(The) study of synthesis of metal nanoparticles and self-assembly of organic molecules

Abstract

The shape and size of platinum and gold nanoparticles were controlled by the changes in the concentration ratio of the capping materials to the metal. Synthesis of gold nanoparticles shows that the higher the ratio of capping materials to metal, the smaller the size of nanoparticles obtained. Quantum size effects of nano-sized particles are presented by a blue shift of maximum absorption wavelength as the size of gold nanoparticles decrease. And X-ray diffraction patterns shows that the structure of nanoparticles is the same as the bulk metal structure. Self-assembly of organic molecules on n-type Si(111) surface is the basis of producing gold nanoparticle film. An hydroxyl functional species bond with the hydrogen terminated silicon surface. Therefore, alcohols with thiol functional species are self-assembled on silicon surface and gold nanoparticle films are produced by the bonding of gold with thiol. A Current vs. potential curve of self-assembled silicon wafer doesn``t show the normal redox peak of the $Ru^{3+}$ electrolyte. This is the indication of successful self-assembly of organic molecules on Si surface.