Metal nanostructured networks and transparent conductive material
Metal nanowires, such as silver nanowires coated on a substrate were sintered together to form fused metal nanowire networks that have greatly improved conductivity while maintaining good transparency and low haze. The method of forming such a fused metal nanowire networks are disclosed that involves exposure of metal nanowires to various fusing agents on a short timescale. The resulting sintered network can have a core-shell structure in which metal halide forms the shell. Additionally, effective methods are described for forming patterned structure with areas of sintered metal nanowire network with high conductivity and areas of un-sintered metal nanowires with low conductivity. The corresponding patterned films are also described. When formed into a film, materials comprising the metal nanowire network demonstrate low sheet resistance while maintaining desirably high levels of optical transparency with low haze, making them suitable for transparent electrode, touch sensors, and other electronic/optical device formation.
1. A material comprising a transparent conductive coating and a substrate on which the coating is supported, the coating comprising a fused metal nanowire network comprising fused metal nanowires, wherein the coating has a transmittance for visible light of at least about 90%, a sheet resistance of no more than about 250 Ohms/square, and a haze of no more than 0.5%.
2. The material of claim 1 wherein the coating has a sheet resistance of no more than about 200 Ohms/square.
3. The material of claim 1 wherein the substrate comprises a polymer film.
4. The material of claim 1 wherein the fused metal nanowires comprise fused silver nanowire.
5. The material of claim 4 wherein the fused metal network comprises a metal halide shell layer.
6. The material of claim 1 wherein the coating has a transmittance for visible light of at least about 95%.
7. The material of claim 1 wherein the coating has a surface loading level of the fused metal network from about 0.1 micrograms/cm 2 to about 5 mg/cm 2 .
8. The material of claim 1 wherein the coating has a haze of no more than about 0.4%.
9. The material of claim 1 wherein the substrate comprises polyethylene terephthalate.
10. The material of claim 1 further comprising a polymer coating over the transparent conductive coating.
11. The material of claim 1 wherein the fused metal nanowire network comprises silver.
12. The material of claim 1 further comprising fluoride ions.
13. The material of claim 1 wherein the transparent conductive coating has a transmittance of at least about 95% for visible light and a sheet resistance of no more than about 100 Ohms/sq.
14. A material comprising a transparent conductive coating and a substrate on which the coating is supported, the coating comprising a fused metal nanowire network with a metal halide shell layer over a metallic core, wherein the metal halide shell layer has an average thickness of at least about 1 nanometer and wherein the coating has a sheet resistance of no more than about 250 Ohms/square and a surface loading level of the fused metal network from about 0.1 micrograms/cm 2 to about 5 mg/cm 2 .
15. The material of claim 14 wherein the fused metal nanowire network comprises fused silver nanowires.
16. The material of claim 15 wherein the silver nanowires incorporated into the fused network have an average diameter of no more than about 75 nm and an average length of at least about 5 microns and wherein the material has a surface loading level of the fused silver nanowires in the network from about 0.1 micrograms/cm 2 to about 5 mg/cm 2 .
17. The material of claim 14 wherein the coating has a transmittance of at least about 90% for visible light.
18. The material of claim 17 wherein the coating has a sheet resistance of no more than about 200 Ohms/square and an average thickness of no more than about a micron.
19. The material of claim 14 wherein the halide comprises chloride.
20. The material of claim 14 wherein the transparent conductive coating has a transmittance of at least about 95% for visible light and a sheet resistance of no more than about 100 Ohms/sq.
21. The material of claim 14 wherein the substrate comprises a polymer sheet.
22. The material of claim 14 further comprising a polymer coating over the transparent conductive coating.
23. A material comprising a transparent conductive coating and a substrate on which the coating is supported, the coating comprising a fused metal nanowire network with a metal halide shell layer over a metallic core, wherein the metal halide shell layer has an average thickness of at least about 1 nanometer, wherein the halide comprises fluoride.