Shedding Light on the Moisture Stability of 3D/2D Hybrid Perovskite Heterojunction Thin Films
Shedding Light on the Moisture Stability of 3D/2D Hybrid Perovskite Heterojunction Thin Films
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DOI：
10.1021/acsaem.9b00005
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发表时间：
2019-02
影响因子：
6.4
通讯作者：
Johannes Schlipf;Yinghong Hu;Shambhavi Pratap;Lorenz Bießmann;Nuri Hohn;L. Porcar;T. Bein;P. Docampo;P. Müller‐Buschbaum
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作者：
Johannes Schlipf;Yinghong Hu;Shambhavi Pratap;Lorenz Bießmann;Nuri Hohn;L. Porcar;T. Bein;P. Docampo;P. Müller‐Buschbaum
为了提高复合钙钛矿光伏电池的湿度稳定性，通常采用三维(3D)和薄层二维(2D)钙钛矿长链有机阳离子相结合的方式作为光吸收材料。然而，水与3D/2D钙钛矿异质结之间的详细相互作用还没有被阐明。利用原位中子和X射线散射技术，我们发现，尽管存在疏水的大体积阳离子，3D/2D钙钛矿薄膜仍具有惊人的强吸水能力。结果表明，在湿度下，甲基碘化铅(MAPI)/2D薄膜的初始2D相(层数，m=5)迅速歧化为低m相。然而，2D钙钛矿抑制了PbI2的不可逆形成，这表明抑制I-和MA+离子的迁移，从而抑制MAI逃逸与提高MAPI/2D钙钛矿薄膜的水分稳定性有关。相比之下，包括Rb+在内的四阳离子钙钛矿型钙钛矿表现出较好的稳定性。
To increase the moisture stability of hybrid perovskite photovoltaics, a combination of three-dimensional (3D) and a thin layer of two-dimensional (2D) perovskite incorporating long-chained organic cations is often employed as photoabsorber. However, the detailed interaction between water and 3D/2D perovskite heterojunctions has not been elucidated yet. Using in situ neutron and X-ray scattering techniques, we reveal surprisingly strong water uptake into 3D/2D perovskite films despite the presence of hydrophobic bulky cations. Our results show rapid disproportionation of the initial 2D phase (number of layers, m = 5) in methylammonium lead iodide (MAPI)/2D films into lower m phases under humidity. Nevertheless, the 2D perovskite inhibits the irreversible PbI2 formation, which suggests that the suppression of I– and MA+ ion migration and consequently of MAI escape is related to the improved moisture stability of MAPI/2D perovskite films. In comparison, quadruple-cation perovskites including Rb+ exhibit poo...