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采用水热法制备了一系列稀土Dy 3+, Tb 3+, Eu 3+掺杂的极性Gd 2Te 4O 11(GTO)亚碲酸盐荧光粉. 对样品的物相结构、形貌和热稳定性等进行了表征, 测试了样品的发光性能. 结果显示, 所制样品均为单相, 呈短杆状形貌, 尺寸在微米量级, 热稳定性能良好. 对于GTO:Dy 3+荧光粉, 在紫外光激发下的发光主要位于黄绿光区, 获得最强发光强度的掺杂浓度为2.5%, 色坐标为(0.39, 0.43); 荧光衰减曲线表明GTO:Dy 3+样品发光寿命随着掺杂浓度增大逐渐减小, 与Dy 3+离子间的交叉弛豫有关. 对于GTO:Eu 3+荧光粉, 在紫外光激发下的发光主要位于红光和橙红光区, 其发射强度随着Eu 3+掺杂浓度的增大而增强. 当掺杂浓度为10%时, 样品发光的色坐标为(0.62, 0.38), 位于橙红光区, 且样品的发光寿命几乎不受掺杂浓度影响. 对于GTO:Tb 3+荧光粉, 随着Tb 3+掺杂浓度的增大, 受Tb 3+离子间交叉弛豫的影响, 荧光粉在紫外光激发下的发射从蓝紫区向黄绿光区转变; 其中, 当Tb 3+浓度为0.5%时, 样品表现为白光发射, 色坐标为(0.33, 0.35), 显色指数达86. 变温荧光光谱测试结果显示, 上述荧光粉具有良好的发光热稳定性. 对三类荧光粉的内量子效率进行了测试, 其中GTO:Eu 3+量子效率优于GTO:Dy 3+和GTO:Tb 3+, 各样品量子效率仍有较大提升空间.A series of rare earth Dy 3+, Tb 3+, Eu 3+singly doped Gd 2Te 4O 11(GTO) tellurite phosphors with intrinsic polarity are prepared by hydrothermal method. The phase structures, morphologies and thermal stabilities of these phosphors are characterized. Their luminescence properties are tested in detail. The results show that all those phosphors are crystalized into single phase of digadolinium tellurite with short rod-like shape. The maximum size in the axial direction is microns. The phosphor has good thermal stability. For the GTO:Dy 3+, the fluorescence emission under UV excitation is mainly located in the yellow-green region. The optimal doping concentration corresponding to the strongest excitation and emission is 2.5%, and the CIE color coordinates are (0.39, 0.43). The fluorescence decay curve shows that the lifetime of the GTO:Dy 3+on 4F 9/2energy level decreases gradually with doping concentration of Dy 3+increasing, which may be related to the cross relaxation (CR) between Dy 3+ions. For the GTO:Eu 3+, the fluorescence emission under UV excitation is mainly located in the red region and orange-red region. The emission intensity is enhanced with the doping concentration of Eu 3+increasing. When the doping concentration is 10%, the CIE color coordinates are (0.62, 0.38), which are located in the orange-red region with high color purity. The fluorescence lifetime of Eu 3+on 5D 0energy level is hardly affected by the change of Eu 3+doping concentration. For the GTO:Tb 3+, with the increase of the Tb 3+concentration, the fluorescence emission under UV excitation changes from blue-violet region to yellow-green region, which can be ascribed to the influence of CR between Tb 3+ions. The fluorescence decay behavior reveals that the Tb 3+ions on 5D 4excited state may undergo energy transfer and reabsorption, which can deviate the fluorescence decay from the single exponential model. When the concentration of Tb 3+is 0.5%, the sample exhibits white light emission with the CIE color coordinates of (0.33, 0.35) and color rendering index of 86. The measurements of temperature-dependent emission spectra show that the above-mentioned phosphors have good luminescent thermal stability. The internal quantum efficiencies (IQEs) of those three types of phosphors are measured, and the IQE of GTO:Eu 3+is better than those of GTO:Dy 3+and GTO:Tb 3+. There is still much room for improvement in the luminescent performance of all these phosphors. These phosphors have potential to be used in UV-excited white LEDs.
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掺杂浓度 CIE色坐标 色温/K 色纯度/% 0.5 (0.53, 0.45) 2197 93.96 1.0 (0.56, 0.43) 1857 96.70 2.5 (0.59, 0.40) 1631 97.17 5.0 (0.60, 0.39) 1621 97.14 7.5 (0.62, 0.37) 1752 97.56 10.0 (0.62, 0.38) 1689 98.51 
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A1 τ1 A2 τ2 A3 τ3 平均荧光寿命 GTO:0.5%Tb3+ 18.9 7.5 69.4 46.9 11.0 180.8 95.4 GTO:1.0%Tb3+ 8.2 3.2 82.3 47.6 9.0 226.4 108.4 GTO:2.5%Tb3+ 34.6 6.6 52.2 48.3 14.1 199.7 123.2 GTO:5.0%Tb3+ 41.5 7.1 46.2 51.3 13.5 214.8 134.2 GTO:10%Tb3+ 21.5 3.9 69.7 48.2 7.3 358.7 181.6 下载:
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