摘要
采用高温固相反应合成了LaPO4∶Eu2+和LaPO4∶Ce3+,Eu2+样品,报道了Eu2+在LaPO4中的发光性质和Ce3+→Eu2+的能量传递现象。文中探讨了Ce3+→Eu2+的能量传递机理,根据Dexter电多极相互作用的理论证明其为偶极子 偶极子相互作用的共振能量传递。
A new luminescence material——LaPO4 doped with Eu2+ and Ce3+ was prepared by high temperature solid state reaction. And the optical properties of Eu2+activated and Ce3+,Eu2+ coactivated lanthanum phosphates were investigated by using photoluminescence(PL) measurements.Emission spectrum of LaPO4∶Eu2+ recorded at room temperature with 324nm excitation shows a broad emission band centered at 423nm. And it is possible to determine the distribution of this broad emission band in the spectrum associated with transition from the 4f5d level of Eu2+ ion.The excitation spectrum of Eu2+activated lanthanum phosphate recorded at room temperature monitoring 423nm emission exhibits absorption in UV region (220~400nm) assigned to the 4f→5d transition of Eu2+ ion.Lanthanum phosphate doped with Ce3+ was also prepared by high temperature solid state reaction. The room temperature photoluminescence spectra of LaPO4∶Ce3+ show the broad emission and excitation band of Ce3+ ion ,around 342nm and 284nm,respectively.From these spectra above, it's possible to deduce that energy transfer between the Eu2+ and Ce3+ ion will probably happen because of the well overlapping between Ce3+ emission and Eu2+ excitation. And it's well proved in the excitation spectrum of LaPO4 coactivated by Eu2+ and Ce3+ at room temperature, monitoring Eu2+ emission. This spectrum shows a strong absorption band of Ce3+, ranging over 220~340nm, in addition to original f→d transition of Eu2+(220~400nm). That is to say there happens a sensitization of Eu2+ by the presence of Ce3+ ion. The Eu2+ emission intensity of LaPO4∶Ce3+001, Eu2+001 is 56 times higher than that of the corresponding phosphor activated by Eu2+ only.A series of LaPO4∶Ce3+001, Eu2+x were prepared to study the mechanism of the energy transfer between the Eu2+ and Ce3+ ion. The emission spectra of the LaPO4∶Ce3+001, Eu2+x at room temperature were measured. The relationship between the Ce3+ donor emission intensity and the Eu2+ acceptor concentration was fit to the d→d (dipoledipole) energy transfer model for multipolemultipole interaction. So it is concluded that the energy transfer between the Ce3+ and Eu2+ ions in lanthanum phosphate is to be a process of dipoledipole resonance interaction.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2003年第3期234-238,共5页
Chinese Journal of Luminescence
基金
天津市自然科学基金资助项目(01360191)
天津市"材料物理与化学"重点学科资助项目