Patent ID: 9634172
Date: 2017-04-25
CPC Classifications: H01L,Y02E,Y02P

Claim:
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 (In