To obtain an in-depth understanding of the dynamics and mechanism of carrier recombination in CsPbBr₃ nanocrystals (NCs), we have investigated the photoluminescence (PL) of this material at the single-particle level using the time-tagged–time-resolved method. The study reveals two distinct types of PL fluctuations of the NCs, which are assigned to flickering and blinking. The flickering is found to be due to excess surface trap on the NCs, and the flickering single particles are transformed into blinking ones with significant enhancement of PL intensity and stability on postsynthetic surface treatment. Intensity-correlated lifetime analysis of the PL time trace reveals both trap-mediated nonradiative band-edge carrier recombination and positive trion recombination in single NCs. Dynamical and statistical analysis suggests a diffusive nature of the trap states to be responsible for the PL intermittency of the system. These findings throw light on the nature of the trap states, reveal the manifestation of these trap states in PL fluctuation, and provide an effective way to control the dynamics of CsPbBr₃ NCs.

中文翻译：

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单个CsPbBr ₃钙钛矿纳米晶体的光致发光闪烁和闪烁：揭示明确的载体复合动力学。

深入了解CsPbBr ₃中载流子重组的动力学和机理纳米晶体（NCs），我们使用时间标记-时间分辨方法研究了这种材料在单粒子水平上的光致发光（PL）。这项研究揭示了NC的PL波动的两种不同类型，分别是闪烁和闪烁。发现闪烁是由于NC上过多的表面陷阱所致，并且闪烁的单个粒子已转变为闪烁的粒子，从而显着增强了PL强度和合成后表面处理的稳定性。对PL时间迹线的强度相关寿命分析揭示了单个NC中陷阱介导的非辐射带边缘载流子重组和正Trion重组。动态和统计分析表明陷阱状态的扩散性是造成系统PL间歇性的原因。_3个NC。