Optics and Photonics Society of Iran

This paper describes the syntheses of high luminescence CdTe, core–shell CdTe-CdS and CdTe-ZnS quantum dots (QDs) in aqueous solution. The UV-vis spectra and the fluorescence spectra measurements reveal that the shell thickness of CdS and ZnS change during the heating time for the growth. Red shift of a maximum emission wavelength was observed via fluorescence spectra, which inferred the growth of QDs and formation of CdS and ZnS shells. The PL intensity is significantly enhanced to 2.8 times of the bare core by growing CdS shell on CdTe core. The results demonstrate that the rate of PL intensity reduction of CdTe/ZnS is much faster than that of plain CdTe/CdS samples. The obtained QDs will have great potential application in biological researches and biosensing system.