The First 2D Homochiral Lead Iodide Perovskite Ferroelectrics: [R‐ and S‐1‐(4‐Chlorophenyl)ethylammonium]2PbI4
The First 2D Homochiral Lead Iodide Perovskite Ferroelectrics: [R‐ and S‐1‐(4‐Chlorophenyl)ethylammonium]2PbI4
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DOI：
10.1002/adma.201808088
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发表时间：
2019-03
影响因子：
29.4
通讯作者：
C. Yang;Wang-Nan Chen;Yan-Ting Ding;Jing Wang;Yin Rao;Weiqiang Liao;Yuan‐Yuan Tang;Peng-Fei Li-Peng-Fei-L
中科院分区：
文献类型：
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作者：
C. Yang;Wang-Nan Chen;Yan-Ting Ding;Jing Wang;Yin Rao;Weiqiang Liao;Yuan‐Yuan Tang;Peng-Fei Li-Peng-Fei-L
2D有机-无机碘化铅钙钛矿由于其优异的光电性能、结构可调谐性和环境稳定性，最近作为用于太阳能电池的有前途的光吸收剂受到极大关注。然而，尽管已经做出了很大的努力，但是还没有发现2D碘化铅钙钛矿作为铁电体，其中铁电性可以改善光伏性能。在此，通过引入同手性阳离子，成功地获得了2D碘化铅钙钛矿铁电体[R-1-（4-氯苯基）乙铵] 2 PbI 4和[S-1-（4-氯苯基）乙铵] 2 PbI 4。振动圆二色光谱和晶体结构分析表明它们是同手性的。它们在室温下都属于极性空间群P1，并发生422 F1型铁电相变，相变温度分别高达483和473.2K，表现出多轴铁电性质。它们还具有直接带隙为2.34 eV的半导体特性。然而，它们的外消旋类似物在室温下采用中心对称空间群P21/c，没有高温相变。2D碘化铅钙钛矿中的同手性促进极性空间群中的结晶。这一发现为设计高性能二维碘化铅钙钛矿铁电体提供了一条有效途径，具有广阔的应用前景。
2D organic–inorganic lead iodide perovskites have recently received tremendous attention as promising light absorbers for solar cells, due to their excellent optoelectronic properties, structural tunability, and environmental stability. However, although great efforts have been made, no 2D lead iodide perovskites have been discovered as ferroelectrics, in which the ferroelectricity may improve the photovoltaic performance. Here, by incorporating homochiral cations, 2D lead iodide perovskite ferroelectrics [R‐1‐(4‐chlorophenyl)ethylammonium]2PbI4 and [S‐1‐(4‐chlorophenyl)ethylammonium]2PbI4 are successfully obtained. The vibrational circular dichroism spectra and crystal structural analysis reveal their homochirality. They both crystalize in a polar space group P1 at room temperature, and undergo a 422F1 type ferroelectric phase transition with transition temperature as high as 483 and 473.2 K, respectively, showing a multiaxial ferroelectric nature. They also possess semiconductor characteristics with a direct bandgap of 2.34 eV. Nevertheless, their racemic analogue adopts a centrosymmetric space group P21/c at room temperature, exhibiting no high‐temperature phase transition. The homochirality in 2D lead iodide perovskites facilitates crystallization in polar space groups. This finding indicates an effective way to design high‐performance 2D lead iodide perovskite ferroelectrics with great application prospects.