This application is a U.S. National Stage application under 35 U.S.C. § 371 of International Patent Application No. PCT/US2015/029288, filed May 5, 2015.

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INCORPORATION BY REFERENCE

This application is related to U.S. patent application Ser. No. 12/404,829 filed on Mar. 16, 2009 the contents of which are hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The disclosed subject matter is in the field of transparent conductive coatings for display and touch screen applications. In particular, the disclosed subject matter relates to the improvement of mechanical properties of ceramic oxide based transparent conductive oxides like sputtered indium tin oxide (ITO) coatings on flexible substrates such as polyester films (e.g., polyethylene terephthalate “PET”).

SUMMARY

In an aspect, a multi-layered film including a substrate; a layer of a hybrid film including a three dimensionally interconnected network of carbon nanotubes (CNTs) and a plurality of metal oxide nanoparticles (MONs); wherein, the plurality of metal oxide nanoparticles are randomly distributed in the interconnected network; and a layer of a transparent conductive oxide (TCO) coating; wherein, the transparent conductive oxide is sputter deposited to form a distinct layer in contact with the hybrid film.

In some embodiments, the transparent conductive oxide (TCO) coating is disposed on the substrate and the transparent conductive oxide (TCO) coating is disposed between the hybrid film and the substrate. In some other embodiments, the transparent conductive oxide (TCO) coating is disposed on the hybrid film and the hybrid film is disposed between the TCO coating and the substrate.

In some embodiments, the substrate is selected from a group consisting of metals, silicon, silicon oxide, plastics, organic polymers, inorganic polymers, glasses, crystals, and composite materials. In some embodiments, the substrate is transparent.

In some embodiments, the metal oxide nanoparticles (MONs) are indium tin oxide (ITO). In some other embodiments, the metal oxide nanoparticles (MONs) are selected from a group consisting of ZnO, SnO2, ZnSnO3, Cd2SnO4, In2O3: Sn, ZnO:F, Cd2SnO4, ZnO:Al, SnO2:F, ZnO:Ga, ZnO:B, SnO2:Sb, ZnO:In and mixtures thereof.

In some embodiments, the transparent conductive oxide (TCO) coating is sputtered indium tin oxide. In some other embodiments, the transparent conductive oxide (TCO) coating is made of a material selected from a group consisting of ZnO, SnO2, ZnSnO3, Cd2SnO4, In2O3: Sn, ZnO:F, Cd2SnO4, ZnO:Al, SnO2:F, ZnO:Ga, ZnO:B, SnO2:Sb, ZnO:In and mixtures thereof.

In some embodiments, the carbon nanotubes (CNTs) are chemically derivatized (functionalized).

In some embodiments, the metal oxide nanoparticles are functionalized with a surface chemical species. In some embodiments, a moiety of the surface chemical species used to functionalize the metal oxide nanoparticle is selected from a group consisting of —OH, —COOH, —NH2, ether, ester, amide, —Cl, and —Br.

In some embodiments, the carbon nanotubes (CNTs) are long nanotubes with lengths longer than 1, 2, 3, 4, or 5 microns. In some other embodiments, the carbon nanotubes (CNTs) are single walled carbon nanotubes (SWCNTs).

In some embodiments, the metal oxide nanoparticles (MON) has a mean particle size in the range of 1 nm to about 500 nm.

In some embodiments, the surface coverage of the hybrid film is greater than 10%.

In some embodiments, the ratio of the amount of CNT:MON ranges from about 1:99 to 99:1. In some other embodiments, the ratio of the amount of CNT:MON is about 50:50.

In some embodiments, the optical transparency of the multi-layered film is greater than about 70%.

In some embodiments, the electrical conductance of the multi-layered film is less than 2000 ohms/square.

In some embodiments, the optical transparency of the multi-layered film is between 75-95% and the surface resistance of the hybrid film is about 10-2000 ohms/square.

In some embodiments, the metal oxide nanoparticles (MONs) are spherical, oblong, prismatic, ellipsoidal, rods, and irregularly shaped.

In some embodiments, the thickness of the hybrid film ranges from about 2 nm to about 100 nm.

In some embodiments, the metal oxide nanoparticles (MONs) have an aspect ratio of about 1 to about 5.

In some embodiments, the layer of the hybrid film and the layer of the transparent conductive oxide (TCO) coating form a repeat unit and the repeat unit is repeatedly stacked over one another to form a multi-stacked structure. In certain embodiments, the multi-stacked structure has at least 2 repeat units.

In an aspect, a method of forming a multi-layered film includes, providing a substrate; providing a first suspension of carbon nanotubes (CNTs) in a first solvent; providing a second suspension of metal oxide nanoparticles (MONs) in a second solvent; applying, in any order, the carbon nanotubes to the substrate from the first solvent and the metal oxide nanoparticles (MONs) from the second solvent, wherein, a plurality of the metal oxide nanoparticles are distributed throughout the carbon nanotubes to form an interconnected network; repeating said applying of the carbon nanotubes from the first solvent and said applying the metal oxide nanoparticles (MONs) from the second solvent to form a hybrid film; and before or after formation of the hybrid film, applying a distinct layer of a transparent conductive oxide (TCO) coating over the substrate.

In some embodiments, the layer of the hybrid film and the layer of the transparent conductive oxide (TCO) coating form a repeat unit and the repeat unit is repeatedly stacked over one another to form a multi-stacked structure. In certain embodiments the multi-stacked structure has at least 2 repeat units.

In some embodiments, the application of the first solvent is done by a process selected from a group consisting of spraying, reel to reel coating, dip coating, spin coating and roll coating.

In some embodiments, the carbon nanotubes (CNTs) in the first solvent carry an opposite charge to that of the charge carried by the metal oxide nanoparticles (MONs) in the second solvent. In some other embodiments, the method further includes providing a binder between providing and applying the first suspension of carbon nanotubes (CNTs) and the second suspension of metal oxide nanoparticles (MONs), wherein, the carbon nanotubes (CNTs) in the first solvent and the metal oxide nanoparticles (MONs) in the second solvent carry a same charge and the binder carries an opposite charge relative to the charge carried by the carbon nanotubes and the metal oxide nanoparticles (MONs).

