consisting of ZnO microwires with quadrate cross-section and planar multilayer metal-insulator-metal (MIM) homostructures with a nanoscale SiO₂ gap in between. MIM homostructures can be used to create a micro-resonator that simultaneously provides feedback for laser action and supports the coupling between the plasmonic waveguide modes and microwire modes across the gap. The hybridization of ZnO microwire modes and surface plasmons across the gap forms hybrid plasmonic F-P microcavity modes, which are highly confined to the low-loss SiO₂ gap region. By comparing with bare ZnO microwires, an enhancement in photoluminescence (PL) intensity of two orders of magnitude is realized experimentally due to the coupling between plasmonic MIM homostructures and ZnO microwires. The controllability and miniaturization emission properties of this type of microcavity are potentially important for designing laser cavity applications and information transmission.

To increase the responsivity is one of the vital issues for a photodetector. By employing ZnO as a representative material of ultraviolet photodetectors and Si as a representative material of visible photodetectors, an impact ionization process, in which additional carriers can be generated in an insulating layer at a relatively large electric field, has been employed to increase the responsivity of a semiconductor photodetector. It is found that the responsivity of the photodetectors can be enhanced by tens of times via this impact ionization process. The results reported in this paper provide a general route to enhance the responsivity of a photodetector, thus may represent a step towards high-performance photodetectors.

The invention of paper as a writing material greatly promoted the development and spread of civilization. However, its large-scale production and utilization has also brought about huge environmental and sustainability concerns. It is desirable to develop a strategy for paper that can be used in a reprintable manner. In this work, ZnO-based photocatalytic reactions have been applied in preparing a reprintable paper that works through the color conversion of methylene blue. The resulting paper does not require additional ink and can be repeatedly printed for 20 cycles keeping over 77% of the initial contrast ratio. The reprintable raw materials can be retained for more than 2 months in the ambient environment. A fast color-switching time of about 10 s has been achieved, which can be attributed to the high photo-induced electron transfer rate from the ZnO to the dyes. [ABSTRACT FROM AUTHOR]

Well-aligned ZnO nanowire arrays have been prepared, and p-MgZnO has been deposited onto the nanowires to form core–shell heterostructures. Transmission electron microscopy confirms the formation of n-ZnO/p-MgZnO core–shell nanowire heterostructures. Under injection of a continuous current, random lasing with a threshold current of around 15 mA has been observed from the heterostructures. The low threshold may be due to the relatively high crystalline quality of the ZnO nanowires as well as the carrier confinement in the heterostructures. [ABSTRACT FROM AUTHOR]

Au/MgO/ZnO/MgO/Au structures have been designed and constructed in this study. Under a bias voltage, a carrier avalanche multiplication will occur via an impact ionization process in the MgO layer. The generated holes will be drifted into the ZnO layer, and recombine radiatively with the electrons in the ZnO layer. Thus obvious emissions at around 387 nm coming from the near-band-edge emission of ZnO will be observed. The reported results demonstrate the ultraviolet (UV) emission realized via a carrier multiplication process, and so may provide an alternative route to efficient UV emissions by bypassing the challenging p-type doping issue of ZnO. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, n-ZnO/i-ZnO/MgO/p-GaN structured light-emitting devices have been designed and constructed, and Ag nanoparticles whose surface plasmon resonance absorption spectrum overlaps well with the electroluminescence (EL) of the structure were employed to improve the emission characteristics of the devices. A noticeable enhancement in the EL intensity has been obtained, and the enhancement can be attributed to the resonant coupling between the electron–hole pairs in the structure and the surface plasmons of the Ag nanoparticles. [Copyright &y& Elsevier]

Abstract: Zinc oxide (ZnO) p–i–n structured ultraviolet (UV) photodetector has been constructed in this paper. The photodetector exhibits an obvious response to ultraviolet light at 0V bias, which is a typical character of p–i–n structured photodetectors. The maximum responsivity of the photodetector, which is located at around 390nm, is about 0.45mAW−1 at 0V bias, and the responsivity increases with increasing reverse bias voltage applied. The response decay time of the p–i–n structured photodetector is about 260ns. This is the first report on ZnO p–i–n homojunction structured photodetectors to the best of our knowledge. Considering that p–i–n structure is the most promising configuration for high performance photodetectors, the results reported in this paper may provide a clue for high-performance ZnO based UV photodetectors. [Copyright &y& Elsevier]

Abstract: A phosphor-converted light-emitting diode (LED) was realized by coating BaMg2Al16O27:Eu2+·Mn2+ and (SrCaPO4)·B2O3:Eu2+·Na+ phosphors onto an n-ZnO/i-MgO/p-GaN heterojunction diode. Two emission bands at around 450 and 520nm were observed in the phosphor-converted LED under the injection of continuous current. By analyzing the optical properties of the heterojunction diode and phosphors, it is concluded that the emission at 450nm comes from (SrCaPO4)·B2O3:Eu2+·Na+ phosphor, while the one at 520nm comes from BaMg2Al16O27:Eu2+·Mn2+ phosphor under the excitation of the light emitted from the n-ZnO/i-MgO/p-GaN heterojunction diode. The results reported in this paper may provide a route to ZnO-based phosphor-converted LEDs for future lighting or displaying purpose. [ABSTRACT FROM AUTHOR]

Plasmonic lasers, which make use of the strong confinement of surface plasmon polaritons (SPPs), are key components to realize ultracompact coherent light sources at deep subwavelength scale. Currently, large metal and radiation losses of their metallic cavities limit electrically driven plasmonic lasers operation mainly at cryogenic temperature, where sufficient gain can be obtained. It is a crucial challenge to accomplish high performance electrically driven plasmonic lasers operated at room temperature. Benefiting from the large exciton binding energy and large oscillator strength of zinc oxide (ZnO) gain media, an optically pumped ultraviolet (UV) plasmonic laser is demonstrated from a hybrid metal–insulator–semiconductor structure, in which a magnesium oxide (MgO) gap layer plays a critical role in reducing the metallic loss. Further optimizing the thickness of the MgO gap layer and ZnO active layer, room temperature electrically driven UV plasmonic lasers with a threshold of 70.2 A cm‐2 are realized for the first time under the injection of electrical carriers through the metallic electrode of the hybrid structure. Localizing light in subwavelength dimension, this novel type of UV plasmonic nanolasers may find various applications in photolithography, sensing, integrated microfluidic systems for surface sterilizations and nanoscale treatment processes. [ABSTRACT FROM AUTHOR]

ZnO as an eco-friendly material shows bright luminescence under UV illumination when it is tailored into nanoscale size, which makes it a promising luminescent nanomaterial. However, the poor stability of ZnO hinders its applications drastically. In this work, multi-ZnO-cores@uni-BaSO 4 -shell (mZnO@uBaSO 4 ) nanocomposite has been prepared through a non-equilibrium sorption process employing ZnO QDs as the “seeds” and BaSO 4 as the “valve”. The mZnO@uBaSO 4 nanocomposite shows improved photo-, thermal- and ambient-stability compare with bare ZnO QDs. The fluorescence efficiency of the mZnO@uBaSO 4 nanocomposite decreases little even after 60 h of UV irradiation compare with ZnO QDs. The mZnO@uBaSO 4 nanocomposite shows bright luminescence with little decrease even the ambient temperature up to 160 °C and the nanocomposite shows strong resistance to harsh environment. By coating the mZnO@uBaSO 4 nanocomposite and commercial phosphors onto UV-chip, light-emitting diode (LED) with correlated color temperature, Commission Internationale de L'Eclairage coordinate, color rendering index and luminous efficiency of 6109 K, (0.32, 0.33), 85 and 47.33 lm/W have been realized, and this will make a great step towards eco-friendly UV-pumped LEDs. [ABSTRACT FROM AUTHOR]

Although nitrogen-doped zinc oxide has been fabricated as a light-emitting diode, the origin of its p-type conductivity remains mysterious. Here, by analyzing the surface reaction pathway of N in ZnO with first-principles density functional theory calculations, we demonstrate that the origin of p-type conductivity of N-doped ZnO can originate from the defect complexes of NZn-VO and NO-VZn. Favored by the Zn-polar growth, the shallow acceptor of N0-VZn actually evolves from the double-donor state of NZn-VO- While NO-VZn is metastable, the p-doping mechanism of NZn-VO → NO-VZn in ZnO will be free from the spontaneous compensation from the intrinsic donors. The results may offer clearer strategies for doping ZnO p-type more efficiently with N. [ABSTRACT FROM AUTHOR]

Chemiluminescence (CL) induced by peroxalate fuel and hydrogen peroxide has been widely applied in chemical detection and bioimaging. Nevertheless, the chemiluminescent emitters in the CL are focused on organic small-molecular dyes, most of which encounter serious obstacles in practical application due to their potential biotoxicity and low photostability. Here, bright blue CL is observed when biocompatible zinc oxide nanoparticles (ZnO NPs) with yellow photoluminescence (PL) are added into peroxalate and hydrogen peroxide solution, which is originated from the interaction between the zinc interstitial of ZnO NPs and the energy-rich intermediate produced in the CL process. With the modification of silane coupler, the CL quantum yield of ZnO NPs presents two orders of magnitude increase from 6.2× 10−6 to record 3.7 × 10−4 E⋅mol−1 for inorganic NPs owing to the protective effect from silicon oxide shell layer. By virtual of excellent CL ability, ZnO NPs have been firstly used as CL probes in bioimaging, which opens the way to a new design freedom for biosensor or bioimaging in the future. • Chemiluminiscence quantum yield of ZnO NPs with silane shell presents two orders of magnitude increase. • ZnO NPs with silane shell show the highest chemiluminiscence quantum yield value for the inorganic NPs. • ZnO NPs have been served as CL probes in bioimaging for the first time. • The chemiluminiscence of ZnO NPs has been clarified through the chemically initiated electron exchange. • The excitation electron of ZnO can transit from the zinc interstitial atom energy level to valence band and emit blue light. [ABSTRACT FROM AUTHOR]