Nanocomposite barrier films for photovoltaic applications
Polymer-clay nanocomposites thin film coatings have improved water vapor and oxygen permeability, in addition to improved corrosion resistance, while retaining high transparency, high electrical resistivity, and excellent fire-retardant properties for use as encapsulants for photovoltaic module assemblies and barrier coatings in other photovoltaic applications.
1. A layered nanocomposite barrier film for the encapsulation of solar photovoltaics, comprising at least one layer of dispersed and aligned clay platelets in a polyelectrolyte polymer matrix encapsulating a photovoltaic module.
2. The barrier film of claim 1 , wherein the clay platelets are anionic and the polyelectrolyte polymer is cationic.
3. The barrier film of claim 2 , wherein the anionic clay platelets comprise montmorillonite or vermiculite.
4. The barrier film of claim 2 , wherein the cationic polyelectrolyte polymer comprises polyethyleneimine or ethylene vinyl amine.
5. The barrier film of claim 1 , wherein the clay platelets are cationic and the polyelectrolyte polymer is anionic.
6. The barrier film of claim 5 , wherein the cationic clay platelets comprise layered double hydroxides.
7. The barrier film of claim 5 , wherein the anionic polyelectrolyte polymer comprises poly(acrylic acid).
8. The barrier film of claim 1 , wherein the polyelectrolyte polymer matrix comprises a combination of oppositely charged polymers.
9. The barrier film of claim 8 , wherein the oppositely charged polymers comprise polyethyleneimine and poly(acrylic acid).
10. The barrier film of claim 1 , wherein the barrier film further comprises at least one layer of dispersed and aligned platelets of alumina, graphene, or boron nitride.
11. The barrier film of claim 1 , wherein the barrier film further comprises a polymeric encapsulant.
12. The barrier film of claim 11 , wherein the polymeric encapsulant comprises ethylene vinyl acetate, polyvinyl butyral, a polyolefin, an ionomer, or a silicone.
13. The barrier film of claim 1 , wherein the barrier film is deposited by a layer-by-layer process.