US Patent 7431867 - Uniform core/shell nanoparticles

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Core/shell nanocrystals have potential as useful components to LEDs. By tuning the size of the nanocrystals the emission wavelength can be controlled. This patent from Konica Minolta Medical & Graphic teaches a processing method involving mixing silicon tetrachloride and a reducing agent and heating to form Si/SiO2 core/shell nanoparticles with uniform diameters for a better control of the luminescent wavelength. Claim 1 reads:

1. Nanosized semiconductor particles of a core/shell structure, wherein the particles each comprise a core and a shell and exhibit an average particle size of not more than 100 nm and a coefficient of variation in particle size distribution of not more than 30%, and an average core size being from 2 to 20 nm and a coefficient of variation in core size distribution being not more than 30%.