Micro & Nano Letters
Volume 14, Issue 4, 03 April 2019
Volumes & issues:
Volume 14, Issue 4
03 April 2019
Facile fabrication of ZrO2@PMMA@polysiloxane nanohybrids and their application for light diffusing films
- Author(s): Xiaohai Bu ; Dongxian Li ; Zewu Zhang ; Chaofeng Hong ; Li Zhang ; Xiaoming Yang
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 349 –352
- DOI: 10.1049/mnl.2018.5460
- Type: Article
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In this study, novel zirconium dioxide (ZrO2)@poly(methyl methacrylate (PMMA)@polysiloxane nanohybrids were facilely synthesised using a one-pot suspension polymerisation route. Various characterisations including Fourier transform-infrared, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy were performed to record the components and morphology of the ZrO2@PMMA@polysiloxane nanohybrids. The nanohybrids were used as fillers in optical acrylate resins to enhance the optical properties of bare PET film. The ultraviolet (UV)–visible spectra show that the nanohybrids can absorb harmful UV rays, which has a great effect on prolonging the service life of light-diffusing films. The results also show that the transmittances of the films slightly decrease with the increasing filler loading, while the haze values increase. High transmittance and enhanced haze of the films could be achieved by incorporating 6% nanohybrids, which was better than commercial goods.
Application of β-CD/HA composite as a potential SD carrier to improve the dissolution of curcumin
- Author(s): Defeng Xu ; Wenjie Wang ; Mengmeng Yang ; Sarit B. Bhaduri ; Chingcheng Huang ; Lei Yang ; Zhenyi Zhang ; Huan Zhou
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 353 –358
- DOI: 10.1049/mnl.2018.5096
- Type: Article
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Curcumin is a natural active constituent with a great variety of beneficial biological and pharmacological activities, is a practically water-insoluble component. The scope of the present work was to prepare a solid dispersion (SD) formulation to enhance the dissolution rate of curcumin. The SD was prepared using curcumin and β-cyclodextrin (CD)/HA via a classical ethanol-based solvent evaporation method. The as-prepared β-CD/HA and SDs were selectively characterised by various analytical techniques including X-ray diffraction, transmission electron microscopy, scanning electron microscopy, specific surface area/pore size analysis, Fourier transform infrared spectroscopy, and high-performance liquid chromatography. According to the dissolution tests, it was confirmed that β-CD/HA–curcumin SD can significantly enhance the dissolution of curcumin. In addition, an increasing trend was seen between the β-CD weight ratio and the dissolution rate of curcumin, and β-CD/HA–curcumin (9:1) SD was shown to be the best formulation among all tested samples with over 90% curcumin dissolved in 180 min. Besides, β-CD/HA–curcumin (9:1) SD exhibited pH and medium-dependent curcumin release behaviours. The antioxidant activity of released curcumin showed no difference to original curcumin. These results clearly demonstrated β-CD/HA can be a promising SD carrier to improve the dissolution of curcumin.
Salicylic acid-sensitised titanium dioxide for photocatalytic degradation of fast green FCF under visible light irradiation
- Author(s): Wei-Renn Tang ; Tsunghsueh Wu ; Yang-Wei Lin
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 359 –362
- DOI: 10.1049/mnl.2018.5562
- Type: Article
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Synthesis and modification of salicylic acid (SA) adsorbed titanium dioxide (SA-TiO2) was proposed through a sol–gel reaction following annealing treatment. The prepared SA-TiO2 exhibited visible light absorption because of the formation of an intramolecular ligand to metal charge transfer transition. The photocatalytic activity of SA-TiO2 for the degradation of fast green FCF under visible light irradiation was evaluated. The experimental results suggest that the enhanced photocatalytic activity of SA-TiO2 is attributed to the visible light absorption ability. Moreover, •OH and •O2 − radicals are major active species involved in dye degradation. The practicality of SA-TiO2 was validated through the degradation of various dyestuff in environmental water samples under visible light irradiation.
Controlled synthesis of Ag3PO4 microparticles with different morphologies and their photocatalytic degradation of rhodamine B under white light-emitting diode irradiation
- Author(s): Tzu-Ting Wei ; Tsunghsueh Wu ; Yang-Wei Lin
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 363 –366
- DOI: 10.1049/mnl.2018.5561
- Type: Article
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A facile morphological specific precipitation method by volumetric control of the precursors has been demonstrated to achieve tetrapod-like and dodecahedron-like Ag3PO4 microparticles, which show superior visible-light responsive of photocatalytic activity when comparing to TiO2 (P25). This study also reveals that the tetrapod-like Ag3PO4 microparticles exhibit significantly higher photocatalytic activity (95.6% degradation within 20 min, k: 0.1937 min−1) than the dodecahedrons (78.9% degradation within 30 min, k: 0.0593 min−1) for the degradation of rhodamine B (RhB, 10 ppm) under low-power white light-emitting diode irradiation (300 mW cm−2), which may be attributed to the high reactivity of {110} facets. Moreover, holes and superoxide radicals were the main reactive species involved in RhB degradation.
Acorus calamus gold nanoparticles as enhanced anti-microbial agents for transdermal patches
- Author(s): Smina Chappalathottil Sethumadhavan and Lalitha Pottail
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 367 –372
- DOI: 10.1049/mnl.2018.5512
- Type: Article
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During the past 20 years, there has been a drastic advancement in the formulation and administration of drugs. In comparison to the conventional oral, traditional and invasive methods of drug delivery, the transdermal (TD) delivery system offers enhanced drug delivery through skin permeation. TD delivery market is contributing greatly to the medical field as it is as an alternate to all other medicinal intake approaches. Nanoparticles enhance the performance of biomaterials in cancer therapy, drug delivery and microbial management. This study involves the synthesis of gold nanoparticles using the aqueous extracts of Acorus calamus and the incorporation of Acorus gold nanoparticles with the biomaterial collagen extracted and isolated from soy seeds. Collagen exhibits biodegradability, low antigenicity and superior biocompatibility in addition to its physiological properties as a natural extracellular matrix component. Acorus calamus mediated gold nanoparticles were fabricated onto TD patches using sonication technique. The treatment of synthesised gold nanoparticles as anti-microbial agents for TD application against E. coli has been evaluated.
Green fabrication of SH-modified GO composite for heavy metal ions removal in aqueous solution
- Author(s): Yakun Zhang ; Kuan Luo ; Jingang Yu ; Xinyu Jiang
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 373 –378
- DOI: 10.1049/mnl.2018.5576
- Type: Article
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Humic acid (HA) sodium salt (SH)-modified graphene oxide (GO) composite, which could snatch Pb (II), Cd (II) and Cu (II) effectively from aqueous solution, was fabricated by a green hydrothermal method. Here, the morphology and structure of as-synthesised SH–GO composite was presented through scanning electron microscopy, Roman spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermal gravimetric analysis. Owing to the introduction of cheap and readily available HA sodium salt, the adsorption capacity of SH–GO toward heavy metals was improved obviously, and the corresponding removal behaviours were further investigated in detail. Besides, the adsorption results were in good agreement with Langmuir isotherm and the pseudo-second kinetic model, where the thermodynamic parameters revealed the adsorption process was spontaneous and endothermic in essence. Adsorption–desorption result showing its stable adsorption capacity confirmed its great potential as adsorbent for removal of heavy metal ions from aqueous solution.
Superlattice-like Zn15Sb85/Ga30Sb70 thin films for low power and ultrafast phase change memory application
- Author(s): Rui Zhang ; Yifeng Hu ; Qingqian Chou ; Tianshu Lai ; Xiaoqin Zhu
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 379 –383
- DOI: 10.1049/mnl.2018.5483
- Type: Article
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In this study, the amorphous-to-crystalline transitions of superlattice-like (SLL) Zn15Sb85/Ga30Sb70 thin films were investigated by in situ film resistance measurement. The thermal stability, resistance and band gap of the SLL Zn15Sb85/Ga30Sb70 thin film perform well. The data retention temperature for 10 years increases from 177°C of [Zn15Sb857/Ga30Sb703] to 220°C of [Zn15Sb852/Ga30Sb708]. The X-ray diffraction patterns show the presence of a large amount of Sb phase in the Zn15Sb85/Ga30Sb70 thin films, which causes a rapid phase transition. The surface morphology is observed by atomic force microscopy, which indicates that the thickness of Ga30Sb70 in the SLL thin films can affect the grain size and inhibit the crystallisation process. For the Zn15Sb85/Ga30Sb70 thin films, an ultra-short switching time of around 2 ns is achieved. These results indicate that the SLL Zn15Sb85/Ga30Sb70 thin films have a promised application in phase change memory.
Deep insights into electrical parameters due to metal gate WFV for different gate oxide thickness in Si step FinFET
- Author(s): Rajesh Saha ; Brinda Bhowmick ; Srimanta Baishya
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 384 –388
- DOI: 10.1049/mnl.2018.5220
- Type: Article
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A systematic investigation of the impact of Ti metal gate work function variability (WFV) on various electrical parameters against variation in gate oxide thickness in both step-FinFET and conventional FinFET (C-FinFET) using technology computer-aided design simulation is reported. It is seen that WFV of Ti metal gate has a significant influence on electrical parameters such as threshold voltage (σV T), subthreshold swing (σSS), on current (σI on), and off current (σI off) with variation in gate oxide thickness. It is also perceived that the impact of WFV of Ti gate material in step-FinFET is lesser than C-FinFET. Histograms of various electrical parameters are presented for better understanding of the statistical impact of WFV of Ti metal gate in both the structures.
Controlled electrophoretic deposition of electrochemically exfoliated graphene sheets on Ag nanowires network
- Author(s): Mahdi Malekshahi Byranvand ; Fariba Tajabadi ; Saeed Mardi ; Nima Taghavinia ; Ali Amiri Zarandi ; Ali Dabirian
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 389 –393
- DOI: 10.1049/mnl.2018.5071
- Type: Article
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Electrochemical exfoliation of graphite has recently attracted a big attention as a simple, fast and scalable method for the preparation of high quality graphene, but there are some drawbacks that hinder its application. Direct deposition is one of the most critical challenges that makes it difficult to deposit uniform, compact and large scale graphene thin films. This work develops a facile electrophoretic deposition route to fabricate exfoliated graphene (EG) film on Ag nanowires (NWs) networks with a controllable film thickness in nanometers scale. EG thin films are deposited with different applied potentials and times from an EG dispersion in N, N-dimethylformamide solvent. Since confirmed by light transmittance results, the increase in deposition time or applied potential lead to an increase in the number of deposited EG layers. The scanning electron microscopy results confirm the uniformity and compactness of EG films deposited on Ag NWs network. Furthermore, transparency and conductivity of Ag NWs films before and after the deposition of EG are investigated. It shows significant improvement in its performance, as a result, it leads to Ag NWs/EG hybrid films exhibiting a sheet resistance of R s = 30 Ω sq−1, and 85% light transmittance, comparable to conventional transparent conductive oxide films.
Mussel-inspired green synthesis of Ag-coated polydopamine microspheres for selective antibacterial performance
- Author(s): Aiying Guo ; Qianzhu Mu ; Aijun Cai ; Xiuping Wang
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 394 –398
- DOI: 10.1049/mnl.2018.5357
- Type: Article
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Inspired by mussels, the antimicrobial Ag-coated polydopamine microspheres (Ag-coated PDA MSs) composites are synthesised through one-pot method. Ag nanoparticles (NPs) are easily generated using PDA MSs as green reducing agents, and are well-dispersed on the surface of PDA MSs at the same time. The morphology and structure of the Ag-coated PDA MSs are characterised by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The Ag-coated PDA MSs exhibit selective antibacterial activity towards S. aureus. Due to the elevated intracellular reactive oxygen species level, the majority of S. aureus cells are killed, however, the growth of E. coli is not affected evidently in the same condition.
Modelling and analysis of temperature-dependent carrier lifetime and surface recombination velocity of Si–ZnO heterojunction thin film solar cell
- Author(s): Deboraj Muchahary ; Santanu Maity ; Sanjeev Kumar Metya
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 399 –403
- DOI: 10.1049/mnl.2018.5147
- Type: Article
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ZnO–silicon heterojunction solar cell having high efficiency and high fill factor is structured and simulated to study its photovoltaic properties under different device temperature. Current–voltage measurement of dimensionally optimised device structure revealed up to 20.44% efficiency and 83.66% fill factor at 1 Ω-cm2 external series resistance at 300 K. Measured current–voltage shows decrease of open-circuit voltage from 659.13 to 109.1 mV and short-circuit current from 40.65 to 39.5 mA/cm2 with increase of device temperature. Quasi-steady-state photoconductance measurement reveals small recombination current and long Shockley Read Hall lifetime under the selected temperature range indicating superior performance of the device. Adverse effect of surface recombination velocity at rear surface of the device is observed at lower temperature (100–600 K) range indicating better majority carrier collection at very high temperature 700 K and above.
Approach to the preparation of temperature-sensitive poly(N-isopropylacrylamide)/polyethylenimine microgel
- Author(s): Tao Wang ; Yanan Song ; Jiawei Hu ; Jiaxi Li ; Shan Shi
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 404 –408
- DOI: 10.1049/mnl.2018.5359
- Type: Article
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A novel route was developed to the preparation of temperature-sensitive poly(N-isopropylacrylamide)/polyethylenimine (PNIPAM/PEI) microgels by the radical copolymerisation of N-isopropylacrylamide with acryloylated PEI in aqueous media. Here, the acryloylated polyethylenimine (PEI), used as a macromonomer, was synthesised by a dehydration condensation reaction between PEI and acrylic acid. The as-prepared microgels exhibited well-defined core/shell structure with PNIPAM-rich core surrounded by PEI-rich shell. The microgels showed the volume phase transition temperature near physiological temperature, which can be easily regulated by the pH of microgel dispersion.
Effect of different carbon supporter on the Ni/C catalyst for water oxidation
- Author(s): Ke Wang ; Zhiyan Sun ; Yan Zhu ; Li Chunhui
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 409 –411
- DOI: 10.1049/mnl.2018.5367
- Type: Article
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Exploring efficient and inexpensive oxygen evolution reaction (OER) electrocatalysts is essential for clean renewable energy systems. Ni-based nanomaterials have been intensively pursued for NiOOH can play a key role in OER processes in alkaline electrolytes. In this work, Ni nanoparticles (NPs) absorbed onto commercial carbon black and nitrogen-doped reduced graphene oxide as electrochemical catalysts activities in OER have been explored. The study found that the current density and Tafel slope of Ni/C nanocomposite in OER were affected obviously by different carbon supporter and the surface properties of Ni NPs. The work revealed that the Ni NPs electrical contact with supporter and surface hydrophilism of catalytically active species is more important than the size and loaded amount. The awareness of the catalytic kinetics difference deepened their comprehension of the structure–property relationship of the electrocatalyst, which would contribute to the rational design of excellent OER catalysts.
Effects of persistence time and Au catalyst on the morphology and optical properties of ZnO micro/nanostructures
- Author(s): Zohreh Negintaji ; Abdollah Mortezaali ; Amin Torabi Jahromi ; Elham Yousefi
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 412 –415
- DOI: 10.1049/mnl.2018.5440
- Type: Article
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Zinc oxide (ZnO) micro and nanostructures were synthesised on a quartz substrate by the carbothermal evaporation method. The thin layers of gold were used as a catalyst and syntheses were carried out at different persistence time. Characterisation of the layer was conducted in order to study the effect of persistence time on morphology and crystal structure and optical properties of the fabricated ZnO nanostructures. The samples were characterised by scanning electron microscopy, X-ray diffraction (XRD) and UV–vis spectrophotometry which were performed to investigate the optical properties of the fabricated ZnO layer. The XRD spectrum clearly shows that the structure is in a hexagonal wurtzite phase. Optical properties of ZnO micro and nanostructures were evaluated from transmittance data using the method proposed by Swanepoel (in the regions λ = 200–900 nm). The study’s results indicate that increasing the persistence time as well as decreasing the size of ZnO nanostructures enhances the optical bandgap to about 3.46 eV. To the best of this work's knowledge, this is the first report on the study of the correlation of optical properties obtained by Swanepoel method and morphology of ZnO nanostructures.
Facile synthesis of novel ultrathin α-MoO3 square nanosheets with excellent adsorptive capacity and photocatalytic performance for efficient treatment of Rhodamine B
- Author(s): Guogang Tang ; Feixia Zhang ; Jing Xu
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 416 –419
- DOI: 10.1049/mnl.2018.5420
- Type: Article
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Novel ultrathin α-MoO3 square nanosheets with the width of 200–400 nm and the thickness of ∼50 nm were synthesised successfully via a facile and efficient solid sintered method using the carbon@MoS2 nanocomposites as precursor. The as-prepared products were characterised by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and tested in adsorption and photocatalysis to remove Rhodamine B (RhB). Compared with commercial MoO3 and/or MoO3 nanorods, α-MoO3 square nanosheets exhibit greater adsorptive capacity and photocatalytic performance for degrading RhB. Moreover, this combination of adsorption and photocatalysis using α-MoO3 could be promising is demonstrated as a more pressing technique for contaminant removal from wastewater.
Improving breakdown performance for SOI LDMOS with sidewall field plate
- Author(s): Pan-pan Tang ; Ying Wang ; Meng-tian Bao ; Xin Luo ; Fei Cao ; Cheng-hao Yu
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 420 –423
- DOI: 10.1049/mnl.2018.5258
- Type: Article
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In this work, a silicon-on-insulator (SOI) lateral diffused MOSFET (LDMOS) incorporated with sidewall field plate (SEP) is presented and investigated using three-dimensional numeric simulation. A new additional electric field peak is formed, due to the compound field plate established along the n-drift region. The lateral surface electric field can be modulated, which enhances the breakdown voltage. Meanwhile, the doping concentration of n-drift region is increased, which decreases the specific on-resistance. Compared with the superjunction LDMOS, a 23.7% increase in the breakdown voltage and a 21.7% decrease in the specific on-resistance are obtained in the SFP-LDMOS device.
Synergy of surface textures on a hydraulic cylinder piston
- Author(s): Ying Zhang ; Liangcai Zeng ; Zhenpeng Wu ; Xianzhong Ding ; Kuisheng Chen
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 424 –429
- DOI: 10.1049/mnl.2018.5535
- Type: Article
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This paper explores the synergy mechanisms that are associated with the coexistence of multiple textures, to improve the precision control of a hydraulic servo cylinder. Based on the classical Reynolds equation, it establishes a single-texture and a nine-texture model to compare and study the synergy of surface textures. The film thickness is obtained under different working conditions for 1 N. Based on this parameter, it compares the simulation results from the two models with the experimental results to determine if the friction coefficient is reduced when multiple textures exist. When multiple textures exist, the inlet pressures of the central texture increase, but the peak pressure and cavitation pressure decrease. The synergy of the textures acts as an ‘average pressure’ and causes the pressure to decrease, which directly decreases the shear force. As the area ratio of the texture increases, the beneficial effect from the synergy gradually increases and then decreases, which implies that there is an optimum area ratio. The depth of the texture was 10 μm and the optimum depth-to-diameter ratio was 0.009. When the speed increases for a light load, the oil film thickness increases. However, this phenomenon does not substantially change the synergistic effect.
Synthesis of submicrometre Cu particles via a reduction in triethanolamine solvent
- Author(s): Myeong In Kim and Jong-Hyun Lee
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 430 –435
- DOI: 10.1049/mnl.2018.5606
- Type: Article
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With the aim of preparing a low-cost filler material to enhance the bondability of a sinter-bonding paste, submicrometre Cu particles with little agglomeration were successfully synthesised by a simple solvothermal recipe using CuO as a precursor and triethanolamine as a solvent. The required synthesis time and the average size (216–821 nm) of the synthesised Cu particles decreased proportionally with the increasing synthesis temperature. The required synthesis times were found to be 30 and 60 min and the particle sizes of 410 and 821 nm were achieved at synthesis temperatures of 200 and 180°C, respectively. The CuO particles were transformed into Cu2O nanoparticles by accepting the hydrogen ions and electrons released during the conversion of the triethanolamine to the aldehyde by the oxidation of its three hydroxyl groups. Submicrometre pure Cu particles could be subsequently formed from aggregates of the Cu2O nanoparticles by removing O ions from Cu2O during the continuous conversion of the aldehyde to nitrilotriacetic acid.
Preparation of a SiO2-covered amorphous CoFeSiB microwire and study on the current amplitude effect on the transverse giant magnetoimpedance
- Author(s): Tao Wang ; Yi He ; Yuyi Chen ; Dongya Huang ; Jun Yang ; Jinjun Rao ; Hengyu Li ; Bicong Wang ; Bowen Wang ; Mei Liu
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 436 –439
- DOI: 10.1049/mnl.2018.5547
- Type: Article
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A SiO2-covered amorphous wire was prepared by the melt spinning technique for investigation of the current amplitude effect on the giant magnetoimpedance (GMI). The raw alloy (CoFeSiB) was placed in a SiO2 tube and heated by induced current (600 A) for 50 s, then the SiO2-covered amorphous wire was formed through external traction and cooling water. The current amplitude effects on the transverse GMI, giant magnetoresistance (GMR) and giant magnetoreactance (GMX) in the SiO2-covered amorphous CoFeSiB wire were studied thoroughly. It was observed that the transverse GMI ratio, GMR ratio, and GMX ratio all increase with decreasing the current amplitude, demonstrating the possibility of using them to design low-consumption, high-sensitive and muti-dimension magnetometer.
Preparation of CQDs with hydroxyl function for Fe3+ detection
- Author(s): Limin Dong ; Wanqi Zhang ; Xuejiao Li ; Xiaoyao Geng
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 440 –444
- DOI: 10.1049/mnl.2018.5369
- Type: Article
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Owing to its excellent fluorescence stability, unique up-conversion fluorescence properties and biocompatibility, carbon-quantum dots (CQDs) have become a research hot spot in the field of carbon materials. This study used a series of different preparation strategies to synthesise CQDs such as microwave method, solvothermal method and hydrothermal method. The prepared quantum dots can be further applied to design and metal ion detection. It is worth noting that the CQDs prepared by the hydrothermal method are evenly distributed in the range of 2–3 nm without any agglomeration. Fluorescence quenching was performed by Fe3+, and the introduction of PO4 3− ion could increase the fluorescence intensity of CQDs-Fe3+ system. Furthermore, CQDs were hydroxyl functionalised by treating with ethanol. The functionalised CQDs synthesised by solvothermal method greatly enhanced the fluorescence intensity.
Preparation and structural characterisation of magnetic NiFe2O4@ABS@Ag nanocompound with antibacterial property
- Author(s): Maryam Mohebbi ; Alireza Allafchian ; Parviz Kameli ; Seyed Amirhoosien Jalali
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 445 –449
- DOI: 10.1049/mnl.2018.5175
- Type: Article
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The present research attempted to characterise the structural and magnetic characteristics of NiFe2O4@ABS@Ag nanoparticles (NPs) made of nickel ferrite (NiFe2O4), acrylonitrile butadiene styrene (ABS) and silver NPs (Ag NPs), this was done by employing techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy, as well as a vibrating sample magnetometer. The XRD patterns obtained indicated that following ABS and Ag NPs coating, the crystallite size (from Scherrer formula) was increased from 32 to 40 nm. It was confirmed by the magnetic measurements that the maximum magnetisation of the NiFe2O4 core was dropped when the surface was coated with ABS and Ag NPs. The antimicrobial activity of this three-component nanocomposite was tested, showing that the nanocomposite NiFe2O4@ABS@Ag could be isolated from a water solution by using a magnet.
Design structure of tunnel FET by combining thermionic emission with tunneling phenomenon
- Author(s): Shivendra Yadav ; Madhuri Vemulapaty ; Dheeraj Sharma ; Anju Gedam ; Neeraj Sharma
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 450 –454
- DOI: 10.1049/mnl.2018.5548
- Type: Article
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This study proposes a novel electrically doped tunnel field effect transistor (ED-TFET), which combines thermionic emission and band to band tunnelling by using an additional metal source (MS) of appropriate work function (WF; 3.9 eV) by forming an ohmic junction between metal and silicon. The ohmic junction is created below the channel region near the source channel junction by depositing of appropriate workfunction metal (lower than silicon) which injects extra electrons through over the barrier along with band to band tunneling (BTBT) in the channel of the device. Therefore, a drastic improvement in the ON state current is observed which is numerically about 107 times greater than conventional ED-TFET. Furthermore, the radiofrequency figures of merit such cut-off frequency, gain band width product, and maximum oscillating frequency are enhanced by ∼, 20 and 1000 times, respectively, however, intrinsic gain and transconductance generation factor have nearly 66.66 and 14.28% improvement compared to conventional ED-TFET. Furthermore, the concepts of drain underlapping and dual metal gate have been used to checkout OFF-state current and negative conductance as a final proposal. In addition, this study has also investigated the performance variations in the proposed structure due to the WF change of CG2, length of and position of MS.
Hydrothermal synthesis of novel Ni microflowers with enhanced ferromagnetic properties
- Author(s): Xinghua Han ; Chunju Xu ; Huiyu Chen
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 455 –457
- DOI: 10.1049/mnl.2018.5666
- Type: Article
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Novel nickel microflowers assembled with many thin nanoplates were synthesised through a simple hydrothermal method using sodium hypophosphite as a green reducing reagent. Sodium tartrate served as a complexing reagent and cetyltrimethylammonium bromide (CTAB) was used as a surfactant. It was found that the amount of sodium hydroxide played a key role in determining both the shape and to further the self-assembly process of nickel flowers. Such a flower-like nickel microstructure shows a great enhancement of the ferromagnetic properties with a coercivity of 308.7 Oe, which may be ascribed to the distinctive two-dimensional (2D) anisotropic structure of the nanoplates and the final hierarchically flower-like shape. This work presents a preferred approach to fabricate high-quality magnetic nickel microflowers which have potential applications in electrochemical devices, magnetic sensors, and catalytic agents.
Orderly deposition of multi-layer nanofibrous membrane by electrohydrodynamic direct writing
- Author(s): Gaofeng Zheng ; Ping Zhu ; Jiaxin Jiang ; Weizheng Zhong ; Jianyi Zheng ; Juan Liu ; Xiang Wang ; Wenwang Li ; Shumin Guo
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 458 –461
- DOI: 10.1049/mnl.2018.5692
- Type: Article
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High sensitivity bio-detection puts forward great requirement on the orderly deposition of multi-layer nanofibrous membrane within the substrate. Electrohydrodynamic direct writing was utilised to realise the precise deposition of nanofibres, then multi-layer nanofibrous membrane can be gained by controlling the collector to move at the pre-designed trajectory repeatedly. How to overcome the fusion between layers has been the key to the orderly deposition of multi-layer nanofibrous membrane. The deposition and deformation behaviours and optimised controlling strategies of the deposited multi-layer nanofibrous membrane were studied. The distance between the parallel nanofibres was decreased and a time interval was introduced to adjust the solidification process to overcome the fibre fusion between two adjacent layers. The uniform solid nanofibres without obvious deformation can be printed layer by layer to build the orderly multi-layer nanofibrous membrane. This work provides an excellent way for the fast fabrication of high sensitivity bio substrate.
Two-dimensional functionalised methacrylated graphene oxide nanosheets as simple and inexpensive electrodes for biosensing applications
- Author(s): Seyed Morteza Naghib
- Source: Micro & Nano Letters, Volume 14, Issue 4, p. 462 –465
- DOI: 10.1049/mnl.2018.5320
- Type: Article
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Biosensors based on immobilised enzyme propose determination of analytes with excellent selectivity and sensitivity while their stability is still a challenge. Thus, promoting the selective, sensitive, rapid, inexpensive, and reliable strategies to fabricate new biosensors is a critical issue for the analyte determination. In this study, a novel functionalised graphene, methacrylated graphene oxide (MeGO), was utilised as an advanced biosensing device for non-enzyme determination of ascorbic acid (AA). The MeGO-based sensor was fabricated by a very simple coating approach on a glassy carbon electrode. The cyclic voltammogram of the new biosensor demonstrated a pair of well defined, reversible, and stable peaks for redox systems in a buffer solution. The exploited nanobiosensor depicted high catalytic bioactivity towards the oxidation of AA at a positive potential in the buffer solution. The biosensing characteristics of the developed nanobiosensor presented excellent sensitivity, low limit of detection, and wide linear range. To the best of this study's knowledge, this is the first research that uses MeGO in biosensing applications. Moreover, the sensing characteristics of the device are compared with other developments previously reported for non-enzyme AA sensors.
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