蓝色荧光碳点的制备及检测、防伪应用

Preparation ofbluecarbon dots and its application in detection and anti-counterfeiting

摘要:

以柠檬酸钠为碳源、以氨水为氮源，采用一步水热法制备了非激发波长依赖型氮掺杂碳点（NCDs），在优化制备条件后采用荧光光谱仪、TEM、AFM、XPS、及FTIR对最优条件下制备的NCDs进行表征，并探索了NCDs在Fe3+检测及荧光防伪中的应用。结果表明，NCDs的最优制备条件为柠檬酸钠浓度为0.1 mol/L、氨水浓度为1.8 mol/L、反应温度为200 ℃、反应时间6 h、装载体积25 mL。在最优条件下制备的NCDs的荧光为典型的非激发波长依赖型，最佳激发波长为343 nm，最佳发射波长为443 nm，荧光量子产率可达54.9%。NCDs为球形结构，平均粒径为4.96 nm，碳核为类石墨烯结构且其表面含有—NH2、—OH及—COOH。NCDs的荧光可被Fe3+选择性淬灭，且荧光淬灭程度ΔF与Fe3+浓度在0.1~87.5 μmol/L范围内线性关系良好，检测限为50 nmol/L。此外，将NCDs配制成荧光墨水，利用喷墨打印机打印出的图案整体饱满、边缘细节清晰具有很强的可识别性。

Abstract:

Nitrogen-doped Carbon Dots (NCDs) exhibiting excitation independent emission properties were synthesized by one-step hydrothermal method with sodium citrate as carbon source and ammonia as nitrogen source. NCDs prepared under optimal conditions were characterized by fluorescence spectrometer, TEM, AFM, XPS, and FTIR. The application of NCDs in Fe3+ detection and fluorescence anti-counterfeiting is also explored. The results showed that the optimal preparation conditions of NCDs were sodium citrate concentration of 0.1 mol/L, ammonia concentration of 1.8 mol/L, reaction temperature of 200 ℃, reaction time of 6 h, loading volume of 25 mL. The results demonstrated that the location of fluorescence emission peak of NCDs prepared under the optimal conditions is independent on the wavelength of excitation light, the best excitation wavelength is 343 nm and the best emission wavelength is 443 nm, while the fluorescence quantum yield is 54.9%.In terms of structure, NCDs are spherical with an average particle size of 4.96 nm. The carbon core is graphene-like structure and its surface contains —NH2, —OH and —COOH. The fluorescence of NCDs can be selectively quenched by Fe3+, and the degree of fluorescence quenching ΔF is linear related with the concentration of Fe3+ in the range of 0.1 and 87.5 μmol/L with the limit of detection of 50 nmol/L. In addition, fluorescent ink is prepared with the addition of NCDs, and the pattern printed by the inkjet printer is full as a whole, with clear edge details and strong identification.