Patent ID: 7200318

Claim:
A composite material comprising a host material in which is incorporated semiconductor nanocrystals, wherein: said host material is light-transmissive or light-emissive or both light-transmissive and light-emissive and is electrical charge-transporting such as to permit electrical charge transport through said host to the core of said nanocrystals; and said nanocrystals comprise a semiconductor nanocrystal core that emits and absorbs energy in the near infra red (NIR), and comprise at least one crystalline shell layer encapsulating said core, said shell causing said semiconductor nanocrystals to have values of quantum yield and chemical stability and photostability that are changed from the values of an identical non-encapsulated nanocore, wherein said nanocrystal has removable or substitutable organic ligands on the outer surface thereof characterized in that materials and thickness of said crystalline shell and/or said organic ligands are chosen so as to decouple the energies of said core and said host material at the near infrared (NIR) sufficiently to avoid quenching of the emission of energy by said core through interaction with said host thereby at least partially shielding said core from the absorption resonances of said host material and allowing said cores of said nanocrystals to emit light by electroluminescence in the near infrared spectral range when an electrical potential exists in or an electrical current flows through said composite material and allowing an electrical current to flow in said composite material when light in the near infrared range is absorbed by said cores of nanocrystals.