Tunable color, optical properties, and energy transfer of Tb-Sm-Yb tri-doped lithium-niobium-tellurite glass for applications in color display devices and WLEDs.

A TeO-NbO-LiO-CaO (TNLC) lithium-niobium-tellurite glass single-doped and co-doped with Tb, Sm, and Yb ions was synthesized a conventional melt-quenching method. The Tb-Sm co-doped TNLC glass could be tuned to emit white light effectively by controlling the ratio of Tb and Sm in the glass. The fluorescence lifetime of the Tb-Sm co-doped TNLC glass indicated the existence of multiple energy transfer channels, including from Tb to Sm ions and the reverse energy transfer from Sm to Tb ions. Taking advantage of these energy transfer channels, the color coordinates of the material could be changed from yellowish-pink and yellowish-green emissions to white emission by controlling the ratio of ions doped in TNLC glasses. The optimal molar concentration ratio between Tb and Sm ions for the best white light emission was 0.83 for the TNLC-0.5Tb0.6Sm sample. Changing the ratio of these rare-earth (RE) ions allowed tuning the color temperature of the material from 5616 to 7699 K. Thus, Tb-Sm co-doped and Tb-Sm-Yb tri-doped TNLC glasses are promising materials for color display applications and white light-emitting diodes (WLEDs).