The present invention provides a solar cell module comprising a terionomer containing film or sheet, wherein the terionomer is derived from an acid terpolymer that comprises copolymerized units derived an α-olefin, about 15 to about 30 wt % of an α,β-ethylenically unsaturated carboxylic acid having 3 to 8 carbons, and about 0.5 to about 40 wt % of an α,β-ethylenically unsaturated carboxylic acid ester having 4 to 12 carbons, based on the total weight of the acid terpolymer, and is about 5% to about 90% neutralized with one or more metal ions, based on the total carboxylic acid content of the acid terpolymer.