Gold Colloids with Unconventional Angled Shapes (original) (raw)
Related papers
From Porous Gold Nanocups to Porous Nanospheres and Solid Particles – A New Synthetic Approach
Journal of Colloid and Interface Science, 2015
We report a versatile approach for the synthesis of porous gold nanocups, porous gold nanospheres and solid gold nanoparticles. Gold nanocups are formed by the slow reduction of gold salt (HAuCl 4 Á3H 2 O) using aminoantipyrene (AAP) as a reducing agent. Adding polyvinylpyrrolidone (PVP) to the gold salt followed by reduction with AAP resulted in the formation of porous gold nanospheres. Microwave irradiation of both of these porous gold particles resulted in the formation of slightly smaller but solid gold particles. All these nanoparticles are thoroughly characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and bright-field tomography. Due to the larger size, porous nature, low density and higher surface area, these nanomaterials may have interesting applications in catalysis, drug delivery, phototherapy and sensing.
Synthesis and characterization of Raman active gold nanoparticles
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011
Luminescent and Raman active gold-based nanoparticles were synthesized by the chemical adsorption of a Raman reporter molecule on gold colloids. 10 nm diameter gold nanoparticles were functionalized with Rhodamine 6G molecules and covered with a polyelectrolyte multilayer. A full characterization of their dimension and chemical composition was performed by scanning electron microscopy and X-ray photoelectron spectroscopy. Raman measurements put in evidence the intense signal coming from the dye molecules adsorbed on the nanoparticle surface. Moreover, laser scanning confocal microscopy analysis reveals the intrinsic luminescence of the dye allowing the use of these nanoparticles for multimodal imaging.
Porous gold nanodisks with multiple internal hot spots
Physical chemistry chemical physics : PCCP, 2012
For increasing the number of internal hot spots in the individual plasmonic nanoparticles, porous Au nanostructures were synthesized by a hybrid approach combining a physical process, which defined the overall shapes and dimensions of the nanostructures, and a chemical process, which incorporated nanopores inside the patterned nanostructures. This approach allows us to synthesize lithographically designed Au nanodisks containing numerous internal Raman hot spots in the form of nanopores. The increased number of hot spots successfully improved SERS intensity, and this experimental result was further elucidated by numerical electromagnetic simulations. The highly improved and homogeneous SERS intensities illustrate the great potential of the porous plasmonic nanodisks as a sensitive molecular imaging agent.
Porous gold nanodisks with multiple internal hot spotsw
For increasing the number of internal hot spots in the individual plasmonic nanoparticles, porous Au nanostructures were synthesized by a hybrid approach combining a physical process, which defined the overall shapes and dimensions of the nanostructures, and a chemical process, which incorporated nanopores inside the patterned nanostructures. This approach allows us to synthesize lithographically designed Au nanodisks containing numerous internal Raman hot spots in the form of nanopores. The increased number of hot spots successfully improved SERS intensity, and this experimental result was further elucidated by numerical electromagnetic simulations. The highly improved and homogeneous SERS intensities illustrate the great potential of the porous plasmonic nanodisks as a sensitive molecular imaging agent.
Gold-silver bimetallic porous nanowires for surface-enhanced Raman scattering
Chemical communications (Cambridge, England), 2011
Highly porous bimetallic nanowires manufactured via a simple galvanic reaction have demonstrated superior activity in surface-enhanced Raman scattering, allowing ultrasensitive chemical detections on isolated porous nanowires in comparison to pristine silver nanowires.
Journal of Electroanalytical Chemistry, 2011
The one-step electrochemical fabrication of 3D-nano-porous gold films (NPGFs) was optimised to function as a Surface Enhanced Raman Spectroscopy (SERS) substrate at 785 nm by a central composite experimental design. The concentration of the acid electrolyte (HCl), the potential step time, and the interaction between the acid concentration and the step time all had significant influence on the SERS intensity. The substrate with an optimum SERS intensity of the 1610 cm À1 band from 1,4-benzenedimethanethiol, which was self-assembled on the surface, was fabricated by applying 1.4 V (v Ag|AgCl|3.0 M NaCl) from open circuit potential for 50 s in 2.0 M HCl. The optimised 3D-NPGF substrates have highly uniform coverage of gold nanopores that leads to homogenous SERS intensities across 1000 lm 2 of surface. SERS spectra of self-assembled monolayers of organic molecules including 1,4-benzenedimethanethiol, trithiocyanuric acid, 4-mercaptopyridine and 4-mercaptobenzoic acid were obtained using 3D-NPGF substrates.
Biological synthesis of triangular gold nanoprisms
Nature Materials, 2004
The optoelectronic and physicochemical properties of nanoscale matter are a strong function of particle size. Nanoparticle shape also contributes significantly to modulating their electronic properties. Several shapes ranging from rods to wires to plates to teardrop structures may be obtained by chemical methods; triangular nanoparticles have been synthesized by using a seeded growth process. Here, we report the discovery that the extract from the lemongrass plant, when reacted with aqueous chloroaurate ions, yields a high percentage of thin, flat, single-crystalline gold nanotriangles. The nanotriangles seem to grow by a process involving rapid reduction, assembly and room-temperature sintering of 'liquid-like' spherical gold nanoparticles. The anisotropy in nanoparticle shape results in large near-infrared absorption by the particles, and highly anisotropic electron transport in films of the nanotriangles.
The Formation of Gold Nanospikes for Sensing and Electrocatalytic Applications
The formation of new materials for catalytic and sensing applications is an area of continuing interest to both the scientific and industrial communities. Presented in this work is a study of the formation of gold nanospikes which show applications across a wide range of fields, including activity towards glucose electro-oxidation, the detection of dopamine in the presence of uric acid and ascorbic acid and also surface-enhanced Raman scattering (SERS) properties.
Structure and Applications of Gold in Nanoporous Form
2017
Nanoporous gold (np-Au) has many interesting and useful properties that make it a material of interest for use in many technological applications. Its biocompatible nature and ability to serve as a support for self-assembled monolayers of alkanethiols and their derivative make it a suitable support for the immobilization of carbohydrates, enzymes, proteins, and DNA. Its chemically inert, physically robust and conductive high-surface area makes it useful for the design of electrochemistry-based chemical/bio-sensors and reactors. Furthermore, it is also used as solid support for organic molecular synthesis and biomolecules separation. Its enhanced optical property has application in design of plasmonics-based sensitive biosensors. In fact, np-Au is one of the few materials that can be used as a transducer for both optical and electrochemical biosensing. Due to the presence of low-coordination surface sites, np-Au shows remarkable catalytic activity for oxidation of molecules like carb...