NOVELTY - The multilayer barrier film comprises a substrate layer (50) coated on one side with a barrier layer (51), a nanostructured metal compound layer (60) arranged on the barrier layer, and a planarizing layer (70) arranged on the nanostructured layer. The planarizing layer comprises: a nanostructured material that is distributed in a polymeric binder and is made of carbon and/or a metal or a metal oxide; and an UV absorbing organic compound. The nanostructured metal compound layer is extending into or filling (partially or fully) the defects comprised in the barrier layer.    USE - The multilayer optical graded barrier film is useful to protect solar cells and organic/inorganic emissive devices such as organic light emitting diode displays against moisture and/or oxygen.    ADVANTAGE - The multilayer optical graded barrier film can be effectively manufactured without cracks, pinholes or gaps at grain boundaries and with decreased oxygen transmission rate and water vapor transmission rate and high packing-density, and is capable of efficiently protecting the solar cells and organic light emitting diode displays against moisture and/or oxygen thus ensuring reliable performance and extending the lifespan of the displays.    DETAILED DESCRIPTION - The multilayer barrier film comprises a substrate layer (50) coated on one side with a barrier layer (51), a nanostructured metal compound layer (60) arranged on the barrier layer, and a planarizing layer (70) arranged on the nanostructured layer. The planarizing layer comprises: a nanostructured material that is distributed in a polymeric binder and is made of carbon and/or a metal or a metal oxide; and an UV absorbing organic compound. The nanostructured metal compound layer is extending into or filling (partially or fully) the defects comprised in the barrier layer, and has a thickness of 200 nm to 10 mu m. The nanostructure of the nanostructured metal compound layer consists of a nanowire, a single-crystal nanostructure, a double-crystal nanostructure, a polycrystalline nanostructure and an amorphous nanostructure. The nanostructured material comprised in the planarizing layer is rod-shaped material, and has a length of less than 200 nm and a surface area to weight ratio of 1-200 m2/g. The rod-shape has a diameter of 10-50 nm, a length of 50-400 nm, and an aspect ratio of greater than or equal to 5. 16. An amount of nanostructured material in the nanostructured layer is 0.0000001-50 wt.% related to the total weight of the monomer of the polymeric binder. The substrate is made of an organic polymer and/or an inorganic polymer, where the polymers are transparent or semitransparent or opaque. The barrier layer, nanostructured metal compound layer and planarizing layer are arranged on both sides of the substrate. The barrier layer is further arranged on the planarizing layer, and has a thickness of 5-500 nm. The substrate has a thickness of 1 mu m to 3 mm. The planarizing layer has a thickness of 200 nm to 1 mu m. An INDEPENDENT CLAIM is included for a method of manufacturing a multilayer barrier film.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a structure of a multilayer barrier film.    Substrate layer (50)    Barrier layer (51)    Nanostructured metal compound layer (60)    Planarizing layer. (70)