摘要
本文采用BaF_2作为助熔剂和抑制剂经固相反应合成了一系列以LnAlO_3(Ln=La,Gd,Y)为基质的磷光体,系统地研究了LnAlO_3中Ce^(3+),Tb^(3+),Dy^(3+)的发光及Ce-Tb,Ce-Dy的敏化发光,发现随Ln的不同,LnAlO_3作为基质对激活剂的发光性质的影响也不同,本文得到一些规律性结果,并作了讨论。
The phosphors of LnAlO3 doped with Ce3 + , Tb3 + , Dys + were gynthetized by solid state reaction at 1200℃. BaF2 was used as a flux. The luminescence of Ce3+, Tb3+, Dy3+ and the sensitized luminescence of Ce-Tb, Ce-Dy in LnAlO3 (Ln = La, Gd or Y) were systematically investigated. It is shown that with different Ln, the influence of the LnAlO3 host on the luminescence of activators is different.1.The main features of the luminescence of Ce3+ in LnAlO3 are summarized in Table 1. The position of the peaks in the spectra of Ce3+ in LaAlO3 shift to longer wavelength with reference to those in GdAlO3 and YAlO3. This fact is clearly due to the variation of the crystal stiucture of host which is hexagonal for LaAlO3 but orthorhombic for GdAlO3 and YAlO3. As the ionic radius of Y3+ is smaller than that of Gd3+ and the covalent bonding of Ln-O in Y AlO3 is stronger, the position of the emission peak of Ce3+ in YAlO3 shifts to low energy side with respect to that in GdAlO3, as expected.2.In the excitation spectra of LnAlO3:Tb there is a band corresponding to 4f8-4f7 5d transition of Tb3+ .The position of this band varies with the host with the same trend as observed in the case of the luminescence of Ce3+ (see Fig.1).3.Tb3+ can be sensitized by Ce3+ in LnAlO3. The sensitized efficiency varies with host. LaAlO3 is the best one, while YAlO3 is the worst.4.From Fig.3 (a, b, c), it can be seen that the intensity ratio of the two peaks corresponding to 4F9/2 - 6H13/2 and 4F9/2 - 8H15/2 is the largest in LaAlO3, and the smallest in YA1O3. 5. Ce3+ can also sensitize Dy3+, and the relationship between sensitized efficiency and host is the same as observed in the case of Ce-Tb.(See 3), But, Dy3+ is easily quenched by Ce3+, So the concentration ratio of Ce3+ to Dy3+ is smaller than that of Ce3+ to Tb3+ in the same host, when the energy transfer is optimum.
出处
《发光学报》
EI
CAS
CSCD
北大核心
1990年第1期35-43,共9页
Chinese Journal of Luminescence
基金
中国科学院科学基金
