(La,Ce,Tb)(PO4,BO3)的光谱特性研究

本文合成制备了(La,Ce,Tb)(PO4,BO3)(Gp)绿色发光材料,比较了CeMgAl11O19:Tb(GA1)和Gp在室温下的发光、激发光谱的差异,Gp的5D4-7F5跃迁谱线的半宽度及相对强度均小于GA1,而5D4-7F3、5D4-7F3跃迁谱线的相对强度则大于GA1.激发光谱的差异主要是Gp的激发带强度高于GA1,自310nm后明显升高,在313nm处的强度比GA1提高近3倍,在351、369、377nm处的强度也比GA1分别提高近2.3-3.3倍,分析井讨论了Gp和GA1在发光、激发光谱上的差异对材料发光性能的影响.发光光谱的差异引起Gp发光色坐标的x值比GA1大,而y值变小.激发光谱的差异使得Gp在254nm激发下的发光亮度高于GA1,在313、365nm激发下的发光亮度则明显高于GA1.本文还讨论发La、Ce比对Gp发光性能的影响,只有在Ce的含量为0情况下,Gp的发光性能才显著变化.

SPECTROSCOPY OF(La,Ce, Tb)(PO4, BO3 )

Ce, Tb activated LaPO4(GP) is one of the high effective rare earth green luminescent materials, which has been applied in three basic color fluorescent lamp in the last ten years. In present work, GP has been synthesized, analysed and compared with pratical green phosphor CeMgA111O19;Tb(GA1) on excitation and emission spectra. It can be seen on emission spectra that the 543nm (5D4-7F5) halfwidth of Gp is 3nm smaller than GA1, and its intensity is lower. The intensities for longer wavelengths 584nm (5D4-7F4) and 620nm (5D4-7F3) are stronger than that of GA1, however the y value of which is smaller than GA1 Therefore, in order to get the same color temperature, when GP is selected for the green component, the amount of red phosphor can be deduced.There are some differences in excitation spectra. One is that the measured brightness of GP is 7% higher than GA1 when excited under 254nm. The other is the excitation spectra bands sited after 310nm of Gp are increased, excited intensity of which at 313nm is three times higher than GA1. In addition, intensities of GP at 351, 369 and 377nm are 2-3 times increased than GA1. When rare earth three basic phosphors are used for lamps,the luminescence caused by the secondary mercury lines (313, 365nm) must be considered. According to the relative intensities of 313nm and 365nm line in low pressure mercury lamp and relative excited intensities of 313nm and 365nm in GA1, the brightness increased by 313nm and 365nm excitation is calculated. The increasing factor for GP is about 1%, but for GA1, it is only 0.1%. Thus, it is shown that GP is of more benefit to the increase of luminous flux in lamp fabrication.This paper also deals with the effects of La,Ce proportion on emission and excitation spectra of GP. It is indicated that emission and excitation spectra of GP are all the same when La, Ce proportions are different (La is changed from 0 to 0.58, Ce is varied from 0.8 to 0.22). The above fact means that the function of Ce is not only sentisizer but also a part of host which plays the same role as La. In the case of lack of Ce, the emission spectra of GP still shows the Tb luminescent lines, but the brightness of which is obviously decreased.