Nucleation layer for thin film metal layer formation
A conductive film is formed on a flexible polymer support by applying a seed layer comprising gallium oxide, indium oxide, magnesium oxide, zinc oxide or mixture (including mixed oxides) thereof to the flexible polymer support, and applying an extensible, visible light-transmissive metal layer over the seed layer. The seed layer oxide desirably promotes deposition of the subsequently-applied metal layer in a more uniform or more dense fashion, or promotes earlier formation (viz., at a thinner applied thickness) of a continuous metal layer. The resulting films have high visible light transmittance and low electrical resistance.
1. A conductive film comprising a flexible polymer support; a discontinuous seed layer as a series of islands having a physical thickness less than 3 nanometers and comprising a mixture selected from two or more of gallium oxide, indium oxide, magnesium oxide, zinc oxide, and tin oxide on the support; and a visible light-transmissive metal layer atop the seed layer.
2. The film of claim 1 , further comprising an organic support coating between the support and the seed layer.
3. The film of claim 1 , wherein the seed layer comprises indium oxide:zinc oxide, indium oxide:tin oxide, or indium gallium zinc oxide.
4. The film of claim 1 , wherein the metal layer physical thickness is about 5 to about 50 nm.
5. The film of claim 1 , wherein the film has at least about 70% visible light transmittance and less than about 20 ohms per square sheet resistivity.
6. The film of claim 1 , wherein the film has from about 7.5 to about 15 ohms per square sheet resistivity.
7. The film of claim 1 , wherein the seed layer comprises zinc oxide.
8. The film of claim 7 , wherein the zinc oxide is doped with aluminum or aluminum oxide.
9. The film of claim 1 , further comprising a second discontinuous seed layer as a series of islands atop the metal layer and a second metal layer atop the second discontinuous seed layer.
10. The film of claim 9 , wherein the metal layers are separated by a polymeric spacing layer and provide an infrared-rejecting Fabry-Perot stack.
11. The film of claim 9 , further comprising third, fourth, fifth or sixth discontinuous seed layers as a series of islands and third, fourth, fifth or sixth metal layers atop the second metal layer, wherein the metal layers are separated by polymeric spacing layers and provide an infrared-rejecting Fabry-Perot stack.
12. An electrical device comprising the film of claim 1 .
13. A method for forming a conductive film on a flexible polymer support, which method comprises:
a) forming on the flexible polymer support or on an organic support coating on the flexible polymer support, a discontinuous seed layer formed as a series of islands having a physical thickness less than 3 nanometers and comprising a mixture selected from two or more of gallium oxide, indium oxide, magnesium oxide, zinc oxide, and tin oxide; and
b) depositing a visible light-transmissive metal layer over the seed layer.
14. The method of claim 13 , wherein the seed layer comprises zinc oxide.
15. The method of claim 13 , wherein the seed layer is formed using a sputtering target comprising zinc oxide:alumina, indium oxide:zinc oxide, indium oxide:tin oxide, indium oxide:tin oxide:zinc oxide, indium:zinc, indium:tin, or indium gallium zinc oxide.
16. The method of claim 13 , wherein the metal layer comprises silver.
17. The method of claim 13 , wherein the metal layer physical thickness is about 5 to about 50 nm.
18. The method of claim 13 , wherein the film has at least about 70% visible light transmittance and less than about 20 ohms per square sheet resistivity.
19. The method of claim 13 , further comprising;
c) forming a second discontinuous seed layer as a series of islands comprising gallium oxide, indium oxide, magnesium oxide, zinc oxide, tin oxide or mixtures including mixed oxides or doped oxides thereof over the metal layer; and
d) depositing a second visible light-transmissive metal layer over the second seed layer.
20. The method of claim 19 , further comprising forming a polymeric spacing layer between the metal layers to provide an infrared-rejecting Fabry-Perot stack.
21. A method for making a glazing article, which method comprises:
a) assembling a layer of glazing material and a film comprising:
a flexible polymer support;
a discontinuous seed layer on the flexible polymer support or on an organic support coating on the flexible polymer support, formed as a series of islands having a physical thickness less than 3 nanometers and comprising a mixture selected from two or more of gallium oxide, indium oxide, magnesium oxide, zinc oxide, and tin oxide; and
a visible light-transmissive metal layer atop the discontinuous seed layer; and
b) bonding the glazing material and film together into a unitary article.
22. The method of claim 21 , wherein the glazing material comprises glass and the glazing article further comprises an energy-absorbing layer between the film and the glass.
23. The method of claim 21 , wherein the seed layer comprises indium oxide:zinc oxide, indium oxide:tin oxide, or indium gallium zinc oxide.
24. The method of claim 21 , further comprising at least a second discontinuous seed layer as a series of islands atop the metal layer and at least a second metal layer atop the second discontinuous seed layer, wherein the metal layers are separated by a polymeric spacing layer and provide an infrared-rejecting Fabry-Perot stack, and the metal layer physical thicknesses are about 5 to about 50 nm.