Sm^(3+)离子激活Y_(2)MgTiO_(6)橙红色荧光粉的制备及发光性质研究

Preparation and Luminescence Properties of Y_(2)MgTiO_(6) Red-Orange Phosphors Activated by Sm^(3+) Ions

采用溶胶-凝胶法合成了一系列橙红色发光的Y_(2-2x)MgTiO_(6)∶2xSm^(3+)(YMT∶2xSm^(3+),0≤x≤0.11)荧光粉。通过粉末X射线衍射仪(XRD)、扫描电子显微镜(SEM)、光致发光激发和发射光谱对样品进行了表征分析。结果表明,所制备的YMT∶Sm^(3+)样品为纯相,无任何杂质;荧光粉颗粒尺寸为2~3μm,分散性较好且无明显团聚。在407 nm的近紫外光激发下,样品的发射光谱在500~700 nm波长范围内存在三个显著的发射峰,分别是603 nm(~4G_(5/2)→~6H_(7/2))和650 nm(~4G_(5/2)→~6H_(9/2))处较强的红光,以及566 nm(~4G_(5/2)→~6H_(5/2))处较弱的绿光。Sm^(3+)离子的最佳掺杂浓度为5 mol%,理论计算出Sm^(3+)离子的临界转移距离为1.619 nm。当Sm^(3+)浓度超过5 mol%时,出现明显的浓度猝灭效应,该效应归因于Sm^(3+)离子之间电四极子-电四极子(q-q)相互作用。YMT∶Sm^(3+)荧光粉的CIE色度坐标位于橙红光区域,是一种具有潜在应用价值的白光LED用红色荧光粉。

A series of red-orange luminescent Y_(2-2x)MgTiO_6∶2xSm^(3+)(YMT∶2xSm^(3+),0≤x≤0.11) phosphors were synthesized by sol-gel method.The samples were characterized and analyzed by powder X-ray diffractometer(XRD),scanning electron microscopy(SEM),photoluminescence excitation and emission spectroscopy.The results show that the as-prepared YMT∶Sm^(3+) exhibits a pure-phase structure with no impurity phases.The SEM images show an average diameter of about 2~3 μm for the particles and good dispersibility without overt agglomeration phenomenon.Under the excitation of a 407 nm near-ultraviolet light,the emission spectrum of YMT∶Sm^(3+) phosphors has three significant emission peaks in the wavelength range of 500~700 nm,which are the stronger orange-red light emission at 603 nm(~4G_(5/2)→~6H_(7/2)) and 650 nm(~4G_(5/2)→~6H_(9/2)),and the weaker green light emission at 569 nm(~4G_(5/2)→~6H_(5/2)).The optimal doping concentration of Sm^(3+) ions is about 5 mol%,and the theoretically calculated critical transfer distance of Sm^(3+) ions is 1.619 nm.When the concentration of Sm^(3+) exceeds 5 mol%,there is an obvious concentration quenching effect,which is attributed to the electric quadrupole-electric quadrupole(q-q) interaction between Sm^(3+) ions.The CIE chromaticity coordinates of YMT∶Sm^(3+) phosphors are located in the orange-red region,indicating that it has potential application value in red phosphors for white LEDs.