Nowadays semiconductor quantum dots (QDs) is a popular luminescent material for different kinds of bioapplications. Core-shell CdSe/ZnS QDs obtained by the high-temperature synthesis are traditional luminescent nanocrystals with high quantum yield and narrow emission peak. But this type of QDs must be hydrophilized before their use in a water or biological environment. The goal of our work was the comparison of hydrophilized QDs properties, obtained from one initial sample using two different hydrophilization methods. Core-shell type QDs with CdSe/ZnS semiconductors composition was synthesized and hydrophilized by two ligand exchange methods: silanization and coating with dihydrolipoic acid (DHLA). Quantum yield, size and colloidal stability of the nanoparticles obtained via both methods were investigated. The collected data allows making the conclusions about perspectives to use the described methods in different bioapplications.
We demonstrate a one-pot synthesis of CdSeZnS/ZnS alloyed blue (482 nm) and green (526 nm) quantum dots in organic solvents. During the formation of core/shell quantum dots (QDs), a blue-shift was observed after coating with ZnS shell. A wavelength tuning of alloyed QDs emission is obtained by the different ratios of Se-precursor in the cores. Silica surface was formed to make water-soluble alloyed QDs. The alloyed QDs were characterized by absorbance and photoluminescence (PL) spectroscopy and PL quantum yield.