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Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response
摘要： Carbon dots (CDs) are an emerging family of nanosystems displaying a range of fascinating properties. Broadly speaking, they can be described as small, surface-functionalized carbonaceous nanoparticles characterized by an intense and tunable ?uorescence, a marked sensitivity to the environment and a range of interesting photochemical properties. CDs are currently the subject of very intense research, motivated by their possible applications in many ?elds, including bioimaging, solar energy harvesting, nanosensing, light-emitting devices and photocatalyis. This review covers the latest advancements in the ?eld of CDs, with a focus on the fundamental understanding of their key photophysical behaviour, which is still very debated. The photoluminescence mechanism, the origin of their peculiar ?uorescence tunability, and their photo-chemical interactions with coupled systems are discussed in light of the latest developments in the ?eld, such as the most recent results obtained by femtosecond time-resolved experiments, which have led to important steps forward in the fundamental understanding of CDs. The optical response of CDs appears to stem from a very complex interplay between the electronic states related to the core structure and those introduced by surface functionalization. In addition, the structure of CD energy levels and the electronic dynamics triggered by photo-excitation ?nely depend on the microscopic structure of any speci?c sub-type of CD. On the other hand, this remarkable variability makes CDs extremely versatile, a key bene?t in view of their very wide range of applications.
关键词： femtosecond,photophysics,ultrafast,carbon dots,nanocarbon,photochemistry,fluorescence
更新于2025-09-04 15:30:14
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One-Step Synthesis of Fluorescent Carbon Dots for Bio-Labeling Assay
摘要： Luminescent carbon dots, a newcomer in the domain of nanolights and nanomaterials have been studied extensively since past few years due to their fascinating properties of sensor design, biocompatibility, cell tracking, or fluorescence based live cell assays, medical diagnosis, photocatalysts, and also being potential building blocks for nanodevices. In this study, one-pot green synthesis of water dispersible fluorescent carbon dots have been synthesized by using roasted gram shells. The structural and optical properties of the as-prepared carbon dots are characterized by TEM, FTIR, UV-vis absorption, photoluminescence spectra. The carbon dots showed greenish blue fluorescence under UV irradiation, excitation dependent emission, upconverted emission, high pH tolerance, and good biocompatibility. The carbon dots labeled Escherichia coli (E. coli) unveiled multicolor emission behavior under different excitation wavelength. These carbon dots showed their superiority with respect to commercially available synthetic dyes which have severe limitations including photobleaching effect, high cost, etc. The incorporation of carbon dots in the bacterial culture medium does not show any kind of growth delay of the bacterium up to 400 mg mL?1. The goal is to establish this carbon dots in bio-labeling assay with its physicochemical features (small particle size, high luminescence efficiency, good biocompatibility, low toxicity) against various environments such as wide range of pH, high ionic medium. Concisely, this work bestows an innovative aspect to the commercialization of carbon dots as a potent alternative to synthetic organic dyes for multicolor emitting probes for cell-labeling gram negative bacteria E. coli.
关键词： carbon dots,E. coli,bio-labeling,cytotoxicity,fluorescence
更新于2025-09-04 15:30:14
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Nitrogen-Doped Durian Shell Derived Carbon Dots for Inner Filter Effect Mediated Sensing of Tetracycline and Fluorescent Ink
摘要： Photoluminescent carbon dots have gained increasing attention in recent years due to their unique optical properties. Herein, a facile one-pot hydrothermal process is used to develop nitrogen-doped carbon dots (NCDs) with durian shell waste as the precursor and Tris base as the doping agent. The synthesized NCDs showed a quantum yield of 12.93% with a blue fluorescence under UV-light irradiation and maximum emission at 414 nm at an excitation wavelength of 340 nm. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy showed the presence of nitrogen and oxygen functional groups on the NCD surface. The particles were quasi-spherical with an average particle diameter of 6.5 nm. The synthesized NCDs were resistant to photobleaching and stable under a wide range of pH but were negatively affected by increasing temperature. NCDs showed high selectivity to Tetracycline as the fluorescence of NCDs was quenched significantly by Tetracycline as a result of the inner filter effect. Based on sensitivity experiments, a linear relationship (R2 = 0.989) was developed over a concentration range of 0–30 μM with a detection limit of 75 nM (S/N = 3). The linear model was validated with two water samples (lake water and tap water) with relative recoveries of 98.6–108.5% and an RSD of <3.5%.
关键词： Fluorescent ink,Tetracycline detection,Durian shell waste,Nitrogen doping,Carbon dots
更新于2025-09-04 15:30:14
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Indian Gooseberry-Derived Tunable Fluorescent Carbon Dots as a Promise for In Vitro/In Vivo Multicolor Bioimaging and Fluorescent Ink
摘要： We report the synthesis of eco-friendly fluorescent nitrogen-doped carbon dots (NCDs) using the renewable resource of Phyllanthus emblica juice as a precursor by the hydrothermal process at 200 °C for 12 h. The synthesized NCDs emitted bright fluorescence without any pretreatment of the sample under the excitation of UV light and exhibited excitation-dependent fluorescence emission. The NCDs have nitrogen-containing and oxygen-containing functional groups such as amino, hydroxyl, and carboxyl on the surface of the carbon structure. Furthermore, the NCDs exhibited excellent water dispersibility with prolonging stability and good biocompatibility. On the basis of the good optical properties, the NCDs have potentially been used as a promising staining agent on HCT-116 human colon cancer cells and Caenorhabditis elegans (nematodes) for multicolor cellular imaging. In the cell cytoplasm, the NCDs showed rapid uptake and high cytocompatibility on cellular morphology with bright fluorescence emission. Furthermore, the NCDs were used as fluorescent ink for writing and drawing with anticoagulation. In addition, the NCDs were significantly utilized as a fluorescent ink for thumb impression, which glows instantly under the illumination of UV light and does not require a secondary treatment. Hence, the synthesized NCDs can be used as ideal multicolor fluorescent probes for bioimaging applications and as fluorescent ink instead of traditional fluorescent ink.
关键词： nitrogen-doped,hydrothermal synthesis,carbon dots,fluorescent ink,bioimaging
更新于2025-09-04 15:30:14