TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Properties: The diameter of a thin layer comprising graphene oxide or reduced graphene oxide is 1 mu m or more. The bilayer has thickness of 1-100 nm. The stack number of the bilayers is 1-10. Preferred Composition: The thin layer comprising graphene oxide or reduced graphene oxide contains 1-10 graphene layers. Preferred Process: The bilayer is formed by an electrostatic attraction between the thin layer and the organic polymer layer, and by evaporating organic monomer or oligomer constituting polymer in a molecule state and by concentrating and polymerizing the evaporated organic monomer or oligomer on a surface of the thin layer comprising graphene oxide or reduced graphene oxide. The bilayer is further formed by printing a solution in which polymer is dissolved, on a surface of the thin layer comprising graphene oxide or reduced graphene oxide to dry the resultant component. The formation of encapsulation film is performed using an electrostatic attraction between the thin layer comprising graphene oxide or reduced graphene oxide and organic polymer layer, and involves forming thin layer on the porous base by a suspension casting process, and forming the organic polymer layer on the thin layer. The suspension casting process involves injecting a suspension in which the thin layer is dispersed in the porous base by capillary pressure, and by forming hydrates through a hydration reaction of the suspension with the porous base, guiding injection of a suspension in which a thin layer is dispersed by applying sound pressure to an opposite surface of the porous base making contact with the suspension, and discharging a suspension in which a thin layer is dispersed through the porous base by applying pressure to the suspension. The organic polymer layer is formed by an electrostatic attraction between the thin layer and the organic polymer layer, evaporating organic monomer or oligomer constituting polymer in a molecule state and by concentrating and polymerizing the evaporated organic monomer or oligomer on a surface of the thin layer composed of the graphene oxide or reduced graphene oxide, and printing a solution in which polymer is melted on a surface of the thin layer composed of the graphene oxide or reduced graphene oxide to dry the resultant object. The bilayer is transferred on the device by lamination process.