Semiconductor nanocrystals, also known as quantum dots (QDs), with diameters generally ranging from 2-10 nm, exhibit distinctive optical properties as a result of quantum confinement effect. Possessing broad excitation wavelength range, narrow emission spectra, high quantum yield and without rare earth elements as component, QDs have potential applications in biology sensors, displays and LED industry.

The aim of the present work is to find a better aqueous synthesis method, especially for QDs containing Te or Se and a convenient way for the fabrication of polymer based composites with aqueous synthesized QDs.

Undoped and doped cadmium sulfide (CdS) QDs were synthesized to optimize the synthesis route and benefit the PL properties. The produced QDs possessed small particle...[ Read more ]

Semiconductor nanocrystals, also known as quantum dots (QDs), with diameters generally ranging from 2-10 nm, exhibit distinctive optical properties as a result of quantum confinement effect. Possessing broad excitation wavelength range, narrow emission spectra, high quantum yield and without rare earth elements as component, QDs have potential applications in biology sensors, displays and LED industry.

The aim of the present work is to find a better aqueous synthesis method, especially for QDs containing Te or Se and a convenient way for the fabrication of polymer based composites with aqueous synthesized QDs.

Undoped and doped cadmium sulfide (CdS) QDs were synthesized to optimize the synthesis route and benefit the PL properties. The produced QDs possessed small particle size, good stability and acceptable PL. QDs were precipitated from water solution with hydrophobic carbon chain outside simply through CTAB addition and mixed into epoxy matrix. Meanwhile, modified silica coating method was developed and ultra-small silica hybridized QDs were acquired so that catalyst poisoning was prevented during the fabrication of silicone based composite.

Besides, without the inert atmosphere protection and precursors preparation, an ultrafast and convenient method for synthesizing high quality CdTe QDs was discovered which based on the simple chemical kinetics theory and growth hypothesis. QDs grew rapidly with high QY and small FWHM. Room temperature synthesis method was also developed. Experiments with various additives, pH values and concentrations were conducted and related phenomena and effects were studied.

These methods are suggested as novel ways for preparing aqueous QDs and composites.