Luminescence Properties Of MgO:V,NaLnTiO₄:Cr And LnBO₃:Sb Phosphors

In this work,the blue-green phosphors MgO:V,red phosphors NaLnTiO₄:Cr³⁺(Ln=Gd³⁺,La³⁺,Y³⁺,Eu³⁺,Dy³⁺)and blue phosphors LnBO₃:Sb(Ln=La³⁺,Y³⁺,Sc³⁺)are synthesized by solid state reaction methods.Their luminescent properties are systemically investigated respectively.Under 300nm excitation,MgO:V phosphors can give out a broad band emission with the maximum at about 500 nm.The XPS results suggest that the majority vanadium ions are in+5 valence state.For the defects induced energy levels,we detected their thermoluminescent curves,the results indicate that there are three types electronic defects with trap depth at about 0.95,1.02,2.01 eV respectively.In order to improve the luminous efficiency,silicon ions are tentatively doped in MgO:V.the according co-doping effects of Si⁴⁺on the luminescence intensity of MgO:V are investigated.The results indicate that Si⁴⁺can effectively improve the emission intensity of 500 nm band.Besides,the effects of charge compensator ions such as Na⁺,K⁺and Li⁺on the luminous properties are also investigated.Then,series of phosphors NaLnTiO₄:Cr³⁺(Ln=Gd³⁺,La³⁺,Y³⁺,Eu³⁺,Dy³⁺)are synthesized and their luminescent properties are investigated as well.Even though these phosphors have similar components,they exhibit quite different luminescent properties.For NaGdTi_0.997O₄:0.003Cr³⁺and NaGdTi_0.995O₄:0.005Cr³⁺,they exhibit red emission with maximum at about 614 nm However,for the phosphors of NaLaTiO₄:Cr³⁺and NaYTiO₄:Cr³⁺,their simultaneously emit two borad bands locating at 480nm and red at614nm respectively under 250 nm excitation.For NaDyTiO₄:Cr³⁺,it has no emission at all in UV-Vis region under UV excitation.Finally,LnBO₃:Sb(Ln=La³⁺,Y³⁺,Sc³⁺)are synthesized by solid state reaction method.And their luminescence properties are investigated.The vacuum referred binding energy levels?VRBE?of Sb²⁺in host band are determined with its charge transfer band combining the Chemical shift Model developed by P.Dorenbos.The results show that the VRBE values of Sb²⁺are almost consistent with about-4.68 eV in a variety of borate compounds.