Super Bright Luminescent Metallic Nanoparticles.

It is found that, by curing the surface defects that quench photoexcited carriers, luminescence efficiency of metallic nanoparticles can be dramatically increased. For Ag nanoparticles, as much as 300 times increase in photoexcitation induced luminescence is observed upon surface adsorption of ethanethiol. The same treatment increases Au nanoparticle luminescence efficiency by a factor of 3. A model based on the elimination of surface defects by the sulfur-metal bond formed upon thiol adsorption can quantitatively account for the observations, which also indicate that nanoparticles without proper surface treatment typically have low luminescence quantum yields.