氮掺杂碳点的光稳定性研究

Photostability of nitrogen doped carbon dots

以柠檬酸、乙二胺为原料,采用水热反应合成了氮掺杂的碳点,系统研究不同pH条件下碳点在光照时的荧光变化规律。结果显示:随着光照时间的延长,碳点的荧光强度会逐渐降低,在pH为9.0的溶液中比pH为5.0和7.4的溶液中下降速率更快。在此基础上,采用紫外-可见吸收光谱及拉曼光谱探讨了碳点在光照后荧光猝灭机制,发现光照会破坏碳点的共轭π电子结构,从而使其荧光产生猝灭,而溶液中的溶解氧对碳点的光稳定性没有明显的影响。

Citric acid and ethylene-diamine were used to synthesize nitrogen-doped carbon dots by hydrothermal reaction.The fluorescence changes of carbon dots under different pH conditions were systematically studied.The results showed that the fluorescence of the carbon dots gradually decreased,and the rate of decline was faster in the solution of pH 9.0 than in the solutions of pH 5.0 and pH 7.4 as the illumination time increased.On this basis,UV-visible absorption spectroscopy and Raman spectroscopy were used to investigate the fluorescence quenching mechanism of carbon dots after illumination.It was found that the illumination destroyed the conjugatedπ-electron structure of the carbon dots,so that the fluorescence was quenched,and the dissolved oxygen in the solution had no significant effect on the photostability of the carbon dots.