ABSTRACTTb and Yb co-doped oxyfluoride glasses were fabricated in a lithium-lanthanum-aluminosilicate matrix by a melt-quench technique. Glass-ceramics were obtained by appropriate heat treatment of the as-prepared glasses. Visible to near-infrared down-conversion quantum cutting was studied for samples with different thermal annealing temperatures and time. Laser light at 488 nm was used to excite Tb3+ ions while Yb3+ ions were excited by energy transfer from the excited Tb3+ ions. Near-infrared emission at 940 – 1020 nm was observed. It has been found that the emission at 940 – 1020 nm increased significantly from the glass-ceramic compared to that of the as-prepared glass. This result suggests that the energy-transfer efficiency increases in glass-ceramics compared to that in glass. A significant portion of rare-earth ions may be incorporated inside LaF3 nanoparticles (NPs) in the glass-ceramic. Because the Yb3+ emission at 940 – 1020 nm is matched well with the band gap of crystalline Si, the quantum cutting effect may have its potential application in silicon-based solar cells.
New insight into two-step near-infrared quantum cutting in Pr^3+ singly doped oxyfluoride glass-ceramics
