Near‐Infrared Excitation/Emission and Multiphoton‐Induced Fluorescence of Carbon Dots |
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Authors: | Di Li Pengtao Jing Lihuan Sun Yang An Xinyan Shan Xinghua Lu Ding Zhou Dong Han Dezhen Shen Yuechen Zhai Songnan Qu Radek Zbo?il Andrey L Rogach |
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Affiliation: | 1. State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences, Changchun, P. R. China;2. Institute of Physics, Chinese Academy of Sciences, Beijing, P. R. China;3. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, P. R. China;4. Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Palacky University Olomouc, Olomouc, Czech Republic;5. Department of Materials Science and Engineering, Centre for Functional Photonics (CFP), City University of Hong Kong, Kowloon, Hong Kong SAR |
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Abstract: | Carbon dots (CDs) have significant potential for use in various fields including biomedicine, bioimaging, and optoelectronics. However, inefficient excitation and emission of CDs in both near‐infrared (NIR‐I and NIR‐II) windows remains an issue. Solving this problem would yield significant improvement in the tissue‐penetration depth for in vivo bioimaging with CDs. Here, an NIR absorption band and enhanced NIR fluorescence are both realized through the surface engineering of CDs, exploiting electron‐acceptor groups, namely molecules or polymers rich in sulfoxide/carbonyl groups. These groups, which are bound to the outer layers and the edges of the CDs, influence the optical bandgap and promote electron transitions under NIR excitation. NIR‐imaging information encryption and in vivo NIR fluorescence imaging of the stomach of a living mouse using CDs modified with poly(vinylpyrrolidone) in aqueous solution are demonstrated. In addition, excitation by a 1400 nm femtosecond laser yields simultaneous two‐photon‐induced NIR emission and three‐photon‐induced red emission of CDs in dimethyl sulfoxide. This study represents the realization of both NIR‐I excitation and emission as well as two‐photon‐ and three‐photon‐induced fluorescence of CDs excited in an NIR‐II window, and provides a rational design approach for construction and clinical applications of CD‐based NIR imaging agents. |
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Keywords: | carbon dots multiphoton‐induced fluorescence near‐infrared absorption near‐infrared fluorescence surface engineering |
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