Facile synthesis and optical properties of Ce:YAG polycrystalline ceramics with different SiO₂ content
2015
Gong, Maogao | Xiang, Weidong | Huang, Jun | Yin, Congfei | Liang, Xiaojuan
Ce:YAG polycrystalline ceramics with different SiO₂ content were successfully prepared by a single-step melt-quenching method. The characterization of the resulting polycrystalline ceramics was accomplished by using X-ray powder diffraction, field emission scanning electronic microscopy and energy dispersive X-ray spectroscopy. Then, the optical properties were investigated using a fluorescence spectrometer. It is found that the glass matrix becomes a glassy state more easily, the photoluminescence excitation (PLE) and PL intensity decrease obviously and crystallization of YAG is difficult to generate as the SiO₂ content increases. What's more, the intensity of the blue LED decreases and that of the yellow emission band instead increases and saturates at a SiO₂ content of 32 mol% in the electroluminescent (EL) spectra. Afterwards, the photoelectric performance was studied by an LED spectrometer. As a consequence, the constructed polycrystalline ceramic based WLED exhibits a high luminous efficiency of 74.44 lm W⁻¹, and a correlated color temperature of 5351 K as well as a color rendering index of 75.91, which reveals the prominent feasibility of the present polycrystalline ceramic material in WLED applications.
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