IBM & Stanford Reveal Production Process for Nanooptic, Nanoelectronic and Nanomagnetic Noble Metal Nanoparticles

Nanoscale objects with size of several hundred nanometers or less have promising potential in optic, electronic, magnetic, and catalytic applications.

 Progression in the production of monodisperse noble metal (Au, Ag, Pt and Pd), semiconducting, and magnetic nanoparticles has provided various systems suitable for nanooptic, nanoelectronic and nanomagnetic studies in mapping the scaling limits of future information technology, understanding spin-dependent transport phenomena, and using nanoparticles as highly sensitive labels (both magnetic and optic) for bio-recognition. 

Dumbbell-like nanoparticles and a process of forming the same  earned United States Patent 7,766,993  for International Business Machines Corporation (Armonk, NY) and  The Board of Trustees Of The Leland Stanford Junior University (Palo Alto, CA)

According to inventors Shouheng Sun (Millwood, NY), Heng Yu (Yorktown Heights, NY) and  Shan X. Wang; (Portola Valley, CA) dumbbell-shaped or flower-shaped nanoparticles and a process of forming the same are covered in the patent.

The process comprises forming a mixture of a nanoparticle with a precursor in a first solvent, wherein the nanoparticle comprises a hydrophobic outer coating; heating the mixture; cooling the mixture to room temperature; modifying the hydrophobic outer coating into a hydrophilic outer coating; precipitating a solid product from the mixture, and dispersing the product in a second solvent.

The nanoparticles comprise any of a semiconducting, magnetic, and noble metallic material, wherein the nanoparticles comprise a first portion comprising any of PbSe, PbS, CdSe, CdS, ZnS, Au, Ag, Pd, and Pt, and wherein the precursor comprises any of a cationic, neutral or particulate Au, Ag, Pd, Pt, or transition metal (Fe, Co, Ni) precursors of Fe(CO)5, Co(CO)8, Ni(CO)4 or their analogues. The first and second solvents comprise any of alkanes, arenes, ethers, nitrites, ketones, and chlorinated hydrocarbons.

FIG. 7 is a TEM image of Fe2O3--Au nanoparticles, wherein the lighter part of the image represents Fe2O3 while the darker part of the image represents Au  

FIG. 8 is another TEM image of Fe2O3--Au nanoparticles, wherein the lighter part of the image represents Fe2O3 while the darker part of the image represents Au  

FIG. 5 is a schematic illustration of a dumbbell-like nanoparticle used as a label for biomolecule detection  

 

FIG. 6 is a schematic illustration of a dumbbell-like nanoparticle used as a bridge for nano-contact