The organic–inorganic halide perovskite solar cells (PSCs) are rapidly developed in just a few years due to its high power conversion efficiency. However, it still faces some critical issues, one of which is the presence of toxic lead (Pb²⁺). Recent researches show that barium (Ba²⁺) can partially replace the Pb²⁺ in perovskite structure and achieve a promising device performance because of its adequate ionic radius. However, the optimal replacement amount of Ba²⁺ in perovskite is still limited. Herein, the methylammonium (MA)/formamidinium (FA) mixed‐cation perovskite is used as the active layer in PSCs and Pb²⁺ is partially substituted with Ba²⁺. Compared with the pure MA system, the best device efficiency can be achieved using higher Ba²⁺ replacement ratio. In addition, while introducing the appropriate polymer additive, the replacement ratio can be further increased without compromise of device efficiency. Using polyethylene glycol as polymer additive, 10.0 mol% Ba‐doped MA/FA mixed‐cation PSC with an efficiency of 16.1% can be realized. It is believed that this report provides an effective strategy to fabricate high‐performance lead‐reduced PSCs.

中文翻译：

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高性能铅还原钙钛矿太阳能电池中用于形态控制的聚合物添加剂

由于其高功率转换效率，有机-无机卤化物钙钛矿太阳能电池（PSC）在短短几年内得到了快速发展。但是，它仍然面临一些关键问题，其中之一就是有毒铅（Pb ²⁺）的存在。最近的研究表明，钡（Ba ²⁺）可以部分取代钙钛矿结构中的Pb ²⁺并由于其足够的离子半径而具有良好的器件性能。但是，钙钛矿中Ba ²⁺的最佳置换量仍然有限。在本文中，甲基铵（MA）/甲din（FA）混合阳离子钙钛矿用作PSC中的活性层，Pb ²⁺被Ba ²⁺部分取代。与纯MA系统相比，使用更高的Ba ²⁺替代率可以实现最佳的器件效率。另外，在引入适当的聚合物添加剂的同时，可以在不损害装置效率的情况下进一步提高替换率。使用聚乙二醇作为聚合物添加剂，可以实现效率为16.1％的10.0 mol％的Ba掺杂的MA / FA混合阳离子PSC。相信该报告提供了一种制造高性能，铅含量降低的PSC的有效策略。