Multijunction solar cell design is guided by both the theoretical optimal bandgap combination as well as the realistic limitations to materials with these bandgaps. For instance, triple-junction III-V multijunction solar cells commonly use GaAs as a middle cell because of its near-perfect material quality, despite its bandgap being higher than optimal for the global spectrum. Here, we modify the middle cell bandgap using thick GaInAs/GaAsP strain-balanced quantum well (QW) solar cells with excellent voltage and absorption. These high-performance QWs are incorporated into a triple-junction inverted metamorphic multijunction device consisting of a GaInP top cell, GaInAs/GaAsP QW middle cell, and lattice-mismatched GaInAs bottom cell, each of which has been highly optimized. We demonstrate triple-junction efficiencies of 39.5% and 34.2% under the AM1.5 global and AM0 space spectra, respectively, and the global efficiency is higher than previous record six-junction devices.

多结太阳能电池设计受理论最佳带隙组合以及具有这些带隙材料的实际限制的指导。例如，三结 III-V 多结太阳能电池通常使用 GaAs 作为中间电池，因为它具有近乎完美的材料质量，尽管其带隙高于全局光谱的最佳值。在这里，我们使用具有出色电压和吸收能力的厚 GaInAs/GaAsP 应变平衡量子阱 (QW) 太阳能电池来修改中间电池带隙。这些高性能 QW 被整合到一个三结倒变质多结器件中，该器件由 GaInP 顶部电池、GaInAs/GaAsP QW 中间电池和晶格失配 GaInAs 底部电池组成，每一个都经过高度优化。我们在 AM1 下展示了 39.5% 和 34.2% 的三结效率。