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Luminescent Properties Of Sm3+,Eu3+,Dy3+,Tb3+ Doped Luminescent Na2CaSiO4 Material

Posted on:2019-02-16Degree:MasterType:Thesis
Country:ChinaCandidate:X N SuFull Text:PDF
GTID:2381330623466373Subject:Optics
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In this paper,a series of rare-earth ions doped with silicate matrix Na2CaSiO4were studied in this paper.A series of Sm3+and Eu3+,Dy3+and Eu3+,Tb3+and Eu3+co-doped Na2CaSiO4 luminescent materials were prepared by the high temperature solid state reaction,luminescent properties,fluorescence lifetime,color purity were analyzed,the details are as follows;?1?A series of Na2CaSiO4:Sm3+,Eu3+phosphors was prepared by the high temperature solid state reaction method at 1150?,and studied their crystal structure,luminescent properties and energy transfer phenomenon influenced by the Sm3+and Eu3+.The XRD results indicates that the samples single and co-doped with Sm3+and Eu3+keeps single-phase and no impurity phases were observed.Under the excitation of 404nm,the Na2CaSiO4:Sm3+samples emit narrow-band spectral fluorescence with lines composed by peak-to-peak value of 565nm,602nm,650nm,713nm,which correspond to the electronic transitions of Sm3+from the ground state level 4G5/2/2 to the 6H5/2,6H7/2,6H9/2,6H11/2.On the other hand,the samples of Na2CaSiO4:Eu3+exhibit a red emission with the peak-to-peak value of 613nm under the excitation of395nm laser.By analyzing the fluorescence's spectra and lifetime,with the increase of Eu3+content,the emission intensity of Sm3+could be observed to decrease,the emission intensity of Eu3+was found to increase.Moreover,the lifetime corresponding to Sm3+at 602nm decrease gradually.It is indicated that the energy transfer between Sm3+to Eu3+.The critical distance of energy transfer is 1.36nm calculated by the concentration quenching method.The energy transfer mechanism is ascribed to the quadrupole-quadrupole interaction.As the Eu3+doping concentration increases,the transfer efficiency increased to 20.6%.In conclusion,the Na2CaSiO4:Sm3+,Eu3+phosphors may have potential as an red component for white light-emitting diodes.?2?The crystal structure of Na2CaSiO4:Dy3+and Eu3+phosphors was prepared by high-temperature solid-state reaction.The crystal structure of Na2CaSiO4:Dy3+and Eu3+was studied by X-ray diffraction.The spectral characteristics and fluorescence lifetime were measured and analyzed.It is also found that there exists energy transfer between Dy3+and Eu3+.After theoretical calculations,it can be concluded that the critical distance of energy transfer between Dy3+and Eu3+is 1.18nm,and the energy transfer efficiency is up to 34.2%.The luminescent color of the sample can also be changed from yellow-green to red according to the doping concentration of Eu3+,so that the luminescent color of the phosphor can be adjusted.?3?Series of Tb3+,Eu3+co-doped Na2CaSiO4 phosphors have been prepared by high temperature solid-state reaction.The phosphors Na2CaSiO4:xmol%Tb3+,ymol%Eu3+?x=0-12?were phosphors were characterized by X-ray diffraction?XRD?,photoluminescence spectra,color coordinates Single-doped Tb3+phosphors show a strong green emission at 374 nm excitation.Their emission colors can be further tuned by co-doping with Eu3+ions and can gradually change from green to orange-red.The optimum doping concentration of Tb3+ion is 2%mol and the optimum doping concentration of Eu3+ion is 8%mol.The critical distance between Tb3+ions and Eu3+ions is about 1.36 nm.Concentration quenching method was used to prove that the energy transfer between Tb3+ions and Eu3+ions occurred through the electric dipole-dipole interaction.These results show that this phosphor is a potential candidate for WLED.
Keywords/Search Tags:Na2CaSiO4, Silicate luminescent material, Photoluminescence, Energy transfer, WLED
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