Showing posts from February, 2013

Plasmonic nanoparticles

Plasmons are free electrons on the surface of metals that become excited by the input of energy, typically from light. Moving plasmons can transform optical energy into heat.  Plasmonic nanoparticles are particles whose electron density can couple with electromagnetic radiation of wavelengths that are far larger than the particle. This is due to the nature of the dielectric-metal interface between the medium and the particles unlike in a pure metal where there is a maximum limit on what size wavelength can be effectively coupled based on the material size. Plasmonic nanoparticles also exhibit interesting scattering, absorbance, and coupling properties based on their geometries and relative positions. These unique properties have made them a focus of research in many applications including solar cells, spectroscopy, signal enhancement for imaging, and cancer treatment. Plasmonic gold nanoparticles Gold nanoparticles can be used for efficiently converting energy because of their optical

Nanosilicon to produce hydrogen

Nanoparticles of silicon can be made to react instantly with water to produce hydrogen without application of any heat, light or electricity. Hydrogen production Traditional techniques to split water to produce hydrogen include electrolysis, thermolysis and photo catalysis.But bulk silicon abundantly available on earth can react slowly with water to produce hydrogen by releasing two moles of hydrogen gas per mole of silicon without releasing any carbon dioxide. Nanosilicon Silicon nanoparticles due to their high surface to volume ratio can generate hydrogen quickly than bulk silicon due to high reaction rate. Researchers at the University at Buffalo (SUNY) in New York have developed this technique. For example nanoparticles 10 nm in size can produce hydrogen in under a minute which is1000 times faster at producing hydrogen than is bulk silicon and nanoparticles of 100 nm in diameter can produce at 45 minutes. During the hydrogen production reaction, the 10 nm silicon particles reduce i