Herein it is demonstrated that, under conditions relevant to perovskite synthesis (>140 °C in air), fluoride can topochemically react across the interface between a halide perovskite and a fluoropolymer when in close contact, thereby creating a small quantity of strongly bonded lead fluoride species. The quantity increases with temperature and processing duration. Photoinduced charge carrier lifetime provides a metric for the resulting changes in electronic structure of the perovskite. Under short-duration and/or moderate temperature processing, fluoride transfer to the perovskite yields increased carrier lifetimes, up to 3-fold longer than control samples, which is attributed to passivation of surface defects. Under more forcing conditions, the trend reverses: excessive fluoridation leads to shortened carrier lifetimes, which is ascribed to substantial interfacial formation of PbF₂. It is demonstrated that an interface with bulk crystalline PbF₂ quenches perovskite photoluminescence, likely due to PbF₂ serving as an electron acceptor for the conduction band of MAPbI₃.

中文翻译：

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含氟聚合物对 MAPbI3 的界面拓扑氟化

本文证明，在与钙钛矿合成相关的条件下（空气中 > 140 °C），当紧密接触时，氟化物可以在卤化物钙钛矿和含氟聚合物之间的界面上发生局部化学反应，从而产生少量强键合的氟化铅物种。数量随着温度和加工持续时间而增加。光致载流子寿命为钙钛矿电子结构的最终变化提供了一个度量标准。在短时间和/或中等温度处理下，氟化物转移到钙钛矿会增加载流子寿命，比对照样品长 3 倍，这归因于表面缺陷的钝化。在更多的强迫条件下，趋势逆转：过度氟化导致载流子寿命缩短，₂ . _{结果表明，与块状结晶 PbF 2 的}界面会淬灭钙钛矿光致发光，这可能是由于 PbF ₂作为 MAPbI ₃导带的电子受体。