Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA.
National Taiwan University, Center for Condensed Matter Sciences, National Taiwan University,, Taipei 10617, Taiwan.
Nat Commun. 2017 Feb 22;8:14521. doi: 10.1038/ncomms14521.
Fluorescence intermittency or blinking is observed in nearly all nanoscale fluorophores. It is characterized by universal power-law distributions in on- and off-times as well as 1/f behaviour in corresponding emission power spectral densities. Blinking, previously seen in confined zero- and one-dimensional systems has recently been documented in two-dimensional reduced graphene oxide. Here we show that unexpected blinking during graphene oxide-to-reduced graphene oxide photoreduction is attributed, in large part, to the redistribution of carbon sp domains. This reclustering generates fluctuations in the number/size of emissive graphenic nanoclusters wherein multiscale modelling captures essential experimental aspects of reduced graphene oxide's absorption/emission trajectories, while simultaneously connecting them to the underlying photochemistry responsible for graphene oxide's reduction. These simulations thus establish causality between currently unexplained, long timescale emission intermittency in a quantum mechanical fluorophore and identifiable chemical reactions that ultimately lead to switching between on and off states.
荧光猝灭或闪烁在几乎所有纳米级荧光体中都能观察到。其特征是在开启和关闭时间上具有普适的幂律分布，以及在相应的发射功率谱密度上呈现 1/f 行为。以前在受限的零维和一维系统中观察到的猝灭现象，最近在二维还原氧化石墨烯中得到了证实。在这里，我们表明，氧化石墨烯还原过程中意想不到的猝灭现象在很大程度上归因于碳 sp 畴的再分布。这种再聚类导致了发射性石墨纳米团簇的数量/大小的波动，其中多尺度模型捕获了还原氧化石墨烯的吸收/发射轨迹的基本实验方面，同时将它们与导致氧化石墨烯还原的潜在光化学反应联系起来。这些模拟因此在一个量子力学荧光体中目前无法解释的长时间尺度发射猝灭和最终导致开启和关闭状态之间切换的可识别化学反应之间建立了因果关系。
