Photoluminescence (PL) blinking is a common phenomenon in nanostructured semiconductors associated with charge trapping and defect dynamics. PL blinking kinetics exhibit very broadly distributed timescales. The traditionally employed analysis of probability distribution of ON and OFF events suffers from ambiguities in their determination in complex PL traces making its suitability questionable. Here, the statistically correct power spectral density (PSD) estimation method applicable for fluctuations of any complexity is employed. PSDs of the blinking traces of submicrometer MAPbI₃ crystals at high frequencies follow power law with excitation power density dependent parameters. However, at frequencies less than 0.3 Hz, the majority of the PSDs saturate revealing the presence of a maximal characteristic timescale of blinking in the range of 0.5–10 s independently of the excitation power density. Super-resolution optical microscopy shows the characteristic timescale to be an inherent material property independent of polycrystallinity. Thus, for the first time the maximum timescale of the multiscale blinking behavior of nanoparticles is observed demonstrating that the power law statistics are not universal for semiconductors. It is proposed that the viscoelasticity of metal-halide perovskites can limit the maximum timescale for the PL fluctuations by limiting the memory of preceded deformations/re-arrangements of the crystal lattice.

中文翻译：

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MAPbI3钙钛矿光致发光闪烁的最大特征时间的存在

光致发光 (PL) 闪烁是与电荷俘获和缺陷动力学相关的纳米结构半导体中的常见现象。PL 闪烁动力学表现出非常广泛分布的时间尺度。传统上采用的 ON 和 OFF 事件概率分布分析在复杂 PL 轨迹中的确定中存在歧义，使其适用性受到质疑。这里，采用了适用于任何复杂度波动的统计上正确的功率谱密度 (PSD) 估计方法。亚微米MAPbI ₃闪烁轨迹的PSDs高频晶体遵循具有激励功率密度相关参数的幂律。然而，在低于 0.3 Hz 的频率下，大多数 PSD 会饱和，这表明在 0.5-10 秒的范围内存在与激发功率密度无关的最大特征时间尺度。超分辨率光学显微镜显示特征时间尺度是独立于多晶性的固有材料特性。因此，首次观察到纳米粒子多尺度闪烁行为的最大时间尺度，证明幂律统计对于半导体并不通用。