Giovanni David, Ramesh Sankaran, Righetto Marcello, Melvin Lim Jia Wei, Zhang Qiannan, Wang Yue, Ye Senyun, Xu Qiang, Mathews Nripan, Sum Tze Chien
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
Energy Research Institute @NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, S2-B3a-01, Singapore 639798, Singapore.
Nano Lett. 2021 Jan 13;21(1):405-413. doi: 10.1021/acs.nanolett.0c03800. Epub 2020 Dec 18.
Two-dimensional (2D) lead halide Ruddlesden-Popper perovskites (RPP) have recently emerged as a prospective material system for optoelectronic applications. Their self-assembled multi quantum-well structure gives rise to the novel interwell energy funnelling phenomenon, which is of broad interests for photovoltaics, light-emission applications, and emerging technologies (e.g., spintronics). Herein, we develop a realistic finite quantum-well superlattice model that corroborates the hypothesis of exciton delocalization across different quantum-wells in RPP. Such delocalization leads to a sub-50 fs coherent energy transfer between adjacent wells, with the efficiency depending on the RPP phase matching and the organic large cation barrier lengths. Our approach provides a coherent and comprehensive account for both steady-state and transient dynamical experimental results in RPPs. Importantly, these findings pave the way for a deeper understanding of these systems, as a cornerstone crucial for establishing material design rules to realize efficient RPP-based devices.
二维（2D）卤化铅Ruddlesden-Popper钙钛矿（RPP）最近已成为光电子应用领域中一种很有前景的材料体系。它们的自组装多量子阱结构引发了新型的阱间能量漏斗现象，这在光伏、发光应用及新兴技术（如自旋电子学）方面引起了广泛关注。在此，我们建立了一个实际的有限量子阱超晶格模型，证实了RPP中激子在不同量子阱间离域的假设。这种离域导致相邻阱间小于50飞秒的相干能量转移，其效率取决于RPP的相位匹配和有机大阳离子势垒长度。我们的方法为RPP中的稳态和瞬态动力学实验结果提供了连贯且全面的解释。重要的是，这些发现为更深入理解这些体系铺平了道路，这是建立材料设计规则以实现高效RPP基器件的关键基石。
