Assignment of Core and Surface States in Multicolor-Emissive Carbon Dots

Bohan Zhang; Bingzhe Wang; Elena V. Ushakova; Bingchen He; Guichuan Xing; Zikang Tang; Andrey L. Rogach; Songnan Qu

doi:10.1002/smll.202204158

Assignment of Core and Surface States in Multicolor-Emissive Carbon Dots

Bohan Zhang (Co-first Author), Bingzhe Wang (Co-first Author), Elena V. Ushakova (Co-first Author), Bingchen He, Guichuan Xing, Zikang Tang, Andrey L. Rogach^*, Songnan Qu^*

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

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Abstract

It is important to reveal the luminescence mechanisms of carbon dots (CDs). Herein, CDs with two types of optical centers are synthesized from citric acid in formamide by a solvothermal method, and show high photoluminescence quantum yield reaching 42%. Their green/yellow emission exhibits pronounced vibrational structure and high resistance toward photobleaching, while broad red photoluminescence is sensitive to solvents, temperature, and UV–IR. Under UV–IR, the red emission is gradually bleached due to the photoinduced dehydration of the deprotonated surface of CDs in dimethyl sulfoxide, while this process is hindered in water. From the analysis of steady-state and time-resolved photoluminescence and transient absorption data together with density functional theory calculations, the green/ yellow emission is assigned to conjugated sp²-domains (core state) similar to organic dye derivatives stacked within disk-shaped CDs; and the broad red emission—to oxygen-containing groups bound to sp²-domains (surface state), whereas energy transfer from the core to the surface state can happen. © 2022 Wiley-VCH GmbH.

Original language	English
Article number	2204158
Journal	Small
Volume	19
Issue number	31
Online published	10 Oct 2022
DOIs	https://doi.org/10.1002/smll.202204158
Publication status	Published - 2 Aug 2023

Funding

B. Zhang, B. Wang and E. V. Ushakova contributed equally to this work. This work was supported by the National Natural Science Foundation of China (61922091), the Science and Technology Development Fund of Macau SAR (0040/2019/A1, 0073/2019/AMJ, 0128/2020/A3, 0131/2020/A3, 0044/2020/A1), the Fund from the University of Macau (MYRG2020-00164-IAPME), the Research and Development Grant for Chair Professor Fund from the University of Macau (CPG2020-00026-IAPME), the Shenzhen-Hong Kong-Macao Science and Technology Innovation Project (Category C) SGDX20210823103803021 and SGDX2020110309360100, the Research Grant Council of Hong Kong S.A.R. (CityU 11306619), the Science Technology and Innovation Committee of Shenzhen Municipality (JCYJ20190808181201899), and the Priority 2030 Federal Academic Leadership Program, and the Russian Science Foundation (RSF22-13-00294).

Research Keywords

carbon dots
core state
emission center
photostability
surface state

Publisher's Copyright Statement

COPYRIGHT TERMS OF DEPOSITED POSTPRINT FILE: This is the peer reviewed version of the following article: Zhang, B., Wang, B., Ushakova, E. V., He, B., Xing, G., Tang, Z., Rogach, A. L., & Qu, S. (2022). Assignment of Core and Surface States in Multicolor-Emissive Carbon Dots. Small, 19(31), [2204158], which has been published in final form at https://doi.org/10.1002/smll.202204158.
This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

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title = "Assignment of Core and Surface States in Multicolor-Emissive Carbon Dots",

abstract = "It is important to reveal the luminescence mechanisms of carbon dots (CDs). Herein, CDs with two types of optical centers are synthesized from citric acid in formamide by a solvothermal method, and show high photoluminescence quantum yield reaching 42%. Their green/yellow emission exhibits pronounced vibrational structure and high resistance toward photobleaching, while broad red photoluminescence is sensitive to solvents, temperature, and UV–IR. Under UV–IR, the red emission is gradually bleached due to the photoinduced dehydration of the deprotonated surface of CDs in dimethyl sulfoxide, while this process is hindered in water. From the analysis of steady-state and time-resolved photoluminescence and transient absorption data together with density functional theory calculations, the green/ yellow emission is assigned to conjugated sp2-domains (core state) similar to organic dye derivatives stacked within disk-shaped CDs; and the broad red emission—to oxygen-containing groups bound to sp2-domains (surface state), whereas energy transfer from the core to the surface state can happen. {\textcopyright} 2022 Wiley-VCH GmbH.",

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author = "Bohan Zhang and Bingzhe Wang and Ushakova, {Elena V.} and Bingchen He and Guichuan Xing and Zikang Tang and Rogach, {Andrey L.} and Songnan Qu",

year = "2023",

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doi = "10.1002/smll.202204158",

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AU - Zhang, Bohan

AU - Wang, Bingzhe

AU - Ushakova, Elena V.

AU - He, Bingchen

AU - Xing, Guichuan

AU - Tang, Zikang

AU - Rogach, Andrey L.

AU - Qu, Songnan

PY - 2023/8/2

Y1 - 2023/8/2

N2 - It is important to reveal the luminescence mechanisms of carbon dots (CDs). Herein, CDs with two types of optical centers are synthesized from citric acid in formamide by a solvothermal method, and show high photoluminescence quantum yield reaching 42%. Their green/yellow emission exhibits pronounced vibrational structure and high resistance toward photobleaching, while broad red photoluminescence is sensitive to solvents, temperature, and UV–IR. Under UV–IR, the red emission is gradually bleached due to the photoinduced dehydration of the deprotonated surface of CDs in dimethyl sulfoxide, while this process is hindered in water. From the analysis of steady-state and time-resolved photoluminescence and transient absorption data together with density functional theory calculations, the green/ yellow emission is assigned to conjugated sp2-domains (core state) similar to organic dye derivatives stacked within disk-shaped CDs; and the broad red emission—to oxygen-containing groups bound to sp2-domains (surface state), whereas energy transfer from the core to the surface state can happen. © 2022 Wiley-VCH GmbH.

AB - It is important to reveal the luminescence mechanisms of carbon dots (CDs). Herein, CDs with two types of optical centers are synthesized from citric acid in formamide by a solvothermal method, and show high photoluminescence quantum yield reaching 42%. Their green/yellow emission exhibits pronounced vibrational structure and high resistance toward photobleaching, while broad red photoluminescence is sensitive to solvents, temperature, and UV–IR. Under UV–IR, the red emission is gradually bleached due to the photoinduced dehydration of the deprotonated surface of CDs in dimethyl sulfoxide, while this process is hindered in water. From the analysis of steady-state and time-resolved photoluminescence and transient absorption data together with density functional theory calculations, the green/ yellow emission is assigned to conjugated sp2-domains (core state) similar to organic dye derivatives stacked within disk-shaped CDs; and the broad red emission—to oxygen-containing groups bound to sp2-domains (surface state), whereas energy transfer from the core to the surface state can happen. © 2022 Wiley-VCH GmbH.

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KW - photostability

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Assignment of Core and Surface States in Multicolor-Emissive Carbon Dots

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GRF: Anisotropic Carbon Nanorods with Polarized Emission for Two-Photon Fluorescence Bioimaging

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Assignment of Core and Surface States in Multicolor-Emissive Carbon Dots

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Funding

Research Keywords

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GRF: Anisotropic Carbon Nanorods with Polarized Emission for Two-Photon Fluorescence Bioimaging

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