A Potential Red-Emitting Phosphor BaZrGe₃O₉:Eu³⁺ for WLED and FED Applications: Synthesis, Structure, and Luminescence Properties

Abstract

A variety of Eu³⁺-activated BaZrGe₃O₉ phosphors was synthesized via solid-state reaction. The phase formation of BaZrGe₃O₉:Eu³⁺ samples was verified by powder X-ray diffraction analysis, while Rietveld refinement method was used to confirm the crystal structure. The electronic structure and characteristic photoluminescence as well as cathodoluminescence properties were researched in detail. The samples show strong absorption at 394 nm, which matches well with the commercial near-ultraviolet chips. Under 394 nm excitation, the phosphors exhibit the characteristic emissions of Eu³⁺ ions consistent with the ⁵D₀-⁷F_J transitions. Then we investigated the thermal stability detailedly. The temperature-dependent photoluminescence emission spectra suggest that the obtained phosphors have favorable thermal stability. A white light-emitting diode (WLED) lamp with low correlated color temperature and good color render index was fabricated with blue-emitting BaMgAl₁₀O₁₇:Eu²⁺, green-emitting Sr₂SiO₄:Eu²⁺ (commercial), and red-emitting BaZrGe₃O₉:Eu³⁺ phosphors in near-ultraviolet light-emitting diodes (λ_max = 395 nm) as well. Furthermore, the phosphor also exhibits red emission with high resistance and high current saturation under low voltage electron bombardment. It has better degradation resistance than the commercial Y₂O₃:Eu phosphor. All the results manifest that the Ba_0.88Eu_0.08ZrGe₃O₉ phosphor can be an eligible red-emitting phosphor candidate for WLEDs and field-emission displays.