“Blinking” behavior of fluorophores, being harmful for the majority of super-resolved techniques, turns into a key property for stochastic optical fluctuation imaging and its modifications, allowing one to look at the fluorophores already used in conventional microscopy, such as graphene quantum dots, from a completely new perspective. Here we discuss fluorescence of aggregated ensembles of graphene quantum dots structured at submicron scale. We study temperature dependence and stochastic character of emission. We show that considered quantum dots ensembles demonstrate rather complicated temperature-dependent intermittent emission, that is, “blinking” with a tendency to shorten “blinking” times with the increase of temperature. We verify “blinking” mechanism demonstrating hysteresis of the optical response under pulsed excitation timed to expected rates of dots transition to “dark” nonemitting states. Experimental results are well fitted by a simple qualitative model of transitions to the “dark” states. The obtained results suggest that this type of standardized quantum dots and even their submicron-size agglomerations can be useful as controlled fluorophores for super-resolution microscopy and, particularly, for SOFI-like microscopy.

中文翻译：

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石墨烯量子点聚集体的滞后和随机荧光

荧光团的“闪烁”行为对大多数超分辨率技术有害，它变成了随机光学波动成像及其修改的关键特性，允许人们查看已经在传统显微镜中使用的荧光团，例如石墨烯量子点，从一个全新的角度。在这里，我们讨论了在亚微米尺度上构造的石墨烯量子点聚合集合的荧光。我们研究温度依赖性和排放的随机特征。我们表明，所考虑的量子点集合表现出相当复杂的温度依赖性间歇发射，即随着温度的升高，“闪烁”具有缩短“闪烁”时间的趋势。我们验证了“闪烁”机制，证明了在脉冲激发下光学响应的​​滞后性，与预期的点转变为“暗”非发光状态的速率相匹配。一个简单的向“暗”状态过渡的定性模型很好地拟合了实验结果。获得的结果表明，这种类型的标准化量子点甚至它们的亚微米级聚集体可用作超分辨率显微镜的受控荧光团，特别是用于 SOFI 样显微镜。