The reduction of RE~(3+) in SrB_6O_(10) prepared in air and the luminescence of SrB_6O_(10):RE~(2+) (RE=Eu, Sm, Tm)

摘要

The reduction of RE~(3+) to RE~(2+) (RE = Eu, Sm and Tm) in SrB_6O_(10) prepared in air by high-temperature solid state reaction was observed. The luminescent properties of Eu~(2+) and Tm~(2+) show f-d transition and Sm~(2+) shows f-f transition at room temperature. Three crystallographic sites for Sm~(2+) in matrix are available. Vibronic transition of ~5D_0-~7F_0 of Sm~(2+) was studied. The coupled phonon energy about 108 cm~(-1), was determined from the vibronic transition. Due to the thermal population from ~5D_0 level, ~5D_(1-) ~7F_1 (J = 0, 1, 2) transition. Due to the thermal population from ~5D_0 level, ~5D_(1-) ~7F_1 (J = 0, 1, 2) transitions of Sm~(2+) were observed at room temperature. A charge compensation mechanism is proposed as a possible explanation.