Method for preparing metal particles

Abstract

A method for preparing metal particles, including the steps of: depositing a metal layer on a substrate, irradiating the metal layer with a laser, a plate of a material transparent or quasi-transparent to the laser wavelength being interposed between the metal layer and the laser source.

1 . A method for preparing metal particles, comprising the steps of:
 depositing a metal layer on a substrate;   irradiating the metal layer with a laser;   
       a plate of a material transparent or quasi-transparent to the laser wavelength being interposed between the metal layer and the laser source. 
     
     
         2 . The method for preparing metal particles of  claim 1 , wherein the laser is an excimer laser. 
     
     
         3 . The method for preparing metal particles of  claim 1 , wherein the plate of transparent material is in contact with the metal layer. 
     
     
         4 . The method for preparing metal particles of  claim 1 , wherein the plate of transparent material and the metal layer are spaced apart by a distance of at most 1 mm. 
     
     
         5 . The method for preparing metal particles of  claim 1 , wherein the plate of transparent material is made of glass, of quartz, of borosilicate, or of plastic. 
     
     
         6 . The method for preparing metal particles of  claim 1 , wherein the laser fluence ranges between 10 and 1,000 mJ/cm 2 . 
     
     
         7 . The method for preparing metal particles of  claim 1 , wherein the metal layer is made of:
 a metal selected from the group comprising gold, copper, nickel, palladium, and silver; or of   a metal oxide, advantageously AgO, ZnO, or ITO.   
     
     
         8 . The method for preparing metal particles of  claim 1 , wherein the metal layer is deposited by physical vapor deposition (PVD), by chemical vapor deposition (CVD), or by printing. 
     
     
         9 . The method for preparing metal particles of  claim 1 , wherein the metal layer has a thickness ranging between 10 and 200 nm when the laser has a wavelength of 248 nm or of 308 nm. 
     
     
         10 . The method for preparing metal particles of  claim 1 , wherein the surface of the plate of transparent material opposite to the metal layer is covered with a fluorinated coating. 
     
     
         11 . The method for preparing metal particles of  claim 1 , wherein the substrate is made of a material selected from the group comprising:
 plastics, such as polyethylene naphthalate or polyimide;   glass;   polycarbonates;   polytetrafluoroethylene;   acrylate polymers;   steel covered with a plastic layer having a 50-nm thickness.   
     
     
         12 . The method for preparing metal particles of  claim 1 , wherein the particle dimension ranges between 10 and 500 nm. 
     
     
         13 . The method for preparing metal particles of  claim 1 , wherein before irradiation, the substrate covered with the metal layer and the plate of transparent material are immersed in a liquid. 
     
     
         14 . The method for preparing metal particles of  claim 13 , wherein the liquid has a heat conductivity greater than that of air and/or an optical index different from that of the plate of transparent material.