Development of highly-efficient GaInP/Si Tandem Solar Cells
inproceedings
2015
authors Essig, S. and Geisz, J. F. and Steiner, M. A. and Merkle, A. and Peibst, R. and Schmidt, J. and Brendel, R. and Ward, S. and Friedman, D. J. and Stradins, P. and Young, D. L.
Dual-junction solar cells consisting of rear-heterojunction GaInP top cells and back-junction, back-contacted crystalline Si bottom cells were fabricated and characterized. Our calculations show that theoretical efficiencies up to 38.9% can be achieved with Si-based tandem devices. In our experiments, the two subcells were fabricated separately and stacked with an index matching fluid. In contrast to conventional mechanically stacked solar cells, that contain two metal grids at the interface, our concept includes a fully back contacted bottom cell which reduces the shadow losses in the device. A 1-sun AM1.5g cumulative efficiency of (26.2 ± 0.6)% has been achieved with this novel GaInP/Si 4-terminal tandem solar cell.