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Incorporating Large A Cations into Lead Iodide Perovskite Cages: Relaxed Goldschmidt Tolerance Factor and Impact on Exciton–Phonon Interaction
ACS Central Science ( IF 12.7 ) Pub Date : 2019-07-24 00:00:00 , DOI: 10.1021/acscentsci.9b00367
Yongping Fu 1 , Matthew P. Hautzinger 1 , Ziyu Luo 2 , Feifan Wang 3 , Dongxu Pan 1 , Michael M. Aristov 1 , Ilia A. Guzei 1 , Anlian Pan 2 , Xiaoyang Zhu 3 , Song Jin 1
Affiliation  

The stability and formation of a perovskite structure is dictated by the Goldschmidt tolerance factor as a general geometric guideline. The tolerance factor has limited the choice of cations (A) in 3D lead iodide perovskites (APbI3), an intriguing class of semiconductors for high-performance photovoltaics and optoelectronics. Here, we show the tolerance factor requirement is relaxed in 2D Ruddlesden–Popper (RP) perovskites, enabling the incorporation of a variety of larger cations beyond the methylammonium (MA), formamidinium, and cesium ions in the lead iodide perovskite cages for the first time. This is unequivocally confirmed with the single-crystal X-ray structure of newly synthesized guanidinium (GA)-based (n-C6H13NH3)2(GA)Pb2I7, which exhibits significantly enlarged and distorted perovskite cage containing sterically constrained GA cation. Structural comparison with (n-C6H13NH3)2(MA)Pb2I7 reveals that the structural stabilization originates from the mitigation of strain accumulation and self-adjustable strain-balancing in 2D RP structures. Furthermore, spectroscopic studies show a large A cation significantly influences carrier dynamics and exciton–phonon interactions through modulating the inorganic sublattice. These results enrich the diverse families of perovskite materials, provide new insights into the mechanistic role of A-site cations on their physical properties, and have implications to solar device studies using engineered perovskite thin films incorporating such large organic cations.

中文翻译:

将大型阳离子纳入碘化钙钛矿铅笼中:松弛的Goldschmidt耐受因子及其对激子-Phonon相互作用的影响

钙钛矿结构的稳定性和形成是由Goldschmidt公差系数决定的,这是一般的几何准则。公差因子限制了3D碘化铅钙钛矿(APbI 3)中阳离子(A)的选择,3D碘化钙钛矿(APbI 3)是用于高性能光伏和光电子学的一类引人入胜的半导体。在这里,我们显示了2D Ruddlesden-Popper(RP)钙钛矿中的耐受因子要求得到了放宽,从而允许在碘化铅钙钛矿笼中首次引入除甲基铵(MA),甲ami和铯离子之外的各种更大的阳离子。时间。新合成的胍基(GA)基(n -C 6 H 13 NH32(GA)Pb 2 I 7,其钙钛矿笼子明显变大且变形,其中含有空间受限的GA阳离子。与(n -C 6 H 13 NH 32(MA)Pb 2 I 7的结构比较揭示了结构稳定源自缓解二维RP结构中的应变积累和自调节应变平衡。此外,光谱研究表明,大的A阳离子会通过调节无机亚晶格显着影响载流子动力学和激子-声子相互作用。这些结果丰富了钙钛矿材料的各种种类,提供了有关A部位阳离子在其物理性质上的机械作用的新见解,并且对使用结合了这种大有机阳离子的工程化钙钛矿薄膜的太阳能器件研究产生了影响。
更新日期:2019-07-24
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