Authors: M. Balaguera, O. Perales-Perez, L. Rivera-Montalvo, R. Singhal and M.S. Tomar
Affilation: University of Puerto Rico, Puerto Rico
Pages: 340 - 343
Keywords: quantum dots, core-shell, CdS, ZnS, CdS-ZnS
The objective of the current research is to synthesize CdS, ZnS nanocrystals through a two phases-method were quantum dots moved from the aqueous phase to the organic one after proper coating of the particles by decylamine. The UV-visible spectra of CdS dots suspended in toluene presented very sharp peaks in the range of 364-370 nm and confirmed the presence of CdS. ZnS quantum dots absorbed light in the 400-430 nm range. The sharpness in the absorption peak for CdS dots suggests a highly monodisperse suspension of synthesized nanocrystals. According to UV-Vis information, the crystal size of CdS could be estimated at 3.5 nm. Based on our experimental work, a Cd/S mole ratio of 0.78 and a SNTA concentration of 0.25 M were considered optimum synthesis conditions. PL spectra for CdS and ZnS are show blue shift in emission peak for ZnS dots with increasing decylamine volumes suggests the drop in crystal size.