Luminescent Manganese/Europium doped ZnS quantum dots: Tunable emission and their application as fluorescent sensor

Manganese and europium doped zinc sulphide (Mn 2+ /Eu 3+ @ZnS) quantum dots (QDs) were prepared via direct aqueous route in order to broaden tunable emission. We report a new strategy featuring enhanced photoluminescence through Mn 2+ /Eu 3+ @ZnS QDs leading to an intense orange-red emission and thus remarkably enhancing PL QY up to 41.35%. The X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) studies revealed the cubic crystalline structure with average crystalline sizes in the range of 1.5–2.5 nm. The Mn 2+ /Eu 3+ @ ZnS QDs was applied as an exceptional chemical sensor for Cu 2+ via quenching mechanism due to competitive coordination between QDs and Cu 2+ with the limit of detection (LOD) of 0.036 μM. Furthermore, the proposed approach is capable of detecting Cu 2+ in water samples with satisfactory recoveries highlighting viability and prospective applications of the sensing platform. We finally demonstrate from CIE Chromaticity diagram that doped QDs show meliorated colorimetric properties which render this new class of QDs a promising prospect to be employed in white LEDs. • Highly fluorescent Mn 2+ /Eu 3+ @ZnS QDs are synthesized by direct aqueous route. • Tunable emission and enhanced colorimetric properties are achieved which are useful for white LEDs. • The increasing doping concentration effectively enhance PLQY up to 41.35%. • Fast and reliable sensing probe are established for Cu 2+ detection with LOD of 0.036 μM. • The probe was successfully applied in real samples to detect Cu 2+ yielding satisfactory recoveries (96−105)%.