Self-trapped exciton engineering for white-light emission in colloidal lead-free double perovskite nanocrystals  

非铅双钙钛矿胶体纳米晶的自缺陷态激子调控白光发射

作　　者：Muyu Cong Bin Yang Feng Hong Tiancheng Zheng Youbao Sang Jingwei Guo Songqiu Yang Keli Han 丛沐宇;杨斌;洪峰;郑天成;桑友宝;郭敬为;羊送球;韩克利(State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,China;University of the Chinese Academy of Sciences,Beijing 100039,China;Institute of Molecular Sciences and Engineering,Shandong University,Qingdao 266237,China;Key Laboratory of Chemical Lasers,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,China)

机构地区：[1]State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,China [2]University of the Chinese Academy of Sciences,Beijing 100039,China [3]Institute of Molecular Sciences and Engineering,Shandong University,Qingdao 266237,China [4]Key Laboratory of Chemical Lasers,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,China

出　　处：《Science Bulletin》2020年第13期1078-1084,M0003,共8页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(21533010,21525315);the National Key Research and Development Program of China(2017YFA0204800);DICP DMTO201601,DICP ZZBS201703,and the Science Challenging Program(JCKY2016212A501).

摘　　要：Intrinsic broadband photoluminescence(PL)of self-trapped excitons(STEs)are systematically studied in lead-free double perovskite nanocrystals(NCs).It is clarified that bandgap(direct/indirect)has important influence on the PL properties of STEs:indirect bandgap NCs exhibit strong exciton-phonon coupling which results in non-radiative STEs,while direct bandgap NCs exhibit moderate exciton-phonon coupling,inducing bright STE PL.Furthermore,by alloying K+and Li+ions in Cs2AgInCl6 NCs,the NCs exhibit broadband white-light emission.Charge-carrier dynamics study indicates that the efficient white-light emission originates from the further suppressed non-radiative processes of the STEs in the direct bandgap structure.This work may deepen the understanding of STEs and guide the design of highperformance lead-free perovskites.系统研究了非铅双钙钛矿纳米晶中自缺陷态激子引起的宽带荧光现象.带隙类型(直接、间接)对自缺陷态荧光的性质有着重要的影响:间接带隙纳米晶中,其激子-声子耦合作用较强,产生了非辐射自缺陷态,而直接带隙纳米晶中的激子-声子耦合相对较弱,因此,可以发射出较强的自缺陷态荧光.此外,通过在Cs2AgInCl6中引入K+和Li+,纳米晶可以发射出强白光.电荷载流子动力学研究表明,导致这种高效白光发射的原因是自缺陷态激子地非辐射复合过程被进一步抑制.该研究将进一步加深对自缺陷态的理解并对设计出优异性质的非铅钙钛矿具有指导意义.

关 键 词：Double perovskite Nanocrystal Trap state Hot-carrier cooling Carrier-phonon coupling 

分 类 号：TB383.1[一般工业技术—材料科学与工程]