US Patent 7816669 - Electroluminescent material with controlled nanocrystal distribution

http://www.freepatentsonline.com/7816669.html

Hybrid light emitting systems have been proposed combining both semiconductor nanocrystals and organic polymers. One problem with such systems is uneven distribution of the nanocrystals which lead to diminishing or inconsistent efficiency over time. This patent from HP teaches polymer mixtures which can help avoid this problem. Claim 1 reads:

1. A light emitting system, comprising:

a polymer mixture including at least two partially miscible or non-miscible different polymers that segregate, the polymer mixture having a thickness ranging from about 10 nm to about 1000 nm; and

a controlled distribution of a plurality of nanocrystals occupying predefined, discrete positions of the polymer mixture, the controlled distribution being achieved due to properties of the at least two partially miscible or non-miscible different polymers selected for the polymer mixture and properties of the plurality of nanocrystals selected for the polymer mixture.