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Composition‐Dependent Hot Carrier Relaxation Dynamics in Cesium Lead Halide (CsPbX 3 , X=Br and I) Perovskite Nanocrystals
Author(s) -
Chung Heejae,
Jung Seok Il,
Kim Hyo Jin,
Cha Wonhee,
Sim Eunji,
Kim Dongho,
Koh WeonKyu,
Kim Jiwon
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201611916
Subject(s) - perovskite (structure) , halide , relaxation (psychology) , caesium , nanocrystal , materials science , ultrafast laser spectroscopy , spectroscopy , chemical physics , chemistry , nanotechnology , crystallography , inorganic chemistry , psychology , social psychology , physics , quantum mechanics
Cesium‐based perovskite nanocrystals (NCs) have outstanding photophysical properties improving the performances of lighting devices. Fundamental studies on excitonic properties and hot‐carrier dynamics in perovskite NCs further suggest that these materials show higher efficiencies compared to the bulk form of perovskites. However, the relaxation rates and pathways of hot‐carriers are still being elucidated. By using ultrafast transient spectroscopy and calculating electronic band structures, we investigated the dependence of halide in Cs‐based perovskite (CsPbX 3 with X=Br, I, or their mixtures) NCs on the hot‐carrier relaxation processes. All samples exhibit ultrafast (<0.6 ps) hot‐carrier relaxation dynamics with following order: CsPbBr 3 (310 fs)>CsPbBr 1.5 I 1.5 (380 fs)>CsPbI 3 NC (580 fs). These result accounts for a reduced light emission efficiency of CsPbI 3 NC compared to CsPbBr 3 NC.