Effect of the A-Site Cation on the Biexciton Dynamics in Lead Bromide Perovskite Nanocrystals

作者：Xing Ji, Rong Lü, Anchi Yu · 发表于：The Journal of Physical Chemistry C · 年份：2023 · DOI：10.1021/acs.jpcc.3c04148 · 被引用次数：11 · 研究领域：Perovskite Materials and Applications、Quantum Dots Synthesis And Properties、Chalcogenide Semiconductor Thin Films

A systematic and comprehensive understanding of different aspects of the carrier dynamics of lead halide perovskite nanocrystals (LHP NCs) is the key to improving the performance of this highly anticipated material. Recent research suggests that the A-site cation of LHP materials has a significant effect on their photophysical processes, but there is still a lack of a systematic study on how the A-site cation affects their biexciton dynamics. Herein, we fabricated CsPbBr 3, MAPbBr 3, and FAPbBr 3 NCs with similar sizes and morphologies and conducted femtosecond transient absorption (FTA) experiments on them. By a global analysis, we found that all the FTA spectra of CsPbBr 3, MAPbBr 3, and FAPbBr 3 NCs include three decay-associated spectra (DAS) components under high pump fluence, which, respectively, are attributed to hot carrier cooling, biexciton Auger recombination (AR), and exciton recombination. By analyzing the DAS component of biexciton of CsPbBr 3, MAPbBr 3, and FAPbBr 3 NCs, we extract their biexciton AR lifetime and biexciton binding energy. It is found that the biexciton AR lifetime of APbBr 3 NCs becomes shorter as the A-site cation changes from Cs + to MA + and to FA + (∼77 ps for CsPbBr 3, ∼56 ps for MAPbBr 3, and ∼42 ps for FAPbBr 3 ), while the biexciton binding energy of APbBr 3 NCs becomes greater as the A-site cation changes from Cs + to MA + and to FA + (∼32 meV for CsPbBr 3, ∼39 meV for MAPbBr 3, and ∼45 meV for FAPbBr 3 ). We also investigated how the ...