Giant Enhancement of Fluorescence Emission by Fluorination of Porous Graphene with High Defect Density and Subsequent Application as Fe3+ Ion Sensors
Giant Enhancement of Fluorescence Emission by Fluorination of Porous Graphene with High Defect Density and Subsequent Application as Fe3+ Ion Sensors
复制标题
高缺陷密度多孔石墨烯的氟化极大增强了荧光发射及其作为 Fe3 离子传感器的后续应用
DOI：
10.1021/acsami.0c11141
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发表时间：
2020
影响因子：
9.5
通讯作者：
Xu Wang
中科院分区：
文献类型：
--
作者：
Kun Fan;Liansi Peng;Yang Liu;Yu Li;Yue Chen;Yeqiao Meng;Xiangyang Liu;Wei Feng;Xu Wang
传统半导体材料如多孔石墨烯中的缺陷介导的非辐射复合极大地降低了荧光发射，从而极大地限制了它们在更广泛领域的应用。在这里，我们报告了具有高缺陷密度的多孔石墨烯的荧光发射通过直接和简单的双折射策略具有巨大的增强（约两个数量级），显示出良好的缺陷容限特性。同时，相应的氟碳键具有优异的热稳定性（在N2甚至空气中超过500 °C），也带来了良好的稳定性。进一步探讨了整个光致发光演化过程中的物理根源。在激发过程中，氟化多孔石墨烯（FPG）中氟和芳香区的共存有助于产生新的电子带隙结构以匹配最大激发波长，从而产生大量激子，这是产生强荧光发射的前提条件。在发射过程中，弱的电子-声子相互作用，大的刚性，以及在FPG中的缺陷处的约束电子大大减少了非辐射复合损失。此外，缺陷处的氟还减少了FPG纳米片之间的层间相互作用，并抵抗吸收的杂质的影响，从而进一步限制了非辐射复合途径。高荧光FPG已被用作一个迷人的工具，以实现灵敏和裸眼检测的Fe 3+离子具有高选择性。当Fe ~（3+）浓度为396 μ M时，荧光猝灭率达到84%。
Defect-mediated nonradiative recombination in traditional semiconductors, such as porous graphene, tremendously lowers the fluorescence emission, thus greatly restricting their applications in more extensive fields. Here, we report that the fluorescence emission of porous graphene with a high defect density has a giant enhancement (about two orders of magnitude) by a direct and simple fluorination strategy, showing a fine defect-tolerance characteristic. Meanwhile, the corresponding fluorocarbon bonds with excellent thermostability (over 500 °C in N2even air) also bring about good stability. The photophysical origins during the whole photoluminescence evolution are further investigated. In the excitation process, the coexistence of fluorine and aromatic regions in fluorinated porous graphene (FPG) contributes to producing a new electronic band gap structure to match the maximum excitation wavelength, then numerous excitons generate, which is a precondition for strong fluorescence emission. In the emission process, weak electron–phonon interactions, large rigidity, and constrained electron at the defects in FPG greatly reduce nonradiative recombination loss. Moreover, fluorine at the defects also reduces interlayer interactions among FPG nanosheets and resists the influence of absorbed impurities, thereby further restricting nonradiative recombination pathway. Highly fluorescent FPG has been utilized as a fascinating tool to achieve sensitive and naked-eye detection of Fe3+ions with a high selectivity. The fluorescence quenching efficiency reaches 24% even with an ultralow concentration of Fe3+(0.06 μM), and that increases to 84% when the concentration of Fe3+is 396 μM.