Synthesis, Characterization and Assemblies of Gold Nanorods and Copper Nanocrytals

 

Yonglin Liu and A. R. Hight Walker

Optical Technology Division, Physics Laboratory

 

Two colloidal nanoparticle solutions have been produced and studied; gold nanorods and copper nanocrystals.  Gold nanorods have been explored for biological and medical use as optical contrast agents in two-photon luminescence diagnostic imaging, and photothermal therapy of cancer cells.  A persistent challenge limiting their applications is the reproducibility of the chemical synthesis.  Our research has enable gold nanorod production with high yield and uniformity of both size and shape, via a colloidal, seed-mediated, and surfactant-assisted method.  2-D ordered structures of the nanorods are self-assembled during evaporation of solvent on a substrate, while the presence of organic molecules such as homocysteine, glutathione, and glucose facilitates other assemblies.  Chemical-induced transverse overgrowth of gold nanorods leads to the formation of peanut-shape nanocrystals.   Secondly, copper nanoparticles have multiple applications due to their catalytic, electrochemistry, magnetic and optical properties.  Our approaches to the synthesis of crystalline Cu nanoparticles will be presented, both aqueous and organic solvents procedures.  By using glucose as a nontoxic and renewable biochemical reducing agent in aqueous solutions, the reductive reactions from Cu(II) to Cu(0) are found to be finished in just half an hour at the low temperature of 60 °C in the presence of poly-vinylpyrrolidone.  The experimental results show the nanoparticles to be crystalline and mainly composed of face-centered cubic Cu with a fairly narrow size distribution (50-200 nm).  We further found that these Cu nanoparticles form one-dimensional structures by self-assembly.  Cu nanoparticles produced in organic solvents involved manipulation of reaction temperatures in the presence of amine and acid capping agents and will also be presented. All nanoparticles are characterized using TEM, HR-TEM, XRD, and UV-visible spectroscopic techniques.  The mechanistic aspects of particles size control and shape formation will also be discussed.

 

Author Information:

Name:  Yonglin Liu

Mentor’s name: Angela R. Hight Walker

Division: Optical Technology, 844

Laboratory: Physics

Building/Room: 216/B219

Mail Stop: 8443

Telephone #: 301-975- 8568

Fax #:

Email:  yonglin.liu@nist.gov

Sigma Xi: not a member

Category: Physics