Today’s dominant photovoltaic technologies rely on single-junction devices, which are approaching their practical efficiency limit of 25–27%. Therefore, researchers are increasingly turning to multi-junction devices, which consist of two or more stacked subcells, each absorbing a different part of the solar spectrum. Here, we show that dual-junction III–V//Sidevices with mechanically stacked, independently operated III–V and Si cells reach cumulative one-sun efficiencies up to 32.8%. Efficiencies up to 35.9% were achieved when combining a GaInP/GaAs dual-junction cell with a Si single-junction cell. These efficiencies exceed both the theoretical 29.4% efficiency limit of conventional Si technology and the efficiency of the record III–V dual-junction device (32.6%), highlighting the potential of Si-based multi-junction solar cells. However, techno-economic analysis reveals an order-of-magnitude disparity between the costs for III–V//Si tandem cells and conventional Si solar cells, which can be reduced if research advances in low-cost III–V growth techniques and new substrate materials are successful.

当今占主导地位的光伏技术依赖于单结器件，其接近其实际效率极限25-27％。因此，研究人员越来越多地转向由两个或更多堆叠的子电池组成的多结器件，每个子电池吸收太阳光谱的不同部分。在这里，我们显示具有机械堆叠，独立操作的III-V和Si电池的双结III–V // Si器件达到的累计单太阳效率高达32.8％。当将GaInP / GaAs双结电池与Si单结电池结合使用时，效率最高可达到35.9％。这些效率超过了常规硅技术的理论上29.4％的效率极限和创纪录的III–V双结器件（32.6％）的效率，突出了基于硅的多结太阳能电池的潜力。然而，