A composition includes a chemical reaction product defining a first surface and a second surface, characterized in that the chemical reaction product includes a segregated phase domain structure including a plurality of domain structures, wherein at least one of the plurality of domain structures includes at least one domain that extends from a first surface of the chemical reaction product to a second surface of the chemical reaction product. The segregated phase domain structure includes a segregated phase domain array. The plurality of domain structures includes i) a copper rich. indium/gallium deficient Cu(In,Ga)Se2 domain and ii) a copper deficient, indium/gallium rich Cu(In,Ga)Se2 domain.