Recently, Dr. Tan Jing, the first author of our institute, published a research paper entitled “Time-Dependent Phosphorescence Colors from Carbon Dots for Advanced Dynamic Information Encryption" in the Journal of advanced materials (IF=27.398).
Room temperature phosphorescence refers to the luminescence phenomenon that can continue to emit light for several seconds or even more than several hours after the excitation stops. This long-life and high signal-to-noise ratio characteristics give it a wide application prospect in the fields of information storage, encryption, display and biological imaging. in recent years, Room temperature phosphorescent materials (including organic, inorganic nanocrystals and carbon dots) have attracted more and more attention and made rapid development. However, most phosphorescent materials only show a single and static phosphorescent color, which is not conducive to the practical application of advanced anti-counterfeiting and data encryption. Time-dependent phosphorescence colors materials have a long time range after the light excitation stops (seconds to minutes) can display polychromatic phosphorescence, has the characteristics of dynamic differential luminescence, and can provide additional encryption mode and storage space, which has gradually attracted extensive attention of researchers. However, at present, this kind of Time-dependent phosphorescence colors materials is very rare, and there are still great challenges for its development.
By doping the core and regulating the surface state of carbon nanodots, the team printed them on paper and realized the Time-dependent phosphorescence colors of carbon dots for the first time. After the material stops light excitation in a specific wavelength range (395 nm), the phosphorescent color exhibits a dynamic change from orange to green within a few seconds. In addition, the dynamic discoloration behavior of the material exhibit unique wavelength dependence, it has a dynamic color change behavior only after excitation at a specific wavelength, and only exhibits a single green or red phosphorescence above or below the wavelength (e.g. 365 nm or 425 nm). Based on the excellent characteristics of carbon dots, it is applied to three-dimensional color coding for the first time to realize multi-level encryption, storage and dynamic display of information. This study proposes a new method to realize Time-dependent phosphorescence colors of carbon dots based on core doping and surface state regulation. The application of multi-level encryption and dynamic storage of information provides new tools and opportunities.
Tan Jing, a young teacher from our institute, is the first author of this article. Li Qijun, a young teacher from the Institute for Energy Research of our school, Professor Ren Xudong from the School of Mechanical Engineering, and Professor Qu Songnan from the University of Macau are the co-corresponding authors of the paper. Other authors of the article include Professor Ye Yunxia, graduate students Meng Shuai, Li Yuchen and Yang Jian from Institute of Micro-nano Optoelectronics and Terahertz Technology, and Professor Tang Zikang from the University of Macau. The research was funded by the National Natural Science Foundation of China, the Natural Science Foundation of Jiangsu Province, and the National Postdoctoral Fund.
