College of Materials Science and Engineering, Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, Hunan University, Changsha, 410082, China.
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
Adv Mater. 2018 May;30(22):e1705801. doi: 10.1002/adma.201705801. Epub 2018 Apr 16.
A fundamental understanding of the interplay between the microscopic structure and macroscopic optoelectronic properties of organic-inorganic hybrid perovskite materials is essential to design new materials and improve device performance. However, how exactly the organic cations affect the structural phase transition and optoelectronic properties of the materials is not well understood. Here, real-time, in situ temperature-dependent neutron/X-ray diffraction and photoluminescence (PL) measurements reveal a transformation of the organic cation CH NH from order to disorder with increasing temperature in CH NH PbBr perovskites. The molecular-level order-to-disorder transformation of CH NH not only leads to an anomalous increase in PL intensity, but also results in a multidomain to single-domain structural transition. This discovery establishes the important role that organic cation ordering has in dictating structural order and anomalous optoelectronic phenomenon in hybrid perovskites.
对有机-无机杂化钙钛矿材料的微观结构和宏观光电性能之间的相互作用有一个基本的了解，对于设计新材料和提高器件性能是至关重要的。然而，有机阳离子究竟如何影响材料的结构相变和光电性能，目前还不是很清楚。在这里，实时、原位的温度依赖中子/ X 射线衍射和光致发光（PL）测量揭示了在 CH3NH3PbBr3 钙钛矿中，有机阳离子 CH3NH3 从有序到无序的转变随着温度的升高而增加。CH3NH3 的分子级有序到无序的转变不仅导致 PL 强度的异常增加，而且还导致多畴到单畴结构的转变。这一发现确立了有机阳离子有序在决定杂化钙钛矿中的结构有序和异常光电现象方面的重要作用。
