US Patent 7279832 - Group IV nanoparticle light source

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CdSe and CdS material have been favored candidates as nanoparticles used in lighting applications however, due to the toxic nature of these materials, other nanoparticle materials would be desirable. This patent from Innovalight presents some basic claims toward silicon or germanium based nanoparticles in white light sources. Claims 1 and 28 recite:

1. A light emitting device comprising: (a) a primary light source which emits primary light; and (b) a phosphor material comprising a plurality of nanoparticles, the nanoparticles comprising a Group IV semiconductor, which absorbs at least a portion of the primary light and emits a secondary light, wherein the secondary light or the combination of the secondary light with the primary light comprises a white light.

28. A phosphor material comprising a plurality of domains deposited on an organic film, each domain comprising a plurality of luminescent semiconductor nanoparticles having a substantially monodisperse size distribution.