Bi^(3+)、Eu^(3+)共掺杂La_(4)GeO_(8)荧光粉的制备及可调发光

Preparation and Color-tunable Luminescence of La_(4)GeO_(8)∶Bi^(3+),Eu^(3+) Phosphors

为了开发出高效稳定的单一基质白光发射荧光材料,本工作通过高温固相法成功合成了一系列La_(4)GeO_(8)∶Bi^(3+),Eu^(3+)荧光粉样品,并通过X射线衍射、室温光谱、变温光谱等手段研究了实验样品的结构与发光性能。研究发现,Bi^(3+)离子在该结构中占据两种不同的格位(Bi^(3+)(Ⅰ)和Bi^(3+)(Ⅱ)),且在紫外光激发下呈现两个峰值分别在475 nm和620 nm的宽带发射。对于Bi^(3+)、Eu^(3+)共掺样品,由于Bi^(3+)(Ⅰ)与Eu^(3+)之间的竞争吸收、Bi^(3+)(Ⅰ)至Bi^(3+)(Ⅱ)以及Bi^(3+)(Ⅱ)至Eu^(3+)的能量传递作用,可实现蓝色至红色、橙红色至红色的可调发光。特别地,样品La_(4)GeO_(8)∶0.07Bi^(3+),0.06Eu^(3+)在313 nm光激发下可获得CIE值为(0.335,0.319)的优异白色发光。此外,该白光发射材料具有较佳的发光热稳定性,当温度升高至380 K时,发光积分强度仍然为室温的59%,表明其在白光二极管上具有潜在的应用价值。

In order to develop efficient and stable single matrix white light emitting fluorescent materials,a series of La_(4)GeO_(8)∶Bi^(3+),Eu^(3+) phosphors were successfully synthesized by high-temperature solid-state method.The structural and luminescent properties of the experimental samples were studied by X-ray diffraction,room temperature spectra,and variable temperature spectra.It was found that Bi^(3+) ions occupy two different lattice positions(Bi^(3+)(Ⅰ) and Bi^(3+)(Ⅱ)) in this structure,and exhibit two broadband emission peaks at 475 nm and 620 nm under UV excitation,re⁃spectively.The tunable emission from blue to red and orange red to red can be achieved due to the competitive ab⁃sorption process of Bi^(3+)(Ⅰ) and Eu^(3+),energy transfer of Bi^(3+)(Ⅰ)→Bi^(3+)(Ⅱ)and Bi^(3+)(Ⅱ)→Eu^(3+).Specially,excellent white light emission with CIE(0.335,0.319)was obtained in sample of La_(4)GeO_(8)∶0.07Bi^(3+),0.06Eu^(3+)under 313 nm excitation.In addition,the white light emission sample presents excellent luminescent thermal stability(the integrat⁃ed emission intensity at 380 K remains 59%of that at room temperature),indicating that the material has potential application in white light-emitting diodes.