Study on mechanism controlling 5D3/5D4emissions of Tb3+ in glasses

Tb3+ doped SiO2-ZnO-BaO glasses are prepared by melting quenching method and their unique photoluminescent properties for the UV excitation are studied by using emission/excitation spectra and decay curves. Glasses in the composition (mol%) of 60SiO2-xZnO-(40-x)BaO-0.2Tb3+(x=30, 20, 10) show the strongest emission peaking at 436 nm which is different from majority of other reported work. Lower content of the free OH groups mainly contribute to this phenomenon due to the decreased probability of the multi-phonon aided non-radiative relaxation process from 5D3 to 5D4 energy levels of Tb3+ ions. The Tb3+ concentration also affects the 5D3/5D4 emissions as a result of the cross-relaxation effect on two nearby Tb3+ ions (5D3-5D4⇒7F6-7F0). Moreover, by adjusting Tb3+ concentration and/or ZnO/BaO concentration ratio of the host glass we obtained the adjustable emission with the required CIE chromaticity from blue to green, suggesting that the present Tb3+-doped SiO2-ZnO-BaO glasses are potential as blue/green dual-color luminescent materials for different applications.