Abstract: A method of manufacturing a multijunction solar cell having an upper first solar subcell composed of a semiconductor material having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; a graded interlayer adjacent to the third solar subcell; and a fourth solar subcell adjacent to said graded interlayer and composed of a semiconductor material having a fourth band gap smaller than the third band gap and being lattice mismatched with respect to the third solar subcell; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.