Metal Inks

Abstract

Self-reducing metal inks and systems and methods for producing and using the same are disclosed. In an exemplary embodiment, a method may comprise selecting a metal-organic (MO) precursor, selecting a reducing agent, and dissolving the MO precursor and the reducing agent in an organic solvent to produce a metal ink that remains in a liquid phase at room temperature. Metal inks, including self-reducing and fire-through metal inks, are also disclosed, as are various applications of the metal inks.

1 . A method comprising:
 selecting a metal-organic (MO) precursor;   selecting a reducing agent; and   dissolving the MO precursor and the reducing agent in an organic solvent to produce a metal ink that remains in a liquid phase at room temperature.   
     
     
         2 . The method of  claim 1 , wherein the MO precursor and the reducing agent are non-reacting at room temperature. 
     
     
         3 . The method of  claim 1 , further comprising selecting the organic solvent from organic solvents that have a sufficiently high boiling point so as to remain in a liquid phase at room temperature. 
     
     
         4 . The method of  claim 1 , further comprising selecting the organic solvent from organic solvents that provide viscosity and wetting properties for inkjet printing. 
     
     
         5 . The method of  claim 1 , wherein selecting the MO precursor is from MO precursors having a metal ion that is reduced to a pure metallic state at a potential positive of a reduction potential of the reducing agent. 
     
     
         6 . The method of  claim 5 , wherein the reducing agent includes formate ions. 
     
     
         7 . The method of  claim 1 , further including reacting the MO precursor and the reducing agent at an activating temperature. 
     
     
         8 . The method of  claim 7 , further including reacting the MO precursor and the reducing agent at temperatures in the range of about 150-250° C. 
     
     
         9 . The method of  claim 8 , wherein reacting the MO precursor and the reducing agent produces substantially pure metal deposits on a substrate. 
     
     
         10 . The method of  claim 1 , further comprising
 elevating the temperature of the metal ink;   reacting the reducing agent with the MO precursor; and   producing a substantially uncontaminated metal deposit on a substrate.   
     
     
         11 . A metal ink produced according to the process of  claim 1 . 
     
     
         12 . The metal ink of  claim 11 , wherein the metal ink forms metal deposits at elevated temperatures. 
     
     
         13 . The metal ink of  claim 12 , wherein the metal deposits consist of copper (Cu), gold (Au), silver (Ag), lead (Pb), palladium (Pd), platinum (Pt), cobalt (Co), iron (Fe), Tin (Sn), and metal alloys. 
     
     
         14 . A self-reducing metal ink produced according to the process of  claim 1 . 
     
     
         15 . A fire-through metal ink produced according to the process of  claim 1 . 
     
     
         16 . The fire-through metal ink of  claim 15  further comprising a soluble metal complex and soluble organo-metallic reagent in a solution containing a particulate metal or metal organic precursor at room temperature. 
     
     
         17 . A method comprising:
 providing a metal ink in a liquid phase at room temperature; and   applying the metal ink to a substrate at an elevated temperature, wherein the metal ink reacts in a single step at the elevated temperature to produce substantially pure metal deposits on the substrate.   
     
     
         18 . The method of  claim 17  wherein applying the metal ink to the substrate is by at least one of the following processes: spraying, dipping, spinning, direct-write deposition, and inkjet printing. 
     
     
         19 . A method comprising:
 providing a fire-through metal ink in a liquid phase at room temperature; and   applying the fire-through metal ink to a coated surface of a solar cell, wherein the fire-through metal ink reacts with the coated surface of the solar cell to produce electrical contacts with a p-n layer beneath the coated surface of the solar cell.   
     
     
         20 . The method of  claim 19  wherein applying the metal ink to the substrate is by at least one of the following processes: spraying, dipping, spinning, direct-write deposition, and inkjet printing.