Failure analysis of thin-film four-junction inverted metamorphic solar cells
Failure analysis of thin-film four-junction inverted metamorphic solar cells
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薄膜四结倒置变质太阳能电池失效分析
DOI：
10.1002/pip.3355
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发表时间：
2020-11-22
影响因子：
6.7
通讯作者：
Lu, Shulong
中科院分区：
文献类型：
--
作者：
Long, Junhua;Wu, Dongying;Lu, Shulong
倒置变质型太阳能电池可以根据光谱直接生长不同带隙的叠层串联结，在光伏领域具有重要的应用价值。我们发现，在倒转变质型三结AlGaInP/AlGaAs/InGaAs材料的基础上，禁带宽度为1.96/1.55/1.17/0.83 eV的四结AlGaInP/AlGaAs/InGaAs太阳电池在正常开路电压的情况下，短路电流密度会严重下降。短路电流密度的急剧下降不是由于不匹配的缓冲层位错穿透到InGaAs子单元的有源区，而是由于AlGaInP子单元中的缺陷导致的少数载流子复合所致，这是从透射电子显微镜、外量子效率、电致发光和二次离子质谱仪测量中直接观察到的。金属-有机化学气相沉积生长AlGaInP材料的过程中容易引入Al-O深能级缺陷，导致少数载流子在AlGaInP材料中的收集较差。通过改进AlGaInP材料的生长条件，获得了光电转换效率为34.9%、开路电压为3.53V的四结太阳电池。
Inverted metamorphic solar cells play an important role in the field of photovoltaics, because it can directly grow stacked tandem junctions with different bandgaps according to the spectrum. We have found that the four-junction AlGaInP/AlGaAs/InGaAs/InGaAs solar cells with the bandgap of 1.96/1.55/1.17/0.83 eV on the basis of the inverted metamorphic three-junction AlGaInP/AlGaAs/InGaAs materials will cause a serious decrease in short-circuit current density but with a normal open-circuit voltage. The sharp decrease in short-circuit current density is not attributed to the mismatched buffers dislocations penetrating into the active region of the InGaAs subcells but resulted from the minority carrier recombination due to defects in the AlGaInP subcell, which is observed directly from transmission electron microscopy, external quantum efficiency, electroluminescence, and secondary ion mass spectrometry measurements. The process of growing AlGaInP materials by metal-organic chemical vapor deposition easily introduces Al-O deep-level defects, resulting in the poor collection of minority carriers in AlGaInP materials. After improving the growth conditions of AlGaInP materials, a four-junction solar cell with a photoelectric conversion efficiency of 34.9% and an open-circuit voltage of 3.53 V was obtained.