Green up-conversion luminescence in Yb3+-Pr3+ co-doped BaRE2ZnO5 (RE=Y, Gd)

Yb3+ and Pr3+ co-doped BaRE2ZnO5 (RE=Y, Gd) up-conversion (UC) phosphors were successfully synthesized by a modified sol-gel method. The processing parameters and optimal concentration of Pr3+ and Yb3+ were determined. The structures and luminescent properties of samples were characterized by X-ray diffraction (XRD) and photoluminescence spectra (PL). With the excitation of 980 nm laser diode, UC spectra showed five prominent emission bands centered at 484, 514, 546, 656 and 670 nm, which were attributed to the 1I6→3H4, 3P1→3H4, 3P0→3H5, 3P0→3F2 and 3P0→3F3 transitions of Pr3+, respectively. In the light of the pump power dependence, the possible UC mechanism in Yb3+ and Pr3+ co-doped BaRE2ZnO5 (RE=Y, Gd) was proposed and discussed.