CdSeTe alloying has significantly increased the efficiency of CdTe-based solar technology. Here, computational modeling compares how different CdSeTe bandgrading, carrier lifetimes, band alignment, and carrier concentrations contribute to transport, recombination, and performance. We find that the gain in photocurrent caused by bandgap narrowing alone is insufficient to describe experimental efficiency gains. Performance can be increased by adjusting CdSeTe compositions and bandgrading depths. However, these performance gains are small relative to the contributions of enhanced lifetime by Se alloying, which can explain record cell efficiency gains with minimal open-circuit voltage loss despite significant bandgap narrowing. Similarly, CdSeTe band alignment shifts can significantly increase performance if front interface recombination is prevalent. For a wide range of CdSeTe grading profiles, the hole density is a critical component to achieve efficiencies exceeding 25%.

中文翻译：

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能带分级、寿命、能带排列和载流子浓度在高效 CdSeTe 太阳能电池中的作用

CdSeTe 合金化显着提高了基于 CdTe 的太阳能技术的效率。在这里，计算建模比较了不同的 CdSeTe 能带分级、载流子寿命、能带对齐和载流子浓度对传输、重组和性能的影响。我们发现仅由带隙变窄引起的光电流增益不足以描述实验效率增益。可以通过调整 CdSeTe 成分和带级深度来提高性能。然而，相对于硒合金化延长寿命的贡献而言，这些性能提升很小，这可以解释尽管带隙显着变窄，但开路电压损失最小的电池效率提升。类似地，如果前端界面重组很普遍，CdSeTe 带对齐偏移可以显着提高性能。