Composite-Cell Current Matching in High Efficiency Multijunction Solar Cells

We expand in detail on a new approach to current matching in double junction solar cells that increases the theoretical maximum efficiencies attainable for many bandgap pairs. In this approach, either or both cell types are repeated one or more times, which provides for improved current matching and 2-terminal operation for a wide variety of bandgap pairs, opening up the opportunity to utilize materials not previously considered. While a multijunction design in which the bandgap of every cell is fully optimized will have higher efficiency, this approach achieves simplicity and potential cost savings by only using two cell types.