Nanowire preparation methods, compositions, and articles

Abstract

Methods of preparing nanowires by reducing metal cations are disclosed and claimed, where the metal cation reduction occurs in at least two stages. Such methods can exhibit improved reproducibility and reduced variability. The product nanowires are useful in, for example, electronics applications.

What is claimed: 
     
         1 . A method comprising:
 providing at least one first composition comprising 1,2-propylene glycol, polyvinyl pyrrolidone, and ammonium chloride;   adding at least one second composition to the at least one first composition, the adding occurring over the course of at least about 16 hrs, and the at least one second composition comprising 1,2-propylene glycol and silver nitrate; and   reducing at least a portion of the silver nitrate to silver nanowires.   
     
     
         2 . The method according to  claim 1 , further comprising heating the at least one first composition to a temperature less than about 140° C. 
     
     
         3 . The method according to  claim 1 , further comprising heating the at least one first composition to a temperature between about 80° C. and about 120° C. 
     
     
         4 . The method according to  claim 1 , further comprising heating the at least one first composition to a temperature of about 90° C. 
     
     
         5 . The method according to  claim 1 , wherein the at least one first composition further comprises silver nitrate. 
     
     
         6 . The method according to  claim 5 , wherein providing the at least one first composition comprises:
 providing at least one third composition comprising silver nitrate; and   adding at least one fourth composition to the at least one third composition, the at least one fourth composition comprising ammonium chloride.   
     
     
         7 . The method according to  claim 5 , wherein providing the at least one first composition comprises:
 providing at least one third composition comprising polyvinyl pyrrolidone;   forming at least one fourth composition by adding at least one fifth composition to the at least one third composition, the at least one fifth composition comprising silver nitrate; and   adding at least one sixth composition to the at least one fourth composition, the at least one sixth composition comprising ammonium chloride.   
     
     
         8 . The method according to  claim 7 , further comprising heating the at least one third composition to a temperature less than about 140° C. 
     
     
         9 . The method according to  claim 7 , further comprising heating the at least one third composition to a temperature between about 80° C. and about 120° C. 
     
     
         10 . The method according to  claim 7 , further comprising heating the at least one third composition to a temperature of about 90° C. 
     
     
         11 . The method according to  claim 1 , wherein the adding the at least one second composition to the at least one first composition occurs over the course of between about 20 hrs and about 28 hrs. 
     
     
         12 . The method according to  claim 1 , wherein the adding the at least one second composition to the at least one first composition occurs over the course of about 24 hrs.