Metal halide perovskites are exceptional candidates for inexpensive yet high‐performing optoelectronic devices. Nevertheless, polycrystalline perovskite films are still limited by nonradiative losses due to charge carrier trap states that can be affected by illumination. Here, in situ microphotoluminescence measurements are used to elucidate the impact of light‐soaking individual methylammonium lead iodide grains in high‐quality polycrystalline films while immersing them with different atmospheric environments. It is shown that emission from each grain depends sensitively on both the environment and the nature of the specific grain, i.e., whether it shows good (bright grain) or poor (dark grain) luminescence properties. It is found that the dark grains show substantial rises in emission, while the bright grain emission is steady when illuminated in the presence of oxygen and/or water molecules. The results are explained using density functional theory calculations, which reveal strong adsorption energies of the molecules to the perovskite surfaces. It is also found that oxygen molecules bind particularly strongly to surface iodide vacancies which, in the presence of photoexcited electrons, lead to efficient passivation of the carrier trap states that arise from these vacancies. The work reveals a unique insight into the nature of nonradiative decay and the impact of atmospheric passivation on the microscale properties of perovskite films.

中文翻译：

---

气氛对金属卤化物钙钛矿颗粒局部发光性能的影响

金属卤化物钙钛矿是廉价而高性能的光电器件的最佳选择。然而，由于可能受到光照影响的电荷载流子陷阱状态，多晶钙钛矿薄膜仍然受到非辐射损耗的限制。在这里，使用原位微光致发光测量来阐明将单个甲基铵碘化铅铅晶光浸泡在高质量多晶膜中，同时将其浸入不同的大气环境中的影响。结果表明，每种颗粒的发射都敏感地取决于环境和特定颗粒的性质，即其显示的是良好（明亮的颗粒）还是较差的（深色颗粒）发光特性。发现暗颗粒显示出大量的排放，当在有氧和/或水分子的情况下被照射时，亮颗粒的发射是稳定的。使用密度泛函理论计算解释了该结果，该计算揭示了分子对钙钛矿表面的强大吸附能。还发现，氧分子与表面碘化物空位特别牢固地结合，在存在光激发电子的情况下，其导致由这些空位引起的载流子陷阱态的有效钝化。这项工作揭示了对非辐射衰变的性质以及大气钝化对钙钛矿薄膜微观性质的影响的独特见解。揭示了分子对钙钛矿表面的强大吸附能。还发现，氧分子与表面碘化物空位特别牢固地结合，在存在光激发电子的情况下，其导致由这些空位引起的载流子陷阱态的有效钝化。这项工作揭示了对非辐射衰变的性质以及大气钝化对钙钛矿薄膜微观性质的影响的独特见解。揭示了分子对钙钛矿表面的强大吸附能。还发现，氧分子与表面碘化物空位特别牢固地结合，在存在光激发电子的情况下，其导致由这些空位引起的载流子陷阱态的有效钝化。这项工作揭示了对非辐射衰变的性质以及大气钝化对钙钛矿薄膜微观性质的影响的独特见解。