Abstract: The present disclosure is directed toward a thin film photovoltaic cell including a support substrate; a contact layer disposed adjacent a first side of the substrate; a p-type semiconductor layer disposed on the first side of the substrate; an n-type semiconductor layer disposed on the first side of the substrate; and a protective back side layer structure disposed adjacent a second side of the substrate, wherein the protective back side layer structure may include a corrosion resistant material. In some embodiments, the back side layer includes at least a first layer and a second layer. Additionally and/or alternatively, the back side layer may include a molybdenum alloy, wherein the molybdenum alloy may include an alloy partner selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Al, and Si.