The disordered distribution of trap states and ion migration limit the commercial application of perovskite solar cells (PSCs). Herein, we apply an oxamic acid potassium salt (OAPS) as a bifunctional additive of perovskite film. The Lewis base group C=O of OAPS can interact with the uncoordinated Pb²⁺ caused by the I site substitution by Pb and the dangling bonds of the perovskite, which is beneficial to reduce the nonradiative recombination loss. In addition, the countercation K⁺ of OAPS is confirmed to occupy the perovskite lattice interstitial sites and result in lattice expansion, inhibiting the formation of iodide Frenkel defects and I^– ion migration. As a result, the synergistic effect achieves enhanced power conversion efficiency (PCE) from 19.98 to 23.02%, with a fill factor reaching up to 81.90% and suppressed current–voltage hysteresis. The device also presents improved stability, maintaining 93% of the initial PCE after 2000 h of storage.

中文翻译：

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钾盐配位诱导离子迁移抑制和缺陷钝化用于高效钙钛矿太阳能电池

陷阱态的无序分布和离子迁移限制了钙钛矿太阳能电池（PSC）的商业应用。在此，我们应用草酸钾盐（OAPS）作为钙钛矿薄膜的双功能添加剂。OAPS的Lewis碱基C=O可以与Pb取代I位引起的不配位Pb ^{2+和钙钛矿的悬空键相互作用，有利于降低非辐射复合损失。}此外，OAPS 的反阳离子 K ⁺被证实占据钙钛矿晶格间隙位并导致晶格膨​​胀，抑制碘化物 Frenkel 缺陷和 I ^-离子迁移。结果，协同效应实现了从 19.98% 提高到 23.02% 的功率转换效率 (PCE)，填充因子高达 81.90%，并抑制了电流-电压滞后。该设备还表现出更高的稳定性，在 2000 小时存储后保持初始 PCE 的 93%。