Transparent conductive oxide having an embedded film
The present invention is directed to coated articles. A substrate is coated with an underlayer having at a first underlayer film made of a first high refractive index material. A transparent conductive oxide layer over at least a portion of the underlayer. An embedded film is embedded within the transparent conductive oxide layer wherein the embedded film comprises a second high refractive index material.
1. A coated article comprising
a substrate,
an underlayer over at least a portion of the substrate, the underlayer comprising
a first underlayer film wherein the first underlayer film comprises a first refractive index material, wherein the first underlayer film is in direct contact with the substrate and wherein the first refractive index material comprises zinc, and
a second underlayer film over at least a portion of the first underlayer film wherein the second underlayer film comprises a second refractive index material, and wherein the first refractive index material has a refractive index greater than the second refractive index material,
a transparent conductive oxide layer over at least a portion of the underlayer and
an embedded film embedded within the transparent conductive oxide layer wherein the embedded film comprises a third refractive index material, and wherein the third refractive index material has a refractive index greater than the second refractive index material.
2. The coated article according to claim 1 , wherein the third refractive index material comprises tin oxide and zinc oxide.
3. The coated article according to claim 1 , wherein the embedded film has a thickness in the range of 15 nm to 30 nm.
4. The coated article according to claim 1 , wherein the transparent conductive oxide layer comprises tin-doped indium oxide.
5. The coated article according to claim 1 , wherein the embedded film is positioned closer to a bottom of the transparent conductive oxide layer.
6. The coated article according to claim 1 , wherein the embedded film is positioned closer to a top of the transparent conductive oxide layer.
7. The coated article according to claim 1 , wherein the embedded film is positioned at approximately a middle of the transparent conductive oxide layer.
8. The coated article according to claim 1 , further comprising a protective layer over at least a portion of the transparent conductive oxide layer, wherein the protective layer comprises a first protective film comprising titania, alumina, zinc oxide, tin oxide, zirconia, silica alloys thereof or mixtures thereof; and a second protective film over at least a portion of the first protective film, wherein the second protective film comprises a mixture of titania and alumina.
9. A coated article comprising
a substrate;
an underlayer over at least a portion of the substrate, wherein the underlayer comprises a first underlayer film and a second underlayer film over at least a portion of the first underlayer film, wherein the first underlayer film comprises a first refractive index material that comprises zinc, wherein said second underlayer film comprises a second refractive index material, wherein the first refractive index material is in direct contact with the substrate and has a refractive index greater than the second refractive index material;
a first transparent conductive oxide layer over at least a portion of the underlayer,
an embedded film over at least a portion of the first transparent conductive oxide layer, wherein the embedded film comprises a third refractive index material, and wherein the third refractive index material has a refractive index greater than the second refractive index material; and
a second transparent conductive oxide layer over at least a portion of the embedded film.
10. The coated article according to claim 9 , wherein the embedded film comprises tin oxide and zinc oxide.
11. The coated article according to claim 9 , wherein the first transparent conductive oxide layer and the second transparent conductive oxide layer comprise tin-doped indium oxide (“ITO”).
12. The coated article according to claim 9 , wherein the embedded film has a thickness of at least 15 nm and at most 30 nm.
13. The coated article according to claim 9 , wherein the first transparent conductive oxide layer is thicker than the second transparent conductive oxide layer.
14. The coated article according to claim 9 , further comprising a protective layer over at least a portion of the second transparent conductive oxide layer, wherein the protective layer comprises a first protective film comprising titania, alumina, zinc oxide, tin oxide, zirconia, silica or mixtures thereof; and a second protective film over at least a portion of the first protective film, wherein the second protective film comprises a mixture of titania and alumina.
15. A method of reducing the sheet resistance of a coated article comprising
(a) applying a first underlayer film over at least a portion of a substrate, wherein the first underlayer film comprises a first refractive index material, wherein the first underlayer film is in direct contact with the substrate and wherein the first refractive index material comprise zinc;
(b) applying a second underlayer film over at least a portion of the first underlayer film, wherein the second underlayer film comprises a second refractive index material;
(c) applying a first transparent conductive oxide layer over at least a portion of the second underlayer film;
(d) applying an embedded film over at least a portion of the first transparent conductive oxide layer, wherein the embedded film comprises a third refractive index material, and wherein the third refractive index material has a refractive index greater than the second refractive index material; and
(e) applying a second transparent conductive oxide layer over at least a portion of the embedded film.
16. The method according to claim 15 , wherein the third refractive index material comprises tin oxide and zinc oxide.
17. The method according to claim 15 , wherein the first transparent conductive oxide layer comprises tin-doped indium oxide.
18. The method according to claim 15 , wherein the embedded film is applied at a thickness of at least 15 nm, and at most 30 nm.
19. The method according to claim 15 , wherein the first transparent conductive oxide layer is thicker than the second transparent conductive oxide layer.
20. The method according to claim 15 further comprising applying a first protective film over at least a portion of the second transparent conductive oxide layer, and applying a second protective film over at least a portion of the first protective film, wherein the second protective film comprises a mixture of titania and alumina, and wherein the first protective film comprises titania, alumina, zinc oxide, tin oxide, zirconia, silica or mixtures thereof.