Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
J Mater Chem B. 2019 Mar 7;7(9):1494-1502. doi: 10.1039/c8tb03103g. Epub 2019 Feb 12.
A novel electrochemical strategy for simple and facile synthesis of semicarbazide functionalized nitrogen-doped graphene quantum dots (N-GQDs) was reported, based on direct exfoliation and oxidation from graphite rods. The average diameter of the as-synthesized N-GQDs is about 20 nm, and their dispersion is bright yellow due to the rich nitrogen and oxygen functional groups on their surface. The N-GQD dispersion was further applied in the selective detection of ferric ions (Fe) based on the photoluminescence (PL) quenching of N-GQDs after adding Fe. The fluorescent sensor has a wide linear range of 0-200 μM and a detection limit of 0.87 μM, which is much lower than the maximum level (0.3 mg L, equivalent to 5.4 μM) of Fe permitted in drinking water by the U.S. Environmental Protection Agency (EPA). Moreover, these novel N-GQDs exhibit much wider emission bands, which extend into the entire visible region, and emit three primary color fluorescence independently. This distinctive behavior of the as-prepared GQDs not only breaks the limitation that traditional reported GQDs only exhibit blue emission in the short-wavelength region, but may also provide a new research platform for further applications of GQDs in real environmental detection and biological imaging systems.
本文报道了一种基于石墨棒直接剥离和氧化的新型电化学策略，用于简单、方便地合成氨基功能化的氮掺杂石墨烯量子点（N-GQDs）。所合成的 N-GQDs 的平均直径约为 20nm，由于其表面丰富的氮和氧官能团，其分散体呈亮黄色。N-GQD 分散体进一步应用于基于加入 Fe 后 N-GQDs 的光致发光（PL）猝灭的铁离子（Fe）的选择性检测。荧光传感器具有 0-200μM 的宽线性范围和 0.87μM 的检测限，远低于美国环境保护署（EPA）规定的饮用水中允许的 Fe 最大水平（0.3mg L，相当于 5.4μM）。此外，这些新型 N-GQDs 表现出更宽的发射带，延伸到整个可见光区域，并独立发射三基色荧光。这种独特的行为不仅打破了传统报道的 GQDs 仅在短波长区域显示蓝色发射的限制，而且可能为进一步将 GQDs 应用于实际环境检测和生物成像系统提供新的研究平台。
