Wang Beibei, Luo Wei, Wu Di, Li Shugang, Geng Fang
Institute for Advanced Study, Chengdu University, Chengdu 610106, China.
Engineering Research Center of Bio-process (Ministry of Education), Key Laboratory for Agricultural Products Processing of Anhui Province, School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Dec 15;303:123117. doi: 10.1016/j.saa.2023.123117. Epub 2023 Jul 8.
An easy and effective route for preparing full-color (blue, green, yellow and red) carbon dots (CDs) with brilliant and stable photoluminescent (PL) was developed by using gallic acid and o-Phenylenediamine as precursors. The resulting CDs were then separated by silica-gel column chromatography. The prepared four types of CDs owned high quantum yields (up to 11.2%) and exhibited attractive features such as excellent solubility, high stability, excitation wavelength-independent PL, mono-exponential PL lifetimes, low cell toxicity and homogeneous optical properties. Then, the mechanism of full-color CDs PL was explored. The results suggested that the surface-states of prepared CDs, especially the pyridine N (C = N) and C = O functional groups, were primarily responsible for the full-color PL emission. The blue CDs had the largest content of C = O while the CDs turned to be green as the C = O decreased and the C = N content increased. The surface state regulation of C = N bond was dominant in yellow CDs while red CDs possessed highest content of C = N and new -COOH appeared. The gradual substitution of C = N to C = O made the band gap of CDs narrowed, which is the main reason for the redshift of CDs PL emission peak. Importantly, the easy preparation and unique optical features of these CDs made them potentially useful in numerous applications such as full-color cell labeling, drug delivery and optoelectronic technologies.
以没食子酸和邻苯二胺为前驱体，开发了一种简便有效的制备具有明亮且稳定光致发光（PL）的全色（蓝色、绿色、黄色和红色）碳点（CDs）的方法。然后通过硅胶柱色谱法分离得到的碳点。制备的四种类型的碳点具有高量子产率（高达11.2%），并表现出吸引人的特性，如优异的溶解性、高稳定性、与激发波长无关的PL、单指数PL寿命、低细胞毒性和均匀的光学性质。然后，探索了全色碳点PL的机制。结果表明，制备的碳点的表面态，特别是吡啶N（C=N）和C=O官能团，是全色PL发射的主要原因。蓝色碳点的C=O含量最高，而随着C=O含量降低和C=N含量增加，碳点变为绿色。在黄色碳点中，C=N键的表面态调控起主导作用，而红色碳点的C=N含量最高且出现了新的-COOH。C=N逐渐被C=O取代使得碳点的带隙变窄，这是碳点PL发射峰红移的主要原因。重要的是，这些碳点的简便制备方法和独特的光学特性使其在全色细胞标记、药物递送和光电子技术等众多应用中具有潜在用途。
