二维层状As_(2)S_(3)层间键合诱导超快激发态本征局域化  

Ultrafast Intrinsic Excited State Localization in 2D Layered As_(2)S_(3) by Interlay-er Bond Formation

作　　者：李旭峰 姚莉[2] 陶卫健 赵瑾[2] 朱海明 Xufeng Li;Li Yao;Wejian Tao;Jin Zhao;Haiming Zhu(Department of Chemistry,Zhejiang University,Hangzhou 310027,China;Department of Physics,CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics,and ICQD/Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]浙江大学化学系,杭州310027 [2]中国科学技术大学物理系,合肥微尺度物质科学国家研究中心,中国科学院强耦合量子材料物理重点实验室,国际功能材料量子设计中心,合肥230026

出　　处：《Chinese Journal of Chemical Physics》2023年第6期646-654,I0007-I0013,I0055,共17页化学物理学报（英文）

基　　金：supported by the National Natural Science Foundation of China(No.22273084,No.22022305);the Open Fund of the State Key Labora-tory of Molecular Reaction Dynamics in DICP,CAS.

摘　　要：具有强激子效应的二维层状材料为研究二维极限下的激发态激子行为提供了极好的平台.虽然传统二维层状半导体(如过渡金属二硫族化物)中的激子动力学已经被广泛研究,但对具有强电子/激子-声子耦合的二维层状半导体中的激子特性和动力学知之甚少.本文通过实验和理论相结合的方法,以二维层状As_(2)S_(3)为模型,揭示了由强激子-声子相互作用驱动的本征高度局域化的激子.结果表明,As_(2)S_(3)中光激发电子/空穴电荷在~110飞秒内自发局域化,产生了较大Stokes位移和较宽的光致发光.理论计算表明层间的硫原子之间光激发形成一定的层间键,引发晶格畸变和载流子局域化.本研究为理解二维半导体中激子和晶格动力学之间复杂的相互作用提供了一个全面的物理图像,对其光电特性和应用具有重要意义.The family of two-dimensional(2D)layered materials with strong excitonic effect offers fascinating opportunities for studying excited state exciton behavior at 2D limit.While exciton dynamics in conventional 2D semiconductors(e.g.transition metal dichalcogenides)has been extensively studied,little is known about exciton properties and dynamics in 2D layered semiconductors with strong electron/exciton-phonon coupling.Here,by combining experimental and theoretical approaches,we reveal the intrinsic highly localized exciton(i.e.self-trapped exciton)in 2D layered As_(2)S_(3),driven by strong exciton-phonon interaction.It is shown that photoexcited electron/hole charges in As_(2)S_(3) localize spontaneously in~110 fs,giving rise to large stokes-shifted and broad photoluminescence.An interlayer partial bond is formed between chalcogen atoms,triggering lattice distortion and carrier localization.Together with Urbach-Martienssen analysis,this study provides a comprehensive physical picture to understand the complex interplay between exciton and lattice dynamics in 2D semiconductors,which has strong implications to their optoelectronic properties and applications.

关 键 词：二维半导体 激子局域化 晶格畸变 极化子 超快光谱 

分 类 号：TB34[一般工业技术—材料科学与工程]