Preparation and Color-tunable Luminescence of La4GeO8:Bi3+,Eu3+ Phosphors
In order to develop efficient and stable single matrix white light emitting fluorescent materials,a series of La4GeO8∶Bi3+,Eu3+ 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 Bi3+ ions occupy two different lattice positions(Bi3+(Ⅰ)and Bi3+(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 Bi3+(Ⅰ)and Eu3+,energy transfer of Bi3+(Ⅰ)→Bi3+(Ⅱ)and Bi3+(Ⅱ)→Eu3+.Specially,excellent white light emission with CIE(0.335,0.319)was obtained in sample of La4GeO8∶0.07Bi3+,0.06Eu3+ 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.
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