An encapsulation barrier stack (100, 140, 160) capable of encapsulating a moisture and/or oxygen sensitive article, comprising: a multilayer film (102, 142, 1621, 1622, 212, 222) to be arranged on a substrate (141, 161, 201), said multilayer film (102, 142, 1621, 1622, 212, 222) having at least one barrier layer (103, 143, 163, 203) having low moisture and/or oxygen permeability, and at least one sealing layer (105, 145, 165, 205) arranged to be in contact with a surface of the at least one barrier layer (103, 143, 163, 203), thereby plugging defects (107, 207) present in the barrier layer (103, 143, 163, 203), wherein the at least one sealing layer (105, 145, 165, 205) comprises reactive nanoparticles distributed therein, the reactive nanoparticles comprising nanoparticles which are capable of interacting by way of chemical reaction with moisture and/or oxygen to retard the permeation of moisture and/or oxygen through the defects (107, 207) present in the barrier layer (103, 143, 163, 203); wherein the at least one sealing layer (105, 145, 165, 205) is formed by conformal deposition, wherein the reactive nanoparticles present in the at least one sealing layer (105, 145, 165, 205) plug defects (107, 207) present in the at least one barrier layer (103, 143, 163, 203) by at least partially filling the defects; characterized in that the reactive nanoparticles further comprise carbon nanotubes which are capable of interacting by way of physical interaction with moisture and/or oxygen to retard the permeation of moisture and/or oxygen through the defects (107, 207), and the amount of carbon nanotubes present is about 0.01% to about 10% of the total weight of the reactive nanoparticles present in the sealing layer (105, 145, 165, 205). a multilayer film (102, 142, 1621, 1622, 212, 222) to be arranged on a substrate (141, 161, 201), said multilayer film (102, 142, 1621, 1622, 212, 222) having at least one barrier layer (103, 143, 163, 203) having low moisture and/or oxygen permeability, and at least one sealing layer (105, 145, 165, 205) arranged to be in contact with a surface of the at least one barrier layer (103, 143, 163, 203), thereby plugging defects (107, 207) present in the barrier layer (103, 143, 163, 203), wherein the at least one sealing layer (105, 145, 165, 205) comprises reactive nanoparticles distributed therein, the reactive nanoparticles comprising nanoparticles which are capable of interacting by way of chemical reaction with moisture and/or oxygen to retard the permeation of moisture and/or oxygen through the defects (107, 207) present in the barrier layer (103, 143, 163, 203); wherein the at least one sealing layer (105, 145, 165, 205) is formed by conformal deposition, wherein the reactive nanoparticles present in the at least one sealing layer (105, 145, 165, 205) plug defects (107, 207) present in the at least one barrier layer (103, 143, 163, 203) by at least partially filling the defects; characterized in that the reactive nanoparticles further comprise carbon nanotubes which are capable of interacting by way of physical interaction with moisture and/or oxygen to retard the permeation of moisture and/or oxygen through the defects (107, 207), and the amount of carbon nanotubes present is about 0.01% to about 10% of the total weight of the reactive nanoparticles present in the sealing layer (105, 145, 165, 205).