The use of different Sn valence states (such as Sn⁴⁺ and Sn²⁺) in the Cu₂ZnSn(S,Se)₄ (CZTSSe) precursor solution is especially important for the quality of the subsequent growth of the CZTSSe films. The latest study has found that replacing SnCl₂·2H₂O with anhydrous SnCl₄ can remarkably improve the performance of CZTSSe solar cells, but it needs to be operated in the glovebox. Herein, for the precursor solution, SnCl₄·5H₂O powder is used instead of anhydrous SnCl₄ in air environment, and the proportion of Sn⁴⁺ and Sn²⁺ precursor solutions is further systematically studied. When the ratio of Sn⁴⁺ to Sn²⁺ is 1:1, a uniform, compact, and noncracking CZTSSe thin film is obtained, effectively alleviating the interface recombination and reducing the concentration of deep-level defects. In particular, the concentration of Cu_Zn antisite defects is decreased by an order of magnitude, and the carrier recombination and band tail effect are alleviated. When J_SC is maintained, V_OC and FF are considerably improved. Finally, CZTSSe thin-film solar cells are fabricated with an efficiency of over 11%. Herein, the feasibility of controlling the ratio of Sn⁴⁺ to Sn²⁺ in the CZTSSe precursor solution for higher efficiency of CZTSSe thin-film solar cells is demonstrated.

中文翻译：

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通过空气环境优化高效太阳能电池的 Cu2ZnSn(S,Se)4 前驱体溶液中 Sn4+ 和 Sn2+ 的比例

在 Cu ₂ ZnSn(S,Se) ₄ (CZTSSe) 前驱体溶液中使用不同的 Sn 价态（例如 Sn ⁴⁺和 Sn ²⁺）对于 CZTSSe 膜的后续生长质量尤其重要。最新研究发现，用无水SnCl ₄代替SnCl ₂ ·2H ₂ O可以显着提高CZTSSe太阳能电池的性能，但需要在手套箱中操作。这里，对于前驱体溶液，在空气环境中使用SnCl ₄ ·5H ₂ O粉末代替无水SnCl ₄，Sn ⁴⁺和Sn ²⁺的比例进一步系统地研究了前体溶液。当Sn ⁴⁺与Sn ²⁺的比例为1:1时，可以获得均匀、致密、不开裂的CZTSSe薄膜，有效缓解界面复合，降低深能级缺陷浓度。特别是Cu _Zn反位缺陷的浓度降低了一个数量级，并且减轻了载流子复合和带尾效应。当Ĵ _SC被保持，V _OC和FF被大幅度地改善。最后，以超过 11% 的效率制造了 CZTSSe 薄膜太阳能电池。在此，控制Sn ⁴⁺与Sn ²⁺比例的可行性 在 CZTSSe 前驱体溶液中证明了 CZTSSe 薄膜太阳能电池的更高效率。