Designing green-emitting Li3Gd3Te2O12:Er3+ garnet-type tellurate phosphors for temperature sensing and WLED lighting

The novel Er 3+ -doped Li 3 Gd 3 Te 2 O 12 (LGTO) phosphors were synthesized via the solid-state reaction method. Under the 377 nm excitation, strong green luminescence was observed from the phosphors, resulting from the typical Er 3+ transitions 2 H 11/2 – 4 I 15/2 and 4 S 3/2 – 4 I 15/2 . The optimum doping concentration was 1.5 mol%. The Inokuti-Hirayama (I-H) model and Dexter theory confirmed that the energy transfer mechanism occurs primarily through the nearest neighbor ion interactions. The LGTO:1.5 mol%Er 3+ phosphor exhibited outstanding thermal stability, retaining 125.19% at 480 K. At 300 K, the prepared phosphor exhibited a relative sensitivity of 1.12% K −1 . The fabricated white light-emitting diode (w-LED) showed excellent performance with a high color rendering index ( R a ) of 88, Commission International de L’Eclairage coordinates of (0.341, 0.329), and a low correlated color temperature 5097 K. The LGTO:Er 3+ phosphors not only possess good solid-state luminescent properties but also serve as an outstanding basis for the development of high-sensitivity optical thermometry.