Thursday, October 26, 2006

US Patent 7125605 - >30% Quantum Yield Nanocrystals

Quantum dots (i.e. nanocrystals) are useful for biological tags and in optoelectronic applications such as lasers, radiation sensors, and displays. The size of the quantum dots can be tuned to emit or absorb light of specific frequencies. An important parameter characterizing quantum dots is "quantum yield" which refers the ratio of emitted photons (light) to absorbed photons. This patent from M.I.T. claims-

1. A population of coated nanocrystals each comprising a size-selected core including a first semiconductor material and an overcoating including a second semiconductor material, wherein the population of coated nanocrystals exhibit photoluminescence having a quantum yield of greater than about 30%.