Tb3+/Eu3+ co-doped NaLa(MoO4)2 phosphors: photoluminescence and optical thermometry studies for solid-state lighting and sensor applications.

Autor: Tomar, Sonali, Chauhan, Vaibhav, Jayasimhadri, M., Shivakumara, C.
Zdroj: Journal of Materials Science: Materials in Electronics; Jan2025, Vol. 36 Issue 1, p1-21, 21p
Abstrakt: Tb3+/Eu3+ co-doped NaLa(MoO4)2 phosphors were synthesized by conventional solid-state reaction method. Rietveld refinement of the powder XRD data confirmed that all the compounds crystallized in the scheelite-type tetragonal structure with space group I41/a (No. 88). Photoluminescence results reveal that, upon the excitation at 298 nm, Tb3+-doped NaLa(MoO4)2 phosphors emit intense green light centred at 545 nm. On co-doping of Eu3+ ions in the NaLa(MoO4)2:Tb3+ (7 mol%) phosphor, the energy transfer appears from Tb3+ to Eu3+ ions, and it induces concentration-dependent colour tuning from green to red. The lifetime results confirmed that the maximum energy transfer efficiency 48.20% was observed for the composition NaLa0.84Tb0.07Eu0.09(MoO4)2. Temperature-dependent PL of NaLa0.85Tb0.15(MoO4)2 at 423 K retains about 61% of emission intensity with respect to that at 298 K, and the temperature quenching is characterized by activation energy 0.38 eV. For the NaLa0.88Tb0.07Eu0.05(MoO4)2 phosphor, an activation energy of 0.26 eV was determined for thermal quenching, with a maximum relative sensitivity of approximately 0.15% K−1. The determined radiative properties, CIE, CCT values and temperature-sensing results suggest the usefulness of Tb3+/Eu3+ co-doped NaLa(MoO4)2 phosphors in developing solid-state lighting and high-temperature sensor applications. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
Externí odkaz: