A Simple Method to Self-Assemble Two-dimensional and Three-dimensional Superlattices of Gold Nanoparticles

2007 ◽  
Vol 1056 ◽  
Author(s):  
Tao Fu ◽  
Hai-Yan Qin ◽  
Wen-Jiang Li ◽  
Sailing He
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Particle Dispersion ◽  
Diameter Distribution ◽  
Chloroauric Acid ◽  
Two Dimensional ◽  
Visible Absorption ◽  
Simple Method ◽  
Transmission Electron

ABSTRACTCitrate-capped gold nanoparticles with narrow diameter distribution were prepared by the reduction of chloroauric acid with borohydride. After the gold nanoparticles were transferred to toluene solution through ligand conformation change, close-packed two-dimensional nanocrystal lattices were obtained on transmission electron microscopy (TEM) copper grids by evaporating approximately 10 μL of concentrated particle dispersion. The formation of the thiolate gold nanoparticles was investigated by UV-visible absorption spectroscopy and FTIR spectra. The 2D Fourier transform power spectra of the monolayer confirmed the supperlattices' hexagonal symmetry. Furthermore, long-range-ordered bilayer superlattices, of which the nanoparticles in the top layer piled on the ones in the bottom layer, could also be observed by transmission electron microscopy.

scholarly journals SYNTHESIS AND CATALYTIC ACTIVITY OF BRANCHED GOLD NANOPARTICLES IN AQUEOUS MEDIUM

2018 ◽  
Vol 55 (5B) ◽  
pp. 227
Author(s):  
Phan Ha Nu Diem
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Kinetic Data ◽  
Gold Nanostructures ◽  
Simple Method ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Experimental Parameters

In this article, a simple method for the preparation of multi–branched gold nanoparticles from an aqueous solution of silver seeds, cetyl-trimethylammonium bromide (CTAB), HAuCl4, and Pluronic F–127 was described. It was found that morphologies and sizes of gold nanostructures (AuNPs) depended strongly on such experimental parameters as concentrations of Pluronic F–127 and Au3+. The products were characterized by transmission electron microscopy (TEM). Interestingly, the multi – branched AuNPs were found to serve as an effective catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4. Kinetic data have been obtained from monitoring the concentrations of 4-NP and BH4‒ by UV‒vis spectroscopy.

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

Synthesis and Characterizations of Nanocubes, Monodispersed Nanocrystals and Nanospheres of Au

2007 ◽  
Vol 353-358 ◽  
pp. 2163-2166
Author(s):  
Ming Yang ◽  
Guo Qing Zhou ◽  
Jiang Guo Zhao ◽  
Zhan Jun Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
Scherrer Formula ◽  
Visible Absorption Spectroscopy

Nanocubes, monodispersed nanocrystals and nanospheres of Au have been prepared by a simple reaction between HAuCl4·4H2O, NaOH and NH2OH·HCl in the presence of gelatin. The role of gelatin and the affection of pH in producing the nanoparticles of Au were discussed. The products were characterized by X-ray powder diffraction, transmission electron microscopy, and UV-visible absorption spectroscopy. The sizes of the monodispersed nanocrystals of Au were estimated by Debye-Scherrer formula according to XRD spectrum.

scholarly journals Effects of Different Surfactant Charges on the Formation of Gold Nanoparticles by the LASiS Method

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2937
Author(s):  
Muhammad Zulfajri ◽  
Wei-Jie Huang ◽  
Genin-Gary Huang ◽  
Hui-Fen Chen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Laser System ◽  
Synthesis Process ◽  
Au Nps ◽  
Laser Fluences ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
532 Nm

The laser ablation synthesis in solution (LASiS) method has been widely utilized due to its significant prospects in laser microprocessing of nanomaterials. In this study, the LASiS method with the addition of different surfactant charges (cationic CTAB, nonionic TX-100, and anionic SDS) was used to produce Au NPs. An Nd:YAG laser system at 532 nm excitation with some synthetic parameters, including different laser fluences, ablation times, and surfactant concentrations was performed. The obtained Au NPs were characterized by UV-Vis spectroscopy, transmission electron microscopy, and zeta potential analyzer. The Au NPs exhibited the maximum absorption peak at around 520 nm for all samples. The color of Au NPs was changed from red to reddish by increasing the laser fluence. The surfactant charges also played different roles in the Au NPs’ growth during the synthesis process. The average sizes of Au NPs were found to be 8.5 nm, 5.5 nm, and 15.5 nm with the medium containing CTAB, TX-100, and SDS, respectively. Besides, the different surfactant charges induced different performances to protect Au NPs from agglomeration. Overall, the SDS and CTAB surfactants exhibited higher stability of the Au NPs compared to the Au NPs with TX-100 surfactant.

Aquatic Fern (AzollaSp.) Assisted Synthesis of Gold Nanoparticles

2016 ◽  
Vol 15 (01n02) ◽  
pp. 1650008 ◽  
Author(s):  
Anal K. Jha ◽  
K. Prasad
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Surface Plasmon Resonance ◽  
Au Nanoparticles ◽  
X Ray ◽  
Aquatic Fern ◽  
Transmission Electron ◽  
Anthraquinone Glycosides ◽  
Uv Visible

Aquatic pteridophyte (Azolla sp.) was taken to assess its potential to synthesize the metal (Au) nanoparticles. The synthesized particles were characterized using X-ray, UV-visible, scanning and transmission electron microscopy analyses. Nanoparticles almost spherical in shape having the sizes of 5–17[Formula: see text]nm are found. UV-visible study revealed the surface plasmon resonance at 538[Formula: see text]nm. Responsible phytochemicals for the transformation were principally phenolics, tannins, anthraquinone glycosides and sugars present abundantly in the plant thereby bestowing it adaptive prodigality. Also, the use of Azolla sp. for the synthesis of gold nanoparticles offers the benefit of eco-friendliness.

AQUEOUS SYNTHESIS OF HIGH QUANTUM YIELD AND MONODISPERSED THIOL-CAPPED CdxZn1-xTe QUANTUM DOTS BASED ON ELECTROCHEMICAL METHOD

NANO ◽  
2012 ◽  
Vol 07 (02) ◽  
pp. 1250011 ◽  
Author(s):  
JUNWEI LI ◽  
YANG JIANG ◽  
YUGANG ZHANG ◽  
DI WU ◽  
ANQI LUO ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Electrochemical Method ◽  
Large Scale ◽  
Ostwald Ripening ◽  
Visible Absorption ◽  
Aqueous Synthesis ◽  
Transmission Electron

A facile green approach has been developed to control the growth regime in the aqueous synthesis of CdxZn1-xTe semiconductor quantum dots (QDs) based on the electrochemistry method. The Low growth temperature and slow injection of Te precursor are used to prolong the diffusion controlled stage and thus suppress Ostwald ripening during the nanocrystal growth. The experimental results showed that a low concentration of Te precursor will definitely influence the growth procedure. The UV–visible absorption spectra, as well as transmission electron microscopy (TEM) shows the QDs a good monodispersity at any interval of the reaction procedure. The high-resolution transmission electron microscopy (HRTEM) images and powder X-ray diffraction (XRD) pattern suggested that the as-prepared QDs have high crystallinity and cubic structure. The size and composition-dependent fluorescent emission wavelength of the resultant CdxZn1-xTe alloyed QDs can be tuned from 460 to 610 nm, and their photoluminescent quantum yield can reach up to 70%. Especially in the wavelength range of 510–578 nm, the overall PL QYs of the as-prepared CdxZn1-xTe QDs were above 50%. The current work suggests that electrochemical method is an attractive approach to the synthesis of high-quality II-VI ternary alloyed semiconductor QDs at large-scale with a prominent cost advantage.

scholarly journals Designing Magnetic Layered Double Hydroxides and Two-Dimensional Magnetic Nano-Nets of Cobalt Ferrite through a Novel Approach

2018 ◽  
Vol 8 (11) ◽  
pp. 2099 ◽  
Author(s):  
Osama Saber ◽  
Abdullah Aljaafari ◽  
Sarah Asiri ◽  
Khalid Batoo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layered Double Hydroxides ◽  
Cobalt Ferrite ◽  
High Coercivity ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Double Hydroxides

The present study has a dual aim of supporting magnetic nanoparticles over the nanolayers of LDHs and designing two-dimensional magnetic nano-nets of cobalt ferrite. In this trend, nanoparticles of CoFe2O4 were prepared and supported by Co-Fe LDH through urea hydrolysis. The nanolayered structures of Co-Fe LDH were confirmed by X-ray diffraction, energy-dispersive X-ray spectrometry, FT-IR spectra, thermal analyses, and transmission electron microscopy. In addition, they indicated that 13.2% CoFe2O4 were supported over Co-Fe LDH. Transformation of the nanolayered structures of Co-Fe LDH to nano-nets was achieved by the catalytic effect of the supported CoFe2O4 nanoparticles through solvent thermal technique. X-ray diffraction patterns and transmission electron microscopy images confirmed the transformation of the supported Co-Fe LDH to nano-nets of cobalt ferrite. In order to indicate the effect of the LDH for designing the nano-nets, nanoparticles of cobalt ferrite were prepared by the same technique without LDH. The magnetic behavior of the nano-nets and the supported Co-Fe LDH were measured and compared with the nanoparticles through vibrating sample magnetometer technique. The magnetic parameters indicated that the prepared nano-nets have ferromagnetic behavior and high coercivity. However, the prepared nanoparticles revealed a superparamagnetic state and low coercivity. The experimental results concluded that the incorporation of nanoparticles with nanowires into nano-net structures has been found to be an efficient way to improve their magnetic properties and prevent their agglomerations. Finally, layered double hydroxides are an important source for constructing magnetic nanolayered structures and nano-nets.

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