Up-conversion luminescence properties of Yb3+/Er3+ co-doped AgGd(W,Mo)2O8 phosphors

The up-conversion spectra of the AgGd0.800−xYb0.200Erx(WO4)2 (x = 0.005-0.035) were composed by two parts, which were green region (500-580 nm) and red region (630-690 nm), respectively. Since the emission of red region was rather weak, the color of the samples observed by naked eyes was in green.