Xiao Yu, Hao Zhendong, Zhang Liangliang, Xiao Wenge, Wu Dan, Zhang Xia, Pan Guo-Hui, Luo Yongshi, Zhang Jiahua
State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , 3888 Eastern South Lake Road, Changchun 130033, China.
University of Chinese Academy of Sciences , Beijing 100049, China.
Inorg Chem. 2017 Apr 17;56(8):4539-4545. doi: 10.1021/acs.inorgchem.7b00085. Epub 2017 Mar 30.
This paper demonstrates a highly thermally stable and efficient green-emitting BaYBO:Ce, Tb phosphor prepared by high-temperature solid-state reaction. The phosphor exhibits a blue emission band of Ce and green emission lines of Tb upon Ce excitation in the near-UV spectral region. The effect of Ce to Tb energy transfer on blue to green emission color tuning and on luminescence thermal stability is studied in the samples codoped with 1% Ce and various concentrations (0-40%) of Tb. The green emission of Tb upon Ce excitation at 150 °C can keep, on average, 92% of its intensity at room temperature, with the best one showing no intensity decreasing up to 210 °C for 30% Tb. Meanwhile, Ce emission intensity only keeps 42% on average at 150 °C. The high thermal stability of the green emission is attributed to suppression of Ce thermal de-excitation through fast energy transfer to Tb, which in the green-emitting excited states is highly thermally stable such that no lifetime shortening is observed with raising temperature to 210 °C. The predominant green emission is observed for Tb concentration of at least 10% due to efficient energy transfer with the transfer efficiency approaching 100% for 40% Tb. The internal and external quantum yield of the sample with Tb concentration of 20% can be as high as 76% and 55%, respectively. The green phosphor, thus, shows attractive performance for near-UV-based white-light-emitting diodes applications.
本文展示了一种通过高温固相反应制备的具有高热稳定性和高效绿色发光的BaYBO:Ce,Tb荧光粉。该荧光粉在近紫外光谱区域的Ce激发下呈现出Ce的蓝色发射带和Tb的绿色发射线。在共掺杂1% Ce和不同浓度（0 - 40%）Tb的样品中，研究了Ce到Tb的能量转移对蓝到绿发射颜色调谐以及发光热稳定性的影响。在150℃下，Ce激发时Tb的绿色发射平均可保持其室温强度的92%，对于30% Tb的最佳样品，在高达210℃下30分钟强度无下降。同时，Ce发射强度在150℃时平均仅保持42%。绿色发射的高热稳定性归因于通过快速能量转移到Tb抑制了Ce的热去激发，处于绿色发射激发态的Tb具有很高的热稳定性，以至于升温到210℃时未观察到寿命缩短。由于有效的能量转移，当Tb浓度至少为10%时观察到主要的绿色发射，对于40% Tb，转移效率接近100%。Tb浓度为20%的样品的内量子产率和外量子产率分别可高达76%和55%。因此，这种绿色荧光粉在基于近紫外的白光发光二极管应用中表现出诱人的性能。
