GRAPHENE BASED HYBRID THIN FILMS AND THEIR APPLICATIONS
Graphene-based hybrid films are made by coating electrically conductive nanostructures (such as carbon nanotubes or conductive nanowires) onto a metal substrate, and growing a graphene layer between the nanostructures and the substrate. The nanostructure coating on the substrate yields nucleation sites for the growth of the graphene layer. The process provides hybrid films in which graphene domains are electrically connected by the nanotubes or nanowires. Integral bonds (e.g., chemical bonds) are produced between the nanostructures and the graphene to provide improved electrical conductivity, via contact in excess of van der Waals forces.
1 . A hybrid film, comprising:
a substrate;
nanostructures on the substrate;
graphene domains on the substrate and the nanostructures, the graphene domains being integrally connected to the nanostructures.
2 . The hybrid film according to claim 1 , wherein the nanostructures comprise carbon nanotubes or metallic nanowires.
3 . A method of a making a hybrid film, the method comprising:
coating nanostructures on a metallic substrate;
annealing the nanostructures at a temperature sufficient to deposit graphene on the substrate to form nucleation sites at contact points between the nanostructures and the metallic substrate; and
depositing graphene on the metallic substrate and the nanostructures by growing graphene from the nucleation sites to form a hybrid nanostructures-graphene film.
4 . The method according to claim 3 , wherein the metallic substrate comprises a silver foil, a copper foil, a nickel foil, or a nickel-copper alloy foil.
5 . The method according to claim 3 , wherein the nanostructures comprise carbon nanotubes or metallic nanowires.
6 . The method according to claim 3 , wherein the temperature sufficient to deposit graphene is about 500° C. to about 1080° C.
7 . The method according to claim 3 , wherein the depositing the graphene comprises introducing a carbon source gas to the metallic substrate and the nanostructures, and maintaining the temperature sufficient to deposit graphene.
8 . The method according to claim 3 , further comprising transferring the hybrid nanostructures-graphene film from the metallic substrate to a separate substrate.
9 . The method according to claim 8 , further comprising doping the hybrid nanostructures-graphene film.
10 . The method according to claim 9 , wherein the doping comprises immersing the hybrid nanostructures-graphene film in an HNO 3 solution.
11 . The method according to claim 3 , wherein the annealing the nanostructures and the depositing the graphene are performed by chemical vapor deposition.