Blue, green, and red full-color ultralong afterglow in nitrogen-doped carbon dots

• Published in: Nanoscale Vol. 11; no. 14; pp. 6584 - 6590
• Main Authors: Lin, Cunjian, Zhuang, Yixi, Li, Wuhui, Zhou, Tian-Liang, Xie, Rong-Jun
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 04.04.2019
• Subjects: Carbon dots; Coding; Color; Counterfeiting; Excitation spectra; Fluorescence; Fourier transforms; Image transmission; Infrared spectra; Inks; Phosphorescence; Photodynamic therapy; Photoelectrons; Recrystallization; Spectrum analysis; Synthesis; Transmission electron microscopy; Ultraviolet radiation; Wavelengths
• ISSN: 2040-3364; 2040-3372; 2040-3372
• DOI: 10.1039/C8NR09672D

Carbon dots (CDs) with tunable emission colors and multiple emission modes are highly desirable in advanced optical anti-counterfeiting. Some pioneering efforts to trigger additional long-lived emission modes, nevertheless, did not perfectly solve the issue of printability and color-tunability in practical applications. Herein, we developed an encapsulating-dissolving-recrystallization route for the synthesis of CD-based anti-counterfeiting inks, and accordingly realized blue, green, and red full-color afterglow emissions from these CD-based inks when printed on paper. The printed inks simultaneously possessed triple emission modes including fluorescence (FL), delayed fluorescence (DF), and room-temperature phosphorescence (RTP), among which the long-lived emissions (DF and RTP) could be selectively activated by using different excitation wavelengths. We believe that the proposed synthetic route in this work may promote the development of multicolor-encoded and multiple-mode-integrated optical anti-counterfeiting systems, and will expand the application of CD-based materials to the fields of sensing, photodynamic therapy and bio-imaging.