Transparent Ce3+:GdYAG ceramic phosphors for white LED
Transparent Ce3+:GdYAG ceramic phosphors for white LED
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DOI：
10.1117/12.874118
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发表时间：
2011-02
期刊：
影响因子：
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通讯作者：
S. Nishiura;S. Tanabe;K. Fujioka;Y. Fujimoto
中科院分区：
文献类型：
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作者：
S. Nishiura;S. Tanabe;K. Fujioka;Y. Fujimoto
以（GdγY0.999-γCe0.001）3Al5O12为原料，采用共法制备氧化粉末，合成了透明Ce:GdYAG陶瓷。在800nm处，样品的透明度高达80%。随着Gd含量的增加，Ce3+: 5d→4f跃迁的发射波段从530 nm移至560 nm。用积分球计算蓝色LED激发下的色坐标（x, y）和量子产率（QY）。样品在蓝色LED激发下的颜色坐标随厚度的增加而增加。通过用Gd3+代替Y3+，颜色坐标也向右下移动，更接近色度图中的普朗克轨迹。Ce3+的红移可以用Gd3+取代Y3+后Ce3+ 5d能级的能量变化来解释。随着激发波长的增加，γ=0样品的颜色坐标由蓝色向黄色偏移。这一结果与样品激发带的形状有关。γ=0样品的QY在400 ~470 nm范围内几乎与激发波长无关。
Transparent Ce:GdYAG ceramics were synthesized from the oxide powder produced by a co-preparation method in the composition of (GdγY0.999-γCe0.001)3Al5O12. The sample showed transparency as high as 80 % at 800 nm. A broad emission band of Ce3+: 5d→4f transition shifted from 530 nm to 560 nm with increasing Gd content. The color coordinates (x, y) under blue LED excitation and quantum yield (QY) were evaluated with an integrating sphere. The color coordinates of the sample under blue LED excitation were increased with increasing thickness. By substituting Gd3+ for Y3+, the color coordinates also shifted to lower right and became closer to the Planckian locus in the chromaticity diagram. The red shift was explained by the energy change of 5d level of Ce3+ by the substitution of Gd3+for Y3+. With increasing excitation wavelength, the color coordinates of the γ=0 sample shifted from blue to yellow. This result is related to the shape of excitation band of the sample. The QY of the γ=0 sample was almost excitation wavelength independent in the range of 400 ~470 nm.