Hot Polarons with Trapped Excitons and Octahedra-Twist Phonons in CH3NH3PbBr3 Hybrid Perovskite Nanowires
Hot Polarons with Trapped Excitons and Octahedra-Twist Phonons in CH3NH3PbBr3 Hybrid Perovskite Nanowires
复制标题
CH3NH3PbBr3 混合钙钛矿纳米线中具有俘获激子和八面体扭曲声子的热极化子
DOI：
10.1002/lpor.201900267
复制
发表时间：
2020
影响因子：
11
通讯作者：
Xu Xiulai
中科院分区：
文献类型：
--
作者：
Song Feilong;Qian Chenjiang;Wang Yunuan;Zhang Feng;Peng Kai;Wu Shiyao;Xie Xin;Yang Jingnan;Sun Sibai;Yu Yang;Dang Jianchen;Xiao Shan;Yang Longlong;Jin Kuijuan;Zhong Haizheng;Xu Xiulai
杂化钙钛矿在光电子学和高效率发光器件中显示出巨大的应用潜力。缺陷诱导的陷阱激子和声子之间的相互作用在理解这种优秀品质因数的新兴现象中起着重要作用。在这里，CH3NH3PbBr3纳米线中具有窄线宽的热极化子，其起源于被捕获的激子和八面体扭曲声子之间的相互作用。光致发光中热极化子的观测表明激子与声子之间存在很强的相互作用。多个热极化子进一步证实了磁光光谱与塞曼分裂的捕获激子和声子能量增加与抗磁效应。此外，参与相互作用的声子被证明是八面体扭曲振动，这是横向光学声子，而捕获的激子和纵向光学声子之间的相互作用很弱。这项工作表明，钙钛矿中的捕获激子更喜欢与横向而不是纵向光学声子相互作用。由于体材料通常与纵向光学声子相互作用，这一结果提供了钙钛矿中缺陷的高耐受性的物理解释。
Hybrid Perovskites have shown a great potential for applications in photovoltaics and light‐emitting devices with high efficiency. Interaction between defect‐induced trapped excitons and phonons plays an important role in understanding the emerging phenomena for such an excellent figure‐of‐merit. Here hot polarons with narrow linewidth in CH3NH3PbBr3nanowires, which originate from the interaction between trapped excitons and octahedra‐twist phonons, are demonstrated. The observation of hot polarons in photoluminescence without gain methods indicates the large interaction strength between excitons and phonons. The multiple hot polarons are further confirmed by magneto‐optical spectra with a Zeeman splitting of the trapped excitons and a phonon energy increase with diamagnetic effect. Furthermore, the phonons participating in the interaction are demonstrated to be the octahedra‐twist vibrations which are transverse optical phonons, while the interaction between trapped excitons and longitudinal optical phonons is weak. The work demonstrates that trapped excitons in perovskites prefer to interact with transverse rather than longitudinal optical phonons. Since bulk materials usually interact with longitudinal optical phonons, this result provides a physical explanation of the high tolerance of defects in perovskites.