Optimization of the Single-Phased White Phosphor of Li2SrSiO4: Eu2+, Ce3+ for Light-Emitting Diodes by Using the Combinatorial Approach Assisted with the Ta

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• 作者：Lei Chen ; Anqi Luo ; Yao Zhang ; Fayong Liu ; Yang Jiang ; Qingsheng Xu ; Xinhui Chen ; Qingzhuo Hu ; Shi-Fu Chen ; Kuo-Ju Chen ; Hao-Chung Kuo
• 刊名：ACS Combinatorial Science
• 出版年：2012
• 出版时间：December 10, 2012
• 年：2012
• 卷：14
• 期：12
• 页码：636-644
• 全文大小：560K
• 年卷期：v.14,no.12(December 10, 2012)
• ISSN：2156-8944

文摘

The best performance of the phosphor Li₂SrSiO₄: Eu²⁺, Ce³⁺ in terms of luminescence efficiency (LE), color rendering index (CRI) and color temperature (Tc) for light-emitting diode application was optimized with combinatorial approach. The combinatorial libraries were synthesized with solution-based method and the scale-up samples were synthesized with conventional solid-reaction method. Crystal structure was investigated by using the X-ray diffraction spectrometer. The emission spectra of each sample in combinatorial libraries were measured in situ by using a fiber optic spectrometer. Fluorescence spectrometers were used to record excitation and emission spectra of bulk samples. White light generation was tuned up by tailoring Eu²⁺ and Ce³⁺ concentrations in the single-phased host of Li₂SrSiO₄ under near-ultraviolet excitation, but it exhibited low efficiency of luminescence and poor color rendering index. The effects of each level of the Eu²⁺ and Ce³⁺ concentrations on LE, CRI, and Tc were evaluated with the Taguchi method. The optimum levels of the interaction pairs between Eu²⁺ and Ce³⁺ concentration on LE, CRI, and Tc were [2, 1] (0.006 M, 0.003 M), [1, 2] (0.003 M, 0.006 M), and [3, 1] (0.009 M, 0.00 3M), respectively. The thermal stability of luminescence, the external quantum efficiency (QE), luminance, chromaticity coordinates, correlated color temperature, color purity including the composition ratio of RGB in white light, and color rendering index of the white light emission of phosphor were evaluated comprehensively from a bulk sample.

Keywords:

white light-emitting diodes; luminescence; phosphor; Li₂SrSiO₄: Eu²⁺, Ce³⁺; combinatorial approach; the Taguchi method