Pressure Distinguishes the Dual Emissions in Pseudohalide 2D Ruddlesden-Popper Perovskite Cs_(2)Pb(SCN)_(2)Br_(2)  

作　　者：Songhao Guo Yuhong Mao Congcong Chen Yao Zhang Guoxiang Zhao Kejun Bu Qingyang Hu Haiming Zhu Guifu Zou Wenge Yang Lingling Mao Xujie Lü 

机构地区：[1]Center for High Pressure Science and Technology Advanced Research(HPSTAR),Shanghai [2]Department of Chemistry,Southern University of Science and Technology,Shenzhen [3]Department of Chemistry,Zhejiang University,Hangzhou [4]College of Energy,Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province,Soochow University,Suzhou

出　　处：《CCS Chemistry》2024年第7期1748-1756,共9页中国化学会会刊（英文）

基　　金：supported by the National Natural Science Foundation of China(NSFC)(grant nos.22275004,U1930401,and 52325309);the Shanghai Science and Technology Committee(grant no.22JC1410300);the Shanghai Key Laboratory of Novel Extreme Condition Materials(grant no.22dz2260800);supported by the NSFC(grant no.22275077).Q.H.is supported by the CAEP Research(grant no.CX20210048);the Tencent Xplorer Prize(grant no.XPLORER-2020-1013).

摘　　要：Two-dimensional(2D)Ruddlesden-Popper(RP)halide perovskites with diverse structures and properties have drawn increasing attention due to their promising optoelectronic applications.Recently,a new all-inorganic Cs_(2)Pb(SCN)_(2)Br_(2) has been reported that opens up new potential for the development of 2D RP perovskites.However,recent reports of unusual dual emissions and two-edge absorption in Cs_(2)Pb(SCN)_(2)Br_(2) have generated intense debate about its origin and remains controversial.Here,by combining continuous pressure tuning with in situ diagnostics,we have unambiguously revealed the underlying mechanisms that the 2D Cs_(2)Pb(SCN)_(2)Br_(2) exhibits an intrinsic blue emission at 2.66 eV and an absorption edge close to the emission peak.While the gradually formed CsPbBr_(3) is responsible for the green emission at 2.33 eV with the absorption shoulder at 2.41 eV.Furthermore,by fitting the temperature-dependent intensity of the intrinsic blue emission,we have determined the corrected value of exciton binding energy for 2D Cs_(2)Pb(SCN)_(2)Br_(2) to be 90 meV.Intriguingly,an emission enhancement of 2.5 times is achieved in Cs_(2)Pb(SCN)_(2)Br_(2) under a mild pressure within 0.8 GPa,caused by the pressuresuppressed exciton-phonon interaction.This work not only elucidates the origin of the dual emissions and two-edge absorption in Cs_(2)Pb(SCN)_(2)Br_(2),but it also provides a potential means to regulate and optimize the optoelectronic properties of 2D perovskites.

关 键 词：two-dimensional perovskite dual emissions two-edge absorption high pressure in situ characterization enhanced photoluminescence 

分 类 号：O64[理学—物理化学]