Deposition and post-processing techniques for transparent conductive films

• US 9,694,422 B2
• Filed: 01/09/2015
• Issued: 07/04/2017
• Est. Priority Date: 01/14/2011
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Salleo, Alberto, Christoforo, Mark Greyson, Mehra, Saahil, Peumans, Peter
• Primary Examiner(s): Moore, Whitney T
• Assistant Examiner(s): GALVIN III, JOSEPH M
• Application Number:
  US14/593,840
• Publication Number:
  US 20160372694A1
• Time in Patent Office: 907 Days
• Field of Search: 257431
• CPC Class Codes: B22F 1/0547 Nanofibres or nanotubes
• CPC Class Codes: B22F 1/07 Metallic powder characterised by particles having a nanoscale microstructure nanosized particles B22F1/054
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 2003/248 Thermal after-treatment
• CPC Class Codes: B22F 2301/255 Silver or gold
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/002 Manufacture of articles essentially made from metallic fibres
• CPC Class Codes: B22F 3/105 by using electric current other than for infrared radiant energy, laser radiation or plasma B22F3/11 takes precedence; by ultrasonic bonding B22F3/115 takes precedence
• CPC Class Codes: B22F 3/24 After-treatment of workpieces or articles B22F3/1146 takes precedence
• CPC Class Codes: B22F 7/004 comprising at least one non-porous part
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 9/02 Oxides; Hydroxides
• CPC Class Codes: C22C 32/0021 Matrix based on noble metals, Cu or alloys thereof
• CPC Class Codes: C23C 24/00 Coating starting from inorganic powder spraying of the coating material in molten state C23C4/00; solid state diffusion C23C8/00 - C23C12/00
• CPC Class Codes: C23C 24/08 by application of heat or pressure and heat C23C24/04 takes precedence
• CPC Class Codes: C23C 4/123 Spraying molten metal
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/022483 composed of zinc oxide [ZnO]
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: H10K 30/82 Transparent electrodes, e.g. indium tin oxide [ITO] electrodes
• CPC Class Codes: H10K 30/87 : Light-trapping means
• CPC Class Codes: H10K 50/854 : comprising scattering means
• CPC Class Codes: Y02E 10/50 : Photovoltaic [PV] energy
• CPC Class Codes: Y02E 10/549 : Organic PV cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

In one embodiment, a method is provided for fabrication of a semitransparent conductive mesh. A first solution having conductive nanowires suspended therein and a second solution having nanoparticles suspended therein are sprayed toward a substrate, the spraying forming a mist. The mist is processed, while on the substrate, to provide a semitransparent conductive material in the form of a mesh having the conductive nanowires and nanoparticles. The nanoparticles are configured and arranged to direct light passing through the mesh. Connections between the nanowires provide conductivity through the mesh.

Claims

1. An apparatus, comprising

a substrate;

a layer of one or more photovoltaic cells formed on the substrate; and

a semitransparent conductive film formed on the layer of the one or more photovoltaic cells, the semitransparent conductive film having a mesh of conductive nanowires and nanoparticles pseudo-randomly oriented on the surface of the layer, the nanoparticles arranged throughout the mesh of conductive nanowires at a concentration to cause light scattering through the mesh and wherein connections between the conductive nanowires provide conductivity through the semitransparent conductive film.

2. The apparatus of claim 1, wherein the conductive nanowires are silver.

3. The apparatus of claim 1, wherein the nanoparticles are zinc oxide.

4. The apparatus of claim 1, wherein the photovoltaic cells are organic.

5. The apparatus of claim 1, wherein the conductive nanowires are joined at points at which the nanowires cross.

6. The apparatus of claim 1, wherein a portion of the semitransparent conductive film includes silver spheres that are electrically disconnected, and does not include conductive nanowires.

7. The apparatus of claim 1, wherein the nanoparticles are distributed throughout the mesh and are further configured to scatter light at wavelength ranges that are particular to a material forming the nanoparticles.

8. The apparatus of claim 1, wherein the conductive nanowires form the mesh with the nanoparticles distributed throughout the mesh and are configured to provide conductivity at the connections between the conductive nanowires and allow light to pass through areas of the mesh between the conductive nanowires.

9. The apparatus of claim 1, wherein the nanoparticles scatter light of an infrared and/or near-infrared wavelength range through the semitransparent conductive film.

16. The apparatus of claim 1, wherein the semitransparent conductive film has a sheet resistance of less than 5 Ω

/sq.

17. The apparatus of claim 1, wherein the semitransparent conductive film has a transmission of greater than 90 percent.

18. The apparatus of claim 1, wherein the nanoparticles are distributed throughout the mesh of conductive nanowires at a concentration to provide a haze factor at infrared and/or near-infrared wavelengths of greater than 30 percent.

19. The apparatus of claim 1, wherein the semitransparent conductive film has at least two of:

a sheet resistance of less than 5 Ω

/sq, a transmission of greater than 90 percent, and a haze factor at infrared and/or near-infrared wavelengths of greater than 30 percent.

20. The apparatus of claim 1, wherein the semitransparent conductive film has a sheet resistance of less than 5 Ω

/sq, a transmission of greater than 90 percent, and a haze factor at infrared and/or near-infrared wavelengths of greater than 30 percent.

10. An apparatus, comprising

a substrate;

a layer of one or more photovoltaic cells formed on the substrate; and

a semitransparent conductive film formed on the layer of the one or more photovoltaic cells, the semitransparent conductive film having a mesh of conductive nanowires oriented on the surface of the layer and having nanoparticles pseudo-randomly oriented throughout the mesh, the nanoparticles configured to scatter light of a wavelength range that is particular to a material forming the nanoparticles, and wherein connections between the conductive nanowires provide conductivity through the semitransparent conductive film.

11. The apparatus of claim 10, wherein the conductive nanowires are silver and the nanoparticles are zinc oxide.

12. The apparatus of claim 10, wherein a first portion of the semitransparent conductive film includes the conductive nanowires, and a second portion of the semitransparent conductive film includes silver spheres that are electrically disconnected, and does not include conductive nanowires.

13. The apparatus of claim 10, wherein the conductivity through the semitransparent conductive film is set by an overlap of the conductive nanowires and light scatter is set by the nanoparticles distributed throughout the mesh.

14. The apparatus of claim 10, wherein the nanoparticles are configured to scatter the particular wavelength range to increase a path length of sub-band gap photons in the layer of the one or more photovoltaic cells.

15. The apparatus of claim 10, wherein the semitransparent conductive film has a sheet resistance of less than 100 Ω

/sq.