US Patent 7955858 - Quantum dot environmental indicators

http://www.freepatentsonline.com/7955858.html

This patent from Boeing teaches a way to use semiconductor nanocrystal coatings to detect corrosion in aircraft metallic structures. Claim 1 reads:

1. A detection method, comprising:

applying a coating to a substrate;

illuminating the applied coating with a first light having a first predetermined wavelength; and

detecting a second light having a second predetermined wavelength;

wherein the coating comprises a microsphere comprising a quantum dot and a shell surrounding the quantum dot, and the shell is formed of a shell material that reflects the first light; and

wherein the quantum dot is selected to emit the second light when illuminated by the first light; and

wherein the shell material is selected to react in the presence of a corrosive environment to allow the first light to illuminate the quantum dot.