Qu Dan, Miao Xiang, Wang Xintong, Nie Chuang, Li Yuxin, Luo Ling, Sun Zaicheng
Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry and Chemical Engineering, Beijing University of Technology, P. R. China.
J Mater Chem B. 2017 Jul 7;5(25):4988-4992. doi: 10.1039/c7tb00875a. Epub 2017 Jun 6.
Both long wavelength excitation and emission are highly desired for fluorescent carbon dots in bio-related applications. According to semiconductor theory, heteroatom doping is an effective way to tune the band gap of a semiconductor. In this work, we developed an exceedingly simple and mild one-pot method to synthesize selenium and nitrogen co-doped carbon dots (Se&N-CDs) by using low cost citric acid, ethane diamine and selenium powder as the starting materials. After doping the Se element into N-CDs, the absorption of Se&N-CDs was expanded from UV to the visible light region (∼497 nm). More important is that the Se&N-CDs show a strong green light emission with a high quantum yield of ∼52%, attributed to the new Se-state introduced in the Se&N-CDs due to the low electronegativity of Se. Furthermore, we successfully demonstrate that Se&N-CDs have an excellent performance as a dye for fluorescein fundus angiography (FFA). After injection, a clear vascular image in the retina and detailed images of the capillary bed were exhibited in the FFA image. This will provide a great advantage for bio-imaging and diagnosis.
在生物相关应用中，荧光碳点非常需要长波长激发和发射。根据半导体理论，杂原子掺杂是调节半导体带隙的有效方法。在这项工作中，我们开发了一种极其简单温和的一锅法，以低成本的柠檬酸、乙二胺和硒粉为原料合成硒氮共掺杂碳点（Se&N-CDs）。将硒元素掺杂到氮掺杂碳点中后，Se&N-CDs的吸收从紫外光扩展到可见光区域（约497nm）。更重要的是，Se&N-CDs发出强烈的绿色光，量子产率高达约52%，这归因于由于硒的低电负性在Se&N-CDs中引入的新硒态。此外，我们成功证明Se&N-CDs作为荧光素眼底血管造影（FFA）染料具有优异的性能。注射后，FFA图像中显示出视网膜中清晰的血管图像和毛细血管床的详细图像。这将为生物成像和诊断提供巨大优势。
