Current-Matched III–V/Si Epitaxial Tandem Solar Cells with 25.0% Efficiency
Current-Matched III–V/Si Epitaxial Tandem Solar Cells with 25.0% Efficiency
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DOI：
10.1016/j.xcrp.2020.100208
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发表时间：
2020-09
期刊：
影响因子：
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通讯作者：
S. Fan;Zhengshan J. Yu;R. Hool;P. Dhingra;W. Weigand;Mijung Kim;E. D. Ratta;Brian D. Li;Yukun Sun;Z. Holman;M. Lee
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文献类型：
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作者：
S. Fan;Zhengshan J. Yu;R. Hool;P. Dhingra;W. Weigand;Mijung Kim;E. D. Ratta;Brian D. Li;Yukun Sun;Z. Holman;M. Lee
III-V/Si外延串联与1.7-eV的GaAsP顶部电池保证稳定的功率转换效率高于Si单结电池的基本限制。然而，III-V/Si外延串联受到顶部电池中有限的少数载流子扩散长度的影响，导致短路电流密度（JSC）和效率降低。虽然传统的智慧规定，在III-V/Si串联的位错密度必须降低，以提高效率，在这里，我们表明，异质界面的设计和生长顺序也发挥关键作用，在减少复合损失。我们改进的GaAsP电池利用宽带隙AlGaAsP电子阻挡层，与GaAsP形成原始界面，在临界红色波长范围（600-725 nm）内，量子效率比以前的工作提高10%-20%（绝对），尽管位错密度相似。结合改进的顶部电池的载流子收集与Si背面纹理，我们得到25.0%的效率GaAsP/Si串联电池与紧密匹配的JSCof18.8mA/cm 2。
III–V/Si epitaxial tandems with a 1.7-eV GaAsP top cell promise stable power conversion efficiencies above the fundamental limit of Si single-junction cells. However, III–V/Si epitaxial tandems have suffered from limited minority carrier diffusion length in the top cell, leading to reduced short-circuit current densities (JSC) and efficiencies. While conventional wisdom dictates that dislocation density in III–V/Si tandems must be reduced to boost efficiency, here, we show that heterointerface design and growth sequence also play critical roles in reducing recombination losses. Our improved GaAsP cells make use of a wide-band gap AlGaAsP electron-blocking layer that forms a pristine interface with GaAsP, resulting in a 10%–20% (absolute) boost in quantum efficiency over previous work in the critical red wavelength range (600–725 nm), despite similar dislocation density. Combining the improved top cell carrier collection with Si backside texturing, we obtain 25.0% efficient GaAsP/Si tandem cells with a closely matched JSCof 18.8 mA/cm2.