NOVELTY - An assembly (100) comprises: a pressure sensitive adhesive layer (110) at least 0.25 mm in thickness disposed on a barrier assembly, where the barrier assembly comprises a polymeric film substrate (130) and a barrier film (120), and where the assembly is flexible and transmissive to visible and infrared light.    USE - The assembly, and methods are useful for making a photovoltaic module; and for making a pressure sensitive adhesive (claimed), and for protecting solar cells.    ADVANTAGE - The assembly flexible and transmissive to visible and infrared light, and highly cost-effective.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) a method of making the assembly, comprising: providing the barrier assembly comprising the polymeric film substrate and the barrier film; extruding the pressure sensitive adhesive by solvent-less extrusion; and applying the pressure sensitive adhesive to the barrier assembly;    (2) a method of making a photovoltaic module, comprising: applying the assembly to the front surface of a photovoltaic cell;    (3) a pressure sensitive adhesive comprising: a polyisobutylene having a weight average molecular weight less than 300000 g/mole; and a hydrogenated hydrocarbon tackifier, where the pressure sensitive adhesive is in the form of a film at least 0.25 mm thick; and    (4) a method of making a pressure sensitive adhesive, comprising: hot melt extruding an extrudable composition comprising a polyisobutylene having a weight average molecular weight of at least 500000 g/mole and a hydrogenated hydrocarbon tackifier, where the hot melt extruding is carried out at a temperature sufficient to decrease the weight average molecular weight of the polyisobutylene resin to less than 300000 g/mole such that a pressure sensitive adhesive comprising a hydrogenated hydrocarbon tackifier and a polyisobutylene resin having a weight average molecular weight less than 300000 g/mole is formed.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic side view of an assembly.    Assembly (100)    Pressure sensitive adhesive layer (110)    Barrier film (120)    Polymeric film substrate (130)