Up- and down-conversion luminescence in the oxyfluoride glass ceramics containing Ba2+1.5xYb1−xF7:Tb nanocrystals

Transparent oxyfluoride borosilicate glass ceramics containing Ba_2+1.5xYb_1−xF₇:Tb³⁺ nanocrystals were successfully prepared by a melt-quenching method with subsequent heat treatment. The precipitated crystalline phase in the glass matrix changed gradually from BaF₂ to Ba_2+1.5xYb_1−xF₇ with the increase of YbF₃ content, which was confirmed by the results of XRD, HRTEM and EDX measurements. The ultraviolet and visible up-conversion and near-infrared quantum cutting down-conversion emissions were observed and interpreted. These materials could be used to modify the solar spectrum and enhance the silicon solar cell efficiency by the up-conversion and down-conversion luminescence of Tb³⁺–Yb³⁺ couples in the oxyfluoride borosilicate glass ceramics.