Composition‐Dependent Hot Carrier Relaxation Dynamics in Cesium Lead Halide (CsPbX3, X=Br and I) Perovskite Nanocrystals

作者：Heejae Chung, Seok Il Jung, Hyo Jin Kim, Wonhee Cha, Eunji Sim, Dongho Kim, Weon‐kyu Koh, Jiwon Kim · 发表于：Angewandte Chemie International Edition · 年份：2017 · DOI：10.1002/anie.201611916 · 被引用次数：175 · 研究领域：Perovskite Materials and Applications、Quantum Dots Synthesis And Properties、Solid-state spectroscopy and crystallography

Abstract 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 (CsPbX3 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: CsPbBr3 (310 fs)>CsPbBr1.5I1.5 (380 fs)>CsPbI3 NC (580 fs). These result accounts for a reduced light emission efficiency of CsPbI3 NC compared to CsPbBr3 NC.