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Silicon nanoparticles

Yuezhou Wang, Grigorii Drozdov, Erik K Hobbie, Traian Dumitrica
Ultrathin carbon nanotube films have gathered attention for flexible electronics applications. Unfortunately, their network structure changes significantly even under small applied strains. We perform mesoscopic distinct element method simulations and develop an atomic scale picture of the network stress relaxation. On this basis, we put forward the concept of mesoscale design by the addition of excluded-volume interactions. We integrate silicon nanoparticles into our model and show that the nanoparticle-filled networks present superior stability and mechanical response relative to pure films...
March 27, 2017: ACS Applied Materials & Interfaces
Song Chen, Zhuo Chen, Yunjun Luo, Min Xia, Chuanbao Cao
Silicon is a promising alternative anode material since it has a ten times higher theoretical specific capacity than that of a traditional graphite anode. However, the poor cycling stability due to the huge volume change of Si during charge/discharge processes has seriously hampered its widespread application. To address this challenge, we design a silicon hollow sphere nanostructure by selective etching and a subsequent magnesiothermic reduction. The Si hollow spheres exhibit enhanced electrochemical properties compared to the commercial Si nanoparticles...
April 21, 2017: Nanotechnology
Andrzej Borkowski, Tomasz Cłapa, Mateusz Szala, Arkadiusz Gąsiński, Marek Selwet
We describe the synthesis of nanocomposites, based on nanofibers of silicon carbide, silver nanoparticles, and cellulose. Silver nanoparticle synthesis was achieved with chemical reduction using hydrazine by adding two different surfactants to obtain a nanocomposite with silver nanoparticles of different diameters. Determination of antibacterial activity was based on respiration tests. Enzymatic analysis indicates oxidative stress, and viability testing was conducted using an epifluorescence microscope. Strong bactericidal activity of nanocomposites was found against bacteria Escherichia coli and Bacillus cereus, which were used in the study as typical Gram-negative and Gram-positive bacteria, respectively...
September 13, 2016: Nanomaterials
Yinan Zhang, Boyuan Cai, Baohua Jia
Plasmonic metal nanoparticles supporting localized surface plasmon resonances have attracted a great deal of interest in boosting the light absorption in solar cells. Among the various plasmonic materials, the aluminium nanoparticles recently have become a rising star due to their unique ultraviolet plasmonic resonances, low cost, earth-abundance and high compatibility with the complementary metal-oxide semiconductor (CMOS) manufacturing process. Here, we report some key factors that determine the light incoupling of aluminium nanoparticles located on the front side of silicon solar cells...
May 24, 2016: Nanomaterials
Patrick Post, Nicolas Jidenko, Alfred P Weber, Jean-Pascal Borra
The plasma-based aerosol process developed for the direct coating of particles in gases with silicon oxide in a continuous chemical vapor deposition (CVD) process is presented. It is shown that non-thermal plasma filaments induced in a dielectric barrier discharge (DBD) at atmospheric pressure trigger post-DBD gas phase reactions. DBD operating conditions are first scanned to produce ozone and dinitrogen pentoxide. In the selected conditions, these plasma species react with gaseous tetraethyl orthosilicate (TEOS) precursor downstream of the DBD...
May 13, 2016: Nanomaterials
Abhishek Lahiri, Tianqi Lu, Niklas Behrens, Natalia Borisenko, Guozhu Li, Frank Endres
Metal nanoparticles such as Au, Ag, Pt, and so forth have been deposited on silicon by electroless deposition in the presence of hydrofluoric acid (HF) for applications such as oxygen reduction reaction, surface-enhanced Raman spectroscopy, as well as for lithium ion batteries. Here, we show an HF-free process wherein metals such as Sb and Ag could be deposited onto electrodeposited silicon in ionic liquids. We further show that, compared to electrodeposited silicon, Sb-modified Si demonstrates a better performance for lithium storage...
March 24, 2017: ACS Applied Materials & Interfaces
Marta Agati, Guillaume Amiard, Vincent Le Borgne, Paola Castrucci, Richard Dolbec, Maurizio De Crescenzi, My Alì El Khakani, Simona Boninelli
Scanning transmission electron microscopy (STEM) was successfully applied to the analysis of silicon nanowires (SiNWs) that were self-assembled during an inductively coupled plasma (ICP) process. The ICP-synthesized SiNWs were found to present a Si-SiO2 core-shell structure and length varying from ≈100 nm to 2-3 μm. The shorter SiNWs (maximum length ≈300 nm) were generally found to possess a nanoparticle at their tip. STEM energy dispersive X-ray (EDX) spectroscopy combined with electron tomography performed on these nanostructures revealed that they contain iron, clearly demonstrating that the short ICP-synthesized SiNWs grew via an iron-catalyzed vapor-liquid-solid (VLS) mechanism within the plasma reactor...
2017: Beilstein Journal of Nanotechnology
Tapas Ghosh, Biswarup Satpati
Copper nanoparticles have been deposited on silicon surfaces by a simple galvanic displacement reaction, and rapid thermal annealing has been performed under various atmospheric conditions. In spite of the general tendency of the agglomeration of nanoparticles to lower the surface energy at elevated temperatures, our plan-view and cross-sectional transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis shows that the thermal oxidation of the copper nanoparticles and formation of cupric oxide (CuO) on silicon surfaces leads to wetting rather than agglomeration...
2017: Beilstein Journal of Nanotechnology
Youlin Pan, Annalese Maddox, Taewoo Min, Ferdinand Gonzaga, Jonathan Goff, Barry Arkles
Cyclic azasilanes have been synthesized for the purpose of developing coupling agents appropriate for a variety of nanotechnologies including surface modification of nanoparticles, nanocrystals, mesoporous materials and substrates. N-methyl-aza-2,2,4-trimethylsilacyclopentane is representative of this class of compounds. Preliminary data for the treatment of inorganic surfaces, including nanoparticles and oxidized silicon wafers, with cyclic azasilanes suggest high density monolayer deposition by a ring-opening reaction...
March 20, 2017: Chemistry, An Asian Journal
Sanam Nazaralian, Ahmad Majd, Saeed Irian, Farzaneh Najafi, Farrokh Ghahremaninejad, Tommy Landberg, Maria Greger
Silicon (Si) fertilization improves crop cultivation and is commonly added in the form of soluble silicates. However, most natural plant-available Si originates from plant formed amorphous SiO2 particles, phytoliths, similar to SiO2-nanoparticles (SiNP). In this work we, therefore, compared the effect by sodium silicate and that of SiNP on Si accumulation, activity of antioxidative stress enzymes catalase, peroxidase, superoxide dismutase, lignification of xylem cell walls and activity of phenylalanine ammonia-lyase (PAL) as well as expression of genes for the putative silicon transporter (PST), defensive (Tfgd 1) and phosphoenolpyruvate carboxykinase (PEPCK) and protein in fenugreek (Trigonella foenum-graecum L...
March 14, 2017: Plant Physiology and Biochemistry: PPB
Ali Mohammed Alhalafi
We are entering a new era of ophthalmic pharmacology where new drugs are rapidly being developed for the treatment of anterior and posterior segment of the eye disease. The pharmacokinetics of drug delivery to the eye remains a very active area of ophthalmic research. Intraocular drug delivery systems allow the release of the drug, bypassing the blood-ocular barrier. The main advantage of these preparations is that they can release the drug over a long time with one single administration. These pharmaceutical systems are of great important in the treatment of the posterior segment diseases, and they can be prepared from biodegradable or nonbiodegradable polymers...
January 2017: Oman Journal of Ophthalmology
Shuangqiang Chen, Laifa Shen, Peter A van Aken, Joachim Maier, Yan Yu
To address the challenge of huge volume change and unstable solid electrolyte interface (SEI) of silicon in cycles, causing severe pulverization, this paper proposes a "double-shell" concept. This concept is designed to perform dual functions on encapsulating volume change of silicon and stabilizing SEI layer in cycles using double carbon shells. Double carbon shells coated Si nanoparticles (DCS-Si) are prepared. Inner carbon shell provides finite inner voids to allow large volume changes of Si nanoparticles inside of inner carbon shell, while static outer shell facilitates the formation of stable SEI...
March 15, 2017: Advanced Materials
Dohyung Kim, Nigel Becknell, Yi Yu, Peidong Yang
In heterogeneous catalysis, a nanoparticle (NP) system has immediate chemical surroundings with which its interaction needs to be considered, as nanoparticles are typically loaded onto certain supports. Beyond what is known about these interactions, dynamic atomic interactions between the nanoparticle and support could result from the increased energetics at the nanoscale. Here, we show that the dynamic response of atoms in copper nanoparticles to the underlying silica support at room temperature and ambient atmosphere results in the complete disappearance of supported nanoparticles over the course of only a few weeks...
March 15, 2017: Nano Letters
Shankar B Rananavare, Moshood K Morakinyo
Nano-patterns fabricated with extreme ultraviolet (EUV) or electron-beam (E-beam) lithography exhibit unexpected variations in size. This variation has been attributed to statistical fluctuations in the number of photons/electrons arriving at a given nano-region arising from shot-noise (SN). The SN varies inversely to the square root of a number of photons/electrons. For a fixed dosage, the SN is larger in EUV and E-beam lithographies than for traditional (193 nm) optical lithography. Bottom-up and top-down patterning approaches are combined to minimize the effects of shot noise in nano-hole patterning...
February 12, 2017: Journal of Visualized Experiments: JoVE
Aniello Falco, Jose F Salmerón, Florin C Loghin, Paolo Lugli, Almudena Rivadeneyra
A printed passive radiofrequency identification (RFID) tag in the ultra-high frequency band for light and temperature monitoring is presented. The whole tag has been manufactured by printing techniques on a flexible substrate. Antenna and interconnects are realized with silver nanoparticles via inkjet printing. A sprayed photodetector performs the light monitoring, whereas temperature measurement comes from an in-built sensor in the silicon RFID chip. One of the advantages of this system is the digital read-out and transmission of the sensors information on the RFID tag that ensures reliability...
March 8, 2017: Sensors
Hongyan Zhang, Zhenhong Jia
A new type of fluorescence "off-on" probe was designed for L-Cysteine (L-Cys) based on the fluorescence resonance energy transfer (FRET) between negatively charged amino-capped porous silicon nanoparticles (SiNPs) and positively charged citrate-stabilized Au nanoparticles (AuNPs). In this proposed FRET immunosensor, novel water-soluble amino-conjugated porous SiNPs in ethanol with excellent photoluminescence properties act as the energy donor. Excellent quenching efficiency between SiNPs-ethanol and citrate-stabilized AuNPs by electrostatic interaction via FRET provides an ideal "off-state" (turn-off)...
March 5, 2017: Sensors
Tiantian Li, Qixing Zhang, Jian Ni, Qian Huang, Dekun Zhang, Baozhang Li, Changchun Wei, Baojie Yan, Ying Zhao, Xiaodan Zhang
We used silver nanoparticles (Ag-NPs) embedded in the p-type semiconductor layer of hydrogenated amorphous silicon (a-Si:H) solar cells in the Schottky barrier contact design to modify the interface between aluminum-doped ZnO (ZnO:Al, AZO) and p-type hydrogenated amorphous silicon carbide (p-a-SiC:H) without plasmonic absorption. The high work function of the Ag-NPs provided a good channel for the transport of photogenerated holes. A p-type nanocrystalline SiC:H layer was used to compensate for the real surface defects and voids on the surface of Ag-NPs to reduce recombination at the AZO/p-type layer interface, which then enhanced the photovoltage of single-junction a-Si:H solar cells to values as high as 1...
March 17, 2017: ACS Applied Materials & Interfaces
Aubrey E Kusi-Appiah, Melanie L Mastronardi, Chenxi Qian, Kenneth K Chen, Lida Ghazanfari, Plengchart Prommapan, Christian Kübel, Geoffrey A Ozin, Steven Lenhert
Specific size, shape and surface chemistry influence the biological activity of nanoparticles. In the case of lipophilic nanoparticles, which are widely used in consumer products, there is evidence that particle size and formulation influences skin permeability and that lipophilic particles smaller than 6 nm can embed in lipid bilayers. Since most nanoparticle synthetic procedures result in mixtures of different particles, post-synthetic purification promises to provide insights into nanostructure-function relationships...
March 8, 2017: Scientific Reports
Ihfaf AlShibane, Justin S J Hargreaves, Andrew L Hector, William Levason, Andrew McFarlane
The co-ammonolysis of V(NMe2)4 and Si(NHMe)4 with ammonia in THF and in the presence of ammonium triflate ([NH4][CF3SO3]) leads to the formation of monolithic gels. Pyrolysing these gels produces mesoporous composite materials containing nanocrystalline VN and amorphous silicon imidonitride. Elemental mapping indicated a thorough distribution of VN with no evidence of large cluster segregation. Whilst not active for ammonia synthesis, the silicon nitride based materials were found to possess activity for the COx-free production of H2 from methane, which makes them candidates for applications in which the presence of low levels of CO in H2 feedstreams is detrimental...
March 7, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Shaofei Wang, Jiaolai Jiang, Haoxi Wu, Jianping Jia, Lang Shao, Hao Tang, Yiming Ren, Mingfu Chu, Xiaolin Wang
A facile surface-enhanced Raman scattering (SERS) substrate based on the self-assembly of silver nanoparticles on the modified silicon wafer was obtained, and for the first time, an advanced SERS analysis method basing on this as-prepared substrate was established for high sensitive and rapid detection of uranyl ions. Due to the weakened bond strength of OUO resulting from two kinds of adsorption of uranyl species ("strong" and "weak" adsorption) on the substrate, the ν1 symmetric stretch vibration frequency of OUO shifted from 871cm(-1) (normal Raman) to 720cm(-1) and 826cm(-1) (SERS) along with significant Raman enhancement...
February 22, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
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