Effect of Tb~(3+) concentration and co-doping with Ce~(3+) ions on luminescence characteristics of terbium-doped (Luo.2sGdo.75)2Si05 single crystals

摘要

Solid-solution crystals Lu2SiO5-Gd2SiO5 (LGSO) single doped with Tb3+ with concentrations 0.8, 1.5 and 4.0 at % and co-doped with 4.0 at% Tb3+ + 0.6 at% Ce3+ were fabricated by the Czochralski technique. Optical absorption spectra were recorded with polarized light. Luminescence and excitation spectra for Tb3+ and Ce3+ were recorded upon CW excitation. Time resolved spectra of Tb3+ and Ce3+ luminescence excited by femtosecond light pulses were recorded with a streak camera. It was observed that in Tb3+-doped samples the D-5(4) luminescence excited into f-d bands in UV shows an initial rising stage whose dynamics is governed by the decay time of the higher energy D-5(3) level. In the LGSO:Tb, Ce phosphor the highest luminescence intensity occurs for excitation wavelengths between 320 nm and 370 nm providing a broad -band emission consisting of vibronic transitions of Ce3+ ions and of D-5(4) emission of Tb3+ that is fed from excited Ce3+ ions. It was concluded that LGSO:Tb, Ce is a promising visible phosphor for application purposes.