Systems and methods for cavitation of silver

Abstract

Provided in one embodiment is a method of making paste for solar cells. The method can include forcing silver through a feed tube coupled to a hydrodynamic cavitation chamber using an air-driven piston. The method can include subjecting the silver to hydrodynamic cavitation in the hydrodynamic cavitation chamber by using a hydraulic pump to pass the silver sequentially through a primary orifice, a secondary orifice, and a final orifice within the hydrodynamic cavitation chamber to produce the paste for the solar cells. The silver can include up to three unique silver powders having a total particle size distribution from 0.1 microns to 10 microns. A first silver powder can have a first average particle size of 1.5 um, a second silver powder having a second average particle size of 0.5 um, and a third silver powder having a third average particle size of 0.2 um.

What is claimed: 
     
         1 . A method of making paste for solar cells, comprising:
 providing silver;   forcing the silver through a feed tube coupled to a hydrodynamic cavitation chamber using an air-driven piston; and   subjecting the silver to hydrodynamic cavitation in the hydrodynamic cavitation chamber by using a hydraulic pump to pass the silver sequentially through a primary orifice, a secondary orifice, and a final orifice within the hydrodynamic cavitation chamber to produce the paste for the solar cells.   
     
     
         2 . The method of  claim 1 , wherein providing the silver comprises providing a silver alloy comprising up to three unique silver powders having a total particle size distribution from 0.1 microns to 10 microns. 
     
     
         3 . The method of  claim 1 , wherein providing the silver comprises providing a silver alloy consisting of at least 80% of a first silver alloy powder having a first average particle size of 1.5 um, up to 15% of a second silver alloy powder having a second average particle size of 0.5 um, and up to 15% of a third silver powder having a third average particle size of 0.2 um. 
     
     
         4 . The method of  claim 1 , wherein providing the silver comprises providing a silver alloy comprising at least one of: Pd, Au, Pt, Ni, Cu, Ru, or a combination thereof. 
     
     
         5 . The method of  claim 1  wherein providing the silver comprises providing a raw material including the silver and at least one of: carbon black, graphene, carbon nanotubes, and graphite. 
     
     
         6 . The method of  claim 1 , wherein providing the silver comprises providing a raw material including the silver and a glass material. 
     
     
         7 . The method of  claim 1 , wherein providing the silver comprises providing a raw material including the silver and a glass material, wherein the glass material comprises:
 (i) a softening temperature between 330° C. and 450° C.;   (ii) a glass transition temperature between 250° C. and 270° C.; and   (iii) an average particle size between 0.1 microns and 10 microns.   
     
     
         8 . The method of  claim 1 , wherein providing the silver comprises providing a raw material including silver alloy and 8-10 wt. % of at least one of (i) at least one organic solvent and (ii) at least one polymer material. 
     
     
         9 . The method of  claim 1 , wherein providing the silver comprises providing a raw material comprising:
 (i) less than 4.0 wt. % of a glass material;   (ii) about 80 to about 88 wt. % of a composition comprising silver particles;   (iii) about 10.8 to about 14.4 wt. % of an organic solvent; and   (iv) about 1.2 to 1.6 wt. % of a polymer material.   
     
     
         10 . The method of  claim 1 , wherein providing the silver comprises providing a raw material comprising:
 (i) less than 4.0 wt. % of a glass material;   (ii) about 65 to about 75 wt. % of a composition comprising silver particles;   (iii) about 18 to about 27 wt. % of an organic solvent; and   (iv) about 2 to 3 wt. % of a polymer material.   
     
     
         11 . The method of  claim 1 , wherein the method includes one or more processors transmitting an instruction to the hydraulic pump to force the silver through the primary orifice, the secondary orifice, and the final orifice within the hydrodynamic cavitation chamber to produce the paste for the solar cells. 
     
     
         12 . The method of  claim 1 , further comprising subjecting the silver to the hydrodynamic cavitation within the hydrodynamic cavitation chamber by passing the silver sequentially through the primary orifice having a first diameter, the secondary orifice having a second diameter, and the final orifice having a third diameter, to produce the paste for the solar cells, the second diameter larger than the first diameter and the third diameter. 
     
     
         13 . The method of  claim 1 , further comprising subjecting the silver to the hydrodynamic cavitation by:
 subjecting the silver to the hydrodynamic cavitation within the hydrodynamic cavitation chamber by passing the silver sequentially through a first primary orifice having a first diameter, the secondary orifice, and the final orifice; and   subsequently passing the silver within the hydrodynamic cavitation chamber through a second primary orifice having a second diameter, the secondary orifice, and the final orifice to produce the paste for the solar cells, the second diameter smaller than the second diameter.   
     
     
         14 . The method of  claim 13 , wherein the first diameter and the second diameter are between 0.005 inches and 0.050 inches. 
     
     
         15 . The method of  claim 1 , further comprising subjecting the silver to a pressure in a range of 1,000 psi to 45,000 psi in the hydrodynamic cavitation chamber. 
     
     
         16 . The method of  claim 1 , further comprising subjecting the silver to a temperature in a range of 30° C. to 48° C. in the hydrodynamic cavitation chamber. 
     
     
         17 . The method of  claim 1 , further comprising subjecting the silver to the hydrodynamic cavitation until the paste has a conductivity of less than 2 micro-ohm*cm. 
     
     
         18 . The method of  claim 1 , further comprising subjecting the silver to the hydrodynamic cavitation until particles contained in the silver are de-agglomerated and dispersed to produce the paste having a thickness of 12 um to 20 um and a width of less than 50 microns. 
     
     
         19 . The method of  claim 1 , further comprising disposing the paste in a gridline pattern onto a substrate that is part of the solar cells. 
     
     
         20 . The method of  claim 19 , further comprising subsequently sintering the paste to the substrate at a temperature between 700° C. to 900° C.