Identification of the Band Gap Energy of Two-dimensional (OA)2(MA)n-1PbnI3n+1 Perovskite with up to 10 Layers
Identification of the Band Gap Energy of Two-dimensional (OA)2(MA)n-1PbnI3n+1 Perovskite with up to 10 Layers
复制标题
多达 10 层的二维 (OA)(2)(MA)(n-1)PbnI3n 1 钙钛矿带隙能量的识别
DOI：
10.1021/acs.jpclett.9b02823
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发表时间：
2019-11-21
影响因子：
5.7
通讯作者：
Tian, Yuxi
中科院分区：
文献类型：
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作者：
Hua, Yan;Zhou, Yipeng;Tian, Yuxi
二维（2D）钙钛矿由于其稳定性和波长可调谐性而引起广泛关注。然而，样品制备的随机结晶使得难以获得具有纯结构的2D钙钛矿，特别是当层数很大时。本文中，我们制备了具有不同层（n = 1-10）的二维钙钛矿（C8 H17 NH3）（2）（MA）（n-1）PbnI 3 n +1。首次通过荧光显微镜观察具有纯发射光谱的特定晶体片，实验确定了2D钙钛矿（C8 H17 NH3）（2）（MA）（n-1）PbnI 3 n +1的带隙能量E-g，其中层数为10。有趣的是，E-g和n之间的关系完全符合指数函数，而不是纯粹的量子限制效应，与基于第一原理的理论计算非常一致。研究结果表明，二维钙钛矿结构的禁带宽度不仅取决于量子限制效应，而且还受到其他因素的影响，包括化学成分。
Two-dimensional (2D) perovskites are attracting broad attention for their stability and wavelength tunability. However, random crystallization of sample preparation makes it difficult to obtain 2D perovskites with pure structure, especially when the number of layers is large. Herein, we prepared 2D perovskite (C8H17NH3)(2)(MA)(n-1)PbnI3n+1 with different layers (n = 1-10). For the first time, we experimentally identified the band gap energy E-g of 2D perovskite (C8H17NH3)(2)(MA)(n-1)PbnI3n+1 with layers up to 10 by investigating specific pieces of crystal with pure emission spectra using fluorescence microscopy. Intriguingly, the relationship between E-g and n perfectly fits an exponential function rather than the pure quantum confinement effect in good agreement with the theoretical calculation based on first principles. Our results suggest that the band gap of the 2D perovskite is determined not only by quantum confinement effect, but other factors including chemical components also give significant contribution.