An Orange-Light Emitting Garnet Phosphor: Tb3Ga5O12:Eu3+

Abstract

Tb3Ga5O12:Eu3+ (TGG:Eu3+) orange-light emitting garnet phosphor was synthesized by the solid-state reaction (SSR) method and subsequent calcination at Tc = 800–1400°C in air. The effects of the Eu3+ activator concentration in (Tb1−xEux)3Ga5O12 and calcination temperature (Tc) on the phosphor properties were studied in detail. The strongest Eu3+ luminescence was observed at x ∼ 0.05 and at Tc = 1400°C. An exponential dependence was inferred from the X-ray diffraction and photoluminescence (PL) intensities vs 1/Tc plots, yielding Ea ∼ 1.3 eV and ∼4.0 eV for a formation of the host lattice and an activation of the Eu3+ ions in the TGG host, respectively. The PL properties of the TGG:Eu3+ phosphor were investigated in detail using PL excitation (PLE) spectroscopy and PL decay measurements. The PLE and PL decay characteristics showed an evidence of the energy transfer from the TGG host (Tb3+) to Eu3+ by excitation at λex ≤ 500 nm. The internal quantum efficiency upon excitation at λex = 380 nm was ∼61%. Lattice temperature dependence of the PL intensity at T = 20–450 K was also measured and successfully interpreted using the conventional quenching model. A comparative discussion was given on the structural and PL properties of the SSR-grown TGG:Eu3+ phosphor with those of the metal-organic decomposition-grown TGG:Eu3+ one.