Naresh V, Gupta Kiran, Parthasaradhi Reddy C, Ham Byoung S
Department of Physics, Sri Venkateswara University, Tirupati 517502, AP, India.; PIP Center, School of inform. and commun., Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
Department of Chemistry, Motilal Nehru National Institute of Technology, Allahabad 211004, U.P., India.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Mar 15;175:43-50. doi: 10.1016/j.saa.2016.12.023. Epub 2016 Dec 15.
A promising energy transfer (Tm→Tb→Eu) approach is brought forward to generate white light emission under ultraviolet (UV) light excitation for solid state lightening. Tm/Tb/Eu ions are combinedly doped in zinc borate glass system in view of understanding energy transfer process resulting in white light emission. Zinc borate (host) glass displayed optical and luminescence properties due to formation of Zn(II)-[O(-II)] centres in the ZnB glass matrix. At 360nm (UV) excitation, triply doped Tm/Tb/Eu: ZnB glasses simultaneously shown their characteristic emission bands in blue (454nm: D→F), green (547nm: D→F) and red (616nm: D→F) regions. In triple ions doped glasses, energy transfer dynamics is discussed in terms of Forster-Dexter theory, excitation & emission profiles, lifetime curves and from partial energy level diagram of three ions. The role of Tb in ET from Tm→Eu was discussed using branch model. From emission decay analysis, energy transfer probability (P) and efficiency (η) were evaluated. Colour tunability from blue to white on varying (Tb, Eu) content is demonstrated from Commission Internationale de L'Eclairage (CIE) chromaticity coordinates. Based on chromaticity coordinates, other colour related parameters like correlated colour temperature (CCT) and colour purity are also computed for the studied glass samples. An appropriate blending of such combination of rare earth ions could show better suitability as potential candidates in achieving multi-colour and warm/cold white light emission for white LEDs application in the field of solid state lightening.
提出了一种很有前景的能量转移（Tm→Tb→Eu）方法，用于在紫外（UV）光激发下产生白光发射以用于固态照明。鉴于了解导致白光发射的能量转移过程，将Tm/Tb/Eu离子复合掺杂在硼酸锌玻璃体系中。硼酸锌（基质）玻璃由于在ZnB玻璃基质中形成Zn(II)-[O(-II)]中心而表现出光学和发光特性。在360nm（UV）激发下，三重掺杂的Tm/Tb/Eu:ZnB玻璃在蓝色（454nm:D→F）、绿色（547nm:D→F）和红色（616nm:D→F）区域同时显示出其特征发射带。在三重离子掺杂玻璃中，根据福斯特-德克斯特理论、激发和发射光谱、寿命曲线以及三种离子的部分能级图讨论了能量转移动力学。使用分支模型讨论了Tb在从Tm→Eu的能量转移中的作用。通过发射衰减分析，评估了能量转移概率（P）和效率（η）。从国际照明委员会（CIE）色度坐标证明了在改变（Tb，Eu）含量时从蓝色到白色的颜色可调性。基于色度坐标，还为所研究的玻璃样品计算了其他与颜色相关的参数，如相关色温（CCT）和色纯度。这种稀土离子组合的适当混合在实现用于固态照明领域的白光发光二极管应用的多色和暖/冷白光发射方面可能显示出更好的适用性，作为潜在候选材料。
