Topics: Nanoparticle, Nanotechnology, Light Pages: 4 (618 words) Published: May 3, 2013
Nanotechnology: Footprints to Future

Nanotechnology involves  Chemistry  Physics  Biology  Electronics/Photonics  Materials Science and Technology  Pharmaceuticals  Polymer Scientist etc.

Top-Down and Bottom-Up Approach

Welcome to the Nano-World

Did People know about Nanoparticles earlier ?????

Purple gold synthesized by Michael Faraday in 1889, stored in British Museum

Lycurgus cup: It appears green in reflected light, but appears red when light is shone from inside, and is transmitted through the glass.

Gold nanoparticles were used as a pigment of ruby-colored stained glass dating back to the 17th century. A picture of the Rose Window of the Cathedral of Notre Dame. The bright red and purple colors are due to gold nanoparticles.

People used the materials in the nanometer dimension for various purposes, however they thought these particles as metallic colloids, having the properties and behavior of the other colloids such as milk in water.

Transmission EM

Scanning EM

Atomic Force Microscope

Super-coiled DNA

Quantum corrals showing the de-Broglie hypothesis of wave-particle duality

Writing at the Nanoscale using AFM: Dip-Pen Nanolithography

How Nanoparticles are different from Bulk Materials
• Nanoparticles are different from bulk materials and isolated molecules because of their unique optical, electronic, magnetic and chemical properties. • As the dimensions of the material is reduced the electronic properties change drastically as the density of states and the spatial length scale of the electronic motion are reduced with decreasing size. • Closely related to size-induced changes in the electronic structure are the optical properties of nanoparticles.

Surface plasmon resonance
When a nanoparticle is much smaller than the wave length of light, coherent oscillation of the conduction band electrons induced by interaction with an electromagnetic field. This resonance is called Surface Plasmon...
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