US Patent 7887720 - Polymer-nanocrystal composites for optoelectronics

http://www.freepatentsonline.com/7887720.html

 This patent from the University of Pennsylvania and Louisiana Tech teaches quantum dot photodetectors having an external quantum efficiency greater than 1 for electric fields of about 7×10⁵ V/cm. Claim 1 reads:

1. A method of increasing the external quantum efficiency of an optoelectronic device comprising a semiconductor polymer characterized as having a bandgap in the visible portion of the electromagnetic spectrum, the method comprising:

combining nanocrystals that comprise a Group IV-VI compound with the semiconductor polymer, wherein the nanocrystals have a bandgap in the infrared portion of the electromagnetic spectrum, and the weight ratio of semiconductor polymer to nanocrystals is in the range of from more than about 95:5 to about 1000:1.