Design of a Synthetic Strategy to Achieve Enhanced Fluorescent Carbon Dots with Sulfur and Nitrogen Codoping and Its Multifunctional Applications

Abstract

Here, a rational strategy to achieve multifunctional N, S codoped carbon dots (N, S‐CDs) is reported, aiming to improve the photoluminescence quantum yields (PLQYs) of the CDs. The synthesized N, S‐CDs have excellent stability and emission properties independent of excitation wavelength. Through the introduction of S element doping, the fluorescence emission of CDs is red‐shifted from 430 to 545 nm, and the corresponding PLQYs can be greatly enhanced from 11.2% to 65.1%. It is found that the doping of S elements causes an increase in the size of CDs and an elevated graphite N content, which may be the key factors to cause the redshift of fluorescence emission. Furthermore, the introduction of S element also serves to suppress the nonradiative transitions, which may be responsible for the elevated PLQYs. Besides, the synthesized N, S‐CDs have certain solvent effect and can be applied to detect water content in organic solvents, and have strong sensitivity to alkaline environment. More importantly, the N, S‐CDs can be used to achieve an “on–off–on” dual detection mode between Zr4+ and NO2−. In addition, N, S‐CDs combinedwith polyvinylpyrrolidone (PVP) can also be utilized as fluorescent inks for anti‐counterfeiting applications.

Melatonin-Derived Carbon Dots with Free Radical Scavenging Property for Effective Periodontitis Treatment via the Nrf2/HO-1 Pathway

“…The ultraviolet−visible (UV−vis) spectrum of MT-CDs 1D), corresponding to the π → π* transition of the C�C bonds. 40 Then, the functional groups and chemical structures of CDs were analyzed using Fourier transform infrared (FTIR) spectra (Figure 1E). The FTIR spectrum of MT presented absorption peaks at approximately 3287, 1433, and 1211 cm −1 , attributed to the stretching vibrations of N−H, C−N, and C−O−C, respectively.…”

“…MT-CDs showed an obvious excitation-dependent fluorescence with optimal emission at 382 nm under 330 nm excitation (Figure C). The ultraviolet–visible (UV–vis) spectrum of MT-CDs exhibited three major absorption peaks at around 220, 274, and 294 nm (Figure D), corresponding to the π → π* transition of the CC bonds . Then, the functional groups and chemical structures of CDs were analyzed using Fourier transform infrared (FTIR) spectra (Figure E).…”

Advances in the Research of Photo, Electrical, and Magnetic Responsive Smart Superhydrophobic Materials: Synthesis and Potential Applications

“…The term "responsive factor" typically refers to specific sensitive substances that undergo changes in response to external stimuli. For instance, photoresponsive materials commonly include polyvinylpyrrolidone [72,73] and TiO 2 , [74,75] electric-responsive materials encompass graphene, [76,77] carbon nanotubes, [78,79] and metal oxides, [80,81] while magnetic-responsive materials comprise Fe, Co, Ni, [82] as well as iron oxides (Fe 3 O 4 , [83,84] γ-Fe 2 O 3 [85,86] ), among others. Noteworthy external environmental stimuli include light, electricity, and magnetism.…”

Wavelength-Tuneable Fluorescent Carbon Dots for Nucleic Acid Imaging

“…had been proved to adjust the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), thereby altering change optical properties of CDs. , Among them, nitrogen doping is the most commonly used strategy for adjusting CDs wavelength which provides more hybrid orbitals through forming graphite nitrogen, pyrrole nitrogen, pyridine nitrogen, and amino groups. , For instance, Peng et al utilized glucose and citric acid as carbon sources to prepare nitrogen-CDs which exhibited blue to green emission with the increase of nitrogen content . Moreover, doping CDs with different nitrogen structures offers flexibility in regulating the band gap and adjusting the wavelength. − Unfortunately, there is no literature to report how to regulate the structure and corresponding content of nitrogen in CDs to regulate their wavelength accurately for nucleic acid imaging.…”