NOVELTY - Encapsulation barrier stack comprises a multilayer film that comprises: at least one barrier layer having low moisture and/or oxygen permeability; and at least one sealing layer arranged to be in contact with a surface of the barrier layer, thus covering and/or plugging defects present in the barrier layer. The sealing layer(s) comprise(s) many dendrimer encapsulated nanoparticles, where the nanoparticles are reactive in that they are capable of interacting with moisture and/or oxygen to retard the permeation of moisture and/or oxygen.    USE - The encapsulation barrier stack is useful: for encapsulating a moisture and/or oxygen sensitive article comprising an electroluminescent electronic component or a solar device; in an electronic module comprising an electronic device that is sensitive to moisture and/or oxygen, where the electronic device is an organic light emitting device, a charge-coupled device, a LCD, a solar cell, a thin-film battery, an organic thin film transistor, an organic integrated circuit, an organic sensor, or a micro-electromechanical sensor; and for encapsulating an electronic device, or for food packaging, pharmaceutical packaging or medical packaging. The dendrimer encapsulated reactive nanoparticles are useful for preparing a sealing layer of a barrier stack, where the nanoparticles are reactive in that they are capable of interacting with moisture and/or oxygen to retard the permeation of moisture and/or oxygen through the defects present in the barrier layer (all claimed).    ADVANTAGE - The encapsulation barrier stack: is adapted to be arranged on a substrate, where the substrate is flexible or rigid; and has a water vapor permeation rate of less than 10-3 g/m2/day, preferably less than 10-6 g/m2/day. The sealing layers provide moisture and oxygen barrier properties and at least one property consisting of a UV filter property, an anti-reflection property, a light extraction property and an anti-static property.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) an electronic module comprising an electronic device that is sensitive to moisture and/or oxygen, where the electronic device is arranged within the encapsulation barrier stack; and    (2) manufacturing the encapsulation barrier stack comprising providing the barrier layers, and forming the sealing layers, where forming the sealing layers comprises mixing an encapsulation material consisting of or comprising of dendrimers or their precursors, or dendrons or their precursors, optionally in the presence of a polymerizable compound and/or a crosslinkable compound, with many nanoparticles to form a sealing mixture, and applying the sealing mixture onto the barrier layer under conditions that allow the nanoparticles to be encapsulated by or in the dendrimers, to form the sealing layer.