COATED ARTICLE SUPPORTING PHOTOCATALYTIC LAYER AND UV-REFLECTING UNDERLAYER, AND/OR METHOD OF MAKING THE SAME
Certain example embodiments relate to articles supporting photocatalytic layers that also include UV-reflecting unclerlayers, and/or methods of making the same. In certain example embodiments, the inclusion of a UV-reflecting underlayer surprisingly and unexpectedly results in the reduction of dosing time to enable quick activation of the photocatalytic coating. For example, dosing time may be reduced from a few hours to a few minutes or even seconds in certain example embodiments. The UV-reflecting underlayer may be a single-layer coating or a multi-layer stack.
1 . method of making a coated article, the method comprising:
providing a substrate to be coated;
disposing a UV-reflecting coating, directly or indirectly, on the substrate to be coated; and
disposing a photocatalytic layer over the UV-reflecting coating so that at least some of any UV light that is not initially used in the activation of the photocatalytic layer and otherwise would pass into the substrate is reflected back towards the photocatalytic layer by the UV-reflecting coating.
2 . The method of claim 1 , wherein the photocatalytic layer comprises titanium dioxide.
3 . The method of claim 1 , wherein the UV-reflecting coating is a single layer coating.
4 . The method of claim 3 , wherein the UV-reflecting coating comprises at least 0.1% by weight aluminum oxide, and at least 0.1% by weight material having a refractive index higher than the aluminum oxide.
5 . The method of claim 4 , wherein the material having the refractive index higher than the aluminum oxide includes at least one: zirconium oxide, yttrium oxide, hafnium oxide, and oxides of rare earth metals.
6 . The method of claim 1 , wherein the UV-reflecting coating is a multilayer stack.
7 . The method of claim 6 , wherein each layer in the multilayer stack is selected so that it has a refractive index that substantially matches each of the other layers in the multilayer stack.
8 . The method of claim 1 , wherein the UV-reflecting coating is disposed so as to reflect at least about 90% of any light useful in photocatalytic initiation coming into contact therewith.
9 . The method of claim 1 , wherein the UV-reflecting coating is disposed so as to reflect at least about 90% of any light having an energy per photon greater than about 3 eV.
10 . The method of claim 1 , wherein the coated article has a visible transmission of at least about 90%.
11 - 18 . (canceled)
19 . A method of making a coated article, the method comprising:
providing a substrate to be coated;
disposing a UV-reflecting coating, directly or indirectly, on the substrate to be coated; and
disposing a photocatalytic layer over the UV-reflecting coating so that at least some of any UV light that is not initially used in the activation of the photocatalytic layer and otherwise would pass into the substrate is reflected back towards the photocatalytic layer by the UV-reflecting coating,
wherein the photocatalytic layer comprises titanium dioxide,
wherein the UV-reflecting coating is disposed so as to reflect at least about 90% of any light useful in photocatalytic initiation coming into contact therewith, and
wherein the coated article has a visible transmission of at least about 90%.
20 . The method of claim 19 , wherein the UV-reflecting coating is a single layer coating.