Low-haze transparent conductors

Abstract

This disclosure is related to low-haze transparent conductors, ink compositions and method for making the same.

1 .- 17 . (canceled) 
     
     
         18 . A method, comprising:
 growing metal nanowires from a reaction solution comprising a metal salt and a reducing agent, wherein the growing comprises:
 reacting a first portion of the metal salt and the reducing agent in the reaction solution for a first period of time, and 
 adding a second portion of the metal salt over a second period of time while maintaining a substantially constant concentration of less than 0.1% w/w of the metal salt in the reaction solution. 
   
     
     
         19 . The method of  claim 18 , wherein the metal nanowires are silver nanowires and the metal salt is silver nitrate. 
     
     
         20 . The method of  claim 19 , wherein the reducing agent is at least one of propylene glycol or ethylene glycol. 
     
     
         21 . The method of  claim 20 , wherein the reaction solution further comprises at least one of polyvinylpyrrolidone or tetra-n-butylammonium chloride. 
     
     
         22 . The method of  claim 18 , wherein a ratio of the first portion of the metal salt to the second portion of the metal salt is between 30-70:70-30. 
     
     
         23 . The method of  claim 18 , wherein the first period of time is 12-16 hours. 
     
     
         24 . The method of  claim 18 , wherein reacting the first portion of the metal salt and the reducing agent in the reaction solution for the first period of time comprises:
 adding a fraction of the first portion of the metal salt with an ammonium salt; and   adding a remainder of the first portion of the metal salt.   
     
     
         25 . The method of  claim 24 , wherein the fraction is selected such that a concentration of metal ions in the reaction solution is 0.001% w/w to 0.025% w/w. 
     
     
         26 . The method of  claim 24 , wherein the fraction is less than or equal to 1% of a combination of the first portion and the second portion of the metal salt 
     
     
         27 . The method of  claim 18 , comprising:
 quenching the reaction solution with de-ionized water after the second period of time has lapsed to halt growth of the metal nanowires.   
     
     
         28 . The method of  claim 18 , comprising:
 purging a reaction vessel comprising the reaction solution with an inert gas while growing the metal nanowires.   
     
     
         29 . The method of  claim 18 , wherein the first portion of the metal salt and the second portion of the metal salt are equal. 
     
     
         30 . The method of  claim 18 , comprising:
 combining the metal nanowires and a fluid to form an ink composition, wherein a concentration of the metal nanowires in the ink composition is 0.01% w/w to 1.5% w/w.   
     
     
         31 . The method of  claim 30 , wherein:
 a diameter distribution of the metal nanowires in the ink composition has a standard deviation that is less than 20% of a mean diameter of the metal nanowires in the ink composition, and   more than 99% of the metal nanowires in the ink composition with aspect ratios of at least 10 are no more than 55 μm long.   
     
     
         32 . The method of  claim 18 , comprising:
 performing sedimentation on the reaction solution after the second period of time has lapsed to separate the reaction solution into supernatant and sediment.   
     
     
         33 . A method, comprising:
 growing metal nanowires from a reaction solution comprising a metal salt and a reducing agent, wherein the growing comprises:
 reacting a first portion of the metal salt and the reducing agent in the reaction solution for a first period of time to grow the metal nanowires in an axial direction and a radial direction, and 
 adding a second portion of the metal salt over a second period of time, wherein, during the second period of time, the metal nanowires grow in the axial direction. 
   
     
     
         34 . The method of  claim 33 , wherein growth of the metal nanowires in the radial direction is stopped during the second period of time. 
     
     
         35 . The method of  claim 33 , wherein reacting the first portion of the metal salt and the reducing agent in the reaction solution for the first period of time comprises:
 adding a fraction of the first portion of the metal salt with an ammonium salt; and   adding a remainder of the first portion of the metal salt.   
     
     
         36 . A method, comprising:
 growing metal nanowires from a reaction solution comprising a metal salt and a reducing agent using a two-phase synthesis process in which a concentration of the metal salt in the reaction solution is maintained at less than 0.1% w/w during a second phase of the two-phase synthesis process.   
     
     
         37 . The method of  claim 36 , wherein the reducing agent is at least one of propylene glycol or ethylene glycol.