Green emission from Tb-doped SrSi2O2N2 phosphors under ultraviolet light irradiation

Tb-doped SrSi2O2N2 phosphors with promising luminescent properties were synthesized by the conventional solid-state reaction method, characterized by powder X-ray diffraction and studied by photoluminescence excitation and emission spectra. The synthesized materials exhibited a weak blue emission and a strong green emission in the region of 400–470nm and 480–650nm, which are attributed to 5D3→7Fj (j=5, 4, 3) and 5D4→7Fj (j=6, 5, 4, 3) transitions of Tb3+, respectively. The green emission from 5D4→7F5 at 543nm showed the highest intensity under the optimized concentration of 0.1mol, after which the quenching concentration became relevant. The quenching behavior of the emission of Tb3+ was explained by the cross-relaxation of its excited state.