新型红色发光材料La3PO7∶Eu^3＋的合成及发光性质研究

A Novel Red Phosphor (La_3PO_7∶Eu^(3+)) Prepared by Solid State Method

用固相法合成了La3PO7∶Eu3+,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∶Eu3+属单斜相结构,Eu3+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∶Eu3+发射出较强的红光,表明Eu3+的5D0→7F2跃迁强度远大于5D0→7F1的跃迁强度,其色坐标和Y2O3∶Eu3+的色坐标位置相近。另外,还研究了Eu3+在体相La3PO7材料中的猝灭浓度,发现当掺杂Eu3+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.