Luminescent Properties of ZnS:Mn(2+)/ZnS Core/Shell Nanocrystals

High-quality ZnS:Mn(2+)/ZnS core/shell nanocrystals (NCs) with a core crystal diameter of 6.1 nm and 1.15 nm thick shells were synthesized via a high-boiling solvent process. The energy levels of the conduction band and valance band are estimated to be -3.2 eV and -6.8 eV by cyclic voltammetry and ultraviolet-visible (UV-vis) absorption spectra. The ZnS:Mn(2+)/ZnS NC emission peak is primarily located at 580 nm under 310 nm light excitation, originating from the charge transition from (4)T(1) to (6)A(1) within the 3d(5) configuration of the Mn(2+) ion. Based on ZnS:Mn(2+)/ZnS NCs as the active layer electrolunninescent devices, the emission peak mainly locates at 460 nm with one shoulder emission peaking at 580 nm. The photoluminescence and electroluminescence properties of ZnS:Mn(2+)/ZnS NCs are investigated in the view of charge carrier injection and energy level alignment