The CdS/ZnS nanocrystals quantum dots can be synthesized by the reverse micelle method. The diameters of the CdS nanocrystals have a narrow distribution and their mean value is about from 2.5 to 4 nm. The absorption spectra show that the size of prepared nanocrystals does not depend on their growth time and can be controlled.

CdSe/ZnS semiconductor quantum dots with emission range from 500 nm to 650 nm. CdSe/ZnS quantum dots are gradient alloyed semiconductor materials with size dependent optical/electronic properties, high fluorescence efficiency, low toxicity and easy cell absorb. Through surface passivation of high band gap ZnS shell, low luminescence efficiency caused by defects and surface-trap states can be significantly minimized. Nanoshel CdSe/ZnS quantum dots can be used in highly sensitive cellular imaging, drug delivery and light emitting devices.

CdSe/ZnS quantum dots, powder, hydrophobic - CdSe/ZnS quantum dots are core-shell structured inorganic nanocrystals wherein an outer core of wider band gap ZnS encapsulates an inner core of CdSe. They are highly luminescent semiconductor nanocrystals coated with hydrophobic organic molecules. They are insoluble in ethers, alcohols and water, but soluble in pyridine, tetrahydrofuran, chloroform, toluene, heptanes, and hexane. The wavelength emission spectra range between 530 and 650 nm.

Semiconductor Quantum dots (QDs) have generated extensive interest for biological and clinical applications. These applications arise from their unique properties, such as high brightness, long-term stability, simultaneous detection of multiple signals, tunable emission spectra.

CdS/ZnS quantum dots, a ZnS shell layer can grown on CdS core nanocrystals by using two aqueous solutions of Zn2+ and S2- ions which were obtained by dissolving the compounds of zinc and sodium into water. The aqueous solutions of Zn2+ and S2- can be mixed separately with two identical stock solutions. Then two micellar solutions containing Zn2+ and S2- ions injected at a very slow rate into the CdS nanocrystal micellar solution which had been prepared before. The obtained solution stirred vigorously, so that ions Zn2+ and S2- could hang on the drops containing CdS quantum dots, forming the ZnS shell layer. The CdS/ZnS core/shell quantum dots dispersed in organic solvents.