Nitrogen-doped carbon quantum dots obtained hydrothermally from citric acid and urea: The role of the specific nitrogen centers in their electrochemical and optical responses

Vercelli, Barbara; Donnini, Riccardo; Ghezzi, F.; Sansonetti, Antonio; Giovanella, Umberto; Ferla, Barbara La

doi:10.1016/j.electacta.2021.138557

Cited by 54 publications

(43 citation statements)

References 36 publications

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“…This effect could possibly have been the result of the protonation/deprotonation of the pyridinic N-atoms such that the electrostatic interactions between the NCQDs shifted the Fermi energy levels and affected the FL emission centers of the NCQDs. 33–36 Previous studies have shown that N-doped CQDs may show different FL emission properties based on their interactions with the surrounding medium. 37 Therefore, the luminescence behavior of the NCQDs was assessed in six different solvents ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Hydrothermal synthesis of nitrogen-doped carbon quantum dots from lignin for formaldehyde determination

et al. 2021

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Section: Resultsmentioning

confidence: 99%

Hydrothermal synthesis of nitrogen-doped carbon quantum dots from lignin for formaldehyde determination

et al. 2021

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“…It can be inferred that the N-GQDs should be an excellent candidate for bioimaging. , it was concluded that the as-prepared N-GQDs exhibit good stability under acid and neutral pH environments, and thus the protonation or deprotonation of the N-GQDs is also very weak [60][61][62]. Compared with the results reported in [63], the as-prepared N-GQDs can be used in a wide range of pH environments.…”

Section: Optical Propertiesmentioning

confidence: 93%

“…The fluorescence intensities of the N-GQDs varying with pH value in the range of 2-9 (adjusted by HCl and NaOH) are shown in Figure 5B. Because the intensities did not show any obvious change with pH values in the range of 3-8, it was concluded that the as-prepared N-GQDs exhibit good stability under acid and neutral pH environments, and thus the protonation or deprotonation of the N-GQDs is also very weak [60][61][62]. Compared with the results reported in [63], the as-prepared N-GQDs can be used in a wide range of pH environments.…”

Section: Optical Propertiesmentioning

confidence: 97%

One-Pot Synthesis of Bright Blue Luminescent N-Doped GQDs: Optical Properties and Cell Imaging

Wang

Yang

et al. 2021

Nanomaterials

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High fluorescent graphene quantum dots (GQDs) are promising in bioimaging and optoelectronics. In this paper, bright blue fluorescent N-doped GQDs were synthesized using a ultrasonic-assisted hydrothermal method. The morphology, structure, surface chemistry, optical properties, and stability subject to photo-bleaching, temperature, pH and preservation period for the N-GQDs were investigated in detail using various microscopy and spectroscopy techniques. The results showed that the N-GQDs possessed an average size of 2.65 nm, 3.57% N doping, and up to 54% quantum yield (QY). The photoluminescence (PL) spectra of the N-GQDs are excitation dependent when excited in the range of 300–370 nm and excitation independent in the range of 380–500 nm for the core and surface states emission. The N-GQDs showed excellent photo-bleaching resistance and superior photo-stability. At room temperature and in the pH range of 3–8, the fluorescence of the N-GQDs was almost invariable. The N-GQDs can be stably preserved for at least 40 days. The average decay lifetime of the N-GQDs was 2.653 ns, and the radiative and nonradiative decay rate constants were calculated to be 2.04 × 108 s−1 and 1.73 × 108 s−1, respectively. The PL mechanism was qualitatively explained. The N-GQDs was used for cell imaging, and it showed good results, implying great potential applications for bioimaging or biomarking.

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“…In the present work, we used EDA and urea as precursors for synthesizing nitrogen-doped CDs. EDA and urea are already reported precursors for synthesizing nitrogen-doped carbon dots [22][23][24] In a typical experiment, nitrogen-doped carbon quantum dots (N CDs) were prepared by mixing 500 μl EDA and 0.5 g of urea in 1 ml water. The resulting solution was heated in a domestic microwave oven at 800 W for 2 min.…”

Section: Synthesis Of Cdsmentioning

confidence: 99%

Comparative photoluminescence study of nitrogen‐doped carbon dots co‐doped with boron and sulphur

Joseph

Anappara

2022

Luminescence

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Although different studies in carbon dots (CDs) have been reported based on heteroatom doping, most of them have focussed on the enhancement of fluorescence properties. Here we report a comparative study of both fluorescence and room‐temperature phosphorescence (RTP) of nitrogen–sulphur‐doped CDs (N–S CDs) and nitrogen–boron‐doped CDs (N–B CDs) with N‐doped CDs (N CDs). The CDs used in the study were synthesized through microwave‐assisted pyrolysis. Among the doped CDs, sulphur‐doped CDs showed a high fluorescence quantum yield. Upon irradiation, the aqueous dispersion of the CDs demonstrated blue fluorescence. Furthermore, by incorporating the CDs in a potash alum matrix, blue fluorescence, as well as green phosphorescence was observed. The phosphorescence lifetime measurements indicated that the N–S CDs exhibited a longer emission lifetime and a red‐shifted emission in contrast with other samples, which might be attributed to the presence of a greater proportion of surface states on the N–S CDs.

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Nitrogen-doped carbon quantum dots obtained hydrothermally from citric acid and urea: The role of the specific nitrogen centers in their electrochemical and optical responses

Cited by 54 publications

References 36 publications

Hydrothermal synthesis of nitrogen-doped carbon quantum dots from lignin for formaldehyde determination

Hydrothermal synthesis of nitrogen-doped carbon quantum dots from lignin for formaldehyde determination

One-Pot Synthesis of Bright Blue Luminescent N-Doped GQDs: Optical Properties and Cell Imaging

Comparative photoluminescence study of nitrogen‐doped carbon dots co‐doped with boron and sulphur

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