The first principles calculation and temperature-sensitive luminescence behavior of optimized red phosphor Mg₂Al₄Si₅O₁₈: Eu³⁺

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• 作者：Yue Jing^a ; ¹ ; Qinjia Chen^a ; ¹ ; Mingyu Sui^a ; Zhipeng Ci^a ; ^b ; ^{cizhp@lzu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Lili Han^c ; Yanwen Chen^a ; Jiachi Zhang^a ; ^b ; ^{cizhp@lzu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Ji Ma^a ; Yuhua Wang^a ; ^b
• 关键词：Optical material ; Luminescence ; Optical property
• 刊名：Journal of Luminescence
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：181
• 期：Complete
• 页码：49-55
• 全文大小：3132 K

文摘

Eu³⁺ doped Mg₂Al₄Si₅O₁₈ phosphors were prepared by the solid-state reaction. The first principles calculation, XRD, diffuse reflection spectra, photoluminescence spectra and thermal quenching are carried out to investigate the electron structure, crystal structure, photoluminescence and thermal properties. The calculation results show that Mg₂Al₄Si₅O₁₈ possesses the direct band gap of about 5.1 eV. With the introduction of Eu³⁺, the energy gap becomes obviously smaller due to the discontinuity of exchange-correlation energy. Between HOMOs and LOMOs, a series of f orbitals of Eu³⁺ can be observed, which is the essential condition to realize the efficient 4f–4f transitions of Eu³⁺. The experimental results indicate that the samples can efficiently absorb the UV-light and emit the red light with the highest peak at 614 nm. With the co-doping of Bi³⁺ as sensitizer, the emission intensity of Eu³⁺ increases by about 49% due to the energy transfer between Bi³⁺ and Eu³⁺. With the introduction of Li⁺/Na⁺/K⁺ as charge compensators, the emission intensities of Mg₂Al₄Si₅O₁₈: Eu³⁺ are enhanced by about 22%, 18% and 5%. With the temperature increase, the emission intensity of all samples, especially the Bi³⁺ doped samples, dramatically declines, which reveals two important effects: one is that the Eu³⁺ emission is very sensitive to temperature, and other is that the complex energy transfer process among the excited and ground states of Eu³⁺, Bi³⁺ or host absorption occurs. To explain the degradation, the mechanism based on the configurational coordinate diagram is proposed and this model could be helpful for the understanding of the energy transfer mechanism among the various energy levels in the process of temperature change.