Development of Eu3+ activated monoclinic, perovskite, and garnet compounds in the Gd2O3–Al2O3 phase diagram as efficient red-emitting phosphors
2013; Elsevier BV; Volume: 206; Linguagem: Inglês
10.1016/j.jssc.2013.08.003
ISSN1095-726X
AutoresJinkai Li, Ji‐Guang Li, Jing Li, Shaohong Liu, Xiaodong Li, Xudong Sun, Yoshio Sakka,
Tópico(s)Microwave Dielectric Ceramics Synthesis
ResumoEu3+ doped Gd4Al2O9 (GdAM), GdAlO3 (GdAP), and Gd3Al5O12 (GdAG, containing 10 at% of Lu3+ for lattice stabilization) have been developed in this work as efficient red-emitting phosphors. With coprecipitated carbonate precursors, phase evolution studies found minimum processing temperatures of ~1000, 1100, and 1300 °C for the three phosphors to crystallize as pure phases, respectively. Compared with their yttrium aluminate counterparts, the gadolinium-based phosphors exhibit red-shifted O2−–Eu3+ charge transfer excitation band (CTB) centers due to the lower electronegativity of Gd3+ and appreciably higher quantum yields of photoluminescence owing to the occurrence of efficient Gd3+→Eu3+energy transfer. The optimal Eu3+ contents were determined to be ~7.5 at% for GdAM and 5.0 at% for both GdAP and GdAG, and concentration quenching of luminescence was suggested to be due to exchange interactions. Fluorescence decay analysis found a shorter lifetime for the phosphor powder processed at a higher temperature or with a higher Eu3+ content, and the underlying mechanism was discussed. Fluorescence lifetimes were also compared between the yttrium and gadolinium phosphor systems for the dominant emissions.
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