Narrow-bandgap (NBG) mixed tin/lead-based (Sn-Pb) perovskite solar cells (PSCs) have attracted extensive attention for use in tandem solar cells. However, they are still plagued by serious carrier recombination due to inferior film properties resulting from the alloying of Sn with Pb elements, which leads to p-type self-doping behaviors. This work reports an effective tin oxide (SnO_x) doping strategy to produce high-quality Sn-Pb perovskite films for utilization in efficient single-junction and tandem PSCs. SnO_x can be naturally oxidized from tin diiodide raw powders and successfully incorporated into Sn-Pb perovskite films. Consequently, Sn-Pb perovskite films doped with SnO_x exhibit dramatically improved morphology, crystallization, absorption, and more interestingly, upward-shifted Fermi levels. The resulting narrow-bandgap Sn-Pb PSCs with natural SnO_x doping have considerably reduced carrier recombination, therefore delivering a maximum power conversion efficiency (PCE) of 22.16% for single-junction cells and a remarkable PCE of 26.01% (with a steady-state efficiency of 25.33%) for two-terminal all-perovskite tandem cells. This work introduces a facile doping strategy for the manufacture of efficient single-junction narrow-bandgap PSCs and their tandem solar cells.

中文翻译：

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通过天然氧化锡掺杂的高效窄带隙混合锡铅钙钛矿太阳能电池

窄带隙（NBG）混合锡/铅基（Sn-Pb）钙钛矿太阳能电池（PSC）在串联太阳能电池中的应用引起了广泛的关注。然而，由于Sn与Pb元素的合金化导致p型自掺杂行为导致薄膜性能较差，因此它们仍然受到严重的载流子复合的困扰。这项工作报告了一种有效的氧化锡 (SnO _x ) 掺杂策略，可生产高质量的 Sn-Pb 钙钛矿薄膜，用于高效的单结和串联 PSC。SnO _x可以从二碘化锡原料粉末中自然氧化，并成功地融入 Sn-Pb 钙钛矿薄膜中。因此，掺杂 SnO _x的 Sn-Pb 钙钛矿薄膜表现出显着改善的形态、结晶、吸收，更有趣的是，费米能级向上移动。_{由此产生的具有天然 SnO x}掺杂的窄带隙 Sn-Pb PSC显着减少了载流子复合，因此单结电池的最大功率转换效率 (PCE) 为 22.16%，PCE 高达 26.01%（稳定的 PCE）。两端全钙钛矿串联电池的状态效率为25.33%。这项工作介绍了一种用于制造高效单结窄带隙 PSC 及其串联太阳能电池的简便掺杂策略。