Method for producing silver nanowires, silver nanowires, dispersion, and transparent conductive film

Abstract

In order to provide a method for producing silver nanowires in which a local maximum of optical absorption in the plasmon absorption band can be shifted toward the short wavelength side without making the wire diameter smaller, a method for producing silver nanowires includes a step of heating a mixed liquid of a dispersion of silver nanowires and metal ions of a transition metal that is different from silver, and reducing the metal ions, thereby intermittently precipitating clumps of the transition metal on a surface of the silver nanowires. The thus produced silver nanowires have metal clumps intermittently along the length direction, and a local maximum of optical absorption in the plasmon absorption band of the silver nanowires has been shifted toward the short wavelength side.

1 . A method for producing silver nanowires having metal clumps intermittently along a length direction, comprising a step of heating a mixed liquid of a dispersion of silver nanowires and metal ions of a transition metal that is different from silver, and reducing the metal ions, thereby intermittently precipitating clumps of the transition metal on a surface of the silver nanowires. 
     
     
         2 . The method for producing silver nanowires according to  claim 1 , wherein, in the step of precipitating clumps of the transition metal, a heating temperature of the mixed liquid is 300° C. or less. 
     
     
         3 . The method for producing silver nanowires according to  claim 1 ,
 wherein the transition metal is copper,   in the step of precipitating copper, clumps of silver are also precipitated on both sides of each clump of copper,   the method further comprises a step of removing clumps of copper precipitated on the surface of the silver nanowires, and   the metal clumps are clumps of silver precipitated on both sides of each clump of copper in the step of precipitating copper.   
     
     
         4 . The method for producing silver nanowires according to  claim 1 , wherein the metal clumps are clumps of the transition metal precipitated in the step of precipitating the transition metal. 
     
     
         5 . The method for producing silver nanowires according to  claim 4 , wherein the transition metal is at least one selected from among nickel, iron, and cobalt. 
     
     
         6 . Silver nanowires, comprising metal clumps intermittently along a length direction, wherein the metal clumps are precipitates. 
     
     
         7 . The silver nanowires according to  claim 6 , wherein the metal clumps are clumps of one or more selected from among silver, nickel, iron, and cobalt. 
     
     
         8 . A dispersion comprising the silver nanowires according to  claim 6 . 
     
     
         9 . A transparent conductive film comprising the silver nanowires according to  claim 6 . 
     
     
         10 . A method for producing silver nanowires having metal oxide clumps intermittently along a length direction, comprising a step of heating a mixed liquid of a dispersion of silver nanowires and metal ions of a transition metal that is different from silver, and reducing the metal ions, thereby intermittently precipitating clumps of the transition metal on a surface of the silver nanowires, and exposing, to air, the silver nanowires on whose surface the clumps of the transition metal are precipitated, thereby oxidizing the clumps of the transition metal. 
     
     
         11 . Silver nanowires, comprising metal oxide clumps intermittently along a length direction, wherein the metal oxide clumps are oxide of precipitates of a metal.