@article{Wang_Jiang_Du_Zheng_Li_Li_Lin_2021, title={Green and Near-Infrared Dual-Mode Afterglow of Carbon Dots and Their Applications for Confidential Information Readout}, volume={13}, url={https://nmlett.org/index.php/nml/article/view/964}, DOI={10.1007/s40820-021-00718-z}, abstractNote={<p>Near-infrared (NIR), particularly NIR-containing dual-/multi-mode afterglow, is very attractive in many fields of application, but it is still a great challenge to achieve such property of materials. Herein, we report a facile method to prepare green and NIR dual-mode afterglow of carbon dots (CDs) through in situ embedding o-CDs (being prepared from o-phenylenediamine) into cyanuric acid (CA) matrix (named o-CDs@CA). Further studies reveal that the green and NIR afterglows of o-CDs@CA originate from thermal activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) of o-CDs, respectively. In addition, the formation of covalent bonds between o-CDs and CA, and the presence of multiple fixation and rigid effects to the triplet states of o-CDs are confirmed to be critical for activating the observed dual-mode afterglow. Due to the shorter lifetime and insensitiveness to human vision of the NIR RTP of o-CDs@CA, it is completely covered by the green TADF during directly observing. The NIR RTP signal, however, can be readily captured if an optical filter (cut-off wavelength of 600 nm) being used. By utilizing these unique features, the applications of o-CDs@CA in anti-counterfeiting and information encryption have been demonstrated with great confidentiality. Finally, the as-developed method was confirmed to be applicable to many other kinds of CDs for achieving or enhancing their afterglow performances.</p> <p>Highlights:</p> <p>1 A facile method was developed to achieve visible light (green) and near infrared dual-mode afterglow emissions from carbon dots (CDs)-based materials at ambient conditions for the first time.<br>2 We proposed a promising method in advanced information security applications through a special manner of readout.<br>3 The as-developed method was confirmed to be applicable to many kinds of CDs for achieving or enhancing their afterglow performances.</p>}, journal={Nano-Micro Letters}, author={Wang, Yuci and Jiang, Kai and Du, Jiaren and Zheng, Licheng and Li, Yike and Li, Zhongjun and Lin, Hengwei}, year={2021}, month={Sep.}, pages={198} }