Surface Chemistry Routes to Modulate the Photoluminescence of Graphene Quantum Dots: From Fluorescence Mechanism to Up-Conversion Bioimaging Applications
Surface Chemistry Routes to Modulate the Photoluminescence of Graphene Quantum Dots: From Fluorescence Mechanism to Up-Conversion Bioimaging Applications
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调节石墨烯量子点光致发光的表面化学途径：从荧光机制到上转换生物成像应用
DOI：
10.1002/adfm.201201499
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发表时间：
2012-11-21
影响因子：
19
通讯作者：
Yang, Bai
中科院分区：
文献类型：
--
作者：
Zhu, Shoujun;Zhang, Junhu;Yang, Bai
石墨烯基材料的带隙可以通过改变尺寸和/或表面化学从0 eV调整到苯的带隙，使其成为一种新兴的碳基荧光材料。这里，通过改性或还原可编程地调节小尺寸石墨烯（石墨烯量子点，GQD）的表面化学，并且将绿色发光GQD改变为蓝色发光GQD。几种工具被用来表征合成物的组成和形态。更重要的是，利用该系统，发光机制（缺陷态发射和本征态发射之间的竞争）进行了详细的探讨。实验表明，改性或还原过程中的化学结构变化抑制了局域电子-空穴对的非辐射复合和/或增强了表面p电子网络的完整性。因此，与GQD中的缺陷态发射相反，本征态发射起主导作用。时间分辨的测量结果与所提出的PL机制是一致的。GQDs的上转换发光被成功地应用于近红外激发的生物成像。
The bandgap in graphene-based materials can be tuned from 0 eV to that of benzene by changing size and/or surface chemistry, making it a rising carbon-based fluorescent material. Here, the surface chemistry of small size graphene (graphene quantum dots, GQDs) is tuned programmably through modification or reduction and green luminescent GQDs are changed to blue luminescent GQDs. Several tools are employed to characterize the composition and morphology of resultants. More importantly, using this system, the luminescence mechanism (the competition between both the defect state emission and intrinsic state emission) is explored in detail. Experiments demonstrate that the chemical structure changes during modification or reduction suppresses non-radiative recombination of localized electron-hole pairs and/or enhances the integrity of surface p electron network. Therefore the intrinsic state emission plays a leading role, as opposed to defect state emission in GQDs. The results of time-resolved measurements are consistent with the suggested PL mechanism. Up-conversion PL of GQDs is successfully applied in near-IR excitation for bioimaging.