Sequential Growth of High Quality Sub-10 nm Core-Shell Nanocrystals: Understanding the Nucleation and Growth Process Using Dynamic Light Scattering

Interfacial Nucleation Mechanism of Water-Soluble Ag-In-S Quantum Dots at Room Temperature and Their Visible Light Catalytic Performance

A novel interfacial reaction nucleation mechanism for the preparation of water-soluble Ag-In-S quantum dots (AIS QDs) was proposed in which interfacial acid regulates the concentration of hydroxide ions outside the complex and sulfur sources attack cations at the interface of the complex, covalent bonds between cations and sulfur sources are formed at the interface of the complex, and the nucleation and growth of crystals is finished at room temperature. By bypassing the heating process normally necessary for crystal nucleation and growth, AIS QDs can be produced on a large scale under simple, mild conditions. At the same time, the characteristics of this mechanism enable AIS QDs to be directly synthesized in an organic pollutant solution. This study represents a significant advance in the mechanism of crystal synthesis and contributes to the photocatalytic decomposition of organic pollutants from theory to practice.

Solvothermal synthesis and modification of NaYF4:Yb/Er@NaLuF4:Yb for enhanced up-conversion luminescence for bioimaging

Water-soluble NaYF4:Yb/Er@NaLuF4:Yb up-converting nanoparticles (UCNPs) with a strong green emission were successfully prepared by a solvothermal method in a short period of time and at a low temperature. First, the hydrophobic UCNPs were prepared by a simple solvothermal method, then modified using a polyetherimide (PEI) surfactant or oxidation of the oleic acid ligands with the Lemieux-von Rudloff reagent. The modified UCNPs, having an average particle diameter of 60 ± 5 nm, showed a high dispersity. The oleic acid ligand on the sample surface was oxidized azelaic acid (HOOC(CH2)7COOH), identified from Fourier transform infrared (FTIR) spectroscopy, which results in the generation of free carboxylic acid, hence conferring a high solubility in water. The 3-4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) method and cell-targeted labeling proved that oleic acid-capped UCNPs after oxidation (UCNPs-OAO) have a higher biocompatibility than polyetherimide-capped UCNPs (UCNPs-PEI). Therefore, the UCNPs-OAO have a great potential in biomedical applications, such as multimodal imaging, targeted therapy, and gene therapy.