Scalable fabrication of high-quality crystalline and stable FAPbI3 thin films by combining doctor-blade coating and the cation exchange reaction.
Scalable fabrication of high-quality crystalline and stable FAPbI3 thin films by combining doctor-blade coating and the cation exchange reaction.
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DOI：
10.1039/c8nr10267h
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发表时间：
2019-03
期刊：
影响因子：
6.7
通讯作者：
Sampson Adjokatse;Hong‐Hua Fang;H. Duim;M. Loi
中科院分区：
文献类型：
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作者：
Sampson Adjokatse;Hong‐Hua Fang;H. Duim;M. Loi
甲脒碘化铅（FAPbI 3）是研究最广泛的钙钛矿材料之一，由于其窄的带隙和高的吸收系数，这使得它非常适合于光电应用。含有碘化铅（PbI 2）和碘化甲脒（FAI）的溶液的沉积或PbI 2和FAI的顺序沉积通常导致形成具有差的形态和不稳定的晶体结构的膜，其容易结晶成两种不同的多晶型物：光惰性黄色相和光活性黑色相。在这项工作中，2D 2-苯乙胺碘化铅（PEA 2 PbI 4）薄膜沉积的可扩展的刮刀涂布技术，并作为高品质的3D FAPbI 3钙钛矿薄膜的生长模板，这是通过有机阳离子交换获得。我们报告的结构，形态和光学性质的这些转换的3D FAPbI 3钙钛矿薄膜，我们比较直接沉积的3D FAPbI 3薄膜。与直接沉积的3D薄膜相比，转化的FAPbI 3薄膜是致密的、光滑的和高度取向的，并且表现出更好的结构稳定性。这些结果不仅强调了所采用的沉积技术在制造高度结晶和稳定的钙钛矿薄膜中的重要性，而且还提供了一种使用刮刀涂布容易获得非常致密的钙钛矿层的策略。
Formamidinium lead iodide (FAPbI3) is one of the most extensively studied perovskite materials due to its narrow band gap and high absorption coefficient, which makes it highly suitable for optoelectronic applications. Deposition of a solution containing lead iodide (PbI2) and formamidinium iodide (FAI) or sequential deposition of PbI2 and FAI usually leads to the formation of films with a poor morphology and an unstable crystal structure that readily crystallize into two different polymorphs: the photoinactive yellow phase and the photoactive black phase. In this work, 2D 2-phenylethylammonium lead iodide (PEA2PbI4) thin films are deposited by a scalable doctor-blade coating technique and used as a growth template for the high-quality 3D FAPbI3 perovskite thin films which are obtained by organic cation exchange. We report the structural, morphological and optical properties of these converted 3D FAPbI3 perovskite films which we compare to the directly deposited 3D FAPbI3 films. The converted FAPbI3 thin films are compact, smooth, and highly oriented and exhibit better structural stability in comparison with the directly deposited 3D films. These results not only underscore the importance of the employed deposition techniques in fabricating highly crystalline and stable perovskite thin films but also provide a strategy to easily obtain very compact perovskite layers using doctor-blade coating.