What are nanomaterials and their properties?
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Nanomaterial is an object that has atleast one dimension in the nanometer scale approximately 1-100nm.
In small nano clusters the effect of reduced dimensionality on electronic structure has the most profound effect on the energies of highest occupied molecular orbital (HOMO) which is valence band and the lowest unoccupied molecular orbital(LUMO),essentially the conduction band.
The optical emission and adsorption occurs when the transition of the electrons occur between these two states.
Semiconductors and many metals show large changes in optical properties such as color, as a function of particle size.
Colloidal suspenses of gold nano particles have a deep red color which becomes progressively more yellow as the particle size increases.
Gold spheres of 10-20nm exhibit red color
Gold spheres of 2-5nm exhibit yellow color.
Gold spheres of >20nm exhibit purple color
Similarly,
Silver particles of 40nm exhibit blue color
Silver particles of 100nm exhibit yellow color
Prism shaped Silver particles red color.
Other properties which may be affected by reduced dimensionality include photocatalysis, photoconductivity, photoemission and electroluminescence.
Hope It's Help You
In small nano clusters the effect of reduced dimensionality on electronic structure has the most profound effect on the energies of highest occupied molecular orbital (HOMO) which is valence band and the lowest unoccupied molecular orbital(LUMO),essentially the conduction band.
The optical emission and adsorption occurs when the transition of the electrons occur between these two states.
Semiconductors and many metals show large changes in optical properties such as color, as a function of particle size.
Colloidal suspenses of gold nano particles have a deep red color which becomes progressively more yellow as the particle size increases.
Gold spheres of 10-20nm exhibit red color
Gold spheres of 2-5nm exhibit yellow color.
Gold spheres of >20nm exhibit purple color
Similarly,
Silver particles of 40nm exhibit blue color
Silver particles of 100nm exhibit yellow color
Prism shaped Silver particles red color.
Other properties which may be affected by reduced dimensionality include photocatalysis, photoconductivity, photoemission and electroluminescence.
Hope It's Help You
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