Method for manufacturing silver nanoparticles

Abstract

A novel method for manufacturing tabular silver nanoparticles with high productivity and high reproducibility. The present invention provides a method for manufacturing silver nanoparticles including a first step of preparing a silver ion aqueous solution containing a crystal habit modifier as a starting solution, a second step of adding a reducing agent to the starting solution with stirring to yield an aqueous dispersion of fine silver crystals, and a third step of adding an oxidizing agent to the aqueous dispersion with stirring. The oxidizing agent is preferably added such that the solubility of metal silver in the aqueous dispersion is optimized at an appropriate time in the third step.

1 . A method for manufacturing silver nanoparticles comprising:
 a first step of preparing a silver ion aqueous solution containing a crystal habit modifier as a starting solution;   a second step of adding a reducing agent to the starting solution with stirring to yield an aqueous dispersion of silver crystals; and   a third step of adding an oxidizing agent to the aqueous dispersion with stirring.   
     
     
         2 . The method of  claim 1 , wherein, in the third step, the oxidizing agent is added such that the solubility of metal silver in the aqueous dispersion is timely optimized. 
     
     
         3 . The method of  claim 1 , wherein the crystal habit modifier comprises a low-molecular-weight organic acid or a salt thereof. 
     
     
         4 . The method of  claim 3 , wherein the low-molecular-weight organic acid is a polycarboxylic acid having two or more carboxyl groups. 
     
     
         5 . The method of  claim 4 , wherein the polycarboxylic acid is citric acid. 
     
     
         6 . The method of  claim 1 , wherein the reducing agent is sodium tetrahydroborate. 
     
     
         7 . The method of  claim 1 , wherein the oxidizing agent is hydrogen peroxide. 
     
     
         8 . The method of  claim 1 , wherein, in the third step, tabular silver nanoparticles are selectively manufactured in the water aqueous dispersion. 
     
     
         9 . Silver nanoparticles manufactured by the method of  claim 1 . 
     
     
         10 . A colloidal dispersion of the silver nanoparticles of  claim 9 .