The performance of a tandem solar cell depends on the performance of its constituting subcells. Although this dependency is theoretically straightforward for open-circuit voltage (V_oc) and short-circuit current, it is indirect for fill factor (FF) and thus for efficiency. We study here with simple simulations the effect on the tandem performance of each subcell FF by varying systematically their series resistance, parallel resistance, and local defect. We demonstrate that series resistance impacts strongly FF for single-junction devices but marginally for tandem devices, the opposite holding for parallel resistances (shunting). We show that localized defects will be most stringent to the tandem device when they occur in the current-limiting subcell. There is thus no obvious correlation between FFs of a tandem device and of its subcells. Finally, we compare two bottom-cell designs and highlight the importance of using a high-V_oc bottom cell to reach high tandem efficiencies.

中文翻译：

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子电池性能对钙钛矿-硅串联太阳能电池两末端填充因子的影响

串联太阳能电池的性能取决于其组成子电池的性能。尽管在理论上对于开路电压（V _oc）和短路电流，它对于填充因数（FF）是间接的，因此对效率而言是间接的。我们在这里通过简单的模拟研究，通过系统地改变其串联电阻，并联电阻和局部缺陷，对每个子电池FF的串联性能的影响。我们证明，串联电阻对单结器件的FF影响很大，而对串联器件的影响很小，而并联电阻（并联）的保持相反。我们表明，当局部缺陷出现在限流子电池中时，它们将对串联装置最严格。因此，串联设备及其子单元的FF之间没有明显的相关性。最后，我们比较了两种底部电池设计，并强调了使用高V _oc底部电池达到高串联效率的重要性。