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  • Fabrication of High-Quality and Strain-Relaxed GeSn Microdisks by Integrating Selective Epitaxial Growth and Selective Wet Etching Methods
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-21
    Guangjian Zhu, Tao Liu, Zhenyang Zhong, Xinju Yang, Liming Wang, Zuimin Jiang

    Abstract GeSn is a promising material for the fabrication of on-chip photonic and nanoelectronic devices. Processing techniques dedicated to GeSn have thus been developed, including epitaxy, annealing, ion implantation, and etching. In this work, suspended, strain-relaxed, and high-quality GeSn microdisks are realized by a new approach without any etching to GeSn alloy. The GeSn alloy was grown on pre-patterned Ge (001) substrate by molecular beam epitaxy at low temperatures. The transmission electron microscopy and scanning electron microscopy were carried out to determine the microstructures of the GeSn samples. The microdisks with different diameters of Ge pedestals were fabricated by controlling the selective wet etching time, and micro-Raman results show that the microdisks with different dimensions of the remaining Ge pedestals have different extents of strain relaxation. The compressive strain of microdisks is almost completely relaxed under suitable conditions. The semiconductor processing technology presented in this work can be an alternative method to fabricate innovative GeSn and other materials based micro/nano-structures for a range of Si-compatible photonics, 3D-MOSFETs, and microelectromechanical device applications.

    更新日期:2020-01-22
  • Development of a General Fabrication Strategy for Carbonaceous Noble Metal Nanocomposites with Photothermal Property
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-21
    Hongmei Zhu, Xuchuan Jiang

    Abstract This study demonstrates a simple hydrothermal method while can be generalized for controllable synthesis of noble metallic carbonaceous nanostructures (e.g., Au@C, Ag@C) under mild conditions (180–200 °C), which also provides a unique approach for fabricating hollow carbonaceous structures by removal of cores (e.g., silver) via a redox etching process. The microstructure and composition of the as-achieved nanoparticles have been characterized using various microscopic and spectroscopic techniques. Cetyltrimethylammonium bromide (CTAB), serving as a surfactant in the reaction system, plays a key role in the formation of Ag@C, Au@C nanocables, and their corresponding hollow carbonaceous nanotubes in this work. The dynamic growth and formation mechanism of carbonaceous nanostructures was discussed in detail. And finally, laser-induced photothermal property of Au@C nanocomposites was examined. The results may be useful for designing and constructing carbonaceous metal(s) or metal oxide(s) nanostructures with potential applications in the areas of electrochemical catalysis, energy storage, adsorbents, and biomedicine. Graphic abstract This study demonstrate a facile hydrothermal synthesis of noble metal carbonaceous nanocomposites (e.g., Au@C) with simple procedures under mild conditions, which can be25expanded as a general method for preparing diverse carbonaceous core-shell nanoparticles. The Au@C carbonaceous nanostructures exhibit interesting UV-Vis properties dependent upon shell thickness.

    更新日期:2020-01-22
  • Direct Synthesis of Graphene Dendrites on SiO 2 /Si Substrates by Chemical Vapor Deposition
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-17
    Yingxian Li, Zhenhua Li, Qingbo Li, Meng Tian, Chunhui Li, Li Sun, Jihua Wang, Xian Zhao, Shicai Xu, Fapeng Yu

    The long-standing interest in graphene has recently brought graphene-derived materials including graphene hydrogel, graphene fiber and graphene paper into sharp focus. These graphene-derived materials show outstanding properties in mechanics and physics. In this paper, for the first time, we demonstrate the novel synthesis of graphene dendrites on SiO2/Si substrates by chemical vapor deposition. The tree-like graphene dendrites with well-controlled morphology can be directly grown on both the Si and the SiO2 surfaces of the substrates by using methane and hydrogen as precursors. The graphene dendrites on SiO2/Si substrates can be directly used in the fabrication of the electronic device. The conductivity and the Hall mobility of graphene dendrites are ~ 286 Scm−1 and ~ 574 cm2(Vs)−1, respectively. Young’s modulus of graphene dendrites is up to 2.26 GPa. The developed method avoids the need for a metal substrate and is scalable and compatible with the existing semiconductor technology, making graphene dendrites be very promising in nanoelectronic applications.

    更新日期:2020-01-17
  • Combined Use of Anisotropic Silver Nanoprisms with Different Aspect Ratios for Multi-Mode Plasmon-Exciton Coupling
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-16
    Naoto Takeshima, Kosuke Sugawa, Hironobu Tahara, Shota Jin, Masaki Noguchi, Yutaro Hayakawa, Yuhei Yamakawa, Joe Otsuki

    Abstract Absorption enhancement based on interaction between the localized surface plasmon (LSP) and molecular exciton is one of the most important phenomena for the development of high-performance solar devices. In this study, hybrids of plasmonic metal nanoparticles and dye molecules have been developed, which exhibit enhanced absorption at precisely tuned wavelengths in a visible region. The hybrids consist of a porphyrin derivative, which has four absorption peaks (Q-bands) in a range of 500–700 nm, and triangular silver nanoprisms (AgPRs), which are developed by us to exhibit precisely tuned LSP resonance wavelengths. Absorption enhancement over the whole Q-band range is induced by the combined use of three kinds of AgPRs of different aspect ratios. Furthermore, the quantitative evaluation of absorption enhancement based on the LSP-based fluorescence enhancement phenomenon has demonstrated that efficient absorption enhancement can be effected at multiple wavelengths.

    更新日期:2020-01-17
  • Biosynthesis and Antibacterial Activity of Silver Nanoparticles Using Yeast Extract as Reducing and Capping Agents
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-16
    Mengjun Shu, Fengjiao He, Zhaohui Li, Xingzhong Zhu, Yujie Ma, Zhihua Zhou, Zhi Yang, Feng Gao, Min Zeng

    Abstract Biosynthesis for the preparation of antimicrobial silver nanoparticles (Ag NPs) is a green method without the use of cytotoxic reducing and surfactant agents. Herein, shape-controlled and well-dispersed Ag NPs were biosynthesized using yeast extract as reducing and capping agents. The synthesized Ag NPs exhibited a uniform spherical shape and fine size, with an average size of 13.8 nm. The biomolecules of reductive amino acids, alpha-linolenic acid, and carbohydrates in yeast extract have a significant role in the formation of Ag NPs, which was proved by the Fourier transform infrared spectroscopy analysis. In addition, amino acids on the surface of Ag NPs carry net negative charges which maximize the electrostatic repulsion interactions in alkaline solution, providing favorable stability for more than a year without precipitation. The Ag NPs in combination treatment with ampicillin reversed the resistance in ampicillin-resistant E. coli cells. These monodispersed Ag NPs could be a promising alternative for the disinfection of multidrug-resistant bacterial strains, and they showed negligible cytotoxicity and good biocompatibility toward Cos-7 cells.

    更新日期:2020-01-16
  • Advances of Nano-Structured Extended-Release Local Anesthetics
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-16
    Yumiao He, Linan Qin, Yuguang Huang, Chao Ma

    Abstract Extended-release local anesthetics (LAs) have drawn increasing attention with their promising role in improving analgesia and reducing adverse events of LAs. Nano-structured carriers such as liposomes and polymersomes optimally meet the demands of/for extended-release, and have been utilized in drug delivery over decades and showed satisfactory results with extended-release. Based on mature technology of liposomes, EXPAREL, the first approved liposomal LA loaded with bupivacaine, has seen its success in an extended-release form. At the same time, polymersomes has advances over liposomes with complementary profiles, which inspires the emergence of hybrid carriers. This article summarized the recent research successes on nano-structured extended-release LAs, of which liposomal and polymeric are mainstream systems. Furthermore, with continual optimization, drug delivery systems carry properties beyond simple transportation, such as specificity and responsiveness. In the near future, we may achieve targeted delivery and controlled-release properties to satisfy various analgesic requirements.

    更新日期:2020-01-16
  • Effect of Joule Heating on Resistive Switching Characteristic in AlO x Cells Made by Thermal Oxidation Formation
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-15
    Xinxin Zhang, Ling Xu, Hui Zhang, Jian Liu, Dingwen Tan, Liangliang Chen, Zhongyuan Ma, Wei Li

    The AlOx-based resistive switching memory device is fabricated by an oxidation diffusion process that involves depositing an Al film on an ITO substrate and annealing at 400 °C in a vacuum. An AlOx interface layer with a thickness of ~ 20 nm is formed as a resistance switching layer. Bipolar and unipolar resistive switching (RS) behaviours are obtained when the compliance current is limited (≥ 1 mA). In the unipolar RS behaviour, the devices fail to perform set/reset cycles at a low temperature (40 K), which suggests that Joule heating is essential for the unipolar RS behaviour. In the bipolar RS behaviour, the abrupt reset transforms into a gradual reset with decreasing temperature, which suggests that Joule heating affects the rupture of the conductive filament. In addition, the conductive mechanisms in the high-resistance state and low-resistance state are revealed by the temperature dependence of the I-V curves. For the low-resistance state, the conduction mechanism is due to the electron hopping mechanism, with a hopping activation energy of 9.93 meV. For the high-resistance state, transport mechanism is dominated by the space-charge-limited conduction (SCLC) mechanism.

    更新日期:2020-01-15
  • New Immunosensing-Fluorescence Detection of Tumor Marker Cytokeratin-19 Fragment (CYFRA 21-1) Via Carbon Quantum Dots/Zinc Oxide Nanocomposite
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-15
    Nawal Ahmed Alarfaj, Maha Farouk El-Tohamy, Hesham Farouk Oraby

    The rapid detection of lung cancer in early stages using the antigen cytokeratin-19 fragment (CYFRA 21-1) as a tumor marker in human serum plays an important role in the survival of patients and taking a fast surgical reaction. This study aimed to employ the green synthesized carbon quantum dots conjugated zinc oxide nanocomposite as a highly sensitive fluorescence immunosensing solution for fast determination of CYFRA 21-1 antigen in human serum. The suggested method was conducted by applying a hydrothermal method to prepare carbon quantum dots using Citrus lemon pericarp. The formed carbon quantum dots were used in the reduction and stabilization of zinc acetate to synthesize carbon quantum dots-zinc oxide nanocomposite. To form a sandwich capping antibody-antigen-antibody immunosensing system, a CYFRA 21-1 antigen was trapped by immobilizing a non-conjugated monoclonal antibody BM 19.21 on the surface of carbon quantum dots-zinc oxide nanocomposite and another monoclonal antibody KS 19.1, which was coated on the microtiter well surface. This system has a tunable fluorescence feature recorded at excitation and emission of λex = 470 and λem = 520 nm, respectively. The suggested nanocomposite fluorescence immunosensing system displayed a linear relationship of 0.01–100 ng mL−1 with a limit of detection of 0.008 ng mL−1. The suggested immunosensing system based on carbon quantum dots-zinc oxide nanocomposite provides a promising approach for rapid diagnoses of lung cancer by detecting CYFRA 21-1 in human serum.

    更新日期:2020-01-15
  • Transparent PAN:TiO 2 and PAN-co-PMA:TiO 2 Nanofiber Composite Membranes with High Efficiency in Particulate Matter Pollutants Filtration
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-13
    Dongliang Ruan, Liming Qin, Rouxi Chen, Guojie Xu, Zhibo Su, Jianhua Cheng, Shilei Xie, Faliang Cheng, Frank Ko

    Abstract Particulate matter is one of the main pollutants, causing hazy days, and it has been serious concern for public health worldwide, particularly in China recently. Quality of outdoor atmosphere with a pollutant emission of PM2.5 is hard to be controlled; but the quality of indoor air could be achieved by using fibrous membrane-based air-filtering devices. Herein, we introduce nanofiber membranes for both indoor and outdoor air protection by electrospun synthesized polyacrylonitrile:TiO2 and developed polyacrylonitrile-co-polyacrylate:TiO2 composite nanofiber membranes. In this study, we design both polyacrylonitrile:TiO2 and polyacrylonitrile-co-polyacrylate:TiO2 nanofiber membranes with controlling the nanofiber diameter and membrane thickness and enable strong particulate matter adhesion to increase the absorptive performance and by synthesizing the specific microstructure of different layers of nanofiber membranes. Our study shows that the developed polyacrylonitrile-co-polyacrylate:TiO2 nanofiber membrane achieves highly effective (99.95% removal of PM2.5) under extreme hazy air-quality conditions (PM2.5 mass concentration 1 mg/m3). Moreover, the experimental simulation of the test in 1 cm3 air storehouse shows that the polyacrylonitrile-co-polyacrylate:TiO2 nanofiber membrane (1 g/m2) has the excellent PM 2.5 removal efficiency of 99.99% in 30 min.

    更新日期:2020-01-13
  • Large-Area and Patternable Nano-Dot Array from Electrolysis of ITO Film for Surface-Enhanced Raman Spectroscopy
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-13
    Han Lu, Gengxin Han, Jieping Cao, Mingliang Jin, Qilin Ma, Eser Metin Akinoglu, Xin Wang, Li Nian, Guofu Zhou, Lingling Shui

    Fabrication of large-area devices with patternable nanostructures is important for practical applications in optical or electrical devices. In this work, we describe an easy and environment-friendly method for preparing large-area nano-dot (ND) arrays via the electrolytic reaction of a metal oxide film. NDs with various size and morphology can be obtained by adjusting the applied voltage, electrolysis time, and the film thickness of the indium tin oxide (ITO) layer. High-density NDs with size of 50–60 nm can be obtained by electrolysis of a 25-nm-thick ITO film at 150 V for 1.5 min under a water droplet medium, which have been applied for surface-enhanced Raman spectroscopy (SERS) after depositing a thin layer of silver. The SERS substrate with optimized ND structure exhibits sensitive detection of Rhodamine 6G (R6G) with detection limit down to 5 × 10-12 M. The enhancement factors (EFs) of 1.12 × 106 and 6.79 × 105 have been achieved for characterization of 4-methylbenzenethiol (4-MBT) and R6G, respectively. With an additional photolithographic step, multiple areas of ND arrays can be created on one substrate, enabling simultaneous detection of various samples containing different molecules at once experiment. Such a method is quick, easy, patternable, and environment-friendly, being suitable for on-site quick and synchronous determination of various molecules for applications in point-of-care, environmental monitoring, and airport security fields.

    更新日期:2020-01-13
  • A plasmonic thermal sensing based portable device for lateral flow assay detection and quantification
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-13
    Zhuo Qu, Kan Wang, Gabriel Alfranca, Jesús M. de la Fuente, Daxiang Cui

    Point-of-care testing (POCT) is widely used for early diagnosis and monitoring of diseases. Lateral flow assay (LFA) is a successfully commercial tool for POCT. However, LFA often suffers from a lack of quantification and analytical sensitivity. To solve these drawbacks, we have previously developed a thermal LFA using plasmonic gold nanoparticles for thermal contrast into a portable device. Although this methodology significantly improves the analytical sensitivity compared with conventional visual detection, quantification problems are still remaining. In this study, we optimized the operating conditions for the device using conduction and radiation thermal sensing modes allowing the quantification of LFA. The limit of detection of the strips merely containing nanoparticles was decreased by 5-fold (conduction mode) and 12-fold (radiation mode) compared to traditional visual detection. The effect of the ambient temperature was studied for both methods of detection showing that the radiation mode was more affected by the ambient temperature than the conduction mode. To validate the thermal sensing method, human chorionic gonadotropin (HCG) biomarker was quantified using our LFA strips, obtaining a detection limit of 2.8 mIU/mL when using the radiation method of detection.

    更新日期:2020-01-13
  • Research Progress in Rare Earth-Doped Perovskite Manganite Oxide Nanostructures
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-13
    Weiren Xia, Zhipeng Pei, Kai Leng, Xinhua Zhu

    Perovskite manganites exhibit a broad range of structural, electronic, and magnetic properties, which are widely investigated since the discovery of the colossal magnetoresistance effect in 1994. As compared to the parent perovskite manganite oxides, rare earth-doped perovskite manganite oxides with a chemical composition of LnxA1-xMnO3 (where Ln represents rare earth metal elements such as La, Pr, Nd, A is divalent alkaline earth metal elements such as Ca, Sr, Ba) exhibit much diverse electrical properties due to that the rare earth doping leads to a change of valence states of manganese which plays a core role in the transport properties. There is not only the technological importance but also the need to understand the fundamental mechanisms behind the unusual magnetic and transport properties that attract enormous attention. Nowadays, with the rapid development of electronic devices toward integration and miniaturization, the feature sizes of the microelectronic devices based on rare earth-doped perovskite manganite are down-scaled into nanoscale dimensions. At nanoscale, various finite size effects in rare earth-doped perovskite manganite oxide nanostructures will lead to more interesting novel properties of this system. In recent years, much progress has been achieved on the rare earth-doped perovskite manganite oxide nanostructures after considerable experimental and theoretical efforts. This paper gives an overview of the state of art in the studies on the fabrication, structural characterization, physical properties, and functional applications of rare earth-doped perovskite manganite oxide nanostructures. Our review first starts with the short introduction of the research histories and the remarkable discoveries in the rare earth-doped perovskite manganites. In the second part, different methods for fabricating rare earth-doped perovskite manganite oxide nanostructures are summarized. Next, structural characterization and multifunctional properties of the rare earth-doped perovskite manganite oxide nanostructures are in-depth reviewed. In the following, potential applications of rare earth-doped perovskite manganite oxide nanostructures in the fields of magnetic memory devices and magnetic sensors, spintronic devices, solid oxide fuel cells, magnetic refrigeration, biomedicine, and catalysts are highlighted. Finally, this review concludes with some perspectives and challenges for the future researches of rare earth-doped perovskite manganite oxide nanostructures.

    更新日期:2020-01-13
  • Highly Efficient Synthesis of Carbon-Based Molybdenum Phosphide Nanoparticles for Electrocatalytic Hydrogen Evolution
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-09
    Yang Li, Lun Cai, Qilin Huang, Jun Liu, Ranran Tang, Wenhan Zhou

    Abstract Molybdenum phosphide in transition metal phosphides members are considered as an attractive electrocatalyst for hydrogen evolution reaction (HER). However, its unsatisfactory stability and conductivity in an alkaline environment has dragged on its development. Here, we successfully introduced N, C co-doped MoP (MoP-NC) nanoparticles by a simple and efficient two-step synthesis method using urea as a carbon source into the molybdenum phosphide system. The cheapness of urea and the excellent carbon to nitrogen ratio remove the obstacles ahead of the development of MoP-NC composites. The obtained composites have excellent HER electrocatalytic activity and stability in 1-M potassium hydroxide (KOH) solution, which requires only an overpotential of 131 mV to achieve a current density of 10 mA cm−2 and exhibits negligible performance degradation after 1000 CV cycles.

    更新日期:2020-01-09
  • An Anisotropic Microstructure Evolution in a Solid Oxide Fuel Cell Anode
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-03
    Grzegorz Brus, Hiroshi Iwai, Janusz S. Szmyd

    The presented research shows that the long-term operation of a solid oxide fuel cell can lead to substantial anisotropic changes in anode material. The morphology of microstructure in the investigated stack was observed before and after the aging test using electron nanotomography. The microstructural parameters were estimated based on the obtained digital representation of the anode microstructure. Anisotropy was discovered in two of the three phases that constitute the anode, namely nickel and pores. The third component of the anode, which is yttrium-stabilized zirconia, remains isotropic. The changes appear at the microscale and significantly affect the transport phenomena of electrons and gasses. The obtained results indicate that the reference anode material that represents the microstructure before the aging test has isotropic properties which evolve toward strong anisotropy after 3800 h of constant operation. The presented findings are crucial for a credible numerical simulation of solid oxide fuel cells. They indicate that all homogeneous models must adequately account for the microstructure parameters that define the anisotropy of transport phenomena, especially if microstructural data is taken from a post-operational anode.

    更新日期:2020-01-04
  • ReS 2 Charge Trapping Synaptic Device for Face Recognition Application
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-03
    Ze-Hui Fan, Min Zhang, Lu-Rong Gan, Lin Chen, Hao Zhu, Qing-Qing Sun, David Wei Zhang

    Synaptic devices are necessary to meet the growing demand for the smarter and more efficient system. In this work, the anisotropic rhenium disulfide (ReS2) is used as a channel material to construct a synaptic device and successfully emulate the long-term potentiation/depression behavior. To demonstrate that our device can be used in a large-scale neural network system, 165 pictures from Yale Face database are selected for evaluation, of which 120 pictures are used for artificial neural network (ANN) training, and the remaining 45 pictures are used for ANN testing. A three-layer ANN containing more than 105 weights is proposed for the face recognition task. Also 120 continuous modulated conductance states are selected to replace weights in our well-trained ANN. The results show that an excellent recognition rate of 100% is achieved with only 120 conductance states, which proves a high potential of our device in the artificial neural network field.

    更新日期:2020-01-04
  • 3A-Amino-3A-Deoxy-(2AS, 3AS)-β-Cyclodextrin Hydrate/Tin Disulfide Modified Screen-Printed Carbon Electrode for the Electrochemical Detection of Polychlorinated Biphenyls
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-03
    Xinke Liu, Rajalakshmi Sakthivel, Chia-Yin Cheng, Jiangliu Luo, Lijun Song, Jianhua Wu, Wei He, Usman Younis, Ren-Jei Chung

    Abstract Polychlorinated biphenyls (PCBs) are persistent organic pollutants that are widely distributed in the environment. It is noteworthy that the PCBs are endocrine-disrupting substances, and their toxicity induces cancer and damage to the mammalian reproductive system, immune system, stomach, skin, liver, etc. This work aimed to synthesize 3A-amino-3A-deoxy-(2AS, 3AS)-β-cyclodextrin hydrate/tin disulfide composite material and to study its material properties, electrochemical properties, and application to PCB detection. The nanostructured tin disulfide (SnS2) synthesized by hydrothermal technique and 3A-amino-3A-deoxy-(2AS, 3AS)-β-cyclodextrin hydrate were sequentially modified onto the disposable screen-printed carbon electrode (SPCE) via titration using a micropipette. The 3A-amino-3A-deoxy-(2AS, 3AS)-β-cyclodextrin hydrate (β-CD) improved the selectivity of the modified electrode. The fabricated β-CD/SnS2/SPCE was employed to determine the presence of PCBs by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The detection range was 0.625–80 μM, with a limit detection of approximately 5 μM. The electrodes were as stable as 88% after 7 days’ storage. The results showed that the β-CD successfully encapsulated PCBs to achieve an electrochemical sensor that reduced the time and increased the convenience of PCBs detection.

    更新日期:2020-01-04
  • Dual-Mode On-to-Off Modulation of Plasmon-Induced Transparency and Coupling Effect in Patterned Graphene-Based Terahertz Metasurface
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2020-01-02
    Zhimin Liu, Enduo Gao, Zhenbin Zhang, Hongjian Li, Hui Xu, Xiao Zhang, Xin Luo, Fengqi Zhou

    Abstract The plasmon-induced transparency (PIT), which is destructive interference between the superradiation mode and the subradiation mode, is studied in patterned graphene-based terahertz metasurface composed of graphene ribbons and graphene strips. As the results of finite-difference time-domain (FDTD) simulation and coupled-mode theory (CMT) fitting, the PIT can be dynamically modulated by the dual-mode. The left (right) transmission dip is mainly tailored by the gate voltage applied to graphene ribbons (stripes), respectively, meaning a dual-mode on-to-off modulator is realized. Surprisingly, an absorbance of 50% and slow-light property of 0.7 ps are also achieved, demonstrating the proposed PIT metasurface has important applications in absorption and slow-light. In addition, coupling effects between the graphene ribbons and the graphene strips in PIT metasurface with different structural parameters also are studied in detail. Thus, the proposed structure provides a new basis for the dual-mode on-to-off multi-function modulators.

    更新日期:2020-01-02
  • Local V OC Measurements by Kelvin Probe Force Microscopy Applied on P-I-N Radial Junction Si Nanowires
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-30
    Clément Marchat, Letian Dai, José Alvarez, Sylvain Le Gall, Jean-Paul Kleider, Soumyadeep Misra, Pere Roca i Cabarrocas

    Abstract This work focuses on the extraction of the open circuit voltage (VOC) on photovoltaic nanowires by surface photovoltage (SPV) based on Kelvin probe force microscopy (KPFM) measurements. In a first approach, P-I-N radial junction (RJ) silicon nanowire (SiNW) devices were investigated under illumination by KPFM and current-voltage (I-V) analysis. Within 5%, the extracted SPV correlates well with the VOC. In a second approach, local SPV measurements were applied on single isolated radial junction SiNWs pointing out shadowing effects from the AFM tip that can strongly impact the SPV assessment. Several strategies in terms of AFM tip shape and illumination orientation have been put in place to minimize this effect. Local SPV measurements on isolated radial junction SiNWs increase logarithmically with the illumination power and demonstrate a linear behavior with the VOC. The results show notably that contactless measurements of the VOC become feasible at the scale of single photovoltaic SiNW devices.

    更新日期:2019-12-31
  • Photo-Fenton Degradation of AO7 and Photocatalytic Reduction of Cr(VI) over CQD-Decorated BiFeO 3 Nanoparticles Under Visible and NIR Light Irradiation
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-30
    Tao Xian, Lijing Di, Xiaofeng Sun, Hongqin Li, Yongjie Zhou, Hua Yang

    In this work, the carbon quantum dot (CQD)–decorated BiFeO3 nanoparticle photocatalysts were prepared by a hydrothermal method. The TEM observation and XPS characterization indicate that the CQDs are well anchored on the surface of BiFeO3 nanoparticles. Acid orange 7 (AO7) and hexavalent chromium (Cr(VI)) were chosen as the model pollutants to investigate the photocatalytic/photo-Fenton degradation and photocatalytic reduction performances of the as-prepared CQD/BiFeO3 composites under visible and near-infrared (NIR) light irradiation. Compared with bare BiFeO3 nanoparticles, the CQD/BiFeO3 composites exhibit significantly improved photocatalytic and photo-Fenton catalytic activities. Moreover, the composites possess good catalytic stability. The efficient photogenerated charges separation in the composites was demonstrated by the photocurrent response and electrochemical impedance spectroscopy (EIS) measurements. The main active species involved in the catalytic degradation reaction were clarified by radicals trapping and detection experiments. The underlying photocatalytic and photo-Fenton mechanisms are systematically investigated and discussed.

    更新日期:2019-12-31
  • Engineering the Side Facets of Vertical [100] Oriented InP Nanowires for Novel Radial Heterostructures
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-30
    H. Aruni Fonseka, Philippe Caroff, Yanan Guo, Ana M. Sanchez, Hark Hoe Tan, Chennupati Jagadish

    Abstract In addition to being grown on industry-standard orientation, vertical [100] oriented nanowires present novel families of facets and related cross-sectional shapes. These nanowires are engineered to achieve a number of facet combinations and cross-sectional shapes, by varying their growth parameters within ranges that facilitate vertical growth. In situ post-growth annealing technique is used to realise other combinations that are unattainable solely using growth parameters. Two examples of possible novel radial heterostructures grown on these vertical [100] oriented nanowire facets are presented, demonstrating their potential in future applications.

    更新日期:2019-12-31
  • Using Omniscan-Loaded Nanoparticles as a Tumor-Targeted MRI Contrast Agent in Oral Squamous Cell Carcinoma by Gelatinase-Stimuli Strategy
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-30
    Antian Gao, Yuehui Teng, Pakezhati Seyiti, Yingtzu Yen, Hanqing Qian, Chen Xie, Rutian Li, Zitong Lin

    In this study, the tumor-targeted MRI contrast agent was prepared with gelatinase-stimuli nanoparticles (NPs) and Omniscan (Omn) by double emulsion method. The size, distribution, morphology, stability, drug loading, and encapsulation efficiency of Omn-NPs were characterized. The macroscopic and microscopic morphological changes of NPs in response to gelatinases (collagenases IV) were observed. The MR imaging using Omn-NPs as a contrast agent was evaluated in the oral squamous cell carcinoma models with Omn as a control. We found clear evidence that the Omn-NPs were transformed by gelatinases and the signal of T1-weighted MRI sequence showed that the tumor-to-background ratio was significantly higher in Omn-NPs than in Omn. The peak point of time after injection was much later for Omn-NPs than Omn. This study demonstrates that Omn-NPs hold great promise as MRI contrast agent with improved specificity and prolonged circulation time based on a relatively simple and universal strategy.

    更新日期:2019-12-30
  • Optimization Strategy of 4H-SiC Separated Absorption Charge and Multiplication Avalanche Photodiode Structure for High Ultraviolet Detection Efficiency
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-30
    Jianquan Kou, KangKai Tian, Chunshuang Chu, Yonghui Zhang, Xingye Zhou, Zhihong Feng, Zi-Hui Zhang

    Abstract In this work, parametric investigations on structural optimization are systematically made for 4H-SiC-based separated absorption charge and multiplication (SACM) avalanche ultraviolet photodiode (UV APD). According to our results, the breakdown voltage can be strongly affected by the thickness for the multiplication layer and the doping concentration for the charge control layer. The thickness for the n-type ohmic contact layer, the absorption layer, and the charge control layer can remarkably affect the light penetration depth, which correspondingly influences the number of photo-generated electron-hole pairs, and therefore the aforementioned layer thickness has a strong impact on the responsivity for SACM APD. For enhancing the responsivity of the APD, we require a reduced energy band barrier height at the interface of the optical absorption layer and the charge control layer, so that the promoted carrier transport into the multiplication layer can be favored. In addition, we investigate positive beveled mesas with smaller angles so as to reduce the electric field at the mesa edge. Thus, the dark current is correspondingly suppressed.

    更新日期:2019-12-30
  • Solvent-Free Catalytic Oxidation of Benzyl Alcohol over Au-Pd Bimetal Deposited on TiO 2 : Comparison of Rutile, Brookite, and Anatase
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-27
    Xiaoliang Li, Jiangjiang Feng, Jia Sun, Zhe Wang, Wei Zhao

    TiO2 (P25)-supported Au-Pd bimetal nanoparticles displayed excellent performance in the solvent-free benzyl alcohol catalytic oxidation. However, little research attention has been paid to investigate the effects of TiO2 form on the catalytic activity of Au-Pd/TiO2. In the present research, rutile, brookite, and anatase TiO2 were successfully synthesized and subsequently applied as the carrier to load Au-Pd nanoparticles by the deposition-precipitation method. The experimental results indicated that the benzyl alcohol conversion employing the rutile TiO2-supported Au-Pd catalyst is higher than the conversion of anatase and brookite TiO2-loaded Au-Pd catalysts. However, the Au-Pd/TiO2-rutile displayed the lowest and highest selectivity toward benzaldehyde and toluene, respectively. ICP-AES, XRD, XPS, and TEM were conducted to characterize these catalysts. The corresponding experimental results revealed that the excellent performance of Au-Pd/TiO2-rutile catalyst was attributed to both the smaller Au-Pd nanoparticle size distribution and the higher concentrations of Oα and Pd2+ species on the catalyst surface. In the recycle experiments, the Au-Pd/TiO2-rutile catalyst displayed lower reaction stability compared with the Au-Pd/TiO2-anatase and Au-Pd/TiO2-brookite, which might be due to the coverage of larger amount of aldehyde products on the surface.

    更新日期:2019-12-27
  • Design of Split Hexagonal Patch Array Shaped Nano-metaabsorber with Ultra-wideband Absorption for Visible and UV Spectrum Application
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-26
    Ahasanul Hoque, Mohammad Tariqul Islam, Ali F. Almutairi, Mohammad Rashed Iqbal Faruque

    Solar energy is one of the ambient sources where energy can be scavenged easily without pollution. Intent scavenging by the solar cell to recollect energy requires a state-of-the-art technique to expedite energy absorption to electron flow for producing more electricity. Structures of the solar cell have been researched to improve absorption efficiency, though most of them can only efficiently absorb with narrow-angle tolerance and polarization sensitivity. So, there is a strong demand for broadband absorption with minimal polarization sensitivity absorber, which is required for effective solar energy harvesting. In this paper, we proposed a new Split Hexagonal Patch Array (SHPA) shape metamaterial absorber with Double-negative (DNG) characteristics, which will provide a wide absorption band with low polarization sensitivity for solar spectrum energy harvesting. The proposed new SHPA shape consists of six nano-arms with a single vertical split which with arrowhead symmetry. This arm will steer electromagnetic (EM) resonance to acquire absolute negative permittivity and permeability, ensuring DNG property. This DNG metamaterial features analyzed based on the photoconversion quantum method for maximum photon absorption. The symmetric characteristics of the proposed structure enable the absorber to show polarization insensitivity and wide incident angle absorption capabilities. Simulated SHPA shows a visible and ultraviolet (UV) spectrum electromagnetic wave absorption capacity of more than 95%. The quantum method gives an advantage in the conversion efficiency of the absorber, and the numerical analysis of the proposed SHPA structure provides absorbance quality for THz regime energy harvesting through solar cell or photonic application.

    更新日期:2019-12-27
  • Retraction Note: Flexible Field Emitter for X-ray Generation by Implanting CNTs into Nickel Foil
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-24
    Bin Sun, Yan Wang, Guifu Ding

    The Editors-in-Chief have retracted this article [1] because it significantly overlaps with previously published articles by the same authors [2, 3].

    更新日期:2019-12-25
  • Giant Tunable Circular Dichroism of Large-Area Extrinsic Chiral Metal Nanocrescent Arrays
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-21
    Liyuan Cao, Jiwei Qi, Qiang Wu, Zhixuan Li, Ride Wang, Junan Chen, Yao Lu, Wenjuan Zhao, Jianghong Yao, Xuanyi Yu, Qian Sun, Jingjun Xu

    Abstract Circular dichroism (CD) is an interesting phenomenon originating from the interaction of light with chiral molecules or other nanostructures lacking mirror symmetries in three-dimensional (3D) or two-dimensional (2D) space. While the observable effects of optical chirality are very weak in most of the natural materials, they can be designed and significantly enhanced in synthetic chiral structures, where the spatial symmetry of their component are broken on a nanoscale. Therefore, fabrication of composites capable of cheap, time-saving, and giant CD is desirable for the advanced optical technologies. Here, the giant CD of large-area metal nanocrescent array structures was investigated theoretically and experimentally. The largest value of the CD spectrum measured was larger than 0.5, and the CD spectrum was tuned effectively and extensively while maintaining a large peak intensity, which can be attributed to the selective excitation of the lattice surface modes (LSMs) by circularly polarized light. The analysis of the extrinsic chiral structure shows potential applications in chiral molecule sensing and polarizing imaging.

    更新日期:2019-12-21
  • Synthesis, Characterization, and Evaluation of Redox-Sensitive Chitosan Oligosaccharide Nanoparticles Coated with Phycocyanin for Drug Delivery
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-21
    Ziting Cheng, Wei Zhang, Xiaoya Hou, Bingjie Wang, Yanping Zhu, Peng Zhang, Feng Zhao, Daquan Chen

    Abstract In this paper, a type of phycocyanin (PC)-functionalized and curcumin (CUR)-loaded biotin-chitosan oligosaccharide-dithiodipropionic acid-curcumin (BCSC) nanoparticles, called CUR-BCSC@PCs, were designed to enhance the biocompatibility of CUR. The structure of BCSC was confirmed using 1H-NMR. In CUR-BCSC@PCs with an average hydrodynamic diameter of 160.3 ± 9.0 nm, the biomimetic protein corona gave the nanoparticles excellent stability and the potential to avoid protein adsorption in blood circulation. The in vitro release experiment verified that CUR-BCSC@PCs with redox responsive shells were sensitive to high concentrations of glutathione. In addition, CUR-BCSC@PCs were effective at increasing the inhibitory activity on the proliferation of A549 cells by enhancing the intracellular uptake of CUR. These results indicated that CUR-BCSC@PCs have great application prospects in cancer therapy as effective drug delivery carriers.

    更新日期:2019-12-21
  • Maxwell-Wagner-Sillars Dynamics and Enhanced Radio-Frequency Elastomechanical Susceptibility in PNIPAm Hydrogel-KF-doped Barium Titanate Nanoparticle Composites
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-19
    Ezekiel Walker, Yukikuni Akishige, Tong Cai, James Roberts, Nigel Shepherd, Shijie Wu, Zhiming Wang, Arup Neogi

    Abstract Maxwell-Wagner-Sillars (MWS) dynamics and electromagnetic radio-frequency (RF) actuation of the volumetric phase change are investigated in a hybrid polymer composite consisting of hydrogel suspended with high-k nanoparticles. Poly(N-isopropylacrylamide) (PNIPAm) hydrogels were combined with 10% KF-doped barium titanate (Ba0.9 K0.1 TiO2.9F0.1, KBT) nanoparticles with highly anisotropic dielectric properties using poly(vinyl alcohol) (PVA) to form a nanoparticle-hydrogel composite. Whereas the addition of PVA to the synthesis maintains a strong volumetric phase transition with polarization and relaxation features similar to standard bulk PNIPAm, the addition of KBT nanoparticles results in reduced volumetric phase transition and MWS polarization due to charge screening of intramolecular interactions. The added nanoparticles and modified synthesis process enhanced the dielectric permittivity of bulk PNIPAm, increased RF conductivity up to 7×, and decreased the specific heat while still maintaining a discontinuous volumetric phase transition. An RF antenna emitting at 544 kHz was only able to actuate a phase change in the composites with modified synthesis versus bulk PNIPAm. Measured heating rates were 3× greater than that of un-modified PNIPAm.

    更新日期:2019-12-19
  • A Comparative Study of the Toxicity of Polyethylene Glycol–Coated Cobalt Ferrite Nanospheres and Nanoparticles
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-19
    Shahnaz Akhtar, Qasim Khan, Shahzad Anwar, Ghafar Ali, Muhammad Maqbool, Maaz Khan, Shafqat Karim, Lan Gao

    We present a comparative study of the toxicity of polyethylene glycol (PEG)–coated cobalt ferrite nanoparticles and nanospheres. Nanoparticles were prepared by hydrothermal method while nanospheres were prepared by solvothermal technique. The surface of nanomaterials was successfully modified with polyethylene glycol. To investigate the morphology of the prepared samples, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA), and electron microscopy techniques were employed. Structural analyses confirmed the formation of polycrystalline cobalt ferrite nanoparticles with diameters in the range 20–25 nm and nanospheres in the range 80–100 nm, respectively. Kunming SPF mice (female, 6–8 weeks old) were used to investigate the toxicity induced by cobalt ferrite nanoparticles and nanospheres in different organs of the mice. Biodistribution studies, biochemical indices, histopathological assessments, inflammatory factors, oxidation and antioxidant levels, and cytotoxicity tests were performed to assess the toxicity induced by cobalt ferrite nanoparticles and nanospheres in mice. Cobalt ferrite nanospheres were found to be more toxic than the nanoparticles and curcumin was proved to be a good healing agent for the toxicity induced by PEG-coated cobalt ferrite nanomaterials in mice.

    更新日期:2019-12-19
  • Mesoporous Silica Nanoparticle–Based Combination of NQO1 Inhibitor and 5-Fluorouracil for Potent Antitumor Effect Against Head and Neck Squamous Cell Carcinoma (HNSCC)
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-19
    Jing Chen, Shuzhen Zhang, Shuai Zhang, Shanjun Gao, Jianbo Wang, Dongchun Lei, Pengqiang Du, Zhiwei Xu, Cailiang Zhu, Hongbin Sun

    Abstract Head and neck squamous cell carcinomas (HNSCC) are one of the deadliest forms of cancer, and 90% of its origin is from squamous cells. NAD(P)H:quinone oxidoreductase 1 (NQO1), an enzyme overexpressed in squamous cell carcinoma, plays an important role in proliferation and chemoresistance. The main aims were to study the inhibitory effect of ß-lapachone (ARQ761 in clinical form) in HNSCC and to study the combinational effect of 5-FU and ß-lap in improving the therapeutic efficacy in HNSCC. Lipid bilayer–assembled mesoporous silica nanoparticles loaded with 5-FU/ß-lap were prepared and studied for its physicochemical and biological properties. ß-lap showed a concentration-dependent inhibition of NQO1 enzyme activity in Cal33 cells. Notably, significant inhibitory effect was observed at a dose of 20–50 μg/ml of ß-lap. Combination of 5-FU+ß-lap resulted in lower cell viability; most notably, 5-FU/ß-lap-loaded mesoporous silica nanoparticles (FNQ-MSN) exhibited significantly lower cell viability compared with that of any of the individual drug or physical combinations. ß-lap resulted in a decrease in the protein band of NQO1 compared with control; however, most notable decrease in the NQO1 level was observed in the FNQ-MSN-treated cell group. FNQ-MSN resulted in more than 60% of cell apoptosis (early and late apoptosis) and predominant nuclear fragmentation of cancer cells indicating the superior anticancer effect of a carrier-based combination regimen. Notable decrease in tumor volume was observed with the physical mixture of 5-FU+ß-lap; however, combined treatment of carrier-based 5-FU and ß-lap (FNQ-MSN) significantly delayed the tumor growth and prolonged the survival of tumor-bearing xenograft mice. These findings suggest the potential of NQO1 inhibitor in enhancing the chemotherapeutic potential of 5-FU in the treatment of HNSCC.

    更新日期:2019-12-19
  • Broadband Ultrathin Transmission Quarter Waveplate with Rectangular Hole Array Based on Plasmonic Resonances
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-18
    Yu Wang, Yumin Liu, Jing Li, Chang Liu, Zhongyuan Yu, Han Ye, Li Yu

    The control of the polarization states of light plays an important role in modern optical systems. However, traditional polarization manipulating devices often have narrow bandwidth and their large size makes it difficult for them to achieve miniaturization and integration of optical systems. This work presents an ultrathin quarter waveplate with a periodic silver film 2 × 2 rectangular hole array with a thickness less than λ/50. Numerical simulation shows that the waveplate can efficiently transform a circular polarized wave into a linearly polarized one at the center of 1550 nm, and its bandwidth is 525 nm. Furthermore, the quarter waveplate can efficiently invert linear polarization into circular polarization at 1550 nm, which ellipticity is near unit. With an array of small holes on a metal film to enhance transmission, this structure can increase the transmission to 0.44. The broadband quarter waveplate can be used in communication system and near infrared band system, and be integrated with other optical devices at nanoscale to achieve polarization operation, detection, and sensing.

    更新日期:2019-12-19
  • Upregulating MicroRNA-410 or Downregulating Wnt-11 Increases Osteoblasts and Reduces Osteoclasts to Alleviate Osteonecrosis of the Femoral Head
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-18
    Yukun Yin, Lixiang Ding, Yu Hou, Haoran Jiang, Ji Zhang, Zhong Dai, Genai Zhang

    Little is known regarding the functional role of microRNA-410 (miR-410) in osteonecrosis of the femoral head (ONFH); hence, the aim of the present study was to investigate miR-410 targeting Wnt-11 to modulate the osteogenic and osteoclastic mechanism in the prevention of ONFH.

    更新日期:2019-12-19
  • Facile fabrication of mesostructured natural rubber/silica nanocomposites with enhanced thermal stability and hydrophobicity
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-17
    Supphathee Chaowamalee, Chawalit Ngamcharussrivichai

    Natural rubber (NR)/hexagonal mesoporous silica (HMS) nanocomposites (NRHMS) with enhanced thermal and hydrophobic properties were facilely prepared via in situ sol–gel formation with pH adjustment using a low sulphuric acid (H2SO4) acid concentration. The effect of the amount of 0.5 M H2SO4 (2.5–10 g) added into the pre-synthesis mixture on the physicochemical properties of the obtained NRHMS nanocomposites was investigated. With a small addition of H2SO4 solution, the fabricated NRHMS nanocomposite possessed an improved wormhole-like mesostructure arrangement with a thicker silica wall, which retarded the thermal decomposition of the NR phase, as deduced from the auto-oxidation of NR by thermogravimetric analysis. The H2O adsorption–desorption measurement revealed an increased hydrophobicity of the NRHMS composites, explained by the acid-catalyzed bridging of free silanol groups to siloxane bonds, which was supported by the X-ray photoelectron spectroscopy analysis. Scanning transmission electron microscopy with energy dispersive X-ray spectroscopy elemental mapping revealed a good dispersion of the NR phase within the mesostructured silica. However, a high amount of added H2SO4 solution led to silica–NR phase separation due to the decreased hydrophobic interaction between the silica precursor and rubber chain, as well as an agglomeration of the NR phase itself. The mechanism of NRHMS nanocomposite formation under pH-controlled conditions was proposed to proceed via a cooperative self-assembly route.

    更新日期:2019-12-18
  • Lithia-Based Nanocomposites Activated by Li 2 RuO 3 for New Cathode Materials Rooted in the Oxygen Redox Reaction
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-16
    Byeong Gwan Lee, Yong Joon Park

    Lithia-based materials are promising cathodes based on an anionic (oxygen) redox reaction for lithium ion batteries due to their high capacity and stable cyclic performance. In this study, the properties of a lithia-based cathode activated by Li2RuO3 were characterized. Ru-based oxides are expected to act as good catalysts because they can play a role in stabilizing the anion redox reaction. Their high electronic conductivity is also attractive because it can compensate for the low conductivity of lithia. The lithia/Li2RuO3 nanocomposites show stable cyclic performance until a capacity limit of 500 mAh g−1 is reached, which is below the theoretical capacity (897 mAh g−1) but superior to other lithia-based cathodes. In the XPS analysis, while the Ru 3d peaks in the spectra barely changed, peroxo-like (O2)n− species reversibly formed and dissociated during cycling. This clearly confirms that the capacity of the lithia/Li2RuO3 nanocomposites can mostly be attributed to the anionic (oxygen) redox reaction.

    更新日期:2019-12-17
  • Photogalvanic Effect in Nitrogen-Doped Monolayer MoS 2 from First Principles
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-16
    Wen-Ming Luo, Zhi-Gang Shao, Mou Yang

    We investigate the photogalvanic effect in nitrogen-doped monolayer molybdenum disulfide (MoS2) under the perpendicular irradiation, using first-principles calculations combined with non-equilibrium Green function formalism. We provide a detailed analysis on the behavior of photoresponse based on the band structure and in particular the joint density of states. We thereby identify different mechanisms leading to the existence of zero points, where the photocurrent vanishes. In particular, while the zero point in the linear photovoltaic effect is due to forbidden transition, their appearance in the circular photovoltaic effect results from the identical intensity splitting of the valance band and the conduction band in the presence of Rashba and Dresslhaus spin-orbit coupling. Furthermore, our results reveal a strong circular photogalvanic effect of nitrogen-doped monolayer MoS2, which is two orders of magnitude larger than that induced by the linearly polarized light.

    更新日期:2019-12-17
  • Protective Effects of Carbon Dots Derived from Phellodendri Chinensis Cortex Carbonisata against Deinagkistrodon acutus Venom-Induced Acute Kidney Injury
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-16
    Meiling Zhang, Jinjun Cheng, Ziwei Sun, Hui Kong, Yue Zhang, Suna Wang, Xiaoke Wang, Yan Zhao, Huihua Qu

    As an emerging nanomaterial, carbon dots (CDs) have been the focus of tremendous attention for biomedical applications. However, little information is available on their bioactivity of inhibiting acute kidney injury (AKI) induced by snake venom.

    更新日期:2019-12-17
  • Ferumoxytol Attenuates the Function of MDSCs to Ameliorate LPS-Induced Immunosuppression in Sepsis
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-16
    Yujun Xu, Yaxian Xue, Xinghan Liu, Yi Li, Huaping Liang, Huan Dou, Yayi Hou

    Sepsis-induced immunosuppression is recognized as one of the main features responsible for therapeutic failures. Myeloid-derived suppressor cells (MDSCs), which are mainly characterized by their suppressive properties, have been reported to be expanded in sepsis. Ferumoxytol (FMT), an FDA-approved iron supplement, has been shown to possess immune-modulatory properties in tumors. However, it is unclear whether FMT alters the functions of MDSCs to reduce late-sepsis immunosuppression. Here, we showed an immunomodulatory effect of FMT on MDSCs to ameliorate lipopolysaccharide (LPS)–induced immunosuppression in the late stage of sepsis. Separation of cells with internalized FMT and detection of the intracellular iron content showed that MDSCs could uptake FMT. Low doses of FMT had no effects on the cell viability of MDSCs, but FMT inhibited the expansion of MDSCs in vitro. Moreover, FMT significantly downregulated the expression levels of Arg-1, S100A8, S100A9, and p47phox as well as ROS production in MDSCs. FMT decreased the percentage of granulocytic MDSCs (G-MDSCs) and promoted the differentiation of MDSCs into macrophages. Furthermore, FMT reduced white blood cell recruitment and alveolar wall thickening in the lungs and areas of necrosis in the liver as well as some biochemical markers of liver dysfunction. FMT decreased the percentage of G-MDSCs and monocytic MDSCs (M-MDSCs) in the spleens of LPS-induced septic mice. Of note, FMT reduced the T cell immunosuppressive functions of both G-MDSCs and M-MDSCs. Expectedly, FMT also significantly reduced Arg-1 and p47phox gene expression in splenic CD11b+Gr-1+ cells isolated from LPS-challenged mice. These data indicate that FMT decreased the immunosuppressive functions of MDSCs by decreasing Arg-1 and ROS production, suggesting that FMT may reduce long-term immunosuppression in the late stage of sepsis.

    更新日期:2019-12-17
  • The Study of Enhanced High-Intensity Focused Ultrasound Therapy by Sonodynamic N 2 O Microbubbles
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-16
    Xiaowen Zhong, Mei Zhang, Zedan Tian, Qi Wang, Zhigang Wang

    High-intensity focused ultrasound (HIFU) is a representative non-invasive method of cancer therapy, but its low therapeutic efficacy and risk of damage to surrounding normal tissue hinder its further clinical development and application. Sonodynamic therapy (SDT) kills tumor cells through reactive oxygen molecules produced by sonosensitizers during ultrasound treatment. SDT can enhance HIFU efficacy like microbubbles. In this work, we developed nanoscale N2O microbubbles (N2O-mbs) by an improved mechanical oscillation method. These microbubbles showed good biocompatibility and tumor cell binding. The sonosensitivity of the N2O-mbs was detected both extracellularly and intracellularly through the detection of reactive oxygen species generation. The toxic effects of these sonodynamic microbubbles on tumor cells and the synergistic effect on HIFU treatment were evaluated. Significant apoptosis was caused by reactive oxygen species produced by N2O-mbs under ultrasound irradiation. N2O-mbs combined with HIFU increased tumor cell necrosis and apoptosis in vitro and the coagulative necrotic volume and echo intensity in the bovine liver target area ex vivo. These sonodynamic microbubbles have been also demonstrated to efficiently inhibit tumor growth in vivo. N2O-mbs have a significant impact on the treatment and ablation effect of HIFU due to the advantages of microbubble and extraordinary sonosensitivity. This finding suggests that N2O-mbs may be a novel auxiliary agent for ultrasound that can be used to promote HIFU tumor thermal ablation.

    更新日期:2019-12-17
  • Heating Efficiency of Triple Vortex State Cylindrical Magnetic Nanoparticles
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-16
    De Wei Wong, Wei Liang Gan, Yuan Kai Teo, Wen Siang Lew

    A well-established method for treating cancerous tumors is magnetic hyperthermia, which uses localized heat generated by the relaxation mechanism of magnetic nanoparticles (MNPs) in a high-frequency alternating magnetic field. In this work, we investigate the heating efficiency of cylindrical NiFe MNPs, fabricated by template-assisted pulsed electrodeposition combined with differential chemical etching. The cylindrical geometry of the MNP enables the formation of the triple vortex state, which increases the heat generation efficiency by four times. Using time-dependent calorimetric measurements, the specific absorption rate (SAR) of the MNPs was determined and compared with the numerical calculations from micromagnetic simulations and vibrating sample magnetometer measurements. The magnetization reversal of high aspect ratios MNPs showed higher remanent magnetization and low-field susceptibility leading to higher hysteresis losses, which was reflected in higher experimental and theoretical SAR values. The SAR dependence on magnetic field strength exhibited small SAR values at low magnetic fields and saturates at high magnetic fields, which is correlated to the coercive field of the MNPs and a characteristic feature of ferromagnetic MNPs. The optimization of cylindrical NiFe MNPs will play a pivotal role in producing high heating performance and biocompatible magnetic hyperthermia agents.

    更新日期:2019-12-17
  • Reducing Interface Traps with High Density Hydrogen Treatment to Increase Passivated Emitter Rear Contact Cell Efficiency
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-12
    Chih-Cheng Yang, Po-Hsun Chen, Ting-Chang Chang, Wan-Ching Su, Sung-Yu Chen, Shui-Chin Liu, Sheng-Yao Chou, Yung-Fang Tan, Chun-Chu Lin, Pei-Yu Wu, Tsung-Ming Tsai, Hui-Chun Huang

    In this work, a high-density hydrogen (HDH) treatment is proposed to reduce interface traps and enhance the efficiency of the passivated emitter rear contact (PERC) device. The hydrogen gas is compressed at pressure (~ 70 atm) and relatively low temperature (~ 200 °C) to reduce interface traps without changing any other part of the device’s original fabrication process. Fourier-transform infrared spectroscopy (FTIR) confirmed the enhancement of Si–H bonding and secondary-ion mass spectrometry (SIMS) confirmed the SiN/Si interface traps after the HDH treatment. In addition, electrical measurements of conductance-voltage are measured and extracted to verify the interface trap density (Dit). Moreover, short circuit current density (Jsc), series resistance (Rs), and fill factor (F.F.) are analyzed with a simulated light source of 1 kW M−2 global AM1.5 spectrum to confirm the increase in cell efficiency. External quantum efficiency (EQE) is also measured to confirm the enhancement in conversion efficiency between different wavelengths. Finally, a model is proposed to explain the experimental result before and after the treatment.

    更新日期:2019-12-13
  • Etched p-Type Si Nanowires for Efficient Ozone Decomposition
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-10
    Xuan Li, Linqu Luo, Yicheng Bi, Anqi Wang, Yunfa Chen, Ning Han, Fengyun Wang

    High concentration ozone can damage greatly to the respiratory, cardiovascular systems, and fertility of people, and catalytic decomposition is an important strategy to reduce its harm. However, it remains a challenge to develop efficient ozone decomposition catalysts with high efficiency. In this study, p- and n-type silicon nanowires (Si NWs) are fabricated by wet chemical etching method and are firstly applied to catalytic decompose ozone at room temperature. The p-type Si NWs exhibit 90% ozone (20 ppm O3/air) decomposition efficiency with great stability, which is much better than that of n-type Si NWs (50%) with same crystal orientation, similar diameter and specific surface area. The catalytic property difference is mainly attributed to the more delocalization holes in the p-type Si NWs, which can accelerate the desorption of ozone decomposition intermediates (i.e., adsorbed oxygen species).

    更新日期:2019-12-11
  • Preliminary Studies on Biodegradable Zinc Oxide Nanoparticles Doped with Fe as a Potential Form of Iron Delivery to the Living Organism
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-10
    Paula Kielbik, Jarosław Kaszewski, Bartłomiej Dominiak, Magdalena Damentko, Izabela Serafińska, Julita Rosowska, Mikołaj A. Gralak, Marcin Krajewski, Bartłomiej S. Witkowski, Zdzislaw Gajewski, Marek Godlewski, Michal M. Godlewski

    Iron is the crucial element for living organisms and its deficiency is described as the most common nutritional disorder all over the world. Nowadays, more effective and safe iron supplementation strategies for both humans and animals become one of the most important challenges in the therapy of nutritional deficiencies. Our previous in vivo studies confirmed safety and biodegradability of in-house manufactured zinc oxide-based nanoparticles and their rapid distribution to majority of organs and tissues in the body. In vitro examinations performed on Caco-2 cell line, a model of epithelial cells of the gastrointestinal tract, revealed a low toxicity of studied nanomaterials. In the current study, we investigated biodegradable zinc oxide nanoparticles doped with Fe(III) as a perspective supplementation strategy for iron deficiency. Biodegradable ZnO:Fe nanoparticles were intra-gastrically administered to adult mice and following 24 h, animals were sacrificed with collection of internal organs for further analyses. The iron concentration measured with atomic absorption spectrometry and histological staining (Perl’s method) showed a rapid distribution of iron-doped nanoparticles to tissues specifically related with iron homeostasis. Accumulation of iron was also visible within hepatocytes and around blood vessels within the spleen, which might indicate the transfer of Fe-doped nanoparticles from the bloodstream into the tissue. Reassuming, preliminary results obtained in the current study suggest that biodegradable ZnO nanoparticles doped with Fe might be a good carriers of exogenous iron in the living body. Therefore, subsequent investigations focus on determination an exact mechanisms related with an iron deposition in the tissue and influence of nanoparticle carriers on iron metabolism are required.

    更新日期:2019-12-11
  • Effect of Machining-Induced Subsurface Defects on Dislocation Evolution and Mechanical Properties of Materials via Nano-indentation
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-09
    Quanlong Wang, Meiping Wu, Chaofeng Zhang, Yanming Lv, Xiaogang Ji

    Subsurface defects have a significant impact on the precision and performance of nano-structures. In this paper, molecular dynamics simulation of nano-indentation is performed to investigate the effect of machining-induced subsurface defects on dislocation evolution and mechanical properties of materials, in which the specimen model with subsurface defects is constructed by nano-cutting conforming to reality. The formation mechanism of subsurface defects and the interaction mechanism between machine-induced defects and dislocation evolution are discussed. The hardness and Young’s elastic modulus of single crystal copper specimens are calculated. The simulation results indicate that there exist stable defect structure residues in the subsurface of workpiece, such as atomic clusters, stacking fault tetrahedral, and stair-rod dislocations. Secondary processing of nano-indentation can restore internal defects of the workpiece, but the subsurface damage in the secondary processing area is aggravated. The nano-indentation hardness of specimens increases with the introduction of subsurface defects, which results in the formation of work-hardening effect. The existence of subsurface defects can weaken the ability of material to resist elastic deformation, in which the mutual evolution between dislocations and subsurface defects plays an important role.

    更新日期:2019-12-11
  • Near-Infrared Photoelectric Properties of Multilayer Bi 2 O 2 Se Nanofilms
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-09
    Hang Yang, Wei Chen, Xiaoming Zheng, Dongsheng Yang, Yuze Hu, Xiangzhe Zhang, Xin Ye, Yi Zhang, Tian Jiang, Gang Peng, Xueao Zhang, Renyan Zhang, Chuyun Deng, Shiqiao Qin

    The near-infrared (NIR) photoelectric properties of multilayer Bi2O2Se nanofilms were systematically studied in this paper. Multilayer Bi2O2Se nanofilms demonstrate a sensitive photo response to NIR, including a high photoresponsivity (~ 101 A/W), a quick response time (~ 30 ms), a high external quantum efficiency (~ 20,300%), and a high detection rate (1.9 × 1010 Jones). These results show that the device based on multilayer Bi2O2Se nanofilms might have great potentials for future applications in ultrafast, highly sensitive NIR optoelectronic devices.

    更新日期:2019-12-09
  • Cutting-based single atomic layer removal mechanism of monocrystalline copper: edge radius effect
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-06
    Wenkun Xie, Fengzhou Fang

    The ultimate objective of mechanical cutting is to down minimum chip thickness to single atomic layer. In this study, the cutting-based single atomic layer removal mechanism on monocrystalline copper is investigated by a series of molecular dynamics analysis. The research findings report that when cutting depth decreases to atomic scale, minimum chip thickness could be down to single atomic layer by mechanical cutting using rounded edge tool. The material removal behaviour during cutting-based single atomic layer removal exhibits four characteristics, including chip formation by shearing-stress driven dislocation motion, elastic deformation on the processed surface, atomic sizing effect, and cutting-edge radius effect. Based on this understanding, a new cutting model is proposed to study the material removal behaviour in cutting-based single atomic layer removal process, significantly different from those for nanocutting and conventional cutting. The outcomes provide theoretical support for the research and development of the atomic and close-to-atomic scale manufacturing technology.

    更新日期:2019-12-06
  • A Transient-Enhanced Voltage Regulator with Stability and Power-Supply-Rejection Boosting
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-05
    Yue Shi, Anqi Wang, Jianwen Cao, Zekun Zhou

    A high-stability voltage regulator (VR) is proposed in this paper, which integrates transient enhancement and overcurrent protection (OCP). Taken into consideration the performance and area advantages of low-voltage devices, most control parts of proposed VR are supplied by the regulated output voltage, which forms self-power technique (SPT) with power supply rejection (PSR) boosting. Besides, the stability and transient response are enhanced by dynamic load technique (DLT). An embedded overcurrent feedback loop is also adopted to protect the presented VR from damage under overload situations. The proposed VR is implemented in a standard 350 nm BCD technology, whose results indicate the VR can steadily work with 5.5–30 V input voltage, 0–30 mA load range, and 0.1–3.3 μF output capacitor. A 2.98 μV/V line regulation and a 0.233 mV/mA load regulation are achieved with a 40 mA current limiting. The PSR is better than − 64 dB up to 10 MHz with a 0.1 μF output capacitor.

    更新日期:2019-12-06
  • Enhanced Light-Induced Transverse Thermoelectric Effect in Tilted BiCuSeO Film via the Ultra-thin AuNPs Layer
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-05
    Weiyuan Yu, Guoying Yan, Yuli Xue, Yuejiao Zhang, Jianglong Wang, Guangsheng Fu, Shufang Wang

    Significant enhancement of light-induced transverse thermoelectric (LITT) effect in tilted BiCuSeO film has been achieved via introduction of an ultra-thin layer of gold nanoparticles (AuNPs) with the thickness of a few nanometers. In both cases of pulsed and continuous light irradiation, about two times increment in the LITT voltage sensitivity is observed for the BiCuSeO film coated with 4-nm-thick AuNPs layer. This can be ascribed to the increased photo-thermal conversion efficiency in the LITT effect owing to the efficient usage of the incident light of AuNPs layer. Thicker AuNPs layer will suppress the voltage sensitivity increment due to the electrical connectivity effect. This work provides an effective strategy for optimizing the performance of thermal-type optical detectors based on the LITT effect.

    更新日期:2019-12-05
  • Tailored Solid Polymer Electrolytes by Montmorillonite with High Ionic Conductivity for Lithium-Ion Batteries
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-05
    Yingjian Zhao, Yong Wang

    Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) have important significance for the development of next-generation rechargeable lithium-ion batteries. However, strong coordination between lithium ions and PEO chains results the ion conductivity usually lower than the expectation. In this study, sub-micron montmorillonite is incorporated into the PEO frames as Lewis base center which enables the lithium ions to escape the restraint of PEO chains. After involving montmorillonite (MMT) into the SPEs, the ionic conductivity of SPEs is 4.7 mS cm− 1 at 70 °C which shows a comparable value with that of liquid electrolyte. As coupling with LiFePO4 material, the battery delivers a high discharge capacity of 150.3 mAh g− 1 and an excellent rate performance with a capacity of 111.8 mAh g− 1 at 0.16 C and maintains 58.2 mAh g− 1 at 0.8 C. This study suggests that the customized incorporation of Lewis base materials could offer a promising solution for achieving high-performance PEO-based solid-state electrolyte.

    更新日期:2019-12-05
  • Magnetic Assembly Route to Construct Reproducible and Recyclable SERS Substrate
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-05
    Bingfang Zou, Chunyu Niu, Ming Ma, Lu Zhao, Yongqiang Wang

    The fabrication of a uniform array film through assembly of colloidal building blocks is of practical interest for the integrated individual and collective functions. Here, a magnetic assembly route was put forward to organize monodisperse noble metal microspheres into a uniform array film for surface-enhanced Raman scattering (SERS) application, which demonstrated the integrated signal sensitivity of single noble metal microspheres and reproducibility of their assembled uniform array film. For this purpose, monodisperse multifunctional Fe3O4@SiO2@TiO2@Ag (FOSTA) colloidal microspheres as building blocks were successfully synthesized through a homemade ultrasonic-assisted reaction system. When used in SERS test, these multifunctional microspheres could firstly bind the analyte (R6G) from solution and then assembled into a uniform film under an external magnetic field, which exhibited high SERS detection sensitivity with good reproducibility. In addition, due to the TiO2 interlayer in FOSTA colloidal microspheres, the building blocks could be recycled and self cleaned through photocatalytic degradation of the adsorbed analyte for recycling SERS application.

    更新日期:2019-12-05
  • Ag Nanoparticles Sensitized In 2 O 3 Nanograin for the Ultrasensitive HCHO Detection at Room Temperature
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-05
    Shiqiang Zhou, Mingpeng Chen, Qingjie Lu, Yumin Zhang, Jin Zhang, Bo Li, Haitang Wei, Jicu Hu, Huapeng Wang, Qingju Liu

    Formaldehyde (HCHO) is the main source of indoor air pollutant. HCHO sensors are therefore of paramount importance for timely detection in daily life. However, existing sensors do not meet the stringent performance targets, while deactivation due to sensing detection at room temperature, for example, at extremely low concentration of formaldehyde (especially lower than 0.08 ppm), is a widely unsolved problem. Herein, we present the Ag nanoparticles (Ag NPs) sensitized dispersed In2O3 nanograin via a low-fabrication-cost hydrothermal strategy, where the Ag NPs reduces the apparent activation energy for HCHO transporting into and out of the In2O3 nanoparticles, while low concentrations detection at low working temperature is realized. The pristine In2O3 exhibits a sluggish response (Ra/Rg = 4.14 to 10 ppm) with incomplete recovery to HCHO gas. After Ag functionalization, the 5%Ag-In2O3 sensor shows a dramatically enhanced response (135) with a short response time (102 s) and recovery time (157 s) to 1 ppm HCHO gas at 30 °C, which benefits from the Ag NPs that electronically and chemically sensitize the crystal In2O3 nanograin, greatly enhancing the selectivity and sensitivity.

    更新日期:2019-12-05
  • UV-Visible Photodetector Based on I-type Heterostructure of ZnO-QDs/Monolayer MoS 2
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-04
    Yong Heng Zhou, Zhi Bin Zhang, Ping Xu, Han Zhang, Bing Wang

    Monolayer MoS2 has shown excellent photoresponse properties, but its promising applications in high-sensitivity photodetection suffer from the atomic-thickness-limited adsorption and band gap-limited spectral selectivity. Here we have carried out investigations on MoS2 monolayer-based photodetectors with and without decoration of ZnO quantum dots (ZnO-QDs) for comparison. Compared with monolayer MoS2 photodetectors, the monolayer ZnO-QDs/MoS2 hybrid device exhibits faster response speed (1.5 s and 1.1 s, respectively), extended broadband photoresponse range (deep UV-visible), and enhanced photoresponse in visible spectrum, such as higher responsivity over 0.084 A/W and larger detectivity of 1.05 × 1011 Jones, which results from considerable injection of carries from ZnO-QDs to MoS2 due to the formation of I-type heterostructure existing in the contact interface of them.

    更新日期:2019-12-05
  • Experimental Demonstration of Electromagnetically Induced Transparency in a Conductively Coupled Flexible Metamaterial with Cheap Aluminum Foil
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-02
    Jie Hu, Tingting Lang, Weihang Xu, Jianjun Liu, Zhi Hong

    We propose a conductively coupled terahertz metallic metamaterial exhibiting analog of electromagnetically induced transparency (EIT), in which the bright and dark mode antennae interact via surface currents rather than near-field coupling. Aluminum foil, which is very cheap and often used in food package, is used to fabricate our metamaterials. Thus, our metamaterials are also flexible metamaterials. In our design, aluminum bar resonators and aluminum split ring resonators (SRRs) are connected (rather than separated) in the form of a fork-shaped structure. We conduct a numerical simulation and an experiment to analyze the mechanism of the proposed metamaterial. The surface current due to LSP resonance (bright mode) flows along different paths, and a potential difference is generated at the split gaps of the SRRs. Thus, an LC resonance (dark mode) is induced, and the bright mode is suppressed, resulting in EIT. The EIT-like phenomenon exhibited by the metamaterial is induced by surface conducting currents, which may provide new ideas for the design of EIT metamaterials. Moreover, the process of fabricating microstructures on flexible substrates can provide a reference for producing flexible microstructures in the future.

    更新日期:2019-12-02
  • Voltage-Polarity Dependent Programming Behaviors of Amorphous In–Ga–Zn–O Thin-Film Transistor Memory with an Atomic-Layer-Deposited ZnO Charge Trapping Layer
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-02
    Dan-Dan Liu, Wen-Jun Liu, Jun-Xiang Pei, Lin-Yan Xie, Jingyong Huo, Xiaohan Wu, Shi-Jin Ding

    Amorphous In–Ga–Zn-O (a-IGZO) thin-film transistor (TFT) memories are attracting many interests for future system-on-panel applications; however, they usually exhibit a poor erasing efficiency. In this article, we investigate voltage-polarity-dependent programming behaviors of an a-IGZO TFT memory with an atomic-layer-deposited ZnO charge trapping layer (CTL). The pristine devices demonstrate electrically programmable characteristics not only under positive gate biases but also under negative gate biases. In particular, the latter can generate a much higher programming efficiency than the former. Upon applying a gate bias pulse of +13 V/1 μs, the device shows a threshold voltage shift (ΔVth) of 2 V; and the ΔVth is as large as −6.5 V for a gate bias pulse of −13 V/1 μs. In the case of 12 V/1 ms programming (P) and −12 V/10 μs erasing (E), a memory window as large as 7.2 V can be achieved at 103 of P/E cycles. By comparing the ZnO CTLs annealed in O2 or N2 with the as-deposited one, it is concluded that the oxygen vacancy (VO)-related defects dominate the bipolar programming characteristics of the TFT memory devices. For programming at positive gate voltage, electrons are injected from the IGZO channel into the ZnO layer and preferentially trapped at deep levels of singly ionized oxygen vacancy (VO +) and doubly ionized oxygen vacancy (VO 2+). Regarding programming at negative gate voltage, electrons are de-trapped easily from neutral oxygen vacancies because of shallow donors and tunnel back to the channel. This thus leads to highly efficient erasing by the formation of additional ionized oxygen vacancies with positive charges.

    更新日期:2019-12-02
  • Transparent Polyurethane Nanofiber Air Filter for High-Efficiency PM2.5 Capture
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-02
    Wen Liang, Yuan Xu, Xiao Li, Xiao-Xiong Wang, Hong-Di Zhang, Miao Yu, Seeram Ramakrishna, Yun-Ze Long

    Fine particulate matter (PM) has seriously affected human life, such as affecting human health, climate, and ecological environment. Recently, many researchers use electrospinning to prepare nanofiber air filters for effective removal of fine particle matter. However, electrospinning of the polymer fibers onto the window screen uniformly is only achieved in the laboratory, and the realization of industrialization is still very challenging. Here, we report an electrospinning method using a rotating bead spinneret for large-scale electrospinning of thermoplastic polyurethane (TPU) onto conductive mesh with high productivity of 1000 m2/day. By changing the concentration of TPU in the polymer solution, PM2.5 removal efficiency of nanofiber-based air filter can be up to 99.654% with good optical transparency of 60%, and the contact angle and the ventilation rate of the nanofiber-based air filter is 128.5° and 3480 mm/s, respectively. After 10 times of filtration, the removal efficiency is only reduced by 1.6%. This transparent air filter based on TPU nanofibers has excellent filtration efficiency and ventilation rate, which can effectively ensure indoor air quality of the residential buildings.

    更新日期:2019-12-02
  • Investigation of Band Alignment for Hybrid 2D-MoS 2 /3D-β-Ga 2 O 3 Heterojunctions with Nitridation
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-02
    Ya-Wei Huan, Ke Xu, Wen-Jun Liu, Hao Zhang, Dmitriy Anatolyevich Golosov, Chang-Tai Xia, Hong-Yu Yu, Xiao-Han Wu, Qing-Qing Sun, Shi-Jin Ding

    Hybrid heterojunctions based on two-dimensional (2D) and conventional three-dimensional (3D) materials provide a promising way toward nanoelectronic devices with engineered features. In this work, we investigated the band alignment of a mixed-dimensional heterojunction composed of transferred MoS2 on β-Ga2O3(\( 2- \)01) with and without nitridation. The conduction and valence band offsets for unnitrided 2D-MoS2/3D-β-Ga2O3 heterojunction were determined to be respectively 0.43 ± 0.1 and 2.87 ± 0.1 eV. For the nitrided heterojunction, the conduction and valence band offsets were deduced to 0.68 ± 0.1 and 2.62 ± 0.1 eV, respectively. The modified band alignment could result from the dipole formed by charge transfer across the heterojunction interface. The effect of nitridation on the band alignments between group III oxides and transition metal dichalcogenides will supply feasible technical routes for designing their heterojunction-based electronic and optoelectronic devices.

    更新日期:2019-12-02
  • Development of a 1550-nm InAs/GaAs Quantum Dot Saturable Absorber Mirror with a Short-Period Superlattice Capping Structure Towards Femtosecond Fiber Laser Applications
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-02
    Cheng Jiang, Jiqiang Ning, Xiaohui Li, Xu Wang, Ziyang Zhang

    Low-dimensional III–V InAs/GaAs quantum dots (QDs) have been successfully applied to semiconductor saturable absorber mirrors (SESAMs) working at a 900–1310-nm wavelength range for ultrafast pulsed laser applications benefitting from their broad bandwidth, wavelength flexibility, and low saturation fluence. However, it is very challenging to obtain a high-performance QD-SESAM working at the longer wavelength range around 1550 nm due to the huge obstacle to epitaxy growth of the QD structures. In this work, for the first time, it is revealed that, the InAs/GaAs QD system designed for the 1550-nm light emission range, the very weak carrier relaxation process from the capping layers (CLs) to QDs is mainly responsible for the poor emission performance, according to which we have developed a short-period superlattice (In0.20Ga0.80As/In0.30Ga0.70As)5 as the CL for the QDs and has realized ~ 10 times stronger emission at 1550 nm compared with the conventional InGaAs CL. Based on the developed QD structure, high-performance QD-SESAMs have been successfully achieved, exhibiting a very small saturation intensity of 13.7 MW/cm2 and a large nonlinear modulation depth of 1.6 %, simultaneously, which enables the construction of a 1550-nm femtosecond mode-locked fiber lasers with excellent long-term working stability.

    更新日期:2019-12-02
  • ZIF-67-Derived CoSe/NC Composites as Anode Materials for Lithium-Ion Batteries
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-12-02
    Zongyang Li, Lian Ying Zhang, Lei Zhang, Jiamu Huang, Hongdong Liu

    As a typical metal selenide, CoSe is a kind of foreground anode material for lithium-ion batteries (LIBs) because of its two-dimensional layer structure, good electrical conductivity, and high theoretical capacity. In this work, the original CoSe/N-doped carbon (CoSe/NC) composites were synthesized using ZIF-67 as a precursor, in which the CoSe nanoparticles are encapsulated in NC nanolayers and they are connected through C–Se bonds. The coating structure and strong chemical coupling make the NC nanolayers could better effectively enhance the lithium storage properties of CoSe/NC composites. As a consequence, the CoSe/NC composites deliver a reversible capacity of 310.11 mAh g−1 after 500 cycles at 1.0 A g−1. Besides, the CoSe/NC composites show a distinct incremental behavior of capacity.

    更新日期:2019-12-02
  • Wrinkle Structured Network of Silver-Coated Carbon Nanotubes for Wearable Sensors
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-11-29
    Zhongyun Yuan, Zhen Pei, Muhammad Shahbaz, Qiang Zhang, Kai Zhuo, Chun Zhao, Wendong Zhang, Xingyi Ma, Shengbo Sang

    Soft-strain-based sensors are being increasingly used across various fields, including wearable sensing, behavior monitoring, and electrophysiological diagnostics. However, throughout all applications, the function of these sensors is limited because of high sensitivity, high-dynamic range, and low-power consumption. In this paper, we focus on improving the sensitivity and strain range of the soft-strain-based sensor through structure, surface, and sensitive unit treatment. Nanosilver (Ag)-coated hydroxyl-functionalized multi-walled carbon nanotubes (OH-f MWCNTs) were explored for highly acute sensing. With stretching and depositing methods, Ag@OH-f MWCNTs and polydimethylsiloxane (PDMS) are fabricated into a wrinkled and sandwich structure for a soft-strain-based sensor. The electronic properties were characterized in that the gauge factor (GF) = ΔR/R0 was 412.32, and the strain range was 42.2%. Moreover, our soft-strain-based sensor exhibits features including flexibility, ultra-lightweight and a highly comfortable experience in terms of wearability. Finally, some physiological and behavioral features can be sampled by testing the exceptional resistance change, including the detection of breath, as well as facial and hand movement recognition. The experiment exhibits its superiority in terms of being highly sensitive and having an extensive range of sensing.

    更新日期:2019-11-30
  • Shape Stability of Metallic Nanoplates: A Molecular Dynamics Study
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-11-29
    Xiwen Chen, Rao Huang, Tien-Mo Shih, Yu-Hua Wen

    Metallic nanoplates have attracted widespread interests owing to their functional versatility, which relies heavily on their morphologies. In this study, the shape stability of several metallic nanoplates with body-centered-cubic (bcc) lattices is investigated by employing molecular dynamics simulations. It is found that the nanoplate with (110) surface planes is the most stable compared to the ones with (111) and (001) surfaces, and their shapes evolve with different patterns as the temperature increases. The formation of differently orientated facets is observed in the (001) nanoplates, which leads to the accumulation of shear stress and thus results in the subsequent formation of saddle shape. The associated shape evolution is quantitatively characterized. Further simulations suggest that the shape stability could be tuned by facet orientations, nanoplate sizes (including diameter and thickness), and components.

    更新日期:2019-11-30
  • Raman Spectroscopic Characterizations of Self-Catalyzed InP/InAs/InP One-Dimensional Nanostructures on InP(111)B Substrate using a Simple Substrate-Tilting Method
    Nanoscale Res. Lett. (IF 3.159) Pub Date : 2019-11-28
    Jeung Hun Park, Choong-Heui Chung

    We report optical phonon vibration modes in ensembles of self-catalyzed InP/InAs/InP multi core-shell one-dimensional nanostructures (nanopillars and nanocones) grown on InP(111)B substrates using liquid indium droplets as a catalyst via metal-organic chemical vapor deposition. We characterized the Raman vibration modes of InAs E1(TO), InAs A1(TO), InAs E1(LO), InP E1(TO), InP A1(LO), and InP E1(LO) from the ensemble of as-grown nanostructures. We also identified second-order Raman vibration modes, associated with InP E1(2TO), E1(LO+TO), and E1(2LO), in the InP/InAs/InP core-shell nanopillars and nanocones. Raman spectra of InP/InAs/InP nanopillars showed redshift and broadening of LO modes at low-frequency branches of InAs and InP. Due to the polar nature in groups III–V nanowires, we observed strong frequency splitting between InAs E1(TO) and InAs A1(LO) in InP/InAs/InP nanocones. The Raman resonance intensities of InP and InAs LO modes are found to be changed linearly with an excitation power. By tilting the substrate relative to the incoming laser beam, we observed strong suppression of low-frequency branch of InP and InAs LO phonon vibrations from InP/InAs/InP nanocones. The integrated intensity ratio of InP E1(TO)/E1(LO) for both nanostructures is almost constant at 0-degree tilt, but the ratio of the nanocones is dramatically increased at 30-degree tilt. Our results suggest that Raman spectroscopy characterization with a simple substrate tilting method can provide new insights into non-destructive characterization of the shape, structure, and composition of the as-grown nanostructures for the wafer-scale growth and integration processing of groups III–V semiconducting hetero-nanostructures into nanoelectronics and photonics applications.

    更新日期:2019-11-29
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