NPG Asia Materials ( IF 8.6 ) Pub Date : 2020-10-16 , DOI: 10.1038/s41427-020-00249-w Wen-Cheng Qiao , Jianming Yang , Wei Dong , Guang Yang , Qinye Bao , Rong Huang , Xue Lu Wang , Ye-Feng Yao
Chlorine incorporation engineering has been widely used in optoelectronic devices based on methylammonium lead iodide (MAPbI3) perovskites. However, the characteristics of I/Cl alloying structures in MAPbI3−xClx mixed-halide perovskites and their influences on the optoelectronic properties have been issues of a long-standing controversy. Here, we present a detailed study of the I/Cl alloying structures in MAPbI3−xClx (x = 0.0 to 0.3) single crystals. We found that a small amount of Cl can substitute for the iodide of the PbI3 inorganic lattice, leading to a phase transition from the tetragonal to cubic phase and anomalous cation dynamics evolution. Analyses based on time-dependent X-ray diffraction, 207Pb NMR, and 2H NMR indicate that the alloying structures of the MAPbI3−xClx crystals are metastable and decompose over time. In addition, the photocurrent response measurement of MAPbI3−xClx proved a close correlation between the alloying structures and photoelectric properties of the material. This work sheds light on the essential understanding of the I/Cl alloying structure and provides a plausible explanation for the controversy regarding the role of chloride ions in optoelectronic devices.
中文翻译:
MAPbI 3-x Cl x晶体中的亚稳态合金结构
氯结合工程已广泛用于基于甲基铵碘化铅(MAPbI 3)钙钛矿的光电器件中。然而,MAPbI 3− x Cl x混合卤化物钙钛矿中I / Cl合金结构的特性及其对光电性能的影响一直是一个长期存在的问题。在这里,我们对MAPbI 3- x Cl x(x = 0.0至0.3)单晶中的I / Cl合金结构进行了详细研究。我们发现少量的Cl可以代替PbI 3的碘化物无机晶格,导致从四方相到立方相的相变以及异常的阳离子动力学演化。基于时间相关的X射线衍射,207 Pb NMR和2 H NMR的分析表明,MAPbI 3 - x Cl x晶体的合金结构是亚稳态的,并随时间分解。另外,MAPbI 3 − x Cl x的光电流响应测量证明合金的合金结构与光电性能之间密切相关。这项工作阐明了对I / Cl合金结构的基本理解,并为有关氯离子在光电器件中作用的争论提供了合理的解释。