Photoluminescence of ZnGa2S4 : Eu2+

ZnGa2S4:Eu2+ shows a light green emission at room as well as at low temperatures. The maximum of the band of the 4f65d1 → 4f7 emission is located at about 536 nm (18657 cm–1) and depends slightly on the excitation energy. The respective excitation band has a maximum at 470 nm (21277 cm–1). These results lead to the assumption that the Eu2+ ions are substituted at octahedral voids of the host lattice rather than at cationic sites. This is to be expected also because of the different ionic radii of the cations. Further emission and excitation bands are detected at higher energies in ZnGa2S4:Eu2+ as well as in undoped ZnGa2S4 which depend strongly on the respective excitation and emission energies and can, thus, be assigned to host lattice bands.