Ren Xin, Zhang Fang, Guo Bingpeng, Gao Na, Zhang Xiaoling
School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Analytical and Testing Center, Beijing Institute of Technology, Beijing 100081, China.
Nanomaterials (Basel). 2019 Apr 1;9(4):495. doi: 10.3390/nano9040495.
Pursuit of a simple, fast, and cost-effective method to prepare highly and dual-wavelength fluorescent carbon quantum dots (CQDs) is a persistent objective in recent years. Here, we fabricated N-doped micropore carbon quantum dots (NM-CQDs) with a high quantum yield and dual-wavelength photoluminescence (PL) emission from sustainable biomass using a pulsed laser ablation method. Interestingly, two coexisting indigo⁻blue photoluminescence (PL) emissions were clearly observed, elucidating that the excited electrons transited from the intrinsic π* orbital to the surface state (SS) formed from the saturation passivation. The quantum yield (QY) and fluorescence lifetime (FL) of the obtained NM-CQDs were as high as 32.4% and 6.56 ns. Further investigations indicated that the emission behaviors of NM-CQDs were still stable and independent in various conditions such as various excitation wavelengths, salt ionic concentrations, pH values, irradiation times, and temperatures. The obtained NM-CQDs are very suitable for cellular staining images due to strong and stable PL emission and show good internalization in different cells. Therefore, we propose a new and cost-effective preparation strategy for highly fluorescent NM-CQDs with great potential in biomedical imaging and engineering.
近年来，寻求一种简单、快速且经济高效的方法来制备高荧光和双波长荧光碳量子点（CQDs）一直是一个长期目标。在此，我们采用脉冲激光烧蚀法，利用可持续生物质制备了具有高量子产率和双波长光致发光（PL）发射的氮掺杂微孔碳量子点（NM-CQDs）。有趣的是，清晰观察到两种共存的靛蓝-蓝色光致发光（PL）发射，这表明激发电子从本征π*轨道跃迁到由饱和钝化形成 的表面态（SS）。所制备的NM-CQDs的量子产率（QY）和荧光寿命（FL）分别高达32.4%和6.56 ns。进一步研究表明，在各种激发波长、盐离子浓度、pH值、照射时间和温度等条件下，NM-CQDs的发射行为仍然稳定且不受影响。由于其强而稳定的PL发射，所获得的NM-CQDs非常适合用于细胞染色成像，并在不同细胞中表现出良好的内化效果。因此，我们提出了一种新的、具有成本效益的制备策略，用于制备在生物医学成像和工程领域具有巨大潜力的高荧光NM-CQDs。
