硬脂酸盐熔融法合成(Y,Lu)AG:Ce荧光粉及荧光性能研究

doi:10.15541/jim20140254

摘要/Abstract

摘要：

采用硬脂酸盐熔融新方法合成了[(Y_1-_xLu_x)_1-_yCe_y]₃Al₅O₁₂固溶体荧光粉(x=0’0.5, y=0.005’0.03), 并通过XRD、SEM、BET和PL-PLE等方法对该荧光粉进行了表征。结果表明, 纯相石榴石在800℃的低温下即可生成, 而不经过YAM和YAP中间相。煅烧所得[(Y_1-_xLu_x)_1-_yCe_y]₃Al₅O₁₂荧光粉具有良好的均一性和分散性, 并在455 nm蓝光激发下于544 nm附近呈现最强黄光发射。粉体的发光强度随煅烧温度升高而增大, 归因于结晶度提高和表面缺陷减少。发现Ce³⁺的荧光猝灭浓度为1.5%, 猝灭机制为Ce-Ce间的交换相互作用和晶格缺陷。发现发射峰位随Ce³⁺含量增加而红移, 而最强激发峰和发射峰随Lu³⁺含量增大而蓝移, 归因于Ce³⁺离子5d激发态能级重心移动和晶体场劈裂的共同作用。

关键词: YAG:Ce3+, Lu3+掺杂, 发光性能, 能级重心, 晶体场劈裂

Abstract:

[(Y_1-_xLu_x)_1-_yCe_y]₃Al₅O₁₂ (x=0-0.5, y=0.005-0.03) garnet powders were prepared by a novel stearate melting method. The phosphor powders were analyzed by XRD, SEM, BET and PL-PLE. The results show that phase-pure garnet can be obtained upon calcination at a relatively low temperature of 800℃, without involvement of YAlO₃ (YAP) and Y₄Al₂O₉(YAM) intermediate phases. The resultant [(Y_1-_xLu_x)_1-_yCe_y]₃Al₅O₁₂ phosphor powders are well dispersed, and show the highest emission at 544 nm under excitation wavelength at 455 nm. The emission intensity increases with increasing calcination temperature, due to improved crystallinity of the powder and removal of surface defects at high temperatures. The quenching concentration of Ce³⁺ is found to be 1.5% and the quenching mechanism is proposed to be Ce-Ce interactions and lattice defects. PL band of the phosphor red shifts with the increase of Ce³⁺ content, while the strongest excitation and emission bands are blue shift with increasing Lu³⁺ doping, due to combination effects of centroid shift and crystal field splitting of the Ce³⁺ 5d energy levels.

Key words: YAG:Ce3+, Lu3+ doping, luminescence properties, energy centroid, crystal field splitting

中图分类号:

TB34

李金生, 孙旭东, 李晓东, 刘绍宏, 朱琦. 硬脂酸盐熔融法合成(Y,Lu)AG:Ce荧光粉及荧光性能研究[J]. 无机材料学报, 2015, 30(2): 177-182.

LI Jin-Sheng, SUN Xu-Dong, LI Xiao-Dong, LIU Shao-Hong, ZHU Qi. (Y, Lu)AG:Ce Phosphors Synthesized by Stearate Melting Method and Their Fluorescence Properties[J]. Journal of Inorganic Materials, 2015, 30(2): 177-182.

图/表 9

图1 前驱体经不同温度煅烧所得(Y0.985Ce0.015)3Al5O12粉体的XRD图谱(a)及经1300℃煅烧所得[(Y1-xLux)0.985Ce0.015]3 Al5O12的XRD图谱(b)

Fig. 1 XRD patterns of (Y0.985Ce0.015)3 Al5O12 precursor calcined at different temperatures (a) and a comparison of XRD patterns of [(Y1-xLux)0.985Ce0.015]3Al5O12 powders calcined at 1300℃(b)

图2 经1300℃煅烧所得 [(Y1-xLux)0.985Ce0.015]3Al5O12固溶体的晶格常数和理论密度的变化

Fig. 2 Lattice constants and theoretical densities of the [(Y1-xLux)0.985Ce0.015]3Al5O12 garnet solid solutions calcined at 1300℃, as a function of Lu content

图3 经1000℃(a)、1150℃(b)、1300℃(c)和1500℃(d)煅烧所得(Y0.985Ce0.015)3Al5O12粉体的FE-SEM形貌

Fig. 3 FE-SEM images showing particle morphologies of the powders calcined at 1000℃ (a), 1150℃ (b), 1300℃ (c) and 1500℃ (d)

图4 经1300℃煅烧所得(Y1-xCex)AG (x=0.005~0.03)样品的激发光谱(a)和发射光谱(b)

Fig. 4 Comparison of the PLE (a) and PL (b) spectra of the (Y1-xCex)AG (x=0.005-0.03) phosphors calcined at 1300℃

图5 经1300℃煅烧所得(Y1-xCex)AG (x=0.005~0.03)样品的lg (I /c)和lg c关系

Fig. 5 Relationship between lg(I/c) and lg c for the (Y1-xCex)AG (x=0.005-0.03) phosphors calcined at 1300℃

图6 经1300℃煅烧所得(Y1-xCex)AG (x=0.005~0.03)样品的lg (I /c)和lg (1-c)关系

Fig. 6 Relationship between lg(I/c) and lg(1-c) for the (Y1-xCex)AG (x=0.005-0.03) phosphors calcined at 1300℃

图7 不同温度煅烧所得(Y0.085Ce0.015)AG样品的发射光谱内嵌图为发射强度随温度的变化

Fig. 7 PL spectra of the (Y0.085Ce0.015)AG phosphors calcined at different temperatures.

图8 经1300℃煅烧所得[(Y1-xLux)0.985Ce0.015]AG样品的激发光谱(a)和发射光谱(b)

Fig. 8 Comparison of the PLE (a) and PL (b) spectra of the [(Y1-xLux)0.985Ce0.015]AG phosphors calcined at 1300℃

图9 YAG:Ce和LuAG:Ce基态4f、激发态5d轨道的能级图

Fig. 9 Energy level diagram showing the 4f ground state and 5d excited state of YAG:Ce and LuAG:Ce garnets

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