The size dependence of optical properties in colloidal ZnxCd1-xS:Mn quantum dots in gelatin

Size-selected colloidal ZnxCd1-xS quantum dots were successfully prepared by aqueous synthesis in gelatin. Quantum dots with an average size of a few nanometers were obtained by changing the synthesis conditions such as the amount of precursors and temperature. Variation of the composition and size of particles leads to a change in the optical, in particular, luminescent characteristics of quantum dots. Estimation of particle sizes were performed by several methods based on X-Ray diffraction and optical data. The mechanisms of trap state photoluminescence in ZnxCd1-xS quantum dots are proposed. Models of increasing/decreasing the photoluminescence intensity depending on the composition and particle size are presented.