Study On The Preparation And Luminescent Properties Of The Rare Earth Co-doped Gd₂P₄O₁₃ Phosphor

People have been trying to research the green energy-saving luminescent materials for a long time.The white light-emitting diodes have a wide range of good applications because of their characteristics of high efficiency,energy saving and long service life.It is known as the fourth generation of new lighting source.Phosphate-based phosphor has many characters such as the energy saving traits,long lifetime,and environmentally friendly.So,they are widely used in the field of tunable light-emitting diodes,field emission display devices and mercury-free fluorescent lamps.To achieve white-light-emitting,the phosphor with Dy³⁺-doped was synthesized because of two main emission of Dy³⁺.The emission at 470-500 nm and the emission at 570-600 nm.Therefore,it is possible to obtain near white light with only Dy³⁺-doped in luminescence materials by matching yellow to blue intensity ratio.In this investigation,we studied the structural,luminescence and energy transfer characteristics of Gd₂P₄O₁₃ with Dy³⁺ions,Eu³⁺ions,Dy³⁺/Eu³⁺ions and Tm³⁺/Dy³⁺co-doped.These phosphate-based phosphors can be a single substrate white LED phosphor.Firstly,the Gd₂P₄O₁₃:Dy³⁺phosphor was prepared by the conventional solid-state reaction method.The emission spectra of Gd_2-xP₄O₁₃:xDy³⁺phosphors under 350nm excitation were studied.It is obvious that the quenching concentration of Dy³⁺in the Gd₂P₄O₁₃3 host at about 10%mol.The concentration quenching menchanism of Dy³⁺in the Gd₂P₄O₁₃ host is dipole-dipole interaction.Secondly,the Gd₂P₄O₁₃:Eu³⁺sample was synthesized by the solid-state reaction method.The concentration quenching menchanism of Eu³⁺in the Gd₂P₄O₁₃ host is dipole-dipole interaction by studying the emission spectra of Gd_2-xP₄O₁₃:xEu³⁺phosphors.Then,Gd_2-x-yP₄O₁₃:xDy³⁺,yEu³⁺phosphor was synthesized by the solid-state reaction.The emission spectra were studied carefully.The CIE of Gd_1.96-yP₄O₁₃:0.04Dy³⁺-yEu³⁺?y=0.00,0.02,0.03,0.04,0.05?are located in the white area very well when excited by 350nm.The point of Gd_1.92P₄O₁₃:0.04Dy³⁺-0.04Eu³⁺at?0.320,0.333?is very closer to the ideal white light point?0.333,0.333?in the CIE.And the energy transfer from Dy³⁺to Eu³⁺ions were studied.The photon energy was absorbed by the Dy³⁺ions under 350 nm excitation.After that,the energy is transferred from Dy³⁺ions to the Eu³⁺ions.That energy transfer between Dy³⁺and Eu³⁺ions are through the quadrupole-quadrupole interactions.Gd_2-x-yP₄O₁₃:xDy³⁺,yEu³⁺can be a single substrate white LED phosphor under near-ultraviolet light excitation.Finally,the phosphate-based phosphor Gd_2-x-yP₄O₁₃:xTm³⁺-yDy³⁺was synthesized by the solid-state reaction method.The emission spectra of Gd_2-x-yP₄O₁₃:xTm³⁺-yDy³⁺and energy transfer among Tm³⁺and Dy³⁺ions were researched.Emitting color of the phosphate-based phosphor Gd_2-x-yP₄O₁₃:xTm³⁺-yDy³⁺are located in the white area very well in the CIE.The point of Gd_1.96P₄O₁₃:0.01Tm³⁺-0.03Dy³⁺at?0.300,0.335?is very closer to the ideal white light point.The energy transfer was studied in detail.First photon energy was absorbed by the Tm³⁺ions under 359 nm excitation.Then a portion of the energy was transferred from Tm³⁺to Dy³⁺.And that energy transfer from Tm³⁺to Dy³⁺ions via the dipole-quadrupole interactions.