Transparent electrically conducting oxides

Patent metadata

Field	Value
Publication number	US-9236157-B2
Application number	US-201013393822-A
Country	US
Kind code	B2
Filing date	Sep 2, 2010
Priority date	Sep 3, 2009
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

The invention provides a process for producing a transparent conducting film, which film comprises a doped zinc oxide wherein the dopant comprises Si, which process comprises: disposing a composition which is a liquid composition or a gel composition onto a substrate, wherein the composition comprises Zn and Si; and heating said substrate. The invention further provides transparent conducting films obtainable by the process of the invention, including transparent conducting films which comprise a doped zinc oxide wherein the dopant comprises Si, and wherein the film covers a surface area equal to or greater than 0.01 m 2 . The invention also provides a coated substrate, which substrate comprises a surface, which surface is coated with a transparent conducting film, wherein the film comprises a doped zinc oxide wherein the dopant comprises Si, and wherein the area of said surface which is coated with said film is equal to or greater than 0.01 m 2 . The invention further provides coatings comprising the films of the invention, processes for producing such films and coatings, and various uses of the films and coatings.

First claim

The invention claimed is:

1. A process for producing a transparent conducting film, which film comprises a doped zinc oxide wherein the dopant comprises Si, and which film has an electrical resistivity of less than 2.0×10 −2 Ωcm, which process comprises:
disposing a composition which is a liquid composition or a gel composition onto a substrate, wherein the composition comprises Zn and Si; and
simultaneously heating said substrate,
wherein spraying the composition onto the heated substrate causes pyrolytic decomposition of said composition and formation of a layer of said doped zinc oxide.

2. A process according to claim 1 wherein the composition comprises a sol gel.

3. A process according to claim 1 wherein the composition is a solution or a dispersion.

4. A process according to claim 3 wherein the composition comprises: a compound comprising Zn, a compound comprising Si, and a solvent.

5. A process according to claim 1 wherein said spraying is performed with the aid of a carrier gas.

6. A process according to claim 5 wherein the step of spraying the composition onto the substrate comprises (i) introducing said composition and said carrier gas into a spray head, wherein the composition is introduced at a first flow rate and the carrier gas is introduced at a second flow rate, wherein the first and second flow rates are the same or different, and (ii) spraying the composition onto said substrate from an exit of said spray head.

7. A process according to claim 6 wherein the exit of the spray head comprises a nozzle.

8. A process according to claim 6 wherein the distance between said exit of said spray head and the substrate is from 10 cm to 40 cm.

9. A process according to claim 1 wherein the step of spraying the composition onto said substrate comprises spraying a jet of fine droplets of said composition onto the substrate.

10. A process according to claim 9 wherein said droplets have a diameter of from 1 to 100μm.

11. A process according to claim 1 wherein the step of spraying the composition onto said substrate is performed until a film thickness of from 100 nm to 1000 nm is achieved.

12. A process according to claim 1 wherein the duration of the step of spraying the composition onto said substrate is from 5 minutes to 40 minutes.

13. A process according to claim 1 wherein the step of heating the substrate comprises maintaining the substrate at an elevated temperature for the duration of the step of spraying the composition onto said substrate.

14. A process according to claim 1 wherein the step of heating the substrate comprises maintaining the substrate at a temperature of from 200° C. to 500° C.

15. A process according to claim 1 wherein the step of heating the substrate is performed in air.

16. A process according to claim 1 wherein the molar ratio of Si to Zn in said composition is x:(1−x), wherein x is greater than 0 and less than or equal to 0.25.

17. A process according to claim 1 wherein the molar ratio of Si to Zn in said doped zinc oxide is x:(1−x), wherein x is greater than 0 and less than or equal to 0.25.

18. A process according to claim 1 wherein the doped zinc oxide comprises a compound of formula (I)
Zn 1-x [M] x O 1-y [X] y   (I)

wherein:
x is greater than 0 and less than or equal to 0.25;
y is from 0 to 0.1;
[X], when present, is at least one dopant element which is a halogen; and
[M] is a dopant element which is Si, or a combination of two or more different dopant elements, one of which is Si.

19. A process according to claim 1 wherein the molar ratio of Si to Zn in said composition is x:(1−x), wherein x is from 0.005 to 0.04.

20. A process according to claim 1 wherein the molar ratio of Si to Zn in said doped zinc oxide is x:(1−x), wherein x is from 0.005 to 0.04.

21. A process according to claim 1 wherein the doped zinc oxide comprises a compound of formula (I)
Zn 1-x[M] x O 1-y [X] y   (I)

wherein:
x is from 0.005 to 0.04;
y is from 0 to 0.1;
[X], when present, is at least one dopant element which is a halogen; and
[M] is a dopant element which is Si, or a combination of two or more different dopant elements, one of which is Si.

22. A process according to claim 18 wherein y is other than 0 and:
(i) the composition comprises said at least one dopant element which is a halogen;
(ii) the step of disposing the composition onto a substrate is performed in the presence of a gas comprising said at least one dopant element which is a halogen; and/or
(iii) the step of heating said substrate is performed in the presence of a gas comprising said at least one dopant element which is a halogen.

23. A process according to claim 18 wherein y is other than 0 and [X] is F.

24. A process according to claim 1 wherein the composition is a solution comprising a zinc compound, a silicon compound, and a solvent.

25. A process according to claim 24 wherein the zinc compound is zinc acetate and the silicon compound is silicon tetra-acetate.

26. A process according to claim 24 wherein the concentration of said zinc compound in said solution is from 0.01M to 0.5M.

27. A process according to claim 24 wherein the concentration of said silicon compound in said solution is from 0.0001 M and 0.005 M.

28. A process according to claim 24 wherein the concentration of said zinc compound in said solution is from 0.05 M to 0.1 M.

29. A process according to claim 24 wherein the concentration of said silicon compound in said solution is from 0.001M and 0.002M.

30. A process according to claim 24 wherein the solvent comprises water and/or an alcohol.

31. A process according to claim 24 wherein the solution further comprises an acid.

32. A process according to claim 1 which further comprises annealing the substrate.

33. A process according to claim 32 wherein the substrate is annealed at a temperature of from 200° C. to 500° C.

34. A process according to claim 32 wherein the step of annealing the substrate is performed in a nitrogen atmosphere, or in a mixture of an inert gas and hydrogen.

35. A process according to claim 1 wherein the substrate is transparent in the visible range of the spectrum.

36. A process according to claim 35 wherein the substrate comprises glass, silicon, oxidised silicon, a polymer, a plastic, sapphire, silicon carbide, alumina (Al 2 O 3 ), zinc oxide (ZnO), yttrium-stabilised zirconium (YSZ), zirconium oxide (ZrO 2 ), fused silica or quartz.

37. A process according to claim 1 wherein the composition is disposed on only a portion of the surface of the substrate, in order to form a patterned film.

38. A process according to claim 1 wherein the process further comprises subjecting the film to etching, thereby producing a patterned film.

39. A process according to claim 1 wherein the transparent conducting film has a resistivity, ρ, of less than or equal to 6.0×10 −3 Ω cm.

40. A process according to claim 1 wherein the transparent conducting film has a carrier concentration of at 1.0×10 20 cm −3 .

41. A process according to claim 1 wherein the transparent conducting film has a mean optical transparenc

Assignees

• Kuznetsov Vladimir L
• Edwards Peter P
• Isis Innovation

Inventors

• Kuznetsov Vladimir L
• Edwards Peter P

Classifications

• C23C18/08

  characterised by the deposition of metallic material · CPC title

• C23C18/1291

  by heating of the substrate · CPC title

• Y10T428/24802

  Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.] · CPC title

• C23C18/1254

  Sol or sol-gel processing · CPC title

• C23C18/1258

  Spray pyrolysis · CPC title