NIR to visible frequency upconversion in Er3+ and Yb3+ co-doped BaZrO3 phosphor

Phosphor powders of Yb(3+) co-doped BaZrO3:Er(3+) have been prepared by the urea combustion route. The formation of single-phase BaZrO3:Er(3+) and BaZrO3:Er(3+),Yb(3+) was confirmed by X-ray powder diffraction (XRD). Green and red luminescence along with a weaker blue emission is observed upon excitation at ~978 nm with a diode laser. These emissions are caused by frequency upconversion in the Er(3+)-doped BaZrO3 (BZO) phosphor. Both the green and red upconversion emissions of the Er(3+) are enhanced by about ~3 and ~43 times respectively when triply ionized ytterbium is incorporated as a co-dopant. The frequency upconversion processes responsible for the blue, green and red emissions are discussed on the basis of the experimental data.