CaLaAl_3O_7∶Eu^(3+)的凝胶-燃烧法合成及其发光性能

Synthesis of CaLaAl_3O_7∶Eu^(3+) by Gel-Combustion Method and Its Luminescence Properties

采用柠檬酸凝胶-燃烧法合成了CaLa1-xAl3O7∶xEu3+(0.05≤x≤0.8)材料的前驱粉末,在低于700℃退火处理时,得到非晶态样品,而高于800℃退火处理后为纯相的CaLa1-xAl3O7∶xEu3+粉末样品。通过激发光谱和发射光谱研究了Eu3+在CaLaAl3O7基质中的发光性能及Eu3+掺杂量,退火温度和柠檬酸与金属离子的配比等对发光强度的影响。结果显示,非晶态和晶态CaLa1-xAl3O7∶xEu3+样品均可发光,非晶态样品的最强激发峰出现在7F0—5D2的465 nm处,而晶相样品的最强激发峰为7F0—5L6跃迁的394nm。非晶态粉末在465 nm激发下发射光谱由5D0—7F0的578 nm和5D0—7F1的587 nm及5D0—7F2的615nm组成。而晶态粉末在394 nm激发下的发射光谱与非晶态相比5D0—7F0跃迁消失了,同时5D0—7F1跃迁发生谱线劈裂,出现在587和596 nm两处。随着退火温度的升高,主峰615 nm强度增强了,但5D0—7F1跃迁峰的增强更加明显。

Using the gel-combustion method the precursors of CaLa1-xAl3O7∶xEu^3＋（0.05≤x≤0.8） were prepared.When annealing temperature was below 700 ℃,the materials were in amorphous state,while as annealing temperature was above 800 ℃,the high purity CaLa1-xAl3O7∶xEu^3＋ crystalline materials were obtained.The luminescence properties of CaLa1-xAl3O7∶xEu^3＋ both in amorphous and crystalline phases were investigated,and the results of excitation spectrum show a similar charge transition band of Eu^3＋-O^2-between 230 nm and 320 nm and a series of f-f transition of Eu^3＋ ion.However,the strongest band of amorphous material was at 465 nm corresponding to ^7F0-^5D2 transition,and those of the crystalline materials were at 394 nm corresponding to ^7F0-^5L6 transition of Eu^3＋ ion.In amorphous state materials the emission intensity of excitation wavelength 465 nm was stronger than that of 394 nm,and composition of ^5D0-^7F0 transition at 578 nm,^5D0-^7F1 transition at 587 nm and ^5D0-^7F2 transition at 615 nm.In crystalline material,the emission intensity of excitation wavelength of 394 nm was stronger than that of 465 nm,the ^5D0-^7F0 transition disappeared,and the ^5D0-^7F1 transition split into 587 nm and 596 nm.With the increase in temperature,the strongest band at 615 nm increased,and what is more,the ^5D0-^7F1 transition increased remarkably.In CaLa1-xAl3O7∶xEu^3＋,when x=0.2 for the co-doping Eu^3＋ ion and the mol proportion of citric acid and metal ion（C/M） was 1.2,the luminescence intensity was the highest.