Synthesis And Properties Of Rare Earth Based Borate Phosphors

Recently,rare earth based borate phosphors have been a focus of studies,which can effectively solve the problem of concentration quenching.And borates have advantages of inexpensive raw materials,low synthesis temperature,stable physicochemical properties and so on.This paper investigated the luminescence propertiesofdifferentrareearthbasedpentaphosphorssuchas CeZn_1-x(B₅O₁₀):xMn²⁺phosphors,TbZn_1-x(B₅O₁₀):xMn²⁺phosphorsand Tb_1-xZn(B₅O₁₀):xYb³⁺phosphors.Transition metal doped Ce³⁺-based borate CeZn_1-x(B₅O₁₀):Mn²⁺was synthesized by utilizing conventional solid-state reaction method.The lattice structure and particularly the luminescence properties of the synthesized phosphors were carefully studied.By analyzing the results,it is revealed that Mn²⁺only occupies Zn sites,and it only contributes the light emitting peaked at 615nm under the excitation of 371nm.While the emitting peak at 437nm under the same excitation is verified to be caused by the 5d-4f(²F_5/2 and ²F_7/2)transitions of Ce³⁺-based.Furthermore,by conducting a comprehensive investigation on overlap of emission,excitation spectra and variation of fluorescence decay lifetimes,we make it clear that the energy transfer from Ce³⁺to Mn²⁺is virtually via a resonance-type mechanism.And color-tunable light emitting can be realized by adjusting the concentration of Mn²⁺in our proposed phosphor and using excitation of ultraviolet?UV?light.In addition,close to white light can be realized when doping the Mn²⁺ions to a certain extent.The emission-tunable TbZn_1-x(B₅O₁₀):xMn²⁺phosphor were prepared by the conventional high temperature solid-state method.The lattice structure,and particularly the luminescence properties upon ultraviolet light excitation were studied.It is revealed that Mn²⁺ions only occupy Zn²⁺sites.And the characteristic⁵D₄-⁷F_J emissions of Tb³⁺were also studied in TbZn_1-x(B₅O₁₀):xMn²⁺under the excitation of 365nm.By doping Mn²⁺in the TbZn(B₅O₁₀)host,red light at 625nm was observed due to the transition of ⁴T_1g?G??⁶A_1g?S?.The energy transfer mechanism between Tb³⁺and Mn²⁺was verified by the fluorescence spectra and decay curves.And the energy transfer efficiencies were discussed.Moreover,color-tunablerangefromgreentoredcanberealizedin TbZn_1-x(B₅O₁₀):xMn²⁺?0<x<0.01?by adjusting the concentration of Mn²⁺ions.The near-infrared?NIR?quantum cutting?QC?Tb_1-x-x Zn(B₅O₁₀):xYb³⁺were prepared by the conventional high temperature solid-state method.The lattice structure,and particularly the luminescence properties upon ultraviolet light excitation were studied.It is revealed that Yb³⁺ions only occupy Tb³⁺ions sites.The characteristic⁵D₄-⁷F_J emissions of Tb³⁺and ²F_5/2-²F_7/2 emissions of Yb³⁺were discussed in Tb_1-xZn(B₅O₁₀):xYb³⁺under ultraviolet light excitation.The cooperative energy transfer mechanism between Tb³⁺and Yb³⁺was verified by the fluorescence spectra.