| 主权项 |
1. A multijunction solar cell comprising:
an upper first solar subcell having a first band gap of 1.9 eV; a second solar subcell adjacent to said upper first solar subcell and having a second band gap of 1.41 eV; a first graded interlayer adjacent to said second solar subcell, said first graded interlayer having a third band gap greater than said second band gap and that is constant at 1.6 eV±3% throughout the thickness of the first graded interlayer; and a third solar subcell adjacent to said first graded interlayer, said third solar subcell having a fourth band gap of 1.02 eV, wherein said third solar subcell is lattice mismatched with respect to said second solar subcell; a second graded interlayer adjacent to said third solar subcell, said second graded interlayer having a fifth band gap greater than said fourth band gap and that is constant at approximately 1.1 eV throughout the thickness of the second graded interlayer; and a lower fourth solar subcell adjacent to said second graded interlayer, said lower fourth solar subcell having a sixth band gap of 0.67 eV wherein said fourth solar subcell is lattice mismatched with respect to said third solar subcell; wherein each of the first and second graded interlayers is composed, respectively, of a compositionally step-graded series of (InxGa1-x)yAl1-yAs layers with monotonically changing lattice constant, with x and y selected such that the band gap of each interlayer remains constant throughout its thickness, and wherein 0<x<1 and 0<y<1. |
