Critical roles of high- and low-frequency optical phonons in photodynamics of zero-dimensional perovskite-like (C6H22N4C13)SnCl3 crystals
Critical roles of high- and low-frequency optical phonons in photodynamics of zero-dimensional perovskite-like (C6H22N4C13)SnCl3 crystals
复制标题
高频和低频光学声子在零维类钙钛矿 (C6H22N4C13)SnCl3 晶体光动力学中的关键作用
DOI：
10.1021/acs.jpclett.9b03153
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发表时间：
2019
影响因子：
5.7
通讯作者：
Fan Jiyang
中科院分区：
文献类型：
--
作者：
Liu Xiaoyu;Wu Wenhui;Zhang Yumeng;Li Yuanyuan;Wu Huaxin;Fan Jiyang
由孤立多面体构成的零维钙钛矿结构与由相互连接的多面体构成的三维钙钛矿结构相比，具有独特的物理性质。在这里，我们研究了由孤立的[SnCl 3]−四面体组成的零维类钙钛矿（C6 H22 N4 Cl 3）SnCl 3单晶的光动力学。它们具有很大的斯托克斯位移（2.49 eV）、很大的光谱展宽（416 meV）和很长的寿命（6.9 μs）。实验结合从头计算揭示了高频和低频声子在（C6 H22 N4 Cl 3）SnCl 3晶体光动力学中的特殊作用。与有机阳离子相关的高频光学声子与单重态到三重态跃迁之间的共振诱导了强烈的系间跃迁和由此产生的自旋禁戒发光。低温光谱表征揭示了与电子-四面体相关的强低频光-声子耦合导致了大的光谱展宽。由于电子轨道沿着局域化和系间交叉导致的强晶格弛豫是大的Stokes位移的原因。
The zero-dimensional perovskites composed of isolated polyhedrons have unique and distinct physical properties compared with three-dimensional perovskites composed of interconnected polyhedrons. Here, we study the photodynamics of the zero-dimensional perovskite-like (C6H22N4Cl3)SnCl3single crystals composed of isolated [SnCl3]−tetrahedrons. They exhibit red luminescence with huge Stokes shift (2.49 eV), large spectral broadening (416 meV), and long lifetime (6.9 μs). The experiments in conjunction with the ab initio calculations reveal the special roles of high- and low-frequency phonons in the photodynamics of the (C6H22N4Cl3)SnCl3crystals. The resonance between the organic-cation-related high-frequency optical phonons and the singlet-to-triplet state transition induces strong intersystem crossing and resultant spin-forbidden luminescence. The strong electron–tetrahedron-related low-frequency optical-phonon coupling revealed by the low-temperature spectral characterization causes large spectral broadening. The strong lattice relaxation owing to localization of the electronic orbitals along with intersystem crossing accounts for the large Stokes shift.