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The nucleation mechanism of colloidal semiconductor quantum dots (QDs) in the aqueous phase remains unknown. Using CdS as a model system, we show that prenucleation clusters (PNCs) play a key role in the formation of QDs, which supports the multistep nonclassical nucleation model. For the reaction of CdCl, thioacetamide, and 3-mercaptopropionic (MPA), a prenucleation cluster forms at room temperature via the chemical self-assembly of the precursors. PNCs transform to magic-size clusters (MSCs) in the dispersion with amine and thus are also defined as precursor compounds (PCs) of MSCs. PNCs fragment to monomers (Mos) at elevated temperature or at room temperature after dilution. The supersaturation of Mos leads to the nucleation and growth of QDs, which is influenced by the pH value. Our findings provide a new synthesis route to QDs in aqueous phase and brings an in-depth understanding of the nucleation mechanism.
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http://dx.doi.org/10.1021/acs.jpclett.5c01007 | DOI Listing |
J Dent
August 2025
College & Hospital of Stomatology, Anhui Medical University, Key Lab. of Oral Diseases Research of Anhui Province, Hefei, 230032, China. Electronic address:
Objective: This study aimed to develop an oral environment-responsive complex with mineralisation-antibacterial dual-activities for preventing and treating early dental caries.
Methods: The complex was synthesized with phosphorylated starch serving as a template to stabilize calcium phosphate prenucleation clusters (CaP-PNCs) and silver nanoclusters (AgNCs). The binding properties of the complex on human enamel were evaluated using confocal laser scanning microscopy (CLSM).
Sens Actuators Rep
June 2025
Department of Chemistry, Georgia State University, Atlanta, Georgia, USA, 30302.
The formation of cluster aggregates in a (super)saturated solution prior to protein nucleation is crucial to overcoming the thermodynamic energy barrier which enables further growth of single crystals. This process is important for single crystal growth, separation and energy conversion among other important applications. For structural determination of biomacromolecules, neutron crystallography holds unique advantages in resolving hydrogen/proton over other structure determination techniques but faces technical obstacles in requiring large high-quality single crystals and preferentially hydrogen-deuterium exchanges.
View Article and Find Full Text PDFSmall
July 2025
College of Chemical Engineering, Sichuan University, Chengdu, Sichuan, 610065, P. R. China.
The possible presence of prenucleation clusters (PNCs) in samples of colloidal semiconductor quantum dots (QDs) remains largely unknown. Using CdSe QDs as a model system, It is shown for the first time that samples from both heating-up and hot-injection approaches may contain the PNC. When a sample is dispersed in cyclohexane (CH) or toluene (Tol) at 25 °C, the nucleation and growth (N/G) of small QDs takes place.
View Article and Find Full Text PDFACS Omega
June 2025
Department of Chemistry, Furman University, 3300 Poinsett Highway, Greenville, South Carolina 29613, United States.
A central question in the formation of secondary aerosols is whether organic molecules participate in the formation of prenucleation clusters or are they only adsorbed after formation of larger aerosols? The difficulty in understanding the role of organic molecules in aerosol formation is that there are very few studies of prenucleation clusters produced from various organics and sulfuric acid, so it is uncertain whether organic compounds form prenucleation clusters. Isoprene is the most abundant volatile biogenic organic compound (VOC) emitted into the atmosphere, accounting for about 70% of biogenic VOC emissions, excluding methane. Each year, approximately 600 teragrams of isoprene enter the atmosphere, primarily from natural sources like vegetation.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
College of Environmental Science and Engineering, State Key Laboratory of Water Pollution Control and Green Resource Recycling, Tongji University, Shanghai, 200092, P.R. China.
Metal-organic gels (MOGs), an innovative subset of metal-organic frameworks (MOFs), feature hierarchically porous architecture and self-shaping monolithic morphologies, demonstrating them significantly potential for advanced applications in catalysis, gas storage, and energy conversion. Despite their functional versatility, the synthesis of MOGs remains empirical, as the actual formation mechanisms are largely unexplored. Here, a multiscale characterization strategy integrating time-resolved in-situ small-angle X-ray scattering (SAXS), Zr K-edge X-ray absorption fine structure (XAFS), and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) analyses are systematically employed to elucidate the formation mechanism of UiO-66(Zr) gel.
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