Blue-green color-tunable emissions in novel transparent Sr2LuF7:Eu/Tb glass-ceramics for WLEDs
Blue-green color-tunable emissions in novel transparent Sr2LuF7:Eu/Tb glass-ceramics for WLEDs
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用于 WLED 的新型透明 Sr2LuF7:Eu/Tb 玻璃陶瓷中的蓝绿色可调发射
DOI：
10.3788/col202018.051601
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发表时间：
2020
影响因子：
3.5
通讯作者：
Guo Hai
中科院分区：
文献类型：
--
作者：
Li Xiaoman;Zhou Shaoshuai;Wei Rongfei;Liu Xueyun;Cao Bingqiang;Guo Hai
在具有上级光学和机械性能的透明非晶基体中引入有序的纳米结构具有科学和技术重要性，但取得的成功有限。在这里，通过简单的熔融淬火和随后的热激活，我们报告的成功制备透明的纳米结构的玻璃陶瓷嵌入在Sr 2LuF 7纳米晶体（约26 nm），证明了X射线衍射，透射电子显微镜（TEM），和高分辨率TEM。掺杂剂成功地掺入到形成的Sr 2LuF 7纳米晶体具有低声子能量的结果在高度可调的蓝绿色光电发射，这取决于激发波长，掺杂剂类型，和温度。我们发现，在这种混合光学材料中，Eu 3+和Eu 2+离子共存，并伴随着Eu 2+的宽带蓝光发射和Eu 3+的尖锐红光发射。通过发射光谱、激发光谱和衰减曲线的测量，揭示了Eu ~（3+）还原为Eu ~（2+）的机理。此外，通过将Tb 3 +/Eu 3+富集到结晶的Sr 2LuF 7纳米晶体中，实现了近绿白色的光发射。温度依赖性的可见光电子能谱显示，随着Sr 2LuF 7纳米晶体在玻璃基质中的沉淀，热激活能增加，这表明玻璃陶瓷比前驱体玻璃具有更好的热稳定性。这些结果不仅加深了对玻璃陶瓷的理解，而且表明Eu ~（3+）/Tb ~（3+）离子掺杂的Sr_2LuF_7玻璃陶瓷具有良好的热稳定性，在紫外泵浦白色发光二极管（WLED）中具有广阔的应用前景。
To introduce ordered nano-structures inside a transparent amorphous matrix with superior optical and mechanical properties bears scientific and technological importance, yet limited success has been achieved. Here, via simple melting-quenching and subsequent thermal activation, we report the successful preparation of transparent nano-structured glass-ceramics embedded in Sr2LuF7 nano-crystals (∼26 nm), as evidenced by X-ray diffraction, transmission electron microscopy (TEM), and high resolution TEM. The successful incorporation of dopants into formed Sr2LuF7 nano-crystals with low phonon energy results in highly tunable blue–green photoemission, which depends on excitation wavelength, dopant type, and temperature. We found that Eu3+ and Eu2+ ions co-exist in this hybrid optical material, accompanied by the broadband blue emission of Eu2+ and sharp red emissions of Eu3+. A series of optical characterizations are summoned, including emission/excitation spectrum and decay curve measurement, to reveal the reduction mechanism of Eu3+ to Eu2+. Furthermore, near green–white photoemission is achieved via the enrichment of Tb3+/Eu3+ into crystallized Sr2LuF7 nano-crystals. The temperature-dependent visible photoemission reveals thermal activation energy increases with the precipitation of Sr2LuF7 nano-crystals in a glass matrix, suggesting better thermal stability of glass-ceramics than precursor glasses. These results could not only deepen the understanding of glass-ceramics but also indicate the promising potential of Eu3+/Tb3+-ions-doped Sr2LuF7 glass-ceramics for UV pumped white light emitting diodes (WLEDs) with good thermal stability.