Thursday, August 19, 2010

US Patent 7777233 - Non-blinking quantum dots

Quantum dots are usually fabricated either by self-assembly methods on a substrate by epitaxial growth or in solution by colloidal synthesis. The colloidal quantum dots have the advantage of low cost deposition processes but have demonstrated a "blinking" problem related to intermittent emission which is not found in epitaxially grown quantum dot films. This patent from Kodak teaches a type of colloidal quantum dots which can avoid the blinking problem. Claim 1 reads:

1. An optoelectronic device comprising:

(a) two spaced apart electrodes; and

(b) at least one layer containing ternary core/shell nanocrystals disposed between the spaced electrodes and having ternary semiconductor cores containing a gradient in alloy composition and wherein the ternary core/shell nanocrystals exhibit single molecule non-blinking behavior characterized by on times greater than one minute or radiative lifetimes less than 10 ns.