Sn‐based perovskites have emerged as one of the most promising environmentally‐friendly photovoltaic materials. Nonetheless, the low‐cost production and stable operation of Sn‐based perovskite solar cells (PSCs) are still limited by the costly hole transport layer (HTL) and the under‐optimized interfacial carrier dynamics. Here, we innovatively developed a halogen radical chemical bridging strategy that enabled to remove the HTL and optimize the perovskite‐substrate heterointerface for constructing high‐performance, simplified Sn‐based PSCs. The modification of ITO electrode by highly active chlorine radicals could effectively mitigate the surface oxygen vacancies, alter the chemical constitutions, and favorably down‐shifted the work function of ITO surface to be close to the valence band of perovskites. As a result, the interfacial energy barrier was reduced by 0.20 eV and the carrier dynamics were optimized at the ITO/perovskite heterointerface. Encouragingly, the efficiency of HTL‐free Sn‐based PSCs was enhanced from 6.79% to 14.20%, representing the record performance for the Sn perovskite photovoltaics in the absence of HTL. Notably, the target device exhibited enhanced stability for 2000 h. The Cl‐RCB strategy is also versatile to construct Pb‐based and mixed Sn‐Pb HTL‐free PSCs, achieving efficiencies of 22.27% and 21.13%, respectively, all representing the advanced device performances for the carrier transport layer‐free PSCs.

中文翻译：

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卤素自由基激活钙钛矿衬底埋地异质界面，实现无空穴传输层的锡基太阳能电池，效率超过 14%


Sn 基钙钛矿已成为最有前途的环保光伏材料之一。尽管如此，Sn 基钙钛矿太阳能电池 （PSC） 的低成本生产和稳定运行仍然受到昂贵的空穴传输层 （HTL） 和未优化的界面载流子动力学的限制。在这里，我们创新地开发了一种卤素自由基化学桥接策略，能够去除 HTL 并优化钙钛矿-衬底异质界面，以构建高性能、简化的基于 Sn 的 PSC。高活性氯自由基对 ITO 电极的改性可以有效缓解表面氧空位，改变化学组成，并有利地将 ITO 表面的功函数下移到接近钙钛矿的价带。结果，界面能垒降低了 0.20 eV，并且 ITO/钙钛矿异质界面的载流子动力学得到了优化。令人鼓舞的是，不含 HTL 的 Sn 基 PSC 的效率从 6.79% 提高到 14.20%，这代表了在没有 HTL 的情况下 Sn 钙钛矿光伏的创纪录性能。值得注意的是，目标装置在 2000 小时内表现出增强的稳定性。Cl-RCB 策略也可用于构建基于 Pb 和混合的 Sn-Pb HTL 无 PSC，效率分别为 22.27% 和 21.13%，所有这些都代表了无载流子传递层 PSC 的先进器件性能。