Nanostructure Dispersions And Transparent Conductors

Abstract

A nanostructure dispersion comprising a mixture of host metallic nanostructures and metallic nanoparticles is provided. The nanostructures and nanoparticles are attracted to each other and remain attracted upon deposition of the mixture onto a substrate to form a transparent conductor. Also provided is a method of fabricating a transparent conductor.

What is claimed is: 
     
         1 . A transparent conductor comprising: a substrate and a conductive layer on the substrate, the conductive layer including a nanostructure dispersion comprising: a mixture of a dispersion of host metallic nanostructures having a first organic coating on an exterior surface of the host metallic nanostructures and metallic nanoparticles having a second organic surface coating on an exterior surface of the metallic nanoparticles, the second organic coating being different than the first organic coating such that the nanostructures and nanoparticles are attracted to each other upon admixture of the host metallic nanostructures and metallic nanoparticles and remain attracted upon deposition of the mixture onto a substrate. 
     
     
         2 . The transparent conductor of  claim 1 , wherein the conductive layer includes a first region defined by the metallic nanostructures and metallic nanoparticles attracted to the metallic nanostructures and a second region including an open area, wherein there are substantially no free metallic nanoparticles in the open area. 
     
     
         3 . The transparent conduction of  claim 1 , wherein the first organic coating comprises a polymer. 
     
     
         4 . The transparent conductor of  claim 3 , wherein the first organic coating comprises PVP. 
     
     
         5 . The transparent conductor of  claim 1 , wherein the metallic nanostructures comprise metallic nanowires having an aspect ratio of length/diameter. 
     
     
         6 . The transparent conductor of  claim 5 , wherein the metallic nanowires comprise a metal selected from the group consisting of Ag, Cu, Au, Al, Rh, Ir, Co, Zn, Ni, In, Bi, Pb, Fe, Bi, Pd, Pt, Sn, Ti, combinations thereof and alloys thereof. 
     
     
         7 . The transparent conductor of  claim 6 , wherein the metallic nanowires comprise Ag, and the aspect ratio of the metallic nanowires exceeds 100. 
     
     
         8 . The transparent conductor of  claim 6 , wherein the metallic nanoparticles comprise a metal selected from the group consisting of Au, Ag, Cu, Al, Rh, Ir, Co, Zn, Ni, Bi, Pb, In, Fe, Pd, Pt, Sn, Ti, combinations thereof and alloys thereof. 
     
     
         9 . The transparent conductor of  claim 1 , wherein the nanostructures and nanoparticles are present in a mass ratio of nanowires to nanoparticles between 50:1 to 50,000:1. 
     
     
         10 . The transparent conductor of  claim 1 , wherein the metallic nanoparticles attracted to the metallic nanostructures reduces the sheet resistance of the conductive layer compared to a conductive layer that does not include nanoparticles attracted to the nanostructures. 
     
     
         11 . The transparent conductor of  claim 1 , wherein the conductive layer is a spin-coated layer. 
     
     
         12 . The transparent conductor of  claim 3 , wherein the metallic nanowires comprise silver and the metallic nanoparticles comprise gold. 
     
     
         13 . The transparent conductor of  claim 1 , wherein the conductor has a sheet resistance that is less than 100 Ω/sq at 90% transmittance. 
     
     
         14 . A method for fabricating a transparent conductor, the method comprising:
 providing a metallic nanostructure dispersion;   mixing metallic nanoparticles with the metallic nanostructure dispersion to form a mixture, wherein the nanoparticles are attracted to the nanostructures upon admixture and without application of radiation or heat; and   coating the mixture onto a substrate to form a conductive layer, wherein the metallic nanoparticles remain attracted to the metallic nanostructures.   
     
     
         15 . The method of  claim 14 , wherein the metallic nanoparticles are preformed and provided in a dispersion or in situ generated upon the mixing of the metallic nanoparticles and the metallic nanostructure dispersion. 
     
     
         16 . The method of  claim 14 , wherein the metallic nanostructures comprise metallic nanowires. 
     
     
         17 . The method of  claim 16 , wherein the metallic nanowires comprise a metal selected from the group consisting of Ag, Cu, Au, Al, Rh, Ir, Co, Zn, Ni, In, Bi, Pb, Fe, Pd, Pt, Sn, Ti, combinations thereof and alloys thereof. 
     
     
         18 . The method of  claim 14 , wherein the metallic nanoparticles comprise a metal selected from the group consisting of Au, Ag, Cu, Al, Rh, Ir, Co, Zn, Ni, In, Bi, Pb, Fe, Pd, Pt, Sn, Ti, combinations thereof and alloys thereof. 
     
     
         19 . The method of  claim 14 , wherein the substrate is selected from glass, polyesters, polyolefins, vinyl resins, polyether ether ketone (PEEK), polyether sulphone (PES), polycarbonate (PC), polyamide, polyimide, acrylic resins, triacetyl cellulose (TAC), and combinations thereof. 
     
     
         20 . The method of  claim 14 , wherein the coated layer defines a conductive area including the metallic nanostructures and the metallic nanoparticles and an open area substantially free of nanoparticles.