HRBE diagrams for lanthanides and the temperature dependence of Tb3+ luminescence in zinc-sodium-lanthanum-borate glass

Zinc-sodium-lanthanum-borate (ZNLB) glasses undoped and doped with trivalent lanthanide ions (Ce3+, Eu3+ and Tb3+) ions have been synthesized by the melt-quenching method. The lowest energies of the f-d transition for divalent and trivalent lanthanide ions in ZNLB glass have been predicted based on the redshift model and the excitation spectrum of Ce3+ ions. The 4f and 5d ground-state energy diagrams of the Ln2+ and Ln3+ ions within the bandgap of ZNLB glass have been constructed based on the excitation spectra of Ce3+ and Eu3+ ions by using the chemical shift model. The luminescence quenching of Tb3+ ions due to temperature as well as energy transfer from Ce3+ to Tb3+ has been also predicted from the host referred binding energy (HRBE) diagrams of the lanthanide ions and confirmed by the experimental data. The energy transfer process from charged intrinsic defects to Tb3+ ions in ZNLB glass has also been discussed in detail.