A composite stack may include a first substrate layer, a functional layer that includes silver, a first blocker layer that includes a corrosion resistant material and a second blocker layer that includes a blocker material selected from any one of Ti, Ni, Cr, Cu, Al, Mg, NiCr, or alloys thereof. The second blocker layer may be adjacent to the first blocker layer. The composite stack may further have a VLT of at least about 50% and a TSER of at least about 30%. The composite stack may also or in the alternative have an emissivity of not greater than about 20%.