Conductive films

• US 9,112,166 B2
• Filed: 07/29/2011
• Issued: 08/18/2015
• Est. Priority Date: 07/30/2010
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Gaynor, Whitney, Peumans, Peter
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US13/194,134
• Publication Number:
  US 20120127097A1
• Time in Patent Office: 1,481 Days
• US Class Current: 1/1
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: H10K 30/82 Transparent electrodes, e.g. indium tin oxide [ITO] electrodes
• CPC Class Codes: H10K 30/821 comprising carbon nanotubes
• CPC Class Codes: H10K 30/83 comprising arrangements for extracting the current from the cell, e.g. metal finger grid systems to reduce the serial resistance of transparent electrodes
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 442/10 Scrim [e.g., open net or mesh, gauze, loose or open weave or knit, etc.]

Abstract

Conductive films with transparency characteristics are provided. In accordance with various example embodiments, a transparent conductive film includes an inorganic nanowire mesh embedded in an organic substrate layer. The embedding may involve, for example, embedding a majority of, or substantially all of the nanowire mesh in the organic substrate layer to facilitate a resulting surface roughness of the combined nanowire mesh-polymer that is less than a surface roughness of the mesh alone (e.g., or otherwise embedded), and in turn facilitates desirable conductivity characteristics.

Claims

1. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer being configured with the embedded nanowire mesh to provide a composite morphology for nanowires therein being sufficiently flattened to form a conductive film in which some of the nanowires are exposed and at which RMS surface roughness is between 5 nm and 30nm, wherein the organic substrate layer and the inorganic nanowire mesh form an organic-inorganic compound conductive film having a surface roughness value that is at least 25% lower than a surface roughness of the inorganic nanowire mesh, prior to embedding in the organic substrate layer.

2. The apparatus of claim 1, wherein the organic substrate layer has a thickness of at least about the thickness of the inorganic nanowire mesh.

3. The apparatus of claim 1, wherein the inorganic nanowire mesh and organic substrate layer form a film that passes at least about 70% of light incident thereupon.

4. The apparatus of claim 1, wherein at least 25% of the nanowire mesh is embedded within the organic substrate layer.

5. The apparatus of claim 1, wherein:

the organic substrate layer has a thickness of at least about the thickness of the inorganic nanowire mesh; and

the inorganic nanowire mesh and organic substrate layer form a film that passes at least about 70% of light incident thereupon.

6. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer with the embedded nanowire mesh forming a conductive film, wherein the inorganic nanowire mesh includes a plurality of silver nanowires having diameters that are at least about 40 nanometers different than diameters of other silver nanowires in the mesh, and the organic substrate layer and inorganic nanowire mesh form a film having an RMS surface roughness of less than about 20 nanometers.

7. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer with the embedded nanowire mesh forming a conductive film, wherein the organic substrate layer is a polymer having a high refractive index configured to extend the spectral range over which the inorganic nanowire mesh is transparent into the infrared.

8. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer with the embedded nanowire mesh forming a conductive film, wherein the organic substrate layer includes a polymer having a high refractive index configured to, for incident light of a wavelength that is too long for passing through openings in the nanowire mesh, modify the wavelength of the incident light to permit the light to pass through openings in the inorganic nanowire mesh.

9. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer with the embedded nanowire mesh forming a conductive film, wherein the conductive film is configured to exhibit a conductivity value that is about constant under bending stresses ranging from no bending stress to a bending stress that is about four times a bending stress at which an indium tin oxide film, having dimensions corresponding to the conductive film, exhibits plastic deformation.

10. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer being configured with the embedded nanowire mesh to provide a composite morphology for nanowires therein being sufficiently flattened to form a conductive film in which some of the nanowires are exposed and at which RMS surface roughness is between 5 nm and 30 nm, wherein the organic substrate layer fills in gaps between nanowires in the nanowire mesh, electrically couples portions of the nanowire mesh, and the film surface has an RMS roughness that is less than about half a RMS roughness of the nanowire mesh, prior to embedding.

11. An apparatus comprising:

an organic substrate layer;

embedded in the organic substrate layer, a plurality of electrodes and an inorganic nanowire mesh, the organic substrate layer being configured with the embedded nanowire mesh to provide a composite morphology for nanowires therein being sufficiently flattened to form a conductive film in which some of the nanowires are exposed and at which RMS surface roughness is between 5 nm and 30 nm;

each electrode comprising

the inorganic nanowire mesh embedded in the organic substrate layer, to a depth in the organic substrate layer at which the organic substrate layer and the inorganic nanowire mesh form a conductive film having the RMS surface,

a portion of the organic substrate layer between spaces in the mesh that is configured and arranged to electrically couple portions of the mesh; and

logic circuitry configured to control the display of an image via the organic substrate layer; and

wherein the composite morphology is characterized in the nanowires being flattened due to the depth of the organic substrate layer.

12. A display device comprising:

an organic substrate layer;

embedded in the organic substrate layer, a plurality of electrodes, each electrode comprising;

an inorganic nanowire mesh embedded to a depth in the organic substrate layer at which the organic substrate layer and the inorganic nanowire mesh form a conductive film having a surface roughness value that is at least 25% lower than a surface roughness of the inorganic nanowire mesh, prior to embedding in the organic substrate layer, and

a portion of the organic substrate layer between spaces in the mesh that is configured and arranged to electrically couple portions of the mesh; and

logic circuitry configured to control the display of an image via the organic substrate layer, wherein the organic substrate layer and embedded electrodes form a touch-screen configured to provide an output indicative of the presence and location of a touch on the screen.

13. A display device comprising:

an organic substrate layer;

embedded in the organic substrate layer, a plurality of electrodes, each electrode comprising;

an inorganic nanowire mesh embedded to a depth in the organic substrate layer at which the organic substrate layer and the inorganic nanowire mesh form a conductive film having a surface roughness value that is at least 25% lower than a surface roughness of the inorganic nanowire mesh, prior to embedding in the organic substrate layer, and

a portion of the organic substrate layer between spaces in the mesh that is configured and arranged to electrically couple portions of the mesh; and

logic circuitry configured to control the display of an image via the organic substrate layer, wherein the logic circuitry is configured to

detect a bend in the film in response to an electrical characteristic of the at least one of the plurality of electrodes, and

control the display of the image based on the detected bend.

14. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer being configured with the embedded nanowire mesh to provide a composite morphology for nanowires therein being sufficiently flattened to form a conductive film in which some of the nanowires are exposed and at which RMS surface roughness is between 5 nm and 30 nm, wherein the organic substrate layer fills in gaps between nanowires in the nanowire mesh, electrically couples portions of the nanowire mesh, and the film surface has an RMS roughness that is less than about half a RMS roughness of the nanowire mesh, prior to embedding; and

the organic substrate layer and the inorganic nanowire mesh form an organic-inorganic compound conductive film having a surface roughness value that is at least 25% lower than a surface roughness of the inorganic nanowire mesh, prior to embedding in the organic substrate layer.

15. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer being configured with the embedded nanowire mesh to provide a composite morphology for nanowires therein being sufficiently flattened to form a conductive film in which some of the nanowires are exposed and at which RMS surface roughness is between 5 nm and 30nm, wherein the organic substrate layer has a thickness of at least about the thickness of the inorganic nanowire mesh; and

the inorganic nanowire mesh and organic substrate layer form a film that passes at least about 70% of light incident thereupon;

wherein the organic substrate layer fills in gaps between nanowires in the nanowire mesh, electrically couples portions of the nanowire mesh, and the film surface has an RMS roughness that is less than about half a RMS roughness of the nanowire mesh, prior to embedding; and

the organic substrate layer and the inorganic nanowire mesh form an organic-inorganic compound conductive film having a surface roughness value that is at least 25% lower than a surface roughness of the inorganic nanowire mesh, prior to embedding in the organic substrate layer.

16. An apparatus comprising:

an organic substrate layer; and

an inorganic nanowire mesh embedded in the organic substrate layer, the organic substrate layer with the embedded nanowire mesh forming a conductive film, wherein;

the organic substrate layer includes a polymer having a high refractive index configured to, for incident light of a wavelength that is too long for passing through openings in the nanowire mesh, modify the wavelength of the incident light to permit the light to pass through openings in the inorganic nanowire mesh; and

the conductive film is configured to exhibit a conductivity value that is about constant under bending stresses ranging from no bending stress to a bending stress that is about four times a bending stress at which an indium tin oxide film, having dimensions corresponding to the conductive film, exhibits plastic deformation.