A multimodal emitter comprising of ZnSe:Eu/ZnS (core/shell) quantum dots (QDs) by adding a ZnS precursor in situ during synthesis. ZnSe/Eu2+/Eu3+/ZnS actives both core and core/shell. QDs prepared with the ZnS precursor displayed a luminescence intensity three times that of ZnSe QDs due to the passivation effect of the Shell. While the core QDs display the 450-550 nm emission of Eu2+ ((F6D1)-F-4-D-5 -> F-4(7)), the core/shell system showed no Eu2+ emission but only the sharp peaks in the red at 579, 592, 615, 651, and 700 nm due to the electronic transitions of D-5(0) -> F-7(n) (n = 0-4) depending on leisurely decreased with increased reaction time. These results are in agreement with Eu 3d spectra of XPS analysis results. Microscopic analyses show that the core and core/shell QDs both have a zinc blende structure, and their respective sizes were about 3.19 and 3.44 nm. The lattice constant in the central portion of the core/shell QDs are around d(111) = 3.13 angstrom, which is between the outside and inside ring patterns (d(111) = 3.27 and 3.07 angstrom, respectively). This shows the effective over-capping of shell onto the core QDs. The core/shell structure may contain Eu2O3 bonding the over-coated ZnS surface on the Eu3+-doped ZnSe core. (C) 2017 Published by Elsevier B.V.