Energy transfer and up-conversion luminescence in Er~(3+/Yb~(3+) co-doped transparent glass ceramic containing YF_3 nano-crystals

摘要

Transparent glass ceramics containing YF_3 nano-crystals were fabricated by heat treatment of the SiO_2-Al_2O_3-NaF-YF_3-LnF_3 (Ln = Er, Yb) glasses. X-ray diffraction and transmission electron microscopy analyses evidenced the homogeneous distribution of spherical YF3 nano-crystals sized 25-30 nm among the glassy matrix. Energy dispersive X-ray spectroscopy measurement, combined with the Stark splitting of the absorption and emission bands, verified the incorporation of Er~()3+ and Yb~(3+) ions into YF_3 nano-crystals. The infrared to visible up-conversion emission of Er~(3+) intensified with the increasing of Yb~(3+) concentration, ascribing to the increase of the efficiency of non-radiative energy transfer from Yb~(3+) to Er~(3+) which exceeded 45 percent for the 0.5Er~(3+)/1.0Yb~(3+) co-doped sample. The up-conversion luminescence at 545 and 660 nm were affirmed coming from two-photon excitation process.