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Silicon nanoparticles

A Argente-García, N Jornet-Martínez, R Herráez-Hernández, P Campíns-Falcó
A solid sensor obtained by embedding 1,2-naphthoquinone-4-sulfonate (NQS) into polydimethylsiloxane/tetraethylortosilicate/silicon dioxide nanoparticles composite has been developed to identify and determine amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxymetamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA). The analytes are derivatized inside the composite for 10 min to create a colored product which can be then quantified by measuring the diffuse reflectance or the color intensity after processing the digitalized image...
November 2, 2016: Analytica Chimica Acta
Xiang Gao, Shaolong Wu, Jimu Yan, Xiongfei Zhai, Xiaofeng Li
Semiconductor nanostructure photoelectrochemical (PEC) cells for sunlight conversion have the potential to supply continuous, low-cost, high-efficiency and carbon-free energy; however, in order to provide economically competitive energy, long-time stability and high-efficiency are requisite. In this work, the saturation photocurrent density (Jsat) and stability of the silicon nanowires (SiNWs) in a PEC cell are significantly improved via surface modification with Ag@SiO2 nanoparticles and conformal TiO2 ultrathin film...
October 21, 2016: ACS Applied Materials & Interfaces
Ruchi Agrawal, Anjana Srivastava, A K Verma
Purified β-glucosidase was immobilized on SiO2 nanoparticles with 52 % efficiency and 14.1 % yield. It had a temperature optima at 60 °C and pH optima of 5.0. Immobilized enzyme was fairly stable at 60-70 °C. After immobilization, the Km value of β-glucosidase for p-nitrophenyl-β-d-glucopyranoside (pNPG) increased from 0.9 to 1.074 mM and Vmax decreased from 3.5 to 1.513 U/mg. The immobilized enzyme showed improved storage stability at temperature 4 and 25 °C and was reusable for up to ten cycles with 70 % residual activity in pNPG and 60 % residual activity in sugarcane juice treatment...
July 2016: Journal of Food Science and Technology
Sahar Soltan, Hoda Jafari, Shahrara Afshar, Omid Zabihi
In the present study, silicon dioxide (SiO2) nanoparticles were loaded to titanium dioxide (TiO2) nano-particles by sol-gel method to make a high porosity photocatalyst nano-hybrid. These photocatalysts were synthesized using titanium tetrachloride and tetraethyl orthosilicate as titanium and silicon sources, respectively, and characterized by X-ray powder diffraction (XRD) and scanning electron microscope methods. Subsequently, the optimizations of the component and operation conditions were investigated. Then, nano-sized TiO2 and TiO2-SiO2 were supported on concrete bricks by the dip coating process...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Yiling Zhong, Bin Song, Fei Peng, Yanyan Wu, Sicong Wu, Yuanyuan Su, Yao He
Herein, we demonstrate that at room temperature (20-25 °C) and under atmospheric pressure, small-sized (∼3.1 nm) SiNPs can be rapidly formed in aqueous phase within 60 min, with high photoluminescence quantum yield (PLQY) of ∼50%. This approach is readily scalable and could potentially be used to produce high-quality SiNPs at an industrial level.
October 20, 2016: Chemical Communications: Chem Comm
Taeho Kim, Gary B Braun, Zhi-Gang She, Sazid Hussain, Erkki Ruoslahti, Michael J Sailor
A theranostic nanoparticle with biochemically triggered antibacterial activity is demonstrated. Metallic silver is deposited onto porous silicon nanoparticles (pSiNPs) by galvanic displacement. When aqueous diaminesilver ([Ag(NH3)2](+)) is used as a silver source, the pSiNPs template the crystalline silver as small (mean diameter 13 nm) and well-dispersed nanoparticles embedded within and on the larger (100 nm) pSiNPs. The silver nanoparticles quench intrinsic photoluminescence (PL) from the porous silicon matrix...
October 18, 2016: ACS Applied Materials & Interfaces
Jangsun Hwang, Mintai P Hwang, Moonhyun Choi, Youngmin Seo, Yeonho Jo, Jaewoo Son, Jinkee Hong, Jonghoon Choi
Heavy metal pollution has been a problem since the advent of modern transportation, which despite efforts to curb emissions, continues to play a critical role in environmental pollution. Copper ions (Cu(2+)), in particular, are one of the more prevalent metals that have widespread detrimental ramifications. From this perspective, a simple and inexpensive method of detecting Cu(2+) at the micromolar level would be highly desirable. In this study, we use porous silicon nanoparticles (NPs), obtained via anodic etching of Si wafers, as a basis for undecylenic acid (UDA)- or acrylic acid (AA)-mediated hydrosilylation...
October 18, 2016: Scientific Reports
Robert J Frank-Finney, Malancha Gupta
In this article, we study the growth of polymer nanoparticles that are formed on the surface of silicone oils via initiated chemical vapor deposition. The average radius of the particles can be increased by decreasing the silicone oil viscosity, increasing the deposition time, or increasing the deposition rate. The time series data indicates that there are two stages for particle growth. Particle nucleation occurs in the first stage and the particle size is dependent on the liquid viscosity and deposition rate...
October 14, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Peter Banzer, Paweł Woźniak, Uwe Mick, Israel De Leon, Robert W Boyd
Chirality is an intriguing property of certain molecules, materials or artificial nanostructures, which allows them to interact with the spin angular momentum of the impinging light field. Due to their chiral geometry, they can distinguish between left- and right-hand circular polarization states or convert them into each other. Here we introduce an approach towards optical chirality, which is observed in individual two-dimensional and geometrically mirror-symmetric nanostructures. In this scheme, the chiral optical response is induced by the chosen heterogeneous material composition of a particle assembly and the corresponding resonance behaviour of the constituents it is built from, which breaks the symmetry of the system...
October 13, 2016: Nature Communications
Rocio Nava, Lee Daniel Cremar, Victor Agubra, Jennifer Sanchez, Mataz Alcoutlabi, Karen Lozano
Composites made of silicon nanostructures in carbon matrices are promising materials for anodes in Li ion batteries given the synergistic storage capacity of silicon combined with the chemical stability and electrical conductivity of carbonaceous materials. This work presents the development of Si/C composite fine fiber mats produced by carbonization of Poly (vinyl alcohol) (PVA)/Si composites. PVA has a high carbon content (ca. 54.5%) and being water soluble, it promotes the development of environmentally friendly materials...
October 12, 2016: ACS Applied Materials & Interfaces
Bolin Chen, Nathaniel T Garland, Jason Geder, Marius Pruessner, Eric Mootz, Allison A Cargill, Anne Leners, Granit Vokshi, Jacob Davis, Wyatt Burns, Michael A Daniele, Joshua M Kogot, Igor L Medintz, Jonathan C Claussen
Micro unmanned underwater vehicles (UUVs) need to house propulsion mechanisms that are small in size but sufficiently powerful to deliver on-demand acceleration for tight radius turns, burst-driven docking maneuvers, and low-speed course corrections. Recently, small-scale hydrogen peroxide (H2O2) propulsion mechanisms have shown great promise in delivering pulsatile thrust for such acceleration needs. However, the need for robust, high surface area nanocatalysts that can be manufactured on a large scale for integration into micro UUV reaction chambers is still needed...
October 11, 2016: ACS Applied Materials & Interfaces
Elena P Vetchinkina, Ekaterina A Loshchinina, Ilya R Vodolazov, Viktor F Kursky, Lev A Dykman, Valentina E Nikitina
The work shows the ability of cultured Basidiomycetes of different taxonomic groups-Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum, and Grifola frondosa-to recover gold, silver, selenium, and silicon, to elemental state with nanoparticles formation. It examines the effect of these metal and metalloid compounds on the parameters of growth and accumulation of biomass; the optimal cultivation conditions and concentrations of the studied ion-containing compounds for recovery of nanoparticles have been identified...
October 7, 2016: Applied Microbiology and Biotechnology
Yongqiang Zhang, Yangsheng Lin, Xi Li, Li Zhang, Wei Pan, Huili Zhu, Danfeng Yang
Growing concern has been raised over the potential hazard of nanoparticles (NPs) on human health from ambient particulate air pollution. Silicon dioxide (SiO2) NPs are one of the most widely used nanoparticles in many sectors of industry. Research on NPs has focused mainly on their toxicity in organs. Meanwhile, NPs are present in the air year-round, but are more serious in winter. Thus, the aim of this study was to evaluate the inflammatory response to SiO2 NPs using in vivo test systems. The composition of particulate matter is complicated; however, elemental silicon accounts for a significant proportion...
October 6, 2016: Environmental Science and Pollution Research International
Cristina Botas, Daniel Carriazo, Wei Zhang, Teofilo Rojo, Gurpreet Singh
Silicon-reduced graphene oxide (Si-rGO) composites processed as self-standing aerogels (0.2 g cm-3) and films (1.5 g cm-3) have been prepared by the thermal reduction of composites formed between silicon nanoparticles and a suspension of graphene oxide (GO) in ethanol. The characterization of the samples by different techniques (XRD, Raman, TG and SEM) show that in both cases the composites are formed by rGO sheets homogeneously decorated with 50 nm silicon nanoparticles, and silicon contents of ca. 40% wt...
October 6, 2016: ACS Applied Materials & Interfaces
Mingxia Sun, Dongyan Deng, Kexin Zhang, Ting Lu, Yingying Su, Yi Lv
A new SiC nanoparticles (SiC NPs)-based chemiluminescence (CL) probe for selective and sensitive detecting of ˙OH has been developed. The radiative recombination of ˙OH-injected holes and electrons in the SiC NPs accounts for the CL phenomenon. Furthermore, the as-developed CL probe has been successfully applied to detect ˙OH in PM2.5.
September 13, 2016: Chemical Communications: Chem Comm
Hao Wang, Yanlin Ke, Ningsheng Xu, Runze Zhan, Zebo Zheng, Jinxiu Wen, Jiahao Yan, Pu Liu, Jun Chen, Juncong She, Yu Zhang, Fei Liu, Huanjun Chen, Shaozhi Deng
Due to their optical magnetic and electric resonances associated with the high refractive index, dielectric silicon nanoparticles have been explored as novel nanocavities that are excellent candidates for enhancing various light-matter interactions at the nanoscale. Here, from both of theoretical and experimental aspects, we explored resonance coupling between excitons and magnetic/electric resonances in heterostructures composed of the silicon nanoparticle coated with molecular J-aggregate shell. The resonance coupling was originated from coherent energy transfer between the exciton and magnetic/electric modes, which was manifested by quenching dips on the scattering spectrum due to formation of hybrid modes...
October 4, 2016: Nano Letters
Ondřej Cibulka, Christoph Vorkötter, Adam Purkrt, Jakub Holovský, Jan Benedikt, Kateřina Herynková
This work compares structural and optical properties of silicon nanocrystals prepared by two fundamentally different methods, namely, electrochemical etching of Si wafers and low-pressure plasma synthesis, completed with a mechano-photo-chemical treatment. This treatment leads to surface passivation of the nanoparticles by methyl groups. Plasma synthesis unlike electrochemical etching allows selecting of the particle sizes. Measured sizes of the nanoparticles by dynamic light scattering show 3 and 20 nm for electrochemically etched and plasma-synthetized samples, respectively...
December 2016: Nanoscale Research Letters
Zeyuan Cao, Pengyu Xu, Haowei Zhai, Sicen Du, Jyotirmoy Mandal, Martin Dontigny, Karim Zaghib, Yuan Yang
An important requirement of battery anodes is the processing step involving the formation of the solid electrolyte interphase (SEI) in the initial cycle, which consumes a significant portion of active lithium ions. This step is more critical in nanostructured anodes with high specific capacity, such as Si and Sn, due to their high surface area and large volume change. Prelithiation presents a viable approach to address such loss. However, the stability of prelithiation reagents is a big issue due to their low potential and high chemical reactivity towards O2 and moisture...
October 3, 2016: Nano Letters
Taylor Woehl, Robert Keller
An annular dark field (ADF) detector was placed beneath a specimen in a field emission scanning electron microscope operated at 30kV to calibrate detector response to incident beam current, and to create transmission images of gold nanoparticles on silicon nitride (SiN) substrates of various thicknesses. Based on the linear response of the ADF detector diodes to beam current, we developed a method that allowed for direct determination of the percentage of that beam current forward scattered to the ADF detector from the sample, i...
August 6, 2016: Ultramicroscopy
Feng Kong, Hongbo Zhang, Xiangmeng Qu, Xu Zhang, Dong Chen, Ruihua Ding, Ermei Mäkilä, Jarno Salonen, Hélder A Santos, Mingtan Hai
Gold nanorods, DNA origami, and porous silicon nanoparticle-functionalized biocompatible double emulsion are developed for versatile molecular targeted therapeutics and antibody combination therapy. This advanced photothermal responsive all-in-one biocompatible platform can be easily formed with great therapeutics loading capacity for different cancer treatments with synergism and multidrug resistance inhibition, which has great potential in advancing biomedical applications.
September 30, 2016: Advanced Materials
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