Production Of Carbon Dots Research Articles

Recent advances in green synthesis of carbon dots for heavy metal ion sensing

In recent years, the field of green synthesis for carbon dots has seen significant advancements in the development of materials for heavy metal ion sensing applications. A variety of eco-friendly and sustainable approaches have been explored to synthesize carbon dots (CDs) with enhanced sensing properties. These materials have shown great promise in detecting heavy metal ions due to their high sensitivity, selectivity, and low detection limits One of the key advancements in this area is the utilization of natural sources such as biomass, organic waste, and plant extracts as precursors for the synthesis of CDs. These green precursors not only contribute to the sustainable nature of the synthesis process but also result in the production of carbon dots with unique surface chemistry and optical properties. In addition to the synthesis and functionalization strategies, the understanding of the underlying mechanisms governing the interaction between CDs and heavy metal ions has advanced significantly. This improved understanding has facilitated the design of CDs with tailored sensing capabilities and improved overall performance. Overall, the recent progress in the green synthesis of CDs for heavy metal ion sensing holds great promise for the development of cost-effective, environmentally friendly, and high-performance sensing platforms with potential applications in environmental monitoring, industrial safety, and healthcare diagnostics.

Carbon dots from alcohol molecules: principles and the reaction mechanism.

Carbon dots (CDs) have attracted significant attention in the energy, environment, and biology fields due to their exceptional physicochemical properties. However, owing to the multifarious precursors and complex reaction mechanisms, the production of carbon dots from organic molecules is still a mysterious process. Inspired by the color change of sodium hydroxide ethanol solution after standing for some time, in this work, we thoroughly investigated the reaction mechanism from alcohol molecules to carbon dots through a lot of experiments and theoretical calculations, and it was found that the rate-controlling reaction is the formation of aldehydes, and it is also confirmed that there is a self-catalysis reaction, which can accelerate the conversion from alcohol to aldehyde, further facilitating the final formation of CDs. After the rate-controlling reaction of alcohol to aldehyde, under strongly alkaline conditions, an aldol reaction occurs to form unsaturated aldehydes, followed by further condensation and polymerization reactions to form long carbon chains, which are cross-linked and dehydrated to form carbon dots with a carbon core and surface functional groups. Additionally, it is found that the reaction can be largely accelerated with the assistance of electricity, which indicates the great prospect of industrial production. Furthermore, the obtained CDs with rich functional groups can be utilized as electrolyte additives to optimize the deposition behavior of Na metal, manifesting great potential towards safe and stable Na metal batteries.

A comprehensive review of the importance of thermal activation in the production of carbon dots and the potential for their use in the bioenergy industry

A comprehensive review of the importance of thermal activation in the production of carbon dots and the potential for their use in the bioenergy industry

An Innovative Microwave-Assisted One-Step Green Synthetic Approach of Biowaste Derived Fluorescent Carbon-Dot Invisible Ink for Currency Anti-Counterfeiting Applications

The quest for the design and synthesis of carbon dots with anti-counterfeit properties that are derived via green, environmentally friendly and economical procedures is a continuous process. Carbon dots (C-dots) derived from biowaste are cheap to synthesize, possess good photo-stability and high synthetic yield, making them applicable in the anti-counterfeiting of currency. Herein, we report a novel eco-friendly, cheaper, and faster method for the synthesis of carbon dots with strong photoluminescence properties from monkey orange fruit (Strychnos spinosa) biowaste. The presence of the hydroxyl and carbonyl functional groups of the carbon dots were determined by the Fourier transform infrared spectroscopy (FTIR). The carbon dots showed strong blue emission fluorescence (emission wavelength of 452[Formula: see text]nm) when excited at 330[Formula: see text]nm. The morphology and size were determined by the atomic force microscopy (AFM) which indicated amorphous and spherical nanoparticles with an average size of less than 2[Formula: see text]nm. The no-crystallinity of the as-prepared carbon dots was confirmed using X-ray diffraction which showed the graphite-like structure. The carbon dots were produced and demonstrated good photo and chemical stability as well as high covert properties. The anti-counterfeiting of currency application by the synthesized carbon dots was demonstrated when the subsequent gel ink printed on the currency showed excellent chemical stability when exposed to washing with water, ethanol, and acetone. It also showed superior photostability when exposed to UV light at 365[Formula: see text]nm and daylight for an extended period of up to 6[Formula: see text]h. This work provides a facile, economical, and green approach for large scale production of carbon dots from the abundant biowaste.

Mass spectrometry analysis of C-dots produced by femtosecond laser irradiation of L-lysine film.

The production of carbon dots (C-dots) by femtosecond lasers within living cells and tissues is a novel approach, which has a great potency for intracellular bioimaging. An exact mechanism of fluorescent particles production as well as their composition still remains unknown. In this work we use L-lysine film as a model system to study the mechanism and the composition of C-dots produced by femtosecond laser irradiation investigated by time-of-flight secondary ion mass spectrometry (ToF-SIMS).

Production of carbon dots by pulsed laser ablation: Precursors and photo‐oxidase properties

AbstractLight is indispensable in many biomedical reactions, but there are few nanomaterials capable of light‐activated enzyme‐like activities. In this work, carbon dots (C‐dots) were prepared through one‐step pulsed laser ablation (PLA) treatment of polymers in aqueous solution. The choice of water‐soluble polymers as starting materials could extend the types of carbon sources for PLA reactions. The obtained C‐dots aqueous solution with blue fluorescence could be used directly without any centrifugation and purification. The light‐induced oxidase‐like activity of C‐dots was exploited in sensing Cu2+ ions for the first time. The sensing mechanism was speculated that the decrease in reactive oxygen species (ROS) through the photo‐induced electron transfer (PET) process between C‐dots and Cu2+, thereby inhibiting their photo‐oxidase activity. This work provides a new colorimetric method to detect Cu2+ without using the well‐known fluorescence of C‐dots.

Production of carbon dots during the liquid phase exfoliation of MoS2 quantum dots

N-methyl-2-pyrrolidone (NMP) has been widely used as a solvent for preparing two-dimensional quantum dots (2D-QDs) by probe sonication. Here we found that carbon dots (CDs) are simultaneously produced by the carbonization of NMP when preparing MoS2 QDs in a NMP solvent by probe sonication. These two kinds of QDs are similar in color, crystal structure, excitation wavelength dependent photoluminescence (PL), and have overlaps in their absorption spectra and coincidence of PL peaks. As a result, the co-production of CDs has not previously been recognized. The CDs show strong optical interactions with the MoS2 QDs, which leads to a dramatic decrease in the fluorescence intensity of the CDs/MoS2 QDs. Moreover, we found that the carbonization also occurs for the commonly used organic solvents. These findings suggest that associated production of CDs should be considered when preparing 2D-QDs by probe sonication, and the resulting hybrid CDs/2D-QDs will provide opportunities to design their properties and uses.

Bamboo leaf-based carbon dots for efficient tumor imaging and therapy.

In this study, carbon dots synthesized from bamboo leaf cellulose were used simultaneously as a staining agent and for doxorubicin delivery to target cancer cells. Owing to their nontoxic properties, the production of carbon dots from bamboo leaves is a green approach involving optimized application of bamboo tree waste. For multifunctional applications, the carbon dots were modified with 4-carboxybenzylboronic acid and doxorubicin to improve target specificity and drug delivery to HeLa tumor cells. The resulting modified carbon dots were characterized using different analytical techniques, which showed that they were biocompatible, nontoxic, and highly stable over a wide range of pH values and at high ionic strengths. Furthermore, in vitro confocal microscopy studies demonstrated their blue fluorescence and cellular pathway for entering HeLa cells via folate receptor-mediated endocytosis. Cell viability data and flow cytometry results also confirmed the selective uptake of the carbon dots by HeLa cells, which significantly enhanced cell cytotoxicity.