Summer and Autumn 2016-Cu Nanoparticle (original) (raw)
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Nanochemistry Research, 2016
Here we present our experimental results in synthesizing Au-Cu nano-particles with tunable localized surface plasmon resonance frequency through wet-chemical at temperature room. The reaction is performed in the presence of ascorbic acid as a reducing agent and polyvinyl pyrrolidone as capping agent via four different procedures: (1) mixture of 90% HAuCl4 and 10% CuSO4.5H2O precursors, (2) mixture of 75% HAuCl4 and 25% CuSO4.5H2O precursors, (3) mixture of 50% HAuCl4 and 50% CuSO4.5H2O precursors (4) mixture of 25% HAuCl4 and 75% CuSO4.5H2O precursors. Effect of different percentages of Cu on Au nanoparticles has been analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM with EDAX analysis), DRS UV-Vis, and Fourier transform IR spectra (FTIR) analysis. X-ray diffraction (XRD) analysis revealed that the nanoparticles are of cubic structure without an impure phase. The successful doping of the Cu into the Au host was evident by XRD line shiftings. The increasing percentage of copper leads to the decreasing grain size. With the increase of Cu2+ to Au3+ ratio in the Cu2+/Au3+ mixed solution (> 50% Cu), XRD lines show no shifting. The average crystal sizes of the particles at room temperature were less than 9.9 nm. The surface plasmon resonance peak shifts from 380 to 340 nm, party due to the change in particle size. SEM images show a spherical shape and the size of nanoparticles becomes smaller with increasing the percentage of copper. Moreover, in the molar ratio of Cu2+/Au3+ = 75/25 (>50% Cu), mixture of spherical and trigonal nanoparticles were prepared. Fourier transform infrared spectroscopy (FT-IR) showed the coordination and conjugation nanoparticles with N and O atoms of C-N and C=O bonds.
Development of Au/CuO nanoplasmonic thin films for sensing applications
Surface and Coatings Technology, 2018
Nanocomposite thin films, containing Au nanoparticles dispersed in a CuO matrix, were prepared by reactive DC magnetron sputtering and post-deposition thermal annealing. The CuO matrix was found to be stoichiometric and the atomic concentration of Au was determined to be about 12.3 at.%. After the annealing process, the average size of the crystalline domains of the Au nanoparticles (fcc structure) increased from about 6 nm (at an annealing temperature of 300 ºC) to approximately 13 nm (after annealing at 800 ºC), with a progressive crystallization of the CuO matrix in the monoclinic structure. A nanoplasmonic effect due to the localized surface plasmon resonance (LSPR) phenomenon appeared in the films after annealing temperatures of 400 °C and higher. The correspondent LSPR bands appeared in the visible range of the transmittance spectra, becoming progressively narrower. Angle Resolved X-Ray Photoelectron Spectroscopy results indicated that the surface of Au/CuO nanocomposite thin film is contaminated with a sub-nanometric layer (~0.6 nm) of hydrocarbons and that the Au nanoparticles are relatively homogenously dispersed inside the CuO dielectric matrix. Furthermore, the results seem also to indicate that the Au nanoparticles are covered with about 0.2 nm of
Due to scientific and industrial interest, copper nanoparticles have attracted a lot of interest in the current decade, special due to its applications in antibiotic , anti-microbial and anti-fungal agent, catalysis, conductive inks, coatings, coolant and textiles. The present study focused, on the cost effective synthesis technique and environmental effects on copper nanoparticlesdue to its high surface sensitivity. The structural composition, particle size and optical properties of copper nanoparticleswere determined by X-raysand UV-Visible spectroscopy, reveals that the particles have size in order to 9 nm. A plasmonic study through a UV-visible spectrum shows the peak shift from 411 to 316 nm, with color change in the coppernanoparticles indicate the surface sensitivity due to very large surface area.The synthesis method, reported in current work might be useful for industrial production of Cu nanoparticles.
TEM characterization of chemically synthesized copper–gold nanoparticles
Journal of Nanoparticle Research, 2011
Dodecanethiol-capped Cu-Au nanoparticles, synthesized via a successive two-phase (water/ toluene) and galvanic-exchange procedure, were characterized using transmission electron microscopy (TEM). The size range of the particles is around 1-7 nm. Electron-induced morphological evolution was observed under high resolution (HR) TEM. Cuboctahedral morphology was found to be thermodynamically stable. Electron-induced aggregation of two particles was also observed. Chemical ordering of cuboctahedral particles was studied by atomicresolution high angle annular dark field (HAADF) imaging in scanning TEM (STEM) mode and energy dispersive X-ray (EDX) element mapping using a silicon drift detector (SDD). The particles were found to be Cu-Au mixed, and to be stable in air. Surface plasmon resonance (SPR), which is dependent on local structure and morphology, was investigated by electron energy loss spectroscopy (EELS).
Advances in Materials Science and Engineering, 2015
Au-Cu alloy nanoparticles were synthesized by a chemical reduction method. Five samples having different compositions of Au and Cu (Au-Cu 3 : 1, Au-Cu 2 : 1, Au-Cu 1 : 1, Au-Cu 1 : 2, and Au-Cu 1 : 3) were prepared. The newly synthesized nanoparticles were characterized by electronic absorption, fluorescence, and X-ray diffraction spectroscopy (XRD). These alloy nanoparticles were also analyzed by SEM and TEM. The particle size was determined by SEM and TEM and calculated by Debye Scherrer’s equation as well. The results revealed that the average diameter of nanoparticles gets lowered from 80 to 65 nm as the amount of Cu is increased in alloy nanoparticles. Some physical properties were found to change with change in molar composition of Au and Cu. Most of the properties showed optimum values for Au-Cu alloy nanoparticles of 1 : 3. Cu in Au-Cu alloy caused decrease in the intensity of the emission peak and acted as a quencher. The fluorescence data was utilized for the evaluation of...
Nano Letters, 2020
We report a heterometallic seed-mediated synthesis method for monodisperse penta-twinned Cu 2 nanorods using Au nanocrystals as seeds. Elemental analyses indicate that resultant nanorods consist predominantly of copper with a gold content typically below 3 at. %. The nanorod aspect 4 ratio can be readily adjusted from 2.8 to 13.1 by varying the molar ratio between Au seeds and Cu 5 precursor, resulting in narrow longitudinal plasmon resonances tunable from 762 to 2201 nm. 6 Studies of reaction intermediates reveal that symmetry-breaking is promoted by rapid nanoscale 7 diffusion in Au-Cu alloys and the formation of a gold-rich surface. The growth pathway features 8 co-evolving shape and composition whereby nanocrystals become progressively enriched with Cu 9 concomitant with nanorod growth. The availability of uniform colloidal Cu nanorods with widely 10 tunable aspect ratios opens new avenues toward the synthesis of derivative one-dimensional metal 11 nanostructures, and applications in surface-enhanced spectroscopy, bioimaging, electrocatalysis, 12 among others. ASSOCIATED CONTENT 1 Supporting Information. Experimental section, structural characterization of Cu NRs, FDTD 2 simulation results and studies of reaction intermediates are included. This material is available free 3 of charge via the Internet at http://pubs.acs.org.
Journal of Materials Chemistry A, 2013
Experimental details 2.1 Materials HAuCl 4 •3H 2 O (99.9%), AgNO 3 (99%), Pd(NO 3) 2 •2H 2 O (Pd ~40%), polyvinylpyrrolidone (PVP Mw=55,000), hexadecyltrimethylammonium bromide (CTAB, ≥99%), NaBH 4 (≥99%), ascorbic acid (99%), sodium ascorbate (≥99.0%), sodium dodecyl sulfate (SDS, 99%), NH 2 OH*HCl (99%), sodium sulfide hydrate (Na 2 S•xH 2 O, >= 60%) and trisodium citrate dihydrate (99%) were purchased from Sigma Aldrich. H 2 PtCl 2 •6H 2 O (99.9%) and CuCl 2 (97%) were purchased from Strem. ethylene glycol (EG, 99%) was purchased from Alfa Aesar. All chemicals were used as received. 2.2 Synthesis of Pt Nanocubes Pt Nanocubes coated with PVP with an edge length of ~8 nm were synthesized according to a known procedure with some modifications. 1 2.5 mL of EG were refluxed for 5 min. After that, a total volume of 3 mL of 0.375 M PVP solution in EG, and 1.5 mL of 0.0625 M H 2 PtCl 2 •6H 2 O solution in EG were added over a 16 min period, in 30 sec intervals. The mixture was then refluxed for another 5 min. The product was collected and triple amount of acetone was added in RT. The solution was then centrifuged at 3000 rpm for 10 min. The precipitation was re-dispersed in ethanol and a triple amount of hexane was added. The solution was centrifuged again at 3000 rpm for 10 min. The precipitation was re-dispersed in ethanol and the process was repeated. Finally, the product was dissolved in water for further use. 2.3 Synthesis of Au Nanorods Au NR coated with CTAB were synthesized according to a procedure published elsewhere. 2 First, Au seeds were synthesized as followed: 0.125 mL of 0.01 M HAuCl 4 solution and 5 mL of 0.1 M CTAB solution in water were mixed at 30 o C. Then, 0.3 mL of 0.01 M ice cold NaBH 4 solution was added and the mixture was stirred for 5 min. The formed seeds were used as received. Secondly, 1 mL of 0.01 M HAuCl 4 solution, 0.2mL of 0.01 M AgNO 3 solution and 20mL of 0.1M CTAB solution in water were mixed at 30 o C. 0.4 mL of 1 M HCl solution was added in order to bring the solution to pH of about 3-4. Then, 0.16 mL of 0.1 M ascorbic acid solution and 48 µL of the seeds solution were added and the mixture was stirred for 2 hr. The product was collected by centrifuge at 8500 rpm for 15 min and redispersed in water. The cleaning procedure was repeated twice. 2.4 Synthesis of Pd Nanocubes Pd nanocubes coated with CTAB with an average edge length of ~17 nm were synthesized according to a procedure published elsewhere. 3 0.1820 g CTAB and 0.0099 g of sodium ascorbate were dissolved in 15 ml H 2 O (18MΩ) and heated to 50 o C while stirring. Then, 0.0108 g Pd(NO 3) 2 •2H 2 O in 5 ml H 2 O were added quickly and the solution was stirred at 50 o C for 30 min. after 30 min, the particles were centrifuged twice (7500 rpm, 15min) and redispersed in water.
Preparation, characterization and surface modification of Cu metal nanoparticles
Chemical Physics Letters, 2002
Copper metal nanoparticles have been formed by irradiation with 253.7 nm light from a low pressure Hg-arc lamp in the presence of a protective agent gelatin. The nanoparticles were characterized by their absorption maxima and transmission electron micrographs. The quantum yields of formation of the metal nanoparticles increase in the presence of the stabilizer as well as in the presence of a photosensitizer, benzophenone (BP). Damping of copper plasmon absorption band was not observed in the presence of benzotriazole. Ó 2002 Published by Elsevier Science B.V.