Method of making nanoparticles by electroless plating
View Patent ↗A plurality of gold nanoparticles disposed on a surface of a substrate includes nanoparticles having an average particle density greater than 1.8×10 11 particles per squared centimeter of the surface. The gold nanoparticles include a monomodal diameter distribution and an average diameter capable of being arbitrarily controlled between about 5 nm to about 300 nm. The surface may be a three-dimensional surface or an internal surface.
1. A method of making nanoparticles comprising a first noble metal, the method comprising:
performing electroless plating in to form an island film on a tin-sensitized surface by:
depositing a droplet of a solution comprising a nanoparticle precursor onto a second noble metal disposed on the surface, wherein the droplet comprises a volume less than about 20 microliter, and wherein the nanoparticle precursor comprises ions of the first noble metal; and
galvanically displacing the second noble metal with the nanoparticle precursor, wherein the second noble metal is less noble than the first noble metal; and
annealing the island film to form the nanoparticles, wherein an average diameter of the nanoparticles is controlled during processing from about 5 nm to about 300 nm by controlling the island film thickness or annealing conditions.
2. The method of claim 1 , wherein:
the solution comprises dissolved Na 3 Au(SO 3 ) 2 ;
the tin-sensitized surface comprises a surface formed by exposing a silicon dioxide surface to tin ions;
the second noble metal comprises silver; and
the first noble metal comprises gold.