Energy transfer and tunable photoluminescence of LaBWO6:Tb3+,Eu3+ phosphors for near-UV white LEDs

4 years ago

Energy transfer and tunable photoluminescence of LaBWO6:Tb3+,Eu3+ phosphors for near-UV white LEDs

Tb³⁺ and Eu³⁺ ion co-doped LaBWO6 phosphors with tunable color emissions were synthesized by a conventional high-temperature solid-state reaction technique and were characterized by powder X-ray diffraction, scanning electron microscope, emission and excitation spectra, and decay lifetimes. Under 380 nm near-ultraviolet excitation, the characteristic visible emissions, which originate from the f–f transitions of Tb³⁺ and Eu³⁺ ions, were observed in the emission spectra. By increasing of the Eu³⁺/Tb³⁺ concentration ratio, the LaBWO6:Tb³⁺,Eu³⁺ phosphors were capable of generating color tunability from green to yellow, then to red. The energy transfer process between Tb³⁺ and Eu³⁺ was demonstrated to be a resonant type via a dipole–dipole mechanism, and the critical distance calculated by the concentration quenching method was determined to be 11.1 Å. Moreover, the temperature-dependent emission spectra showed that the as-prepared phosphors possessed good thermal stability with an activation energy of 0.263 eV. These LaBWO6:Tb³⁺,Eu³⁺ phosphors with tunable emissions may have potential applications in near-ultraviolet-pumped white light-emitting diodes.

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DOI: S0143720817319964