PHOTOLUMINESCENCE OF SB-3+ CENTERS IN SRS AND SRSE

Emission and excitation spectra and luminescence decay times of the SrS:Sb3+ and SrSe:Sb3+ powder phosphors are studied over the temperature range from 2 to 372 K. The emission band at 293 K is located at 600 nm for SrS:Sb2S3 (0.05 mol%) and at 633 nm for SrSe:Sb2S3 (0.2 mol%). The excitation processes are attributed to three transitions; (i) the intraionic transitions within Sb3+, (ii) the charge transfer transition from the host anion to Sb3+ and (iii) the fundamental absorption by host crystal, followed by the transfer of the excitation energy to an unexcited Sb3+ ion. The shape of the excitation spectrum of the intraionic transitions is similar to those of the absorption spectra of Tl+-type ions in alkali halides. The results are compared with those of MgS:Sb3+, CaS:Sb3+, CaSe:Sb3+ and SrS:Bi3+.