Photoluminescence of the SrS:Mn2+Phosphor and Pb2+-Sensitized Luminescence of the SrS:Pb2+, Mn2+Phosphor

Emission and excitation spectra of the Mn 2+ ion in the SrS:Mn 2+ and SrS:Pb 2+ , Mn 2+ phosphor are investigated at various temperatures. The analysis of the excitation spectra of the Mn 2+ emission band leads to the Racah parameters B =712 cm -1 , C =3352 cm -1 and the crystal field parameter D q =576 cm -1 with the covalency parameter ε =0.046. By the transient spectroscopy technique, it is found that the emission band due to the single Mn 2+ ion center has a peak at 553 nm and a decay time of ∼5.5 ms, while that due to the paired Mn 2+ center has a peak at 565 nm and a decay time of 0.6 ms. Energy transfer from Pb 2+ ion to Mn 2+ ion is observed in SrS:Pb 2+ , Mn 2+ . By observing the change of band shapes, the intensities and decay characteristics of both the Pb 2+ and Mn +2 lumimescence, it is concluded that the transfer is of resonance type. It is found that the energy of Pb 2+ ion is transferred preferentially to the isolated Mn 2+ ion.