Stabilized sparse metal conductive films and solutions for delivery of stabilizing compounds

Abstract

Metal salt based stabilizers are described that are effective to improve stability of sparse metal conductive films formed with metal nanowires, especially silver nanowires. Specifically, vanadium (+5) compositions can be effectively placed in coatings to provide desirable stabilization under accelerated wear testing conditions. Sparse metal conductive films can comprise fused metal nanostructured networks. Cobalt (+2) compounds can be incorporated as stabilization agents within nanowire inks to provide a high degree of stabilization without significantly interfering with the fusing process.

What is claimed is: 
     
         1 . A system for forming a stabilized transparent conductive film, the system comprising:
 A) a silver nanowire ink comprising solvent and from about 0.05 wt % to about 1 wt % silver nanowires; and   B) a stabilization overcoat precursor solution comprising curable polymer precursors, solvent and from about 0.1 wt % to about 9 wt % stabilization composition relative to the solid weight, the stabilization composition comprising vanadium (+5) ions.   
     
     
         2 . The system of  claim 1  wherein the stabilization composition comprises a metavanadate (VO 3   − ) salt, an orthovanadate (VO 4   −3 ) salt, a vanadium oxytrialkoxide (VO(OR) 3 ) where R is an alkyl group, a vanadium oxytrihalide or combinations thereof. 
     
     
         3 . The system of  claim 1  wherein the stabilization composition comprises ammonium metavanadate (NH 4 VO 3 ), tetrabutylammonium vanadate (NBu 4 VO 3 ), potassium metavanadate (KVO 3 ), sodium metavanadate (NaVO 3 ), sodium orthovanadate (Na 3 VO 4 ), vanadium oxytripropoxide, vanadium oxytriethoxide, vanadium oxytriisopropoxide, vanadium oxytributoxide or combinations thereof. 
     
     
         4 . The system of  claim 1  wherein the stabilization composition comprises a vanadium complex (VO 2 Z 1 Z 2 ) where Z 1  and Z 2  are independently ligands comprising nitrite (NO 2 ), diethyl amine, ethylene diamine (en), nitrilotriacetic acid, iminobis(methylene phosphonic acid), aminotris(methylene phosphonic acid), ethylene diamine tetraacetic acid (EDTA), 1,3-propylenediaminetetraacetic acid (1,3-PDTA), triethylene tetramine, tri(2-aminoethyl) amine, 1,10-phenanthroline, 1,10-phenanthroline-5,6-dione, 2,2′-bipyridine, 2,2′-bipyridine-4,4′-dicarboxylic acid, dimethylglyoxime, salicylaldoxime, diethylenetriaminepentaacetic acid, 1,2-cyclohexanediaminotetraacetic acid, iminodiacetic acid, methyliminodiacetic acid, N-(2-acetamide) iminoacetic acid, N-(2-carboxyethyl) iminodiacetic acid, N-(2-carboxymethyl)imino dipropionic acid, picolinic acid, dipicolinic acid, histidine or a combination thereof. 
     
     
         5 . The system of  claim 1  wherein the vanadium (+5) ions comprise vanadium compounds wherein the vanadium compounds are from about 0.0001 wt % to about 1 wt % of the stabilization overcoat precursor solution. 
     
     
         6 . The system of  claim 1  wherein the curable polymer precursors form a polymer matrix upon curing, wherein the polymer matrix comprises polysiloxanes, polysilsesquioxanes, polyurethanes, acrylic resins, acrylic copolymers, cellulose ethers, cellulose esters, nitrocellulose, other water insoluble structural polysaccharides, polyethers, polyesters, polystyrene, polyimide, fluoropolymer, styrene-acrylate copolymers, styrene-butadiene copolymers, acrylonitrile butadiene styrene copolymers, polysulfides, epoxy containing polymers, copolymers thereof or combinations thereof. 
     
     
         7 . The system of  claim 1  wherein the curable polymer precursors form a crosslinked acrylic resin polymer matrix upon curing. 
     
     
         8 . The system of  claim 1  wherein the stabilization overcoat precursor solution comprises from about 0.025 wt % to about 70 wt % of the curable polymer precursors. 
     
     
         9 . The system of  claim 1  wherein the solvent of the stabilization overcoat precursor solution is nonaqueous. 
     
     
         10 . The system of  claim 1  wherein the stabilization overcoat precursor solution comprises at least about 7 wt % of the solvent. 
     
     
         11 . The system of  claim 1  wherein the stabilization overcoat precursor solution comprises from about 10 wt % to about 70 wt % of the solvent. 
     
     
         12 . The system of  claim 1  wherein the silver nanowire ink further comprises from about 0.0001 wt % to about 1 wt % cobalt +2 complexes comprising Co +2  ions and complexing ligands, and wherein the complexing ligands comprise nitrite (NO 2 ), diethyl amine, ethylene diamine (en), nitrilotriacetic acid, iminobis(methylene phosphonic acid), aminotris(methylene phosphonic acid), ethylene diamine tetraacetic acid (EDTA), 1,3-propylenediaminetetraacetic acid (1,3-PDTA), triethylene tetramine, tri(2-aminoethyl) amine, 1,10-phenanthroline, 1,10-phenanthroline-5,6-dione, 2,2′-bipyridine, 2,2′-bipyridine-4,4′-dicarboxylic acid, dimethylglyoxime, salicylaldoxime, diethylenetriaminepentaacetic acid, 1,2-cyclohexanediaminotetraacetic acid, iminodiacetic acid, methyliminodiacetic acid, N-(2-acetamide) iminoacetic acid, N-(2-carboxyethyl) iminodiacetic acid, N-(2-carboxymethyl)imino dipropionic acid, picolinic acid, dipicolinic acid, histidine or a combination thereof. 
     
     
         13 . The system of  claim 1  wherein the silver nanowire ink further comprises from about 0.01 mg/mL to about 2.0 mg/mL silver ions and a reducing agent. 
     
     
         14 . The system of  claim 1  wherein the silver nanowire ink further comprises from about 0.02 wt % to about 5 wt % polysaccharide based polymer. 
     
     
         15 . The system of  claim 1  wherein the solvent of the silver nanowire ink comprises water and from about 2 wt % to about 60 wt % alcohol. 
     
     
         16 . A method for forming a stabilized transparent conductive film, the method comprising:
 applying a coating with a silver nanowire ink onto a surface of a transparent substrate;   drying the coating to form a transparent conductive film having a sheet resistance of no more than about 150 Ohms/sq and with a transmittance through the coated substrate of at least about 90%;   applying an overcoat precursor solution over the transparent conductive film, wherein the overcoat precursor solution comprises a curable polymer precursor and a vanadium (+5) stabilization composition; and   curing the overcoat precursor solution to form a stabilization overcoat.   
     
     
         17 . The method of  claim 16  wherein the stabilization composition comprises a metavanadate (VO 3   − ) salt, an orthovanadate (VO 4   −3 ) salt, a vanadium oxytrialkoxide (VO(OR) 3 ) where R is an alkyl group, a vanadium oxytrihalide or combinations thereof. 
     
     
         18 . The method of  claim 16  wherein the stabilization composition comprises ammonium metavanadate (NH 4 VO 3 ), tetrabutylammonium vanadate (NBu 4 VO 3 ), potassium metavanadate (KVO 3 ), sodium metavanadate (NaVO 3 ), sodium orthovanadate (Na 3 VO 4 ), vanadium oxytripropoxide, vanadium oxytriethoxide, vanadium oxytriisopropoxide, vanadium oxytributoxide or combinations thereof. 
     
     
         19 . The method of  claim 16  wherein the stabilization composition comprises a vanadium complex (VO 2 Z 1 Z 2 ) where Z 1  and Z 2  are independently ligands comprising nitrite (NO 2 ), diethyl amine, ethylene diamine (en), nitrilotriacetic acid, iminobis(methylene phosphonic acid), aminotris(methylene phosphonic acid), ethylene diamine tetraacetic acid (EDTA), 1,3-propylenediaminetetraacetic acid (1,3-PDTA), triethylene tetramine, tri(2-aminoethyl) amine, 1,10-phenanthroline, 1,10-phenanthroline-5,6-dione, 2,2′-bipyridine, 2,2′-bipyridine-4,4′-dicarboxylic acid, dimethylglyoxime, salicylaldoxime, diethylenetriaminepentaacetic acid, 1,2-cyclohexanediaminotetraacetic acid, iminodiacetic acid, methyliminodiacetic acid, N-(2-acetamide) iminoacetic acid, N-(2-carboxyethyl) iminodiacetic acid, N-(2-carboxymethyl)imino dipropionic acid, picolinic acid, dipicolinic acid, histidine or a combination thereof. 
     
     
         20 . The method of  claim 16  wherein the stabilization overcoat comprises from about 0.1 wt % to about 9 wt % stabilization composition and has an average thickness from about 40 nm to about 1.5 microns. 
     
     
         21 . The method of  claim 16  wherein the stabilization overcoat comprises a polymer matrix formed by curing of the curable polymer precursor, wherein the polymer matrix comprises polysiloxanes, polysilsesquioxanes, polyurethanes, acrylic resins, acrylic copolymers, cellulose ethers, cellulose esters, nitrocellulose, other water insoluble structural polysaccharides, polyethers, polyesters, polystyrene, polyimide, fluoropolymer, styrene-acrylate copolymers, styrene-butadiene copolymers, acrylonitrile butadiene styrene copolymers, polysulfides, epoxy containing polymers, copolymers thereof or combinations thereof. 
     
     
         22 . The method of  claim 16  wherein the stabilization overcoat comprises a crosslinked acrylic resin polymer matrix formed by curing of the curable polymer precursor, and wherein the stabilization overcoat comprises from about 0.1 wt % to about 9 wt % stabilization composition. 
     
     
         23 . The method of  claim 16  wherein the silver nanowire ink comprises 0.05 wt % to about 1 wt % of the silver nanowires, and the silver nanowire ink further comprises from about 0.01 mg/mL to about 2.0 mg/mL silver ions, a reducing agent and optionally from about 0.0001 wt % to about 1 wt % cobalt +2 complexes. 
     
     
         24 . The method of  claim 16  wherein the silver nanowire ink further comprises from about 0.02 wt % to about 5 wt % polysaccharide based polymer. 
     
     
         25 . The method of  claim 16  wherein drying the coating to form the transparent conductive film comprises forming a sparse metal nanostructured network on the surface of the transparent substrate. 
     
     
         26 . The method of  claim 25  wherein the sparse metal nanostructured network comprises a fused metal nanostructured network. 
     
     
         27 . A stabilized transparent conductive film prepared according to the method of  claim 16 .