Synthesis of stable and highly luminescent beryllium and magnesium doped ZnS quantum dots suitable for design of photonic and sensor material

Highly luminescent ZnS quantum dots (QDs) and their Be²⁺ and Mg²⁺ derivatives having nominal compositions Zn_1-xBe _xS and Zn_1-xMg_xS (where x=0.0-0.6 and Δx=0.1) have been synthesized using the co-precipitation technique. The synthesized QDs are stable for a period of up to 7 months. They have a cubic closed packed (zinc blende) structure and average particle size of 2-3 nm as measured by TEM, XRD and UV-vis spectral analysis. Incorporation of Be ²⁺ and Mg²⁺ into the ZnS lattice has shown noteworthy effects on the intensity of defect-states emission that enhances the luminescence intensity of the QDs. The absorption bands in the visible spectral range for ions of Be and Mg elements are observed to overlap with the fluorescence transitions of ZnS QDs. These highly luminescent and stable QDs could be utilized for the development of new quantum dot-based sensors, light emitting diodes, phosphor and coating for long term applications.