用固相法合成了La3PO7∶Eu^3+,用X射线衍射仪测定了其晶体结构,室温下用Hitachi F-4500测定了其光致发光性质。结果表明合成的La3PO7∶Eu^3+属单斜相结构,Eu^3+在单斜结构的La3PO7基质中占据非对称性格位。在254 nm光激发下,La3PO7∶Eu^3+发射出较强的红光,表明Eu^3+的^5D0→^7F2跃迁强度远大于^5D0→^7F1的跃迁强度,其色坐标和Y2O3∶Eu^3+的色坐标位置相近。另外,还研究了Eu^3+在体相La3PO7材料中的猝灭浓度,发现当掺杂Eu^3+浓度增大到7.6 mol%时,出现浓度猝灭。
Novel red phosphor,Eu^3+-doped oxyphosphate(La3PO7∶Eu^3+),was synthesized by a solid state method under high temperature.All the starting materials were analytical grade.La2O3,Eu2O3 and (NH4)2HPO4 weighed in appropriated molar ratios and ground in an agate mortar.Then the powder was treated under 1 000 ℃.The crystal phase of La3PO7∶Eu^3+ was investigated by X-ray diffraction(XRD) using a Cu target radiation resource(λ= 1.540 78 ?) and exhibited prominent peaks accordant with JCPDS standard card(33-0720) of La3PO7 in monoclinic phase.Emission and excitation spectra of La3PO7∶Eu^3+ were recorded at room temperature using a fluorescence spectrometer(Hitachi F-4500).Under 254 nm excitation,intense red fluorescence was observed from La3PO7∶Eu^3+,which was assigned to the ^5D0→^7F2 transition of Eu^3+ ions.The intensity of the ^5D0→^7F2 transition is stronger than that of the ^5D0→^7F1 transition,showing that the Eu^3+ ions were in the non-centrosymmetric sites in La3PO7.The CommissionIn-ternational DeL" Eclairage(CIE) coordinate of La3PO7∶Eu^3+ is(0.63,0.37) in the red area of CIE1931 XY chromaticity coordinate graph and close to that of Y2O3∶Eu^3+,but the cost of La3PO7 host is lower.This novel material may have potential applications in plasma display panels and Hg-free fluorescent lamps in the future.