Preparation and Characterizations of Ce3+-Doped ZnS Quantum Dots

Herein, we report the simple synthesis and characterizations of highly luminescent Ce3+-doped ZnS quantum dots (QDs) via super-micro-emulsifying technique using polyethylene glycol 400 (PEG 400) as emulsifiers. The prepared QDs were characterized by several techniques which revealed the cubic zinc blende crystal structure and size of 6-7 nm for prepared QDs. The optical properties of the synthesized QDs were analyzed by fluorescence and absorption spectrophotometer. The excitation spectra show dual excitation peak, centered at 363 nm and 424 nm. The PL emission spectra of the Ce3+-doped ZnS QDs under excitation at 363 nm also exhibited two emission peaks at 427 nm and 469 nm. The peaks appearing at 427 nm and 469 nm are attributed to state surface defects and presence of sulfur vacancies in the lattice, respectively. However, under excitation at 424 nm, the prepared QDs show two emission peaks at 469 nm and 493 nm which are related with the presence of sulfur vacancies in the lattices. The maximum PL intensity was observed for the QDs doped with 1.5% Ce3+ ions. The presented work demonstrates that the PL QDs can be used for various optoelectronic devices such as light emitting devices, light sensors, and flexible electroluminescence displays.