US Patent 7785496 - Electrochromatic nanoparticle ink

http://ip.com/patent/US7785496

A variety of nanoparticle-based inks have been developed over the past years to be used as low-cost patterning of metal layers in semiconductor devices. This patent from Clemson University also teaches a nanoparticle-based ink but instead of metal patterns the ink is used to fabricate electrochromatic displays. Claim 1 reads:

1. A printable ink comprising

a carrier liquid;

a plurality of a first composite particle dispersed within the carrier liquid, the first composite particle having a maximum cross sectional diameter of less than about 500 nanometers, the first composite particle including a plurality of nanoparticles and an intrinsically conductive polymer, the first composite particle having a conductivity between about 1×10−4 S/cm and about 10 S/cm; and

a monomeric dopant in the intrinsically conductive polymer;

wherein the printable ink is an electrochromic ink, the first composite particles exhibiting a color change upon a change in the electrical state of the ink.