Photoluminescence Properties of Eu3+ in Ga2O3−Tb3Ga5O12:Cr3+ Phosphor Synthesized by Metal Organic Deposition

Abstract

We demonstrated the synthesis of Eu3+-activated Tb3Ga5O12 garnet phosphor by metal-organic deposition and reported the photoluminescence (PL) properties of this garnet phosphor in detail. The phosphors were synthesized from a mixture of organic gallium solution and acetic acid dissolved with TbCl3/Eu2O3. The X-ray diffraction analysis indicated that the synthesized phosphors were a mixture of β-phase Ga2O3 and cubic Tb3Ga5O12 garnet (TGG). The TGG fraction increased with the increase of the TbCl3 addition in the raw solution. The Eu3+ ions were preferentially incorporated into the TGG crystallites rather than β-Ga2O3. The intensities of the Eu3+ emissions in TGG were strongly influenced by the Cr3+ red-line emissions, where the Cr3+ ions were unintentionally introduced in the synthesized phosphors. The PL excitation spectra indicated that the Eu3+ emission at 708 nm (5D0 → 7F4) was gained by the Tb3+ intra-f-shell, Cr3+ intra-d-shell, and charge transfer transitions. Temperature dependences of the Eu3+ and Cr3+ emission intensities were measured at T = 20 − 380 K and explained by the proposed theoretical models very well. The effects of the Eu3+ ion site in the various host materials on the luminous properties were also discussed in detail.