Bi3+ occupancy rearrangement in K2-xAxMgGeO4 phosphor to achieve ultra-broad-band white emission based on alkali metal substitution engineering
Bi3+ occupancy rearrangement in K2-xAxMgGeO4 phosphor to achieve ultra-broad-band white emission based on alkali metal substitution engineering
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DOI：
10.1016/j.apsusc.2021.150252
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发表时间：
2021-10
影响因子：
6.7
通讯作者：
Haifeng Zhu;Shuqing Feng;Z. Kong;Xu Huang;Lu Peng;Jing Wang;W. Wong;Zhi Zhou;M. Xia
中科院分区：
文献类型：
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作者：
Haifeng Zhu;Shuqing Feng;Z. Kong;Xu Huang;Lu Peng;Jing Wang;W. Wong;Zhi Zhou;M. Xia
超宽带白光荧光粉在新一代照明系统中有着广阔的应用前景。由于Bi³⁺对周围环境的敏感性，使得它在不同的晶体位置表现出不同的发光特性，这使得它很容易实现白色发射。阳离子取代工程是控制双位点周围环境和实现频谱调谐的最有效策略。本文采用碱金属A+ (A = Li, Na, Rb)代替K+，对K₂MgGeO₄：Bi³⁺（KMGO:Bi³⁺）进行了置换工程。在不同波长激发的发射光谱差异与KMGO中额外发光中心的产生和Bi³⁺在Li+和Na+的影响下的占位重排有关：Bi³⁺在Li+和Na+的影响下，也导致半最大值全宽度（FWHM）扩展到204nm，形成明亮的白色发射。此外，Rb+的调制作用使其活化能增加，热稳定性提高到88.66%。制备的WLED的高Ra值（93.4）表明K₁₄₅₆Na 0.₅₄MgGeO₄：0.004Bi³⁺可以用作固态照明中的单组分白色荧光粉。我们的研究表明，碱金属替代工程对控制发光发射和提高发光材料的热稳定性具有重要意义。
Ultra-broad-band white emitting phosphors have a wide application prospect in the new generation of illumination systems. Due to the sensitivity of Bi³⁺ to the surrounding environment, it exhibits different luminescence properties in different crystallographic sites, which makes it easy to achieve white emission. Cationic substitution engineering is the most effective strategy for controlling the environment around Bi-site and realizing the spectrum tuning. Herein, we conducted substitution engineering in K₂MgGeO₄:Bi³⁺ (KMGO:Bi³⁺ ) that uses alkali metal A+ (A = Li, Na, Rb) to substitute K+. The difference in emission spectrum excited at various wavelengths is related to extra luminescent centers generation and Bi³⁺ occupancy rearrangement in KMGO:Bi³⁺ under the influence of Li+ and Na+, which also leads to the expansion of full widths at half-maximum (FWHM) to 204 nm forming a bright white emission. Besides, the modulation of Rb+ increases the activation energy and enhances its thermal stability to 88.66%. The high Ra values (93.4) of the fabricated WLED indicate that K₁.₄₅₆Na₀.₅₄MgGeO₄:0.004Bi³⁺ could be used as a single-component white phosphor in solid-state lighting. Our research shows that alkali metal substitution engineering is of great significance to controlling the luminescence emission and improving the thermal stability of luminescent materials.