Electronic structure and photoluminescence properties of yellow-emitting Ca₁₀Na(PO₄)₇: Eu²⁺ phosphor for white light-emitting diodes

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• 作者：Hua Yu ; Degang Deng ; Yinqun Li ; Shiqing Xu ; Yinyan Li ; Cuiping Yu ; Yanyan Ding ; Hongwei Lu ; Haoyong Yin ; Qiulin Nie
• 关键词：Ca10Na(PO4)7 ; Eu2+ ; Yellow-emitting phosphor ; Electronic structure ; Photoluminescence ; White LEDs
• 刊名：Journal of Luminescence
• 出版年：2013
• 出版时间：November, 2013
• 年：2013
• 卷：143
• 期：Complete
• 页码：132-136
• 全文大小：1555 K

文摘

The yellow-emitting Ca₁₀Na(PO₄)₇:Eu²⁺ phosphors were synthesized by conventional high-temperature solid-state reaction method. The phosphors were well characterized by powder X-ray diffraction, FT-IR spectra and diffuse reflectance spectra. DFT calculation results showed that Ca₁₀Na(PO₄)₇ had an indirect bandgap with a bandgap energy of about 3.82 eV. Ca₁₀Na(PO₄)₇:Eu²⁺ showed a yellow emission band peaking at 550 nm under 350 nm excitation. The broad emission bandwidth (about 138 nm) of Ca₁₀Na(PO₄)₇:Eu²⁺ is favorable for white LEDs conversion phosphors. The optimal doping concentration of Eu²⁺ ions in Ca₁₀Na(PO₄)₇:Eu²⁺ phosphor was about 8 mol % . This study demonstrated that the energy transfer among the nearest-neighbor ions was the main mechanism of concentration quenching of Ca₁₀Na(PO₄)₇:Eu²⁺ phosphor. These results indicate that Ca₁₀Na(PO₄)₇:Eu²⁺ may be potentially useful as a UV radiation-converting phosphor for white LEDs.