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Cesare Benedetti, Paraskevi Flouda, Alice Antonello, Christine Rosenauer, Francisco F Perez-Pla, Katharina Landfester, Silvia Gross, Rafael Munoz-Espi
Photoactivated free radical miniemulsion copolymerization of methyl methacrylate (MMA) and the zirconium oxocluster Zr4O2(methacrylate)12 is used as an effective and fast preparation method of polymer/inorganic hybrid nanoparticles. The oxoclusters, covalently anchored to the polymer network, act as metal-organic cross-linkers, thus improving the thermomechanical properties of the resulting hybrid nanoparticles. Benzoin carbonyl organic compounds were used as photoinitiators. The obtained materials are compared in terms of cross-linking, effectiveness of cluster incorporation, and size distribution with the analogous nanoparticles produced by using conventional thermally-induced free radical miniemulsion copolymerization...
June 23, 2017: Nanotechnology
Hicham Bakkali, Eduardo Blanco, Manuel Dominguez, Jose S Garitaonandia
Discontinuous multilayer (DML) thin films, which consist of nano-granular metals (NGMs) embedded in a dielectric matrix, have attracted significant interest as engineered plasmonic metamaterials. In this study, a systematic layer-by-layer deposition of three-dimensional sub-wavelength periodic plasmonic DML structures via the radio frequency sputtering of a composite target has been reported. The overall optical response of the DML films composed of AuAl2O3 NGM homogenous layers, which are periodically sandwiched between two amorphous Al2O3 layers, are studied using reflection spectroscopic ellipsometry and transmission spectroscopy techniques...
June 23, 2017: Nanotechnology
Vasilii I Popov, Danil Nikolaev, Vladimir B Timofeev, Svetlana Smagulova, Irina Antonova
The response of graphene based humidity sensor is considered as a function of film structures. Analysis of resistance changes due to water molecule adsorption on graphene or multigraphene (MLG) surface is performed for films with a different resistivity from hundreds of Ohm/sq to hundreds of kOhm/sq. It has revealed a possible increase, decrease and non monotonous behavior of resistance. Adsorption of water molecules at grain boundary defects is supposed to lead to an increase in film resistivity due to the donor property of water and p-type conductivity of graphene...
June 23, 2017: Nanotechnology
Filiz Keles, Emad O Badraddin, Tansel Karabacak
A critical factor for an efficient light harvesting device is reduced reflectance in order to achieve high optical absorptance. In this regard, refractive index engineering becomes important to minimize reflectance. In this study, a new fabrication approach to obtain the density-modulated CuInxGa(1-x)Se2 (CIGS) thin films with self-anti-reflective properties has been demonstrated. Density-modulated CIGS samples were fabricated by utilizing high pressure sputtering (HIPS) at Ar gas pressure of 2.75 x 10-2 mbar along with the conventional low pressure sputtering (LPS) at Ar gas pressure of 3...
June 23, 2017: Nanotechnology
Md Mehebub Alam, Ayesha Sultana, Debabrata Sarkar, Dipankar Mandal
The electroactive β-phase is most desirable due to its highest piezo-, pyro- and ferro-electric properties in poly(vinylidene fluoride) (PVDF). Induction of β-phase is successfully accomplished in titanium dioxide (TiO2) nanoparticles (NPs) doped spin coated PVDF nanocomposite (PNC) films. The optimized yields of β-phase and homogeneous ultra-smooth free standing PNC film is utilized in mechanical energy harvesting application by fabricating a nanogenerator (NG) where the typical electrical poling step is not undertaken...
June 22, 2017: Nanotechnology
Sai Li, Wang Kang, Yangqi Huang, Xichao Zhang, Yan Zhou, Weisheng Zhao
Neuromorphic computing, inspired by the biological nervous system, has attracted considerable attention. Intensive researches have been conducted in this field for developing artificial synapses and neurons, attempting to mimic the behaviors of biological synapses and neurons, which are two basic elements of a human brain. Recently, magnetic skyrmions have been investigated as promising candidates in neuromorphic computing design owing to their topologically protected particle-like behaviors, nanoscale size and low driving current density...
June 22, 2017: Nanotechnology
Ki Dong Yang, Chan Woo Lee, Jun Ho Jang, Tak Rae Ha, Ki Tae Nam
The electrocatalytic conversion of CO<sub>2</sub> into value-added fuels has received increasing attention as a promising way to mitigate the atmospheric CO<sub>2</sub> concentration and close the broken carbon-cycle. Early studies, focused on polycrystalline metal electrodes, outlined in detail the overall trends in the catalytic activity and product selectivity of pure metals; however, several inherent limitations were found, such as low current density and high overpotential, which hindered electrocatalytic CO<sub>2</sub> reduction from practical application...
June 22, 2017: Nanotechnology
Xiaoxuan Ma, Jun Hu, Bicai Pan
Search for low-dimensional materials with unique electronic properties is important for the development of electronic devices in nano scale. Through systematic first-principles calculations, we found that the band gaps of the two-dimensional honeycomb monolayers and one-dimensional single-walled nanotubes of IIB-VI semiconductors (ZnO, CdO, ZnS and CdS) are nearly chirality-independent and weakly diameter-dependent. Based on analysis of the electronic structures, it was found that the conduction band minimum is contributed by the spherically symmetric $s$ orbitals of cations and the valence band maximum is dominated by the in-plane d<sub>xy</sub>-p<sub>y</sub> and d<sub>x<sup>2</sup>-y<sup>2</sup></sub>-p<sub>x</sub> hybridizations...
June 21, 2017: Nanotechnology
Tao Zhang, Bo Xiao, Pengyu Zhou, Long Xia, Guangwu Wen, Haibin Zhang
Carbon nanofibers decorated with porous carbon nanotubes have been prepared by electrospinning and annealing methods. Microwave reflection loss of the products is investigated in the frequency range of 2-18 GHz. The bandwidth with a reflection loss less than -10 dB covers a wide frequency ranging from 7.0 to 14.1 GHz with the thickness of 3.0-5.5 mm, and the minimum reflection loss is -44.5 dB at 10.7 GHz with a thickness of 2.0 mm. The large reflection loss and wide reflection band reveals that the products could be a promising candidate for microwave absorption...
June 21, 2017: Nanotechnology
Xinyan Jiao, Xifeng Xia, Peng Liu, Wu Lei, Yu Ouyang, Qingli Hao
Strongly coupled boron and nitrogen co-doped graphene (BN-G) hybrids with nickel cobaltite (NiCo2O4) nanosheets (NCO/BN-G) were fabricated by a facile soft-chemical method for asymmetric supercapacitors with high-performance. The strong interaction between BN-G and NiCo2O4 nanosheets are explored by various techniques. The effect of heteroatom doping on electrochemical properties of the hybrids is systematically investigated. The strong synergistic effect between NiCo2O4 and BN-G leads to a specific capacitance of 106...
June 21, 2017: Nanotechnology
Emma Harrison, Jeremy Hamilton, Manuel Montero, Dorian Dixon
We report herein on the synthesis of mixed monolayer gold nanoparticles (AuNPs) capped with both polyethylene glycol (PEG) and one of three peptides. Either a receptor-mediated endocytosis (RME) peptide, an endosomal escape pathway (H5WYG) peptide or the Nrp-1 targeting RGD peptide (CRGDK) labelled with FITC. All three peptides have a thiol containing cysteine residue which can be used to bind the peptides to the AuNPs. In order to investigate the influence of pH on peptide attachment, PEGylated AuNPs were centrifuged, the supernatant removed, and the nanoparticles were then re-suspended in a range of pH buffer solutions above, below and at the respective isoelectric points of the peptides before co-functionalization...
June 20, 2017: Nanotechnology
Ying Wang, Jiahui Guo, Li Li, Yali Ge, Baojun Li, Yingjiu Zhang, Yuanyuan Shang, Anyuan Cao
Single-walled carbon nanotube (SWNT) films are a potential candidate as porous conductive electrodes for energy conversion and storage; tailoring the loading and distribution of active materials grafted on SWNTs is critical for achieving maximum performance. Here, we show that as-synthesized SWNT samples containing residual Fe catalyst can be directly converted to Fe2O3/SWNT composite films by thermal annealing in air. The mass loading of Fe2O3 nanoparticles is tunable from 63 wt.% up to 96 wt.%, depending on the annealing temperature (from 450 C to 600 C), while maintaining the porous network structure...
June 20, 2017: Nanotechnology
Kun Li, Hu Wang, Huiying Li, Ye Li, Guangyong Jin, LanLan Gao, Mazzeo Marco, Yu Duan
Transparent conductive electrode (TCE) platforms are required in many optoelectronic devices, including organic light emitting diodes (OLEDs). To date, Indium Tin Oxide (ITO) based electrodes are widely used in TCEs but they still have few limitations in term of achieving flexible OLEDs and display techniques. In this paper, highly-flexible and ultra-thin TCEs were fabricated for use in OLEDs by combining single-layer graphene (SLG) with thin silver layers of only several nanometers in thickness. The as-prepared SLG+Ag (8nm) composite electrodes showed low sheet resistances of 9Ω/sq, high stability over 500 bending cycles, and 74% transmittance at 550nm wavelength...
June 20, 2017: Nanotechnology
Susann Liedtke, Christoph Grüner, Andriy Lotnyk, Bernd Rauschenbach
Metallic thin films consisting of separated nanostructures are fabricated by evaporative glancing angle deposition at room temperature. The columnar microstructure of the Ti and Cr columns is investigated by high resolution transmission electron microscopy and selective area electron diffraction. The morphology of the sculptured metallic films is studied by scanning electron microscopy. It is found that tilted Ti and Cr columns grow with a single crystalline morphology, while upright Cr columns are polycrystalline...
June 20, 2017: Nanotechnology
Yiwei Liu, Can Yang, Jinyan Zhao, Shengli Wu, Liyan Dai, Gang Niu
Solid state incandescent light emission devices (SSI-LEDs) with metal-oxide-semiconductor structure is a promising candidate for future broad band light emission devices. In this work, electrical and light emission features of SSI-LEDs based on HfO<sub>2</sub> high-k thin films with or without the Ti-embedded layer on p-type silicon wafers have been studied. It turns out that the Ti-embedded layer can effectively reduce the turn-on voltage thus improving the fluorescence efficiency of SSI-LEDs. The combination of scanning electron microscope (SEM), atomic force microscope (AFM) and conductive AFM (CAFM) results unambiguously clarifies that conductive filaments, which are formed due to local thermal excitation during the forming process, are accompanied with the formation of pits on HfO<sub>2</sub> surface and are responsible for the light emitting...
June 20, 2017: Nanotechnology
Kristina Aponiene, Tomas Serevičius, Zivile Luksiene, Saulius Jursenas
Various zinc oxide (ZnO) nanostructures are widely used for photocatalytic antibacterial applications. Since ZnO possess a wide bandgap, it is believed that only UV light may efficiently assist bacterial inactivation and diverse crystal lattice modifications should be applied in order to narrow the bandgap for efficient visible light absorption. In this work we show that even unmodified ZnO nanorods grown by aqueous chemical growth technique were found to possess intrinsic defects which can be activated by visible light ( = 405 nm) and successfully applied for total inactivation of various highly resistant bacterial biofilms rather than more sensitive planktonic bacteria...
June 19, 2017: Nanotechnology
Kuanguo Li, Yong Wang, Kang Jiang, Yuan Ren, Yanqiu Dai, Yonghua Lu, Pei Wang
Large-area ordered arrays with dense hot spots are highly desirable substrates for surface-enhanced Raman scattering (SERS). In this paper, we present a quasi-3D SERS substrate of free-standing Ag triangle arrays (FATA) which was fabricated by nanosphere lithography incorporated with photolithography and Ag covering. Significant SERS effect arises from a strongly enhanced local electric field within the tiny gaps between the suspending Ag triangle and the Ag baseplate. The SERS intensity relative standard deviation (RSD) is less than 7...
June 19, 2017: Nanotechnology
Eliana Vieira, Johann Toudert, Anabela Gomes Rolo, Andrea Parisini, Joaquim Leitão, Maria Rosario Correia, Nuno Franco, Eduardo Alves, Adil Chahboun, Javier Martin-Sanchez, Rosalia Serna, Maria de Jesus de Matos Gomes
In this work, we report on the production of regular (SiGe/SiO2)20 multilayer structures by conventional RF-magnetron sputtering, at 350 ºC. Transmission electron microscopy, scanning transmission electron microscopy, raman spectroscopy, and X-ray reflectometry measurements revealed that annealing at a temperature of 1000 ºC lead to the formation of SiGe nanocrystals between SiO2 thin layers with good multilayer stability. Reducing the nominal SiGe layer thickness (tSiGe) from 3.5 to 2 nm results in a transition from continuous SiGe crystalline layer (tSiGe ~ 3...
June 19, 2017: Nanotechnology
Yan Li, Yu Dai, Xiaojin Zhang, Jihua Chen
MicroRNAs (miRNAs), small non-coding RNAs, play an important role in modulating cell proliferation, migration, and differentiation. Since miRNAs can regulate multiple cancer-related genes simultaneously, regulating miRNAs could target a set of related oncogenic genes or pathways. Owing to their reduced immune response and low toxicity, miRNAs with small size and low molecular weight have become increasingly promising therapeutic drugs in cancer therapy. However, one of the major challenges of miRNAs-based cancer therapy is to achieve specific, effective, and safe delivery of therapeutic miRNAs into cancer cells...
June 19, 2017: Nanotechnology
Kunming Gu, Sheng Yu, Kwesi Eshun, Haiwen Yuan, Huixian Ye, Jiaoning Tang, Dimitris E Ioannou, Changshi Xiao, Hui Wang, Qiliang Li
In this paper, we report a comprehensive modeling and simulation study of constructing hybrid layered materials by alternately stacking MoS2 and WSe2 monolayers. Such hybrid MoS2/WSe2 hetero-multilayers exhibited direct bandgap semiconductor characteristics with bandgap energy (Eg) in a range of 0.45eV - 0.55eV at room temperature, very attractive for optoelectronics (wavelength range 2.5m . 2.75m) based on thicker two-dimensional (2D) materials. It was also found that the interlayer distance has a significant impact on the electronic properties of the hetero-multilayers, for example, a five orders of magnitude change in the conductance was observed...
June 19, 2017: Nanotechnology
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