标题： 卤化物双钙钛矿中由缺陷介导的电子-声子耦合 显示英文标题

标题： Defect-mediated electron-phonon coupling in halide double perovskite

摘要： 光学活性缺陷在控制材料的光发射以及电子性质方面常常起着至关重要的作用。此外，位于带隙中间区域的缺陷介导态可以捕获电子，从而为电子和空穴在低能态下的复合开辟了一条途径，这种复合过程可能需要声子参与。 考虑到这一点，我们通过引入缺陷研究了卤化物钙钛矿体系中的电子-声子相互作用，并探讨了这一相互作用的热效应。在这里，我们报告了对卤化物钙钛矿体系Cs₂AgInCl₆和Cs₂NaInCl₆中可由晶体生长条件调节的电子-声子耦合随温度演化的拉曼光谱研究结果。电子-声子耦合的特征在最低频率的声子模式（51 cm⁻¹）中表现为Fano异常，并随温度变化而演化。 此外，在缺陷介导系统的光致发光(PL)测量中，我们观察到一个宽峰，而在无缺陷的卤化物钙钛矿中则不存在此现象。同时在拉曼光谱中观察到的Fano异常与PL带的出现表明双钙钛矿中存在缺陷介导的中间态以及由此产生的电子-声子耦合。 显示英文摘要

摘要： Optically active defects often play a crucial role in governing the light emission as well as the electronic properties of materials. Moreover, defect-mediated states in the mid-gap region can trap electrons, thus opening a path for the recombination of electrons and holes in lower energy states that may require phonons in the process. Considering this, we have probed electron-phonon interaction in halide perovskite systems with the introduction of defects and investigated the thermal effect on this interaction. Here, we report Raman spectroscopy study of the thermal evolution of electron-phonon coupling, which is tunable with the crystal growth conditions, in the halide perovskite systems Cs2AgInCl6 and Cs2NaInCl6. The signature of electron-phonon coupling is observed as a Fano anomaly in the lowest frequency phonon mode (51 cm-1) which evolves with temperature. In addition, we observe a broad band in the photoluminescence (PL) measurements for the defect-mediated systems, which is otherwise absent in defect-free halide perovskite. The simultaneous observation of the Fano anomaly in the Raman spectrum and the emergence of the PL band suggests the defect-mediated mid-gap states and the consequent existence of electron-phonon coupling in the double perovskite.