Luminescent and Raman active silver nanoparticles with polycrystalline structure.

We report the synthesis of silver nanoparticles with grain sizes down to electron Fermi wavelength. These nanoparticles exhibit bright luminescence and large Raman enhancement effect. The number of photons emitted from these nanoparticles exceeded that from quantum dots or dye molecules by approximately 2 or 5 orders of magnitude, respectively.