Li Bin, Huang He, Zhang Guofeng, Yang Changgang, Guo Wenli, Chen Ruiyun, Qin Chengbing, Gao Yan, Biju Vasudevan P, Rogach Andrey L, Xiao Liantuan, Jia Suotang
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , People's Republic of China.
Collaborative Innovation Center of Extreme Optics , Shanxi University , Taiyuan 030006 , People's Republic of China.
J Phys Chem Lett. 2018 Dec 20;9(24):6934-6940. doi: 10.1021/acs.jpclett.8b03098. Epub 2018 Nov 30.
Colloidal lead halide perovskite quantum dots, due to their optical versatility and facile solution processability, have been recently recognized as components of various optoelectronic devices. Detailed understanding of their exciton recombination dynamics at the single-particle level is necessary for utilizing their full potential. We conducted spectroscopic studies of the excitons and biexciton dynamics in single CsPbBr perovskite quantum dots. It was found that while the rates of radiative recombination remain essentially constant, the overall relaxation process is dominated by nonradiative recombination of single excitons and biexcitons. The radiative lifetime scaling is determined to be ∼1.0 for single exciton and ∼4.4 for biexcitons. A linear dependence of fluorescence lifetime vs intensity distribution agrees well with the prediction of the model of multiple recombination centers. The blinking mechanism of CsPbBr quantum dots is addressed by considering the trion states under higher excitation powers.
由于其光学多功能性和简便的溶液可加工性，胶体卤化铅钙钛矿量子点最近被认为是各种光电器件的组成部分。要充分发挥其潜力，有必要在单粒子水平上详细了解其激子复合动力学。我们对单个CsPbBr钙钛矿量子点中的激子和双激子动力学进行了光谱研究。结果发现，虽然辐射复合速率基本保持恒定，但整体弛豫过程由单激子和双激子的非辐射复合主导。单激子的辐射寿命标度确定为1.0，双激子的辐射寿命标度确定为4.4。荧光寿命与强度分布的线性关系与多重组中心模型的预测非常吻合。通过考虑更高激发功率下的三重态来探讨CsPbBr量子点的闪烁机制。
