Photo-induced halide redistribution in organic-inorganic perovskite films.
Photo-induced halide redistribution in organic-inorganic perovskite films.
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DOI：
10.1038/ncomms11683
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发表时间：
2016-05-24
影响因子：
16.6
通讯作者：
Stranks SD
中科院分区：
文献类型：
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作者：
deQuilettes DW;Zhang W;Burlakov VM;Graham DJ;Leijtens T;Osherov A;Bulović V;Snaith HJ;Ginger DS;Stranks SD
有机-无机钙钛矿如CH 3 NH3 PbI 3是用于各种光电应用的有前途的材料，在太阳能电池中的认证功率转换效率已经超过21%。然而，最先进的膜仍然包含性能限制的非辐射复合位点，并且在照明下表现出一系列复杂的动态现象，这些现象仍然知之甚少。在这里，我们使用一个独特的共聚焦光致发光（PL）显微镜和化学成像相关联的局部变化，在CH 3 NH3 PbI 3薄膜的组成在照明下的physics。我们表明，光致“增亮”的钙钛矿PL可以归因于陷阱态密度的数量级减少。通过用飞行时间二次离子质谱对相同区域成像，我们将这种光致增亮与碘的净迁移相关联。我们的工作为三碘钙钛矿中的光致卤化物迁移提供了视觉证据，并揭示了电荷载流子种群，电子陷阱和移动的卤化物之间的复杂相互作用，共同影响光电性能。 缺乏在没有接触的钙钛矿膜中光致离子迁移的视觉证据。在这里，作者使用了一个独特的共聚焦光致发光显微镜和化学成像相关联的局部变化，在CH 3 NH3 PbI 3薄膜的组成在照明下的physics。
Organic–inorganic perovskites such as CH3NH3PbI3 are promising materials for a variety of optoelectronic applications, with certified power conversion efficiencies in solar cells already exceeding 21%. Nevertheless, state-of-the-art films still contain performance-limiting non-radiative recombination sites and exhibit a range of complex dynamic phenomena under illumination that remain poorly understood. Here we use a unique combination of confocal photoluminescence (PL) microscopy and chemical imaging to correlate the local changes in photophysics with composition in CH3NH3PbI3 films under illumination. We demonstrate that the photo-induced ‘brightening' of the perovskite PL can be attributed to an order-of-magnitude reduction in trap state density. By imaging the same regions with time-of-flight secondary-ion-mass spectrometry, we correlate this photobrightening with a net migration of iodine. Our work provides visual evidence for photo-induced halide migration in triiodide perovskites and reveals the complex interplay between charge carrier populations, electronic traps and mobile halides that collectively impact optoelectronic performance. Visual evidence for photo-induced ionic migration in perovskite films without contacts is lacking. Here, the authors use a unique combination of confocal photoluminescence microscopy and chemical imaging to correlate the local changes in photophysics with composition in CH3NH3PbI3 films under illumination.