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Silicon nanoparticles

Šarūnas Meškinis, Domantas Peckus, Andrius Vasiliauskas, Arvydas Čiegis, Rimantas Gudaitis, Tomas Tamulevičius, Iryna Yaremchuk, Sigitas Tamulevičius
Ultrafast relaxation dynamics of diamond-like carbon (DLC) films with embedded Ag nanoparticles (DLC:Ag) and photovoltaic properties of heterojunctions consisting of DLC:Ag and crystalline silicon (DLC:Ag/Si) were investigated by means of transient absorption (TAS) spectroscopy and photovoltaic measurements. The heterojunctions using both p type and n type silicon were studied. It was found that TAS spectra of DLC:Ag films were dependent on the used excitation wavelength. At wavelengths where Ag nanoparticles absorbed light most intensively, only DLC signal was registered...
December 2017: Nanoscale Research Letters
A Mukherjee, A D Craciun, J L Gallani, M V Rastei
We present experimental and theoretical results on controlling nanoscale sliding friction and adhesion by electric fields on model contacts realized by bringing a conductive atomic force microscope tip into contact with the surface of a silicon-oxide/silicon wafer. We find that applying a bias voltage on silicon (or on the conductive tip) enables a noticeable control of the sliding forces. Two electrostatic interactions are identified as being relevant for the friction variation as a function of applied voltage...
April 21, 2017: Faraday Discussions
Konstantin Tamarov, Maxim Gongalsky, Liubov Osminkina, Yuanhui Huang, Murad Omar, Valery Yakunin, Vasilis Ntziachristos, Daniel Razansky, Victor Timoshenko
The development of suitable contrast agents can significantly enhance the efficiency of modern imaging and treatment techniques, such as thermoacoustic (TA) tomography and radio-frequency (RF) hyperthermia of cancer. Here, we examine the heating of aqueous suspensions of silicon (Si) and gold (Au) nanoparticles (NPs) under RF irradiation in the MHz frequency range. The heating rate of aqueous suspensions of Si NPs exhibited non-monotonic dependency on the electrical conductivity of the suspension. The experimental results were explained by the mathematical model considering oscillating solvated ions as the main source of Joule heating...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
Myeongjin Kim, Jooheon Kim
Composites of micro- and mesoporous SiC flakes (SiCF) and ferroferric oxide (Fe3O4), SiCF/Fe3O4, were prepared via the chemical deposition of Fe3O4 on SiCF by the chemical reduction of an Fe precursor. The SiCF/Fe3O4 electrodes were fabricated at different Fe3O4 feeding ratios to determine the optimal Fe3O4 content that can maintain a high total surface area of SiCF/Fe3O4 composites as well as cause a vigorous redox reaction, thereby maximizing the synergistic effect between the electric double-layer capacitive effects of SiCF and the pseudo-capacitive effects of Fe3O4...
May 12, 2017: Nanotechnology
Shravan Suresh, Zi Ping Wu, Stephen F Bartolucci, Swastik Basu, Rahul Mukherjee, Tushar Gupta, Prateek Hundekar, Yunfeng Shi, Toh-Ming Lu, Nikhil Koratkar
Silicon (Si) shows promise as an anode material in lithium-ion batteries due to its very high specific capacity. However, Si is highly brittle, and in an effort to prevent Si from fracturing, the research community has migrated from the use of Si films to Si nanoparticle based electrodes. However, such a strategy significantly reduces volumetric energy density due to the porosity of Si nanoparticle electrodes. Here we show that contrary to conventional wisdom, Si films can be stabilized by two strategies: (a) anchoring the Si films to a carbon nanotube macrofilm (CNM) current collector and (b) draping the films with a graphene monolayer...
April 20, 2017: ACS Nano
Junlu Sheng, Yue Xu, Jianyong Yu, Bin Ding
Superhydrophobic waterproof-breathable membranes have attracted considerable interest owing to their multifunctional applications in self-cleaning, anti-icing, anticorrosion, outdoor tents, and protective clothing. Despite the researches pertaning to the construction of superhydrophobic functional membranes by nanoparticle finishing have increased drastically, the disconnected particle component is easy to fall off from the membranes under deformation and wear conditions, which has restricted their wide use in practice...
April 21, 2017: ACS Applied Materials & Interfaces
Jan Menser, Kyle Daun, Thomas Dreier, Christof Schulz
The temporal luminescence behavior of silicon atoms during and after laser-heating of gas-borne silicon nanoparticles was investigated. Silicon nanoparticles were formed in the exhaust stream of a microwave plasma reactor at 100 mbar. The observed prompt atomic line intensities correspond with thermal excitation of the evaporated species. A prompt signal at 251.61 and 288.15 nm originating from the 3s<sup>2</sup>3p<sup>2</sup>→3s<sup>2</sup>3p4s transitions showed a lifetime of 16 ns that matches the documented excited-state lifetime for the respective transitions...
April 10, 2017: Applied Optics
Yan Jin, Yingling Tan, Xiaozhen Hu, Bin Zhu, Qinghui Zheng, Zijiao Zhang, Guoyin Zhu, Qian Yu, Zhong Jin, Jia Zhu
Alloy anodes possessed of high theoretical capacity show great potential for next generation advanced lithium ion battery. Even though huge volume change during lithium insertion and extraction leads to severe problems, such as pulverization and unstable Solid-Electrolyte Interphase (SEI), various nanostructures including nanoparticles, nanowires and porous networks can address related challenges to improve electrochemical performance. However, the complex and expensive fabrication process hinders the widespread application of nanostructured alloy anodes, which generate urgent demand of low cost and scalable processes to fabricate building blocks with fine controls of size, morphology and porosity...
April 17, 2017: ACS Applied Materials & Interfaces
Sergey V Makarov, Mihail I Petrov, Urs Zywietz, Valentin A Milichko, Dmitry A Zuev, Natalia Lopanitsyna, Alexey Kuksin, Ivan Mukhin, George Zograf, Evgeniy Ubyivovk, Daria Smirnova, Sergey Starikov, Boris N Chichkov, Yuri S Kivshar
Recent trends to employ high-index dielectric particles in nanophotonics are motivated by their reduced dissipative losses and large resonant enhancement of nonlinear effects at the nanoscale. Since silicon is a centrosymmetric material, the studies of nonlinear optical properties of silicon nanoparticles have been targeting primarily the third-harmonic generation effects. Here we demonstrate, both experimentally and theoretically, that resonantly excited nanocrystalline silicon nanoparticles fabricated by an optimized laser printing technique can exhibit strong second-harmonic generation (SHG) effects...
April 14, 2017: Nano Letters
George P Zograf, Mihail I Petrov, Dmitry A Zuev, Pavel A Dmitriev, Valentin A Milichko, Sergey V Makarov, Pavel A Belov
We propose a novel photothermal approach based on resonant dielectric nanoparticles, which posses imaginary part of permittivity signicantly smaller as compared to metal ones. We show both experimentally and theoretically that a spherical silicon nanoparticle with a magnetic quadrupolar Mie resonance converts light to heat up to 4 times more eectively than similar spherical gold nanoparticle at the same heating conditions. We observe photo-induced temperature raise up to 900 K with the silicon nanoparticle on a glass substrate at moderate intensities (< 2 mW/m2) and typical laser wavelength (633 nm)...
April 14, 2017: Nano Letters
Yan Zhao, Li-Hong Wan, Xiao-Lin Bai, Yi-Ming Liu, Feng-Ping Zhang, Yao-Min Liu, Xun Liao
Detection of mycotoxin contamination in foodstuffs is highly significant for public health. Herein we report an analytical method based on magnetic solid phase extraction (MSPE) and UPLC-MS/MS for simultaneous determination of mycotoxins, including fumonisins B1 (FB1), zearalenone (ZON) and ochratoxin A (OTA) in vegetable oil. Magnetic nanoparticles coated with double layers of silicon dioxide were synthesized and found to be an effective MSPE adsorbent for mycotoxins. The proposed MSPE procedure serves not only for sample cleanup, but also for mycotoxin enrichment that enhances greatly the assay sensitivity...
April 12, 2017: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
Misato Tsugita, Nobuyuki Morimoto, Masafumi Nakayama
Silicon dioxide (SiO2) nanoparticles (NPs) and titanium dioxide (TiO2) NPs are the most widely used inorganic nanomaterials. Although the individual toxicities of SiO2 and TiO2 NPs have been extensively studied, the combined toxicity of these NPs is much less understood. In this study, we observed unexpected and drastic activation of the caspase-1 inflammasome and production of IL-1β in mouse bone marrow-derived macrophages stimulated simultaneously with SiO2 and TiO2 NPs at concentrations at which these NPs individually do not cause macrophage activation...
April 11, 2017: Particle and Fibre Toxicology
Yuan Li, John Dykes, Todd Gilliam, Nitin Chopra
Heterostructures of one-dimensional nanowire supported graphene/plasmonic nanoparticles are promising for future SERS-based chemical sensors. In this paper, we report a novel heterostructured SERS substrate composed of free-standing Si nanowires and surface-decorating Au/graphene nanoparticles. We successfully developed a unique CVD approach for the cost-effective and large-scale growth of free-standing Si nanowires. Au nanoparticles were decorated on the Si nanowires using a galvanic deposition - an annealing approach...
April 20, 2017: Nanoscale
Weien Lai, Oday Mazin Abdulmunem, Pablo Del Pino, Beatriz Pelaz, Wolfgang J Parak, Qian Zhang, Huaiwu Zhang
This paper presents a significant effect of manganese ferrite nanoparticles (MnFe2O4 NPs) on the increase of the surface photoconductivity of semiconductors. Herein, the optical characterization of photo-excited carriers of silicon coated with MnFe2O4 NPs was studied by using THz time-domain spectroscopy (THz-TDs). We observed that silicon coated with MnFe2O4 NPs provided a significantly enhanced attenuation of THz radiation in comparison with bare silicon substrates under laser irradiation. The experimental results were assessed in the context of a surface band structure model of semiconductors...
April 10, 2017: Scientific Reports
Ryo Machida, Rina Nishioka, Masahide Fujiwara, Naoki Furuta
Laser ablation in liquid (LAL) sampling method transformed hard-to-digest materials to soluble particles, and thus allowed for smooth decomposition by acid digestion. LAL sampling is useful to generate nanoparticles from samples with less contamination. After acid digestion, trace elements in the LAL-sampled particles were analyzed by solution nebulization inductively coupled plasma mass spectrometry (ICPMS). For the first time we demonstrated that LAL-ICPMS can be used to determine trace elements in hard-to-digest samples; sintered SiC and single-crystal SiC...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Jing Wang, Mingsha Jie, Haifang Li, Luyao Lin, Ziyi He, Shiqi Wang, Jin-Ming Lin
The gold nanoparticles (Au NPs) modified porous silicon chip based surface assisted laser desorption/ionization mass spectrometry (SALDI-MS) was developed to capture and analyze glutathione (GSH) in cells. With silver-assisted chemical etching, Ag nanoparticles (Ag NPs) were generated and deposited on the silicon surface and the nanopores were etched on silicon substrate. Then Au NPs were in-situ synthesized on the ridges of silicon nanopores. This Ag-Au NPs modified porous silicon surface could specially capture and enrich thiol compounds through Au-S binding, and it could also function as matrix to assist ionization for SALDI-MS...
June 1, 2017: Talanta
Marie Luyckx, Jean-Francois Hausman, Stanley Lutts, Gea Guerriero
Elemental silicon (Si), after oxygen, is the second most abundant element in the earth's crust, which is mainly composed of silicates. Si is not considered essential for plant growth and development, however, increasing evidence in the literature shows that this metalloid is beneficial to plants, especially under stress conditions. Indeed Si alleviates the toxic effects caused by abiotic stresses, e.g., salt stress, drought, heavy metals, to name a few. Biogenic silica is also a deterrent against herbivores...
2017: Frontiers in Plant Science
Jianping Yang, Yunxiao Wang, Wei Li, Lianjun Wang, Yuchi Fan, Wan Jiang, Wei Luo, Yang Wang, Biao Kong, Cordelia Selomulya, Hua Kun Liu, Shi Xue Dou, Dongyuan Zhao
Smart surface coatings of silicon (Si) nanoparticles are shown to be good examples for dramatically improving the cyclability of lithium-ion batteries. Most coating materials, however, face significant challenges, including a low initial Coulombic efficiency, tedious processing, and safety assessment. In this study, a facile sol-gel strategy is demonstrated to synthesize commercial Si nanoparticles encapsulated by amorphous titanium oxide (TiO2 ), with core-shell structures, which show greatly superior electrochemical performance and high-safety lithium storage...
April 4, 2017: Advanced Materials
Elisa Ollikainen, Dongfei Liu, Arttu Kallio, Ermei Mäkilä, Hongbo Zhang, Jarno Salonen, Hélder A Santos, Tiina M Sikanen
Engineered nanoparticles are increasingly used as drug carriers in pharmaceutical formulations. This study focuses on the hitherto unaddressed impact of porous silicon (PSi) nanoparticles on human cytochrome P450 (CYP) metabolism, which is the major detoxification route of most pharmaceuticals and other xenobiotics. Three different surface chemistries, including thermally carbonized PSi (TCPSi), aminopropylsilane-modified TCPSi (APTES-TCPSi) and alkyne-terminated thermally hydrocarbonized PSi (Alkyne-THCPSi), were compared for their effects on the enzyme kinetics of the major CYP isoforms (CYP1A2, CYP2A6, CYP2D6, and CYP3A4) in human liver microsomes (HLM) in vitro...
March 31, 2017: European Journal of Pharmaceutical Sciences
Hong-Lei Shuai, Xu Wu, Ke-Jing Huang, Zi-Bo Zhai
An ultrasensitive sandwich-type electrochemical biosensor for DNA detection is developed based on spherical silicon dioxide/molybdenum selenide (SiO2@MoSe2) and graphene oxide-gold nanoparticles (GO-AuNPs) hybrids as carrier triggered Hybridization Chain Reaction (HCR) coupling with multi-signal amplification. The proposed sensoring assay utilizes a spherical SiO2@MoSe2/AuNPs as sensing platform and GO-AuNPs hybrids as carriers to supply vast binding sites. H2O2+HQ system is used for DNA detection and HCR as the signal and selectivity enhancer...
March 30, 2017: Biosensors & Bioelectronics
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