Fluorescent Carbon Dots In article number 2304123, Zhili Peng and co-workers develop a pre-crystallization-controlled, solid-state synthesis of red carbon dots from o-phenylenediamine on a hectogram scale with a 94% yield. By leveraging the delicate energy transfer between the commercial Y3Al5O12:Ce3+ phosphor and the carbon dots-derived red phosphor, they fabricate white light-emitting diode with an extremely high color rendering index of 97.
The effective control over the self-assembly process of carbon dots (CDs) and their cluster luminescence in the aggregated state is of paramount significance and challenge. This study, for the first time, systematically explores the photoluminescent behavior of CDs in their aggregated state, which is less understood compared to their discrete state. By investigating the effects of concentration and solvent environment, it's demonstrated that CDs could exhibit dual emission properties, shifting from blue particle emissions to red cluster emissions as they aggregate. The key to this tunable luminescence lies in hydrogen bonding, which drives the self-assembly of CDs and modulates their photo physical properties. These findings reveal that through precise control of aggregation, CDs can be engineered for advanced optoelectronic applications, including tunable light-emitting diodes (LEDs), secure information encryption, and fingerprint authentication. This report not only deepens the understanding of the underlying mechanisms governing CDs' cluster luminescence but also introduces a novel approach to exploiting their unique properties for technological innovation.
Considerable efforts have been made to synthesize and characterize protein-nanoparticle conjugates (protein-NPs) for their promising applications in bionanotechnology. However, protein concentration determination in the protein-NPs has so far not been reported. In this Letter, we present a simple and nondestructive approach to quantify the protein concentration in the protein-NPs aqueous solution using circular dichroism (CD) spectroscopy. Carbon dots (∼4 nm), gold nanoparticles (∼10 nm), and polyethylene glycol (PEG, molecular weight ∼3000) were either physically mixed or covalently conjugated (not in the case of gold nanoparticles) with proteins (human transferrin, human serum albumin, and ovalbumin). We were able to quantify the protein concentration in the protein-nanoparticle conjugates using a calibration curve from the CD spectra.
Carbon dots (C-dots) were facilely fabricated via a hydrothermal method and fully characterized. Our study shows that the as-synthesized C-dots are nontoxic, negatively charged spherical particles (average diameter 4.7 nm) with excellent water dispersion ability. Furthermore, the C-dots have a rich presence of surface functionalities such as hydroxyls and carboxyls as well as amines. The significance of the C-dots as highly efficient photocatalysts for rhodamine B (RhB) and methylene blue (MB) degradation was explored. The C-dots demonstrate excellent photocatalytic activity, achieving 100% of RhB and MB degradation within 170 min. The degradation rate constants for RhB and MB were 1.8 × 10-2 and 2.4 × 10-2 min-1, respectively. The photocatalytic degradation performances of the C-dots are comparable to those metal-based photocatalysts and generally better than previously reported C-dots photocatalysts. Collectively considering the excellent photocatalytic activity toward organic dye degradation, as well as the fact that they are facilely synthesized with no need of further doping, compositing, and tedious purification and separation, the C-dots fabricated in this work are demonstrated to be a promising alternative for pollutant degradation and environment protection.
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