Su Rigu, Guan Qingwen, Cai Wei, Yang Wenjing, Xu Quan, Guo Yongjian, Zhang Lipeng, Fei Ling, Xu Meng
State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing) 102249 China
College of Energy, Beijing University of Chemical Technology Beijing 102200 China.
RSC Adv. 2019 Mar 27;9(17):9700-9708. doi: 10.1039/c8ra09868a. eCollection 2019 Mar 22.
Heteroatom doped carbon dots (CDs) with color adjustable properties have attracted extensive attention. The doping of elements can effectively tune the surface chemical properties of CDs, thus resulting in its multi-functional applications such as in bio-imaging, photocatalysis, and photothermal conversion. The facile preparation of single metal-doped CDs with color-tunable properties has been rarely reported yet. Herein, we report a one-step solvothermal method to synthesize CDs with different fluorescent emission varying from red to purple to blue. The luminescence characteristic of CDs can be tuned by simply controlling the ratio of precursors, with the emission wavelength correspondingly adjusted from 610 nm to 390 nm. XPS investigation further demonstrated that the color variation is mainly due to the doping of zinc, which will increase the degree of surface oxidation in the as-prepared CDs. For blue emission CDs, the content of graphitic carbon gradually decreases with the rising of zinc chloride addition, while oxygen content remains around 20%, compared with red emission CDs of which the oxygen content is only 4.42%. We also demonstrated with theoretical simulations that the Zn dopant and the functional groups including -C[double bond, length as m-dash]O, -C-OH, -NH, and pyrrolic N, play an important role in color change. Furthermore, the synthesized CDs have been successfully used into the fabrication of white LEDs. More than that, we produced a sensitive sensor from the prepared CDs for the effective detection of a variety of colorless transparent organic solvents utilizing the robust fluorescence properties of CDs, showing their great potential as fluorescent probes for chemical sensing.
具有颜色可调特性的杂原子掺杂碳点（CDs）引起了广泛关注。元素的掺杂可以有效地调节碳点的表面化学性质，从而使其具有生物成像、光催化和光热转换等多功能应用。然而，关于简便制备具有颜色可调特性的单金属掺杂碳点的报道却很少。在此，我们报道了一种一步溶剂热法来合成荧光发射从红色到紫色再到蓝色变化的碳点。通过简单地控制前驱体的比例就可以调节碳点的发光特性，发射波长相应地从610nm调整到390nm。X射线光电子能谱（XPS）研究进一步表明，颜色变化主要是由于锌的掺杂，这会增加所制备碳点的表面氧化程度。对于蓝色发射的碳点，随着氯化锌添加量的增加，石墨化碳的含量逐渐降低，而氧含量保持在20%左右，相比之下红色发射碳点的氧含量仅为4.42%。我们还通过理论模拟证明，锌掺杂剂以及包括-C=O、-C-OH、-NH和吡咯氮在内的官能团在颜色变化中起重要作用。此外，合成的碳点已成功用于制造白色发光二极管（LED）。不仅如此，利用所制备碳点强大的荧光特性，我们制备了一种灵敏的传感器，用于有效检测多种无色透明有机溶剂，显示出它们作为化学传感荧光探针的巨大潜力。
