Grid and nanostructure transparent conductor for low sheet resistance applications

Abstract

Transparent conductors and methods of forming same are provided. A transparent conductor can include a nanostructure layer and a low sheet resistance grid disposed on a transfer film surface having an acceptable level of surface roughness. The presence of the low sheet resistance grid lowers the sheet resistance of the transparent conductor to an acceptable level. After release of the transparent conductor from the transfer film, the surface roughness of the transparent conductor will be at least comparable to the surface roughness of the transfer film.

1 . A method, comprising:
 providing a transfer film having a transfer film surface;   forming a low sheet resistance grid on the transfer film surface according to a grid pattern; and   forming a nanostructure layer on the transfer film surface;
 wherein the low sheet resistance grid and the nanostructure layer form at least one coplanar transparent conductor surface. 
   
     
     
         2 . The method of  claim 1  wherein forming the nanostructure layer on the transfer film surface comprises forming the nanostructure layer on the transfer film surface according to a nanostructure layer pattern 
     
     
         3 . The method of  claim 2  wherein forming the nanostructure layer on the transfer film surface according to a nanostructure layer pattern comprises direct printing a nanostructure layer on the transfer film surface. 
     
     
         4 . The method of  claim 1 , further comprising:
 exposing the coplanar transparent conductor surface formed by the low sheet resistance grid and the nanostructure layer by removing the transfer film.   
     
     
         5 . The method of  claim 1  wherein forming the low sheet resistance grid on the transfer film surface according to the grid pattern comprises screen printing of the low sheet resistance grid on the transfer film surface. 
     
     
         6 . The method of  claim 1  wherein forming the low sheet resistance grid on the transfer film surface according to a grid pattern comprises screen printing the low sheet resistance grid using a silver paste. 
     
     
         7 . The method of  claim 1  wherein forming the low sheet resistance grid on the transfer film surface according to the grid pattern comprises an overall deposition of a conductive metal followed by a removal via post-patterning of at least a portion of the deposited metal. 
     
     
         8 . The method of  claim 1  wherein the nanostructure layer comprises a plurality of conductive metallic nanowires dispersed within a polymer matrix. 
     
     
         9 . The method of  claim 1  wherein the nanostructure layer comprises a plurality of light-scattering particles. 
     
     
         10 . The method of  claim 1  wherein the nanostructure layer comprises a plurality of light-directing structures. 
     
     
         11 . The method of  claim 1  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 5 ohms/sq. 
     
     
         12 . The method of  claim 1  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 1 ohm/sq. 
     
     
         13 . The method of  claim 1  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.5 ohms/sq. 
     
     
         14 . The method of  claim 1  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.1 ohm/sq. 
     
     
         15 . The method of  claim 1 , further comprising:
 forming a layer proximate the nanostructure layer, the layer including at least one layer selected from the group consisting of: a smoothing layer, a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer.   
     
     
         16 . The method of  claim 1  wherein
 the transfer film surface has a surface roughness of less than 50 nanometers peak-to-peak; and 
 the coplanar transparent conductor surface has a surface roughness of less than 50 nanometers peak-to-peak. 
 
     
     
         17 . The method of  claim 1 , further comprising:
 forming at least one isolation structure on the transfer film surface according to an isolation pattern, the at least one isolation structure patterning the transparent conductor into a plurality of electrically isolated structures.   
     
     
         18 . The method of  claim 17  wherein
 the transfer film surface has a surface roughness of less than 50 nanometers peak-to-peak; and 
 the coplanar transparent conductor surface and the at least one isolation structure forming a coplanar surface having a surface roughness of less than 50 nanometers peak-to-peak. 
 
     
     
         19 . The method of  claim 1 , further comprising:
 forming an planarizing layer at least partially on the low sheet resistance grid and nanostructure layer opposite the transfer film surface.   
     
     
         20 . The method of  claim 19  wherein forming the planarizing layer comprises depositing the planarizing layer according to a planarizing layer pattern. 
     
     
         21 . The method of  claim 19  wherein the planarizing layer comprises an adhesive material. 
     
     
         22 . The method of  claim 21  wherein the adhesive material consists of an adhesive selected from the group consisting of: a photo-cured adhesive and a thermally cured adhesive. 
     
     
         23 . The method of  claim 19  wherein the planarizing layer comprises a material to smoothen a surface formed by the low sheet resistance grid and the nanostructure layer opposite the transfer film. 
     
     
         24 . The method of  claim 19  wherein the planarizing layer comprises a plurality of light-scattering particles. 
     
     
         25 . The method of  claim 19  wherein the planarizing layer comprises a plurality of light-directing structures. 
     
     
         26 . The method of  claim 19 , further comprising affixing the transparent conductor to a substrate via the planarizing layer. 
     
     
         27 . The method of  claim 19 , further comprising applying a protective film to the planarizing layer. 
     
     
         28 . The method of  claim 27 , further comprising:
 removing the protective film layer; and   affixing the transparent conductor to a substrate.   
     
     
         29 . A transparent conductor, comprising:
 a low sheet resistance grid; and   a nanostructure layer, wherein the low sheet resistance grid and the nanostructure layer form at least one coplanar transparent conductor surface.   
     
     
         30 . The transparent conductor of  claim 29  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 5 ohms/sq. 
     
     
         31 . The transparent conductor of  claim 29  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 1 ohm/sq. 
     
     
         32 . The transparent conductor of  claim 29  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.5 ohms/sq. 
     
     
         33 . The transparent conductor of  claim 29  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.1 ohm/sq. 
     
     
         34 . The transparent conductor of  claim 29  wherein the planar transparent conductor surface has a surface roughness of less than 50 nanometers peak-to-peak. 
     
     
         35 . The transparent conductor of  claim 29 , further comprising:
 a layer disposed proximate the nanostructure layer, the layer selected from the group consisting of: a smoothing layer, a hole transport layer disposed according to a hole transport pattern, a hole injection layer disposed according to a hole injection pattern, an electron transport layer disposed according to a electron transport pattern, and an electron injection layer disposed according to a electron injection pattern.   
     
     
         36 . The transparent conductor of  claim 29  wherein the light transmission of the transparent conductor is greater than about 85%. 
     
     
         37 . The transparent conductor of  claim 29  wherein the light transmission of the transparent conductor is greater than about 90%. 
     
     
         38 . The transparent conductor of  claim 29 , further comprising:
 a transfer film having a transfer film surface roughness of less than 10 nanometers peak-to-peak disposed proximate the planar transparent conductor surface.   
     
     
         39 . The transparent conductor of  claim 29  wherein the nanostructure layer comprises a plurality of conductive metallic nanowires dispersed within a polymer matrix. 
     
     
         40 . The transparent conductor of  claim 29  wherein the nanostructure layer comprises a plurality of light scattering particles. 
     
     
         41 . The transparent conductor of  claim 29  wherein the nanostructure layer comprises a plurality of light directing structures. 
     
     
         42 . The transparent conductor of  claim 29 , further comprising:
 at least one isolation structure coplanar with the low sheet resistance grid and the nanostructure layer, the at least one isolation structure, the low sheet resistance grid and the nanostructure layer forming the planar transparent conductor surface.   
     
     
         43 . The transparent conductor of  claim 42  wherein the planar transparent conductor surface has a surface roughness of less than 50 nanometers peak-to-peak. 
     
     
         44 . The transparent conductor of  claim 29 , further comprising:
 a planarizing layer disposed at least partially on the low sheet resistance grid and nanostructure layer opposite the coplanar transparent conductor surface.   
     
     
         45 . The transparent conductor of  claim 44  wherein the planarizing layer comprises an adhesive material. 
     
     
         46 . The transparent conductor of  claim 45  wherein the adhesive material comprises a photo-patterned adhesive. 
     
     
         47 . The transparent conductor of  claim 45  wherein the adhesive material is an adhesive selected from the group consisting of: a photo-cured adhesive and a thermally cured adhesive. 
     
     
         48 . The transparent conductor of  claim 44  wherein the planarizing layer comprises a plurality of light scattering particles. 
     
     
         49 . The transparent conductor of  claim 44  wherein the planarizing layer comprises a plurality of light directing structures. 
     
     
         50 . The transparent conductor of  claim 44 , further comprising a protective film disposed proximate the planarizing layer. 
     
     
         51 . A method, comprising:
 providing a transfer film having a transfer film surface;   forming a nanostructure layer on the transfer film surface; and   forming a low sheet resistance grid on the nanowire layer, opposite the transfer film surface according to a grid pattern;
 wherein the nanowire layer forms at least one planar transparent conductor surface. 
   
     
     
         52 . The method of  claim 51  wherein forming the nanostructure layer on the transfer film surface comprises forming the nanostructure layer on the transfer film surface according to a nanostructure layer pattern. 
     
     
         53 . The method of  claim 51  further comprising laminating the transparent conductor to a substrate using a reel-to-reel process. 
     
     
         54 . The method of  claim 51  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 5 ohms/sq. 
     
     
         55 . The method of  claim 51  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 1 ohm/sq. 
     
     
         56 . The method of  claim 51  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.5 ohms/sq. 
     
     
         57 . The method of  claim 51  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.1 ohm/sq. 
     
     
         58 . The method of  claim 51  wherein
 the transfer film surface comprises a planar surface having a surface roughness of less than 50 nanometers peak-to-peak; and 
 the planar transparent conductor surface comprises a surface having a surface roughness of less than 50 nanometers peak-to-peak. 
 
     
     
         59 . The method of  claim 51 , further comprising:
 forming a layer proximate the nanostructure layer, the layer including at least one layer selected from the group consisting of: a smoothing layer, a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer.   
     
     
         60 . The method of  claim 51  wherein depositing the low sheet resistance grid on the nanostructure layer according to the grid pattern comprises an overall deposition of a conductive metal followed by a removal via post-patterning of at least a portion of the deposited metal. 
     
     
         61 . The method of  claim 51 , further comprising removing the transfer film to expose the planar transparent conductor surface formed by the nanostructure layer. 
     
     
         62 . The method of  claim 51  wherein forming the nanostructure layer on the transfer film surface according to the nanowire layer pattern comprises direct printing of the nanostructure layer on the transfer film surface. 
     
     
         63 . The method of  claim 51  wherein forming the low sheet resistance grid on the nanowire layer according to the grid pattern comprises direct printing of the low sheet resistance grid on the nanowire layer. 
     
     
         64 . The method of  claim 63  wherein the low sheet resistance grid comprises a silver paste. 
     
     
         65 . The method of  claim 51 , further comprising forming at least one isolation structure on the transfer film surface according to an isolation pattern, the at least one isolation structure patterning the nanostructure layer into a plurality of electrically isolated structures. 
     
     
         66 . The method of  claim 65  wherein
 the transfer film surface comprises a planar surface having a surface roughness of less than 50 nanometers peak-to-peak; and 
 the planar transparent conductor surface and the at least one isolation structure form a planar surface having a surface roughness of less than 50 nanometers peak-to-peak. 
 
     
     
         67 . The method of  claim 51  wherein the nanostructure layer comprises a plurality of conductive metallic nanowires dispersed within a polymer matrix. 
     
     
         68 . The method of  claim 51  wherein the nanostructure layer comprises a plurality of light-scattering particles. 
     
     
         69 . The method of  claim 51  wherein the nanostructure layer comprises a plurality of light-directing structures. 
     
     
         70 . The method of  claim 51 , further comprising forming a planarizing layer at least partially on the low sheet resistance grid and nanostructure layer opposite the transfer film surface. 
     
     
         71 . The method of  claim 70  wherein the planarizing layer comprises a plurality of light-scattering particles. 
     
     
         72 . The method of  claim 70  wherein the planarizing layer comprises a plurality of light-directing structures. 
     
     
         73 . The method of  claim 70  wherein forming the planarizing layer comprises forming the planarizing layer according to a planarizing layer pattern. 
     
     
         74 . The method of  claim 70  wherein the planarizing layer comprises an adhesive material. 
     
     
         75 . The method of  claim 74  wherein the adhesive material is selected from the group of adhesive materials consisting of: a thermally cured adhesive and a photo-cured adhesive. 
     
     
         76 . The method of  claim 70 , further comprising applying a protective film to the planarizing layer. 
     
     
         77 . The method of  claim 76 , further comprising:
 removing the protective film layer; and   affixing the transparent conductor to a substrate.   
     
     
         78 . A transparent conductor, comprising:
 a low sheet resistance grid; and   a nanostructure layer contacting the low sheet resistance grid and having a planar transparent conductor surface opposite the low sheet resistance grid.   
     
     
         79 . The transparent conductor of  claim 78  wherein the nanostructure layer and the low sheet resistance grid are patterned to form a plurality of electrically isolated structures. 
     
     
         80 . The transparent conductor of  claim 78  wherein the light transmission of the planar transparent conductor is greater than about 85%. 
     
     
         81 . The transparent conductor of  claim 78  wherein the light transmission of the planar transparent conductor is greater than about 90%. 
     
     
         82 . The transparent conductor of  claim 78 , further comprising:
 a transfer film surface with a surface roughness of less than 50 nanometers peak-to-peak disposed proximate the planar transparent conductor surface.   
     
     
         83 . The transparent conductor of  claim 78  wherein the nanostructure layer comprises a plurality of conductive metallic nanowires dispersed within a polymer matrix. 
     
     
         84 . The transparent conductor of  claim 78  wherein the nanostructure layer comprises a plurality of light scattering particles. 
     
     
         85 . The transparent conductor of  claim 78  wherein the nanostructure layer comprises a plurality of light directing structures. 
     
     
         86 . The transparent conductor of  claim 78  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 5 ohms/sq. 
     
     
         87 . The transparent conductor of  claim 78  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 1 ohm/sq. 
     
     
         88 . The transparent conductor of  claim 78  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.5 ohms/sq. 
     
     
         89 . The transparent conductor of  claim 78  wherein the low sheet resistance grid and the nanostructure layer have a sheet resistance of less than about 0.1 ohm/sq. 
     
     
         90 . The transparent conductor of  claim 78  wherein the planar transparent conductor surface comprises a surface having a surface roughness of less than 50 nanometers peak-to-peak. 
     
     
         91 . The transparent conductor of  claim 78 , further comprising:
 a layer disposed proximate the nanowire layer, the layer selected from the group consisting of: a smoothing layer, a hole transport layer disposed according to a hole transport pattern, a hole injection layer disposed according to a hole injection pattern, an electron transport layer disposed according to a electron transport pattern, and an electron injection layer disposed according to a electron injection pattern.   
     
     
         92 . The transparent conductor of  claim 78 , further comprising:
 a planarizing layer disposed at least partially on the low sheet resistance grid and nanostructure layer opposite the planar transparent conductor surface.   
     
     
         93 . The transparent conductor of  claim 92  wherein the planarizing layer comprises an adhesive material. 
     
     
         94 . The transparent conductor of  claim 93  wherein the adhesive material is selected from the group of adhesive materials consisting of: a thermally cured adhesive and a photo-cured adhesive. 
     
     
         95 . The transparent conductor of  claim 92  wherein the planarizing layer comprises a plurality of light scattering particles. 
     
     
         96 . The transparent conductor of  claim 92  wherein the planarizing layer comprises a plurality of light directing structures. 
     
     
         97 . The transparent conductor of  claim 92 , further comprising a protective film disposed proximate the planarizing layer. 
     
     
         98 . The transparent conductor of  claim 78 , further comprising:
 at least one isolation structure coplanar with the nanostructure layer,
 wherein the at least one isolation structure and the nanostructure layer form the planar transparent conductor surface. 
   
     
     
         99 . The transparent conductor of  claim 98  wherein the planar transparent conductor surface has a surface roughness of less than 50 nanometers peak-to-peak. 
     
     
         100 . A transparent conductor, comprising:
 a low sheet resistance grid; and   a nanostructure layer, wherein the transparent conductor has a sheet resistance of less than 1 ohm/sq and a transparency of greater than 90%.   
     
     
         101 . The transparent conductor of  claim 100  wherein the transparent conductor has a sheet resistance of less than 0.5 ohms/sq. 
     
     
         102 . The transparent conductor of  claim 100  wherein the transparent conductor has a sheet resistance of less than 0.1 ohms/sq. 
     
     
         103 . The transparent conductor of  claim 100  wherein the nanostructure layer comprises a plurality of conductive metallic nanowires.