The Reduction of Re3+ in Srb6O10 Prepared in Air and the Luminescence of Srb6O10:Re2+(Re=Eu, Sm, Tm)

Abstract The reduction of RE3+ to RE2+ (RE=EU, Sm and Tm) in SrB6O10 prepared in air by high-temperature solid state reaction was observed. The luminescent properties of Eu2+ and Tm2+ show f-d transition and Sm2+shows f-f transition at room temperature. Three crystallographic sites for Sm2+ in matrix are available. Vibronic transition of 5D0-7F0 of Sm2+ was studied. The coupled phonon energy about 108 cm−1, was determined from the vibronic transition. Due to the thermal population from 5D0 level, 5D1-7Fj (J=0, 1, 2) transitions of Sm2+ were observed at room temperature. A charge compensation mechanism is proposed as a possible explanation.