Patent ID: 7326908

Claim:
A device for detecting light in a pre-selected wavelength range and converting the detected light into light of at least one pre-selected wavelength and emitting the light at said at least one pre-selected wavelength, comprising: a substrate and a first electrically conducting electrode layer on the substrate; a first layer of first nanocrystals located on the first electrically conducting electrode layer which absorb light in said pre-selected wavelength range; at least one second layer of second nanocrystals which emit light at said at least one pre-selected wavelength located on the first layer of first nanocrystals; and a second electrically conducting electrode layer on the at one least second layer of second nanocrystals, wherein at least one of said substrate and first electrically conducting electrode layer and said second electrically conducting electrode layer is substantially transparent to the light in the pre-selected wavelength range and light at the at least one pre-selected wavelength, and wherein when the light in said pre-selected wavelength range is incident on said first layer of first nanocrystals a photocurrent is responsively produced when a voltage is applied between the first and second electrically conducting electrode layers, and wherein said photocurrent acts to pump the at least one second layer of the second nanocrystals which responsively emit light at the at least one pre-selected wavelength.