Up-conversion luminescence and near-infrared quantum cutting in Dy3+, Yb3+ co-doped BaGd2ZnO5 nanocrystal

BaGd2ZnO5: Dy3+, Yb3+ was successfully synthesized by the sol-gel method. The crystal structure and morphology of the samples were characterized by X-ray powder diffraction (XRD) and scanning electron microscope. Under 3 W 971 nm near-infrared laser excitation, the near-infrared emission of phosphors was intense. The dependence of the up-conversion emission intensities of the phosphors on the working power of laser diode was obtained as an evidence for the energy transfer from Yb3+ to Dy3+. In comparison, under excitation of 354 nm light, the near-infrared quantum cutting for the BaGd2ZnO5: Dy3+, Yb3+ samples is proved by the emission spectra. The corresponding quantum cutting mechanisms are discussed through the energy level. The maximum quantum efficiency calculated approaches 158.0%. This study has the prospect to be applied in silicon-based solar cells to promote the conversion efficiency.