Optical Properties of Ce~(3+),Tb~(3+) Co-doped BaYF_5 Glass Ceramics

A new Ce3+/Tb3+ co-doped BaYF5 glass ceramic was prepared by high temperature melting.The X-ray diffraction spectra,excitation spectra and emission spectra were measured.The results indicate the BaYF5 nanocrystalline phase exists in the glass matrix.Based on the Scherrer equation,the average size about 27 nm of BaYF5 nanocrystalline was calculated.The intense blue emission band(425 nm)assigned to 5d→2F5/2 and 5d→2F7/2 transitions of Ce3+ and blue emission(487 nm),green emission(542 nm),orange emission(582 nm) and red emission(620 nm) assigned to 5D4→7FJ(J=6,5,4,3) transitions of Tb3+ ions,respectively,were observed at room temperature under 338 nm excitation in the glass ceramics.By adjusting the doped concentration of Ce3+ and Tb3+,the chromaticity coordinate of the glass ceramic is measured to be(0.287,0.336).The energy transfer between Ce3+ and Tb3+ was analysised systematically.The results indicate that Ce3+ / Tb3+ co-doped BaYF5 glass ceramics is a potential matrix material for white LED.