NOVELTY - The layered component (11) for encapsulating a component sensitive to air and/or moisture, comprises a polymer layer and a barrier layer on one side of the polymer layer. Each barrier layer comprises a stack (2, 4, 5, 6, 7) of two thin layers of hydrogenated silicon nitride having alternating low and high densities, and a junction area at the interface between a first layer and a second layer of each pair of successive thin layers of the constituting stack. The junction area has a density gradient between the density of the first layer and the density of the second layer.    USE - The layered component is useful for encapsulating a device comprising a component sensitive to air and/or moisture such as collector or emitter component including a photovoltaic cell or an organic LED (claimed).    ADVANTAGE - The layered component is lightweight and flexible and highly sensitive to environmental conditions thus avoiding the degradation of collector or emitter component and providing enhanced protection and high energy conversion efficiency to the photovoltaic cell and organic LED, and prevents the migration of pollutants to the energy conversion elements.    DETAILED DESCRIPTION - The layered component (11) for encapsulating a component sensitive to air and/or moisture, comprises a polymer layer and a barrier layer on one side of the polymer layer. Each barrier layer comprises a stack (2, 4, 5, 6, 7) of two thin layers of hydrogenated silicon nitride having alternating low and high densities, and a junction area at the interface between a first layer and a second layer of each pair of successive thin layers of the constituting stack. The junction area has a density gradient between the density of the first layer and the density of the second layer. A difference between the densities of a high density layer and a low density layer of each pair of thin layers of the stack is greater than or equal to 10% of the density of the low density layer. The barrier layer is either directed towards or away from the collector or emitter element. The polymer layer is a thermoplastic polymer substrate that comprises the barrier layer on one of its sides, and a laminating interlayer that comprises the barrier layer opposite to one of its sides. The polymer layer and the barrier layer are transparent to each other. A geometric thickness of each thin layer of the stack is adapted to maximize the light transmission towards or up to the sensing element through the layered component by an antireflective effect. Each barrier layer comprises superposition of a thin layer of hydrogenated silicon nitride having a refraction index of 1.8-1.9 at 550 nm and a thin layer of hydrogenated silicon nitride having a refraction index of 1.7-1.8 at 550 nm. An INDEPENDENT CLAIM is included for a process for fabrication of a layered component.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of a photovoltaic module.    Front substrate (1)    Stack of layers (2, 4, 5, 6, 7)    Rear substrate (8)    Layered component (11)    Photovoltaic cell. (12)