Raising the one-sun conversion efficiency of III–V/Si solar cells to 32.8% for two junctions and 35.9% for three junctions

To improve the efficiency of photovoltaic devices while keeping the same spatial footprint, solar cells can be stacked on top of each other. Here, Essig et al. fabricate very efficient dual-junction and triple-junction solar cells by placing one or two III–V solar cells on top of a silicon solar cell.