Formable transparent conductive films with metal nanowires
A formable transparent conductive film are described that comprise a sparse metal conductive layer, a thermoplastic polymer substrate supporting the sparse metal conductive layer, a viscoelastic polymer with a thickness from about 15 microns to about 150 microns over the sparse metal conductive layer. A layered film structure can be formed that is suitable for contouring on the surface of a three dimensional object without unacceptable increases in sheet resistance and with good optical transparency and low haze. The formable films can be placed into a frozen configuration bent 90 degrees with a radius of curvature of no more than about 5 centimeters while exhibiting a surface resistance of no more than about 500 ohms/sq. with a total transmittance with respect to visible light of at least about 80%.
1. A formable transparent conductive film comprising a sparse metal conductive layer, a non-elastomeric polymer substrate directly supporting the sparse metal conductive layer, a viscoelastic layer comprising a viscoelastic polymer with a thickness from about 15 microns to about 150 microns over the sparse metal conductive layer on a side of the sparse metal conductive layer opposite the polymer substrate, and a cured polymer overcoat layer between the sparse metal conductive layer and the viscoelastic layer, wherein the film has a total transmittance for visible light of at least about 80%, wherein the cured polymer overcoat layer has a thickness from about 25 nm to about 2 microns, and wherein the formable transparent conductive film has a sheet resistance after bending 180 degrees with a radius of curvature of 0.5 mm of no more than about 1000 ohms/sq.
2. The formable transparent conductive film of claim 1 wherein the sparse metal conductive layer comprises a nanostructured metal network.
3. The formable transparent conductive film of claim 1 wherein the sparse metal conductive layer comprises a polymer binder.
4. The formable transparent conductive film of claim 1 further comprising a cap polymer layer comprising a thermoplastic polymer over the viscoelastic layer.
5. The formable transparent conductive film of claim 1 having a total transmittance of visible light of at least about 88%, a sheet resistance after stretching to 20% strain of no more than about 1000 ohms/sq. and a sheet resistance after bending 180 degrees with a radius of curvature of 0.5 mm of no more than about 800 ohms/sq.
6. The formable transparent conductive film of claim 1 wherein the sparse metal conductive layer is patterned to form regions of low electrical resistance and regions of electrical resistance at least 100 times more resistive than the regions of low electrical resistance.
7. The formable transparent conductive film of claim 1 wherein the film when formed into a frozen configuration bent 90 degrees with a radius of curvature of no more than about 5 centimeters exhibits a surface resistance of no more than about 500 ohms/sq. with a total transmittance with respect to visible light of at least about 80%.
8. A display device comprising a three dimensional surface, light emitting elements positioned to emit light from the surface and the formable transparent conductive film of claim 1 covering at least a portion of the light emitting elements wherein the non-elastomeric polymer substrate that is formed to span an edge of the surface to cover at least portions of two angled surfaces with an angle relating the surfaces of at least about 60 degrees such that the film has a portion with a radius of curvature of no more than about 5 centimeters and wherein the film exhibits a surface resistance of no more than about 500 ohms/sq. with a total transmittance with respect to visible light of at least about 80%.
9. The display device of claim 8 wherein the film exhibits a surface resistance of no more than about 150 ohms/sq. with a total transmittance with respect to visible light of at least about 85%.
10. The display device of claim 8 wherein the film exhibits a surface resistance of no more than about 100 ohms/sq. with a total transmittance with respect to visible light of at least about 87%.
11. A method for forming a device with the display device of claim 8 , the method comprising:
securing the formable transparent conductive film around an edge of the device with the film extending around the edge in contact with at least portions of two surfaces an angle relating the surfaces of at least about 60 degrees to form a film having a surface resistance of no more than about 500 ohms/sq with a total transmittance with respect to visible light of at least about 80%.
12. The formable transparent conductive film of claim 1 having a total transmittance of visible light of at least about 90%.
13. The display device of claim 8 wherein the film exhibits a surface resistance of no more than about 100 ohms/sq. with a total transmittance with respect to visible light of at least about 90%.
14. The display device of claim 8 wherein the sparse metal conductive layer is patterned to form regions of low electrical resistance and regions of electrical resistance at least 100 times more resistive than the regions of low electrical resistance.
15. The method of claim 11 further comprising heating the formable transparent conductive film secured around the edge of the device to form a transparent conductive film, and allowing the transparent conductive film to cool in an angular position.