Metal nanoparticles and methods for producing and using same

Abstract

A composition may have metal nanoparticles having a diameter of 20 nanometers or less and have a fusion temperature of less than about 220° C. A method of fabricating the metal nanoparticles may include preparing a solvent, adding a precursor with a metal to the solvent, adding a first surfactant, mixing in a reducing agent, and adding in a second surfactant to stop nanoparticle formation. Copper and/or aluminum nanoparticle compositions formed may be used for lead-free soldering of electronic components to circuit boards. A composition may include nanoparticles, which may have a copper nanocore, an amorphous aluminum shell and an organic surfactant coating. A composition may have copper or aluminum nanoparticles. About 30-50% of the copper or aluminum nanoparticles may have a diameter of 20 nanometers or less, and the remaining 70-50% of the copper or aluminum nanoparticles may have a diameter greater than 20 nanometers.

What is claimed is: 
     
         1 . A method of manufacturing a printed circuit, the method comprising:
 applying a metal nanomaterial comprising a surfactant to a surface; and   tracing, by a heat source, a circuit line of the printed circuit on the surface, said tracing causing at least a portion of the metal nanomaterial to heat up to its fusion temperature and the surfactant to evaporate from the traced circuit line.   
     
     
         2 . The method of  claim 1 , wherein the metal nanomaterial comprises metal nanoparticles having a diameter of 20 nm or less but greater than zero, the metal nanoparticles having a metal core and a surfactant layer surrounding the metal core. 
     
     
         3 . The method of  claim 2 , wherein about 30-50% of the metal nanoparticles have a diameter of 20 nm or less but greater than zero and the remaining 70-50% of the metal nanoparticles have a diameter greater than 20 nm. 
     
     
         4 . The method of  claim 2 , wherein the metal nanoparticles comprise copper nanoparticles. 
     
     
         5 . The method of  claim 2 , wherein the metal nanoparticles comprise a mixture of copper nanoparticles and aluminum nanoparticles. 
     
     
         6 . The method of  claim 2 , wherein the metal nanoparticles further comprise a metal shell overcoating the metal core, the metal core comprising copper and the metal shell comprising aluminum. 
     
     
         7 . The method of  claim 1 , wherein the surfactant comprises at least one amine surfactant. 
     
     
         8 . The method of  claim 7 , wherein the at least one amine surfactant comprises a primary amine surfactant. 
     
     
         9 . The method of  claim 8 , wherein the at least one amine surfactant further comprises at least one other amine surfactant. 
     
     
         10 . The method of  claim 1 , wherein the heat source is a laser. 
     
     
         11 . The method of  claim 1 , further comprising:
 treating the surface with a solvent to cause the untraced metal nanomaterial to wash off.   
     
     
         12 . The method of  claim 1 , wherein applying the metal nanomaterial to the surface comprises an inkjet printing process.