Carbon Dots: Excitation‐Dependent Photoluminescence from Single‐Carbon Dots (Small 48/2017)

Dam, Bart van; Nie, Hui; Ju, Bo; Marino, Emanuele; Schall, Peter; Li, Minjie; Dohnalová, Kateřina

doi:10.1002/smll.201770251

Cited by 13 publications

(8 citation statements)

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“…It is further supported by the graphical representation of the variation of PL emission maxima upon varying the excitation wavelengths from 300 to 500 nm (Figure S8d). , For further clarification, we performed detailed time-resolved fluorescence lifetime measurements at 340 nm excitation wavelength (depicted in Figure d). N-CDs follow single-exponential decay kinetics, whereas O-CDs and P-CDs follow biexponential decay kinetics (calculated lifetime data are depicted in Table S1a).…”

Section: Results and Discussionmentioning

confidence: 99%

Switching between Fluorescence and Room Temperature Phosphorescence in Carbon Dots: Key Role of Heteroatom Functionalities

et al. 2023

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Herein, we have synthesized three different types of carbon dots, i.e., (a) CDs from citric acid, (b) nitrogen atom functionalized CDs from citric acid and ammonia, and (c) phosphorus atom functionalized CDs from citric acid and sodium dihydrogen orthophosphate through a simple bottom-up carbonization technique. Detailed morphological and elemental features are investigated by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy study, and it is further correlated to the ongoing photophysical properties. To investigate the specific role of the heteroatom functionalities on the room temperature phosphorescence, we have incorporated all these three types of CDs in a boric acid matrix to diminish the flexibility of surface functional groups and decrease the nonradiative relaxation processes. Various heteroatom functionalities play a very specific role to tune the afterglow properties by altering the energy gap (ΔE ST ) between the lowest excited singlet (S 1 ) and triplet state (T 1 ) and the spin−orbit coupling constant which eventually control the radiative recombination from the triplet state. Finally, a switchable fluorescence and room temperature phosphorescence have been observed depending on the specific heteroatom functionalities. A detailed temperature-dependent study has been performed to investigate the tunability between prompt fluorescence and phosphorescence properties. This is further correlated to the conversion of phosphorescence with thermally activated delayed fluorescence (TADF). Computational studies based on time-dependent density functional theory (TD-DFT) have been performed by using optimized model systems in connection to the elemental study, which nicely support our experimental findings.

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Section: Results and Discussionmentioning

confidence: 99%

Switching between Fluorescence and Room Temperature Phosphorescence in Carbon Dots: Key Role of Heteroatom Functionalities

et al. 2023

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“…Van Dam et al pointed out that the characteristic absorption peak of N-CNDs was generally accompanied by excitation dependent behavior. As shown in Figure S1, the emission wavelength increased with a rise in the excitation wavelength, which was consistent with ref .…”

Section: Results and Discussionmentioning

confidence: 92%

“…To further study the influence of the composition of the carbon nanodots on their luminescence behavior, the high-resolution spectra containing C 1s, N 1s, and O 1s peaks are now discussed. In Figure , the four characteristic peaks for the C 1s Gaussian fittings are located at 284.4, 285.2, 286.4, and 288.0 eV, which correspond to the sp 2 hybridized graphite-like carbon atoms, the sp 3 hybridized carbon atoms, the O–C1/4O groups, and the CO/OC–O groups, respectively. , It is observed from the high-resolution spectra of N 1s, that the binding energy peaks of the amino group and the pyrrole nitrogen are 399.5 and 400.5 eV, respectively . It can be seen that the surface of CNDs was modified by the amino groups.…”

Section: Results and Discussionmentioning

confidence: 96%

Synthesis and Photoluminescence Mechanism of Multicolored Nitrogen-Doped Carbon Nanodots and Their Application in Polymer Self-Assemblies

Xie

Tian

et al. 2022

ACS Appl. Polym. Mater.

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For applications in the fields of biological imaging and chemical sensing, fluorescent carbon nanodots (CNDs) have excellent possibilities because of their unique structure and performance. In this work, we synthesized a series of nitrogen-doped CNDs (N-CNDs) with different fluorescent emission, ranging from blue to yellow, via one-pot solvothermal strategy. Citric acid and urea were employed as the precursors. Formamide, ethanol and N,N-dimethylformamide were used as the solvent, respectively. The excitation-dependent emission and the optimal emission were measured with the ultraviolet–visible and photoluminescence spectra. The morphology and chemical structure of the prepared N-CNDs were characterized via high-resolution transmission electron microscope (HRTEM), atomic force microscope (AFM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, carbon nuclear magnetic resonance (13C NMR) spectroscopy, and so forth. The influence of reaction time, temperature, and type of solvent on the structure of N-CNDs were systematically investigated. The photoluminescence mechanism was discussed based on the chemical structure, the crystallinity and the sp2/sp3 carbon ratio of the prepared N-CNDs. In addition, a biocompatible amphiphilic copolymer mPEG-b-PLLA was synthesized and self-assembled in an aqueous system. The prepared N-CNDs were introduced into the polymer self-assemblies as a fluorescent probe by an in situ grafting method. The fluorescence imaging performance of N-CNDs in the polymer self-assemblies was investigated by comparing with organic fluorescent dye coumarin-6.

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“…The CCDs exhibited the greatest emission at 445 nm under 355 nm excitation. The Cu-CCDs exhibited the greatest emission at 440 nm under 360 nm excitation, where Cu-CCDs emitted a stronger fluorescence than CCDs [ 47 ]. This may be because the conjugate structure in ciprofloxacin can interact with Cu 2+ .…”

Section: Resultsmentioning

confidence: 99%

Preparation of Ciprofloxacin-Based Carbon Dots with High Antibacterial Activity

Miao

Wang

Cong

et al. 2023

IJMS

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Nowadays, bacterial infections are attracting great attention for the research and development of new antimicrobial agents. As one of the quinolones, ciprofloxacin (CI) has a broad-spectrum, strong antibacterial effect. However, the clinical use of ciprofloxacin is limited by drug resistance. Ciprofloxacin carbon dots (CCDs) with enhanced antibacterial activity and copper-doped ciprofloxacin carbon dots (Cu-CCDs) were synthesized by a simple hydrothermal method. The results of structural analysis and antibacterial experiments show that CCDs and Cu-CCDs have effective antibacterial properties by retaining the active groups of ciprofloxacin (-COOH, C-N, and C-F), and Cu-CCDs doped with copper have a better antibacterial effect. In addition, experiments have shown that Cu-CCDs show excellent antibacterial activity against E. coli and S. aureus and have good biocompatibility, which indicates that they have great prospects in clinical applications. Therefore, novel modified copper CCDs with broad-spectrum antibacterial activity, which can be used as antibacterial nanomaterials for potential applications in the field of antibacterial drugs, were synthesized in this study.

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Carbon Dots: Excitation‐Dependent Photoluminescence from Single‐Carbon Dots (Small 48/2017)

Cited by 13 publications

References 0 publications

Switching between Fluorescence and Room Temperature Phosphorescence in Carbon Dots: Key Role of Heteroatom Functionalities

Switching between Fluorescence and Room Temperature Phosphorescence in Carbon Dots: Key Role of Heteroatom Functionalities

Synthesis and Photoluminescence Mechanism of Multicolored Nitrogen-Doped Carbon Nanodots and Their Application in Polymer Self-Assemblies

Preparation of Ciprofloxacin-Based Carbon Dots with High Antibacterial Activity

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