Authors: B.S. Mitchell, M.J. Fink
Affilation: Tulane University, United States
Pages: 372 - 375
Keywords: nanoparticle, mechanochemistry
A rapid, direct and efficient method for the fabrication of functionalized semiconductor nanoparticles is described. The mechanochemical method involves the simultaneous top-down formation of nanoparticles using high energy ball milling (HEBM) and reaction with a liquid medium to passivate (functionalize) the surface of nanoparticles as they are formed. In one embodiment of this process, elemental silicon is ball-milled in the presence of a reactive hydrocarbon, such as an n-alkyne. As the silicon fracture during the mechanical attrition, the formation of reactive surface species lead to the reaction with the surrounding organic medium and the creation of direct Si-C bonds. As the particles further fracture into the nano-regime and become sufficiently functionalized with organic molecules, they become soluble in the parent liquor and can be easily removed in a post-milling centrifugation step. Examples of how this method are being adapted to other semiconductors such as germanium, and other reactive organic compounds such as alkenes, alcohols, aldehydes and carboxylic acids are given. Furthermore, the adaptation of this technique to yield water-soluble analogues is elucidated. The importance of these functionalized semiconductor nanoparticles is illustrated through a brief description of the opto-electronic properties, including photoluminescence. Potential applications as biomarkers, solar energy collection media and emissive displays as discussed. Finally, the use of “waste” material from processing for the production of superhydrophobic films and surfaces is described. The importance of processing parameters and continuous operation to scale-up are discussed.