Seeded high yield synthesis of short Au nanorods in ..
The Au-nanorod/SWCNT/Au-nanorod synthesis is depicted schematically in . HiPco SWCNTs were treated with a mixture of concentrated sulfuric and nitric acid (3:1, 98% and 70%, respectively), subjected to bath sonication for 35 min. at 40 °C, and then oxidized with a mixture of concentrated sulfuric acid and hydrogen peroxide (4:1, 98% and 30%, respectively, 35 min.) to functionalize the nanotube termini with carboxylic acid groups, and to remove extraneous carbon particles. Previous studies have demonstrated that the chemical shortening of SWCNTs by mixtures of strong acids leads to oxidation at the nanotube ends and can also introduce sidewall defect sites. The oxidized nanotubes were incubated with Triton X-100/PEG (Mr = 10,000) in an aqueous solution and sonicated for 4 h in an ice bath. This process results in a stable dispersion of SWCNTs wrapped with surfactant and polymer to prevent non-specific surface adsorption and/or unwanted covalent functionalization to defects on nanotube sidewalls., The oxidized termini of the shielded SWCNTs were then selectively coupled to the monofunctionalized 1.4 nm Au-nanoparticles (Au-NPs) bearing a single primary amine group. Efficient coupling was achieved using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS), resulting in SWCNTs functionalized with Au-NPs at their termini. The Au-NP diameter (~1.4 nm) is slightly larger than the diameter of HiPco SWCNTs (between ~0.7–1.2 nm) and the steric bulk of the Au-NPs provides a basis for monofunctionalization of the nanotube ends. The resulting Au-NP conjugated SWCNTs were used to seed the growth of Au-nanorods from the termini of the SWCNTs. Catalytic enlargement of the Au-nanoparticles was achieved using HAuCl4 and CTAB as a template (see ).,
Seed-Mediated Synthesis of Gold Nanorods: Role of …
We report the synthesis of solution dispersible, one-dimensional metal nanostructure arrays as small as 35 nm in diameter using on-wire lithography, wherein feature thickness and spacing in the arrays is tailorable down to approximately 6 and 1 nm, respectively. Using this unique level of control, we present solution-averaged extinction spectra of 35 nm diameter Au nanorod dimers with varying gap sizes to illustrate the effect of gap size on plasmon coupling between nanorods. Additionally, we demonstrate control over the composition of the arrays with Au, Ni, and Pt segments, representing important advances in controlling the ordering of sub-100 nm nanostructures that are not available with current synthesis or assembly methods.
51. Chen YN, Chen PC, Wang CW. . One-pot synthesis of fluorescent BSA-Ce/Au nanoclusters as ratiometric pH probes. 2014;50:8571-4
PDF Downloads : Oriental Journal of Chemistry
182. Au KM, Armes SP. Heterocoagulation as a Facile Route To Prepare Stable Serum Albumin-Nanoparticle Conjugates for Biomedical Applications: Synthetic Protocols and Mechanistic Insights. 2012;6:8261-79
Strategies for Preparing Albumin-based Nanoparticles …
High aspect ratio building blocks such as Au-nanorods and carbon nanotubes are key elements to construct interconnected arrays of electronic materials. The high surface area and restricted electronic conduction pathways are of particular value to create materials that are very sensitive to chemical/physical stimuli for sensor applications.- A wide range of carbon nanotube functionalization methods allow for sidewall immobilization- of tailored metallic and/or semiconducting nanoparticles; however, regioselectivity remains a major problem. The formation of heterojunctions between carbon nanotubes and metals has received increased attention due to the potential electronic and materials properties. Previous heterojunction fabrication methods have relied on vapor phase growth and solid-solid reactions at elevated temperatures >450 °C or ablative techniques using intense electron beam irradiation to destroy the nanotube wall around a metallic core.,, Heterojunctions between gold nanorods and carbon nanotubes have been reported; however, the current method relies on the nonspecific attachment of Au-NPs to the surface of CNTs, resulting in heterogenous structures with multiple random heterojunctions and unpredictable Au-nanorod growth patterns. Harsh experimental conditions and the control/precise positioning of the metal junctions have limited the widespread utility of these methods.,,, Methods for the regioselective synthesis of well-defined Au-nanorod/SWCNT/Au-nanorod nanocomposites would represent a major step forward in the controlled functionalization of SWCNTs with precisely defined metallic heterojunctions. Herein, we report an operationally simple method for the regiospecific synthesis of terminally-linked Au-nanorod/SWCNT/Au-nanorod nanostructures. Our method allows for the growth of Au-nanorods from the termini of SWCNTs creating precisely positioned metallic heterojunctions. These nanocomposites are synthesized in solution and are found to be very stable under a variety of experimental conditions.
Joe Shapter - Flinders University
9001-9009 (2013).This paper describes the synthesis of TiO2 branched nanorodarrays (TiO2 BNRs) with plasmonic Au nanoparticles attachedon the surface.