报告题目：Novel electronic, excitonic, and optical features in low-dimensional lead-halide hybrid perovskites 低维铅-卤化物杂化过氧化物中的新型电子、激子和光学特征

报告时间：2024年5月23日(周四) 10:00 AM

报告地点：tyc1286太阳成集团529报告厅

报告人：Dr. Hong Li

Abstract /报告摘要：

Two-dimensional (2D) lead-halide perovskites have drawn great interest due to their improvedphoto-stability and chemical stability in comparison to their three-dimensional (3D) counterpart.In the past few years, increasing efforts have been made in tunning the chemical nature of theorganic spacers in the 2D perovskites for their applications as light-emitting or photovoltaicmaterials. However, most of these efforts have focused on investigating the inorganic-inorganicor organic-organic interactions while overlooking an interesting feature that could be induced bygenerating significant electronic couplings between the frontier molecular orbitals of the organiccations and the band edge states of the inorganic framework. Such a strong coupling between theorganic and inorganic components may lead to novel electronic, excitonic, and optical propertiesthat can further broaden the perovskite materials applications. In this talk, I will discuss ourrecent work investigating the electronic couplings between the inorganic perovskite layers andthe organic spacer layers in 2D and 1D halide perovskites where the organic spacers consistingof (di)ammonium cations with a π-conjugated backbone. Our results highlighted that a variety ofelectronic and excitonic behaviors could be achieved by tuning the degree of conjugation andpolarizability of the organic cations, and the structural proximity and the electronic couplingsbetween the organic and inorganic constituents.

二维卤化钙钛矿与其三维结构相比，具有更好的光稳定性和化学稳定性，因此引起了人们的极大的研究兴趣。在过去几年中，人们不断尝试通过调控二维钙钛矿晶体中有机间隔分子的化学性质，以将其更好的应用于发光或光伏材料。然而，目前的工作大多集中于研究无机-无机或有机-有机之间的界面相互作用，却忽略了有机阳离子的前沿分子轨道与无机框架的带边态之间电子耦合作用诱发的一系列重要特性。有机成分和无机成分之间的这种强耦合作用可能会产生新的电子、激子和光学特性，从而进一步拓宽钙钛矿材料实际应用的范围。在此学术报告中，我将讨论我们最近开展的二维和一维卤化钙钛矿中无机钙钛矿层和有机间隔层之间电子耦合相关的研究工作，其中有机间隔层由具有π共轭骨架的（二）铵阳离子组成。我们的研究结果表明，通过调整有机阳离子的共轭度和极化性，以及有机成分和无机成分之间的结构接近度和电子耦合，可以实现各种电子和激子行为。

Biography/报告人简介：

Hong Li is a Professor of Chemistry and Biochemistry of the University of Arizona. Her research interests in the electronic, optical, and magnetic properties of various bulk and interfacial systems, especially the two-dimensional organic covalent frameworks and their interfaces with different substrates, the hybrid organic-inorganic perovskites for solar cell applications, and various organic/organic and organic/inorganic interfaces as well as the charge-transfer and charge-separation processes across such interfaces.

Li教授是一名出色的理论模拟科学工作者，目前是美国亚利桑那大学化学与生物学院教授。她的研究兴趣主要包括材料内部及界面间的电子、光学和磁学特性，特别是二维有机共价框架及其与不同基底的界面、用于太阳能电池的杂化有机-无机杂化钙钛矿、各种有机/有机和有机/无机界面以及这些界面间的电荷转移和电荷分离过程。