Halide ion mobility in metal halide perovskites plays an important role in dictating the overall device performance and long-term stability of perovskite solar cells. Alloying with chloride (Cl), which is known to stabilize the perovskite solar cells, has now been found to suppress the photoinduced halide ion segregation in mixed halide (Br/I) perovskites. By varying the chloride concentration of 1–10% (as part of the halide composition), we have probed both photoinduced segregation and dark recovery kinetics at different temperatures. When we increased the concentration of Cl from 0 to 5%, we observed a decrease in the rate constant of segregation by a factor of ∼5 and a decrease in the fraction of halide segregation from 45 to 20%. The activation energy for photoinduced halide segregation increases (∼4 kJ/mol) upon the introduction of chloride into the mixed halide film, reflecting an increased energetic barrier for halide ion migration.

中文翻译：

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氯化物如何抑制混合卤化物钙钛矿中的光致相分离

金属卤化物钙钛矿中卤离子的迁移率在决定钙钛矿太阳能电池的整体器件性能和长期稳定性方面起着重要作用。现已发现，与氯化物（Cl）合金化可稳定钙钛矿太阳能电池，现已发现它可抑制混合卤化物（Br / I）钙钛矿中的光致卤化物离子偏析。通过改变1-10％的氯化物浓度（作为卤化物成分的一部分），我们探索了在不同温度下的光致偏析和暗恢复动力学。当我们将Cl的浓度从0增加到5％时，我们观察到偏析的速率常数降低了约5倍，而卤化物的偏析比例则从45％降低到20％。