Photoluminescence Spectra and Vibrational Structures of the SrS : Ce3 +  and SrSe : Ce3 +  Phosphors

Abstract

The details of photoluminescence and excitation spectra of powder phosphors were obtained at various temperatures between 6 and 300 K. At 300 K, two emission bands originating from the ~T2g(5d)-- ~ 2F7/2, 2F.~/2(4f) transit ions are observed at 480 and 535 nm for SrS:Ce 3+ and at 470 and 527 nm for SrSe:Ce 3+, respect ively. In the exci tat ion spectra, bands corre-sponding to the ~Fsn(4f)-- * 2T2g(5d) transition are observed at 433 (SrS:Ce 3+) and 430 nm (SrSe:Ce3+), and plateaus due to the fundamental absorption of the host crystals in higher energy region. The vibrational structures on the emission a d exci-tation bands are analyzed by the use of energy matrices in order to determine the coupl ing constant of spin-orbit interac-t ion ~ and the crystal field parameters V4 Cf~, V ~ <D for the 4f orbit. A lka l ine earth cha lcogen ides are known as exce l lent host crystals of phosphors. In part icular, the SrS:Ce 3+ phosphor has been invest igated in re lat ion to its availa-b i l i ty for cathodo- (1) and e lec t ro luminescence d v ices (2). Its photo luminescence (PL) and exc i ta t ion spectra, however, are not yet analyzed in detai l f rom the stand-point of the energy terms. The 4f orbit o fa Ce 3+ ion incor-