Energy transfer and luminescent properties of Tb^(3+)and Tb^(3+),Yb^(3+)doped CNGG phosphors  

作　　者：S.Hau G.Stanciu D.Avram L.Gheorghe C.Gheorghe 

机构地区：[1]National Institute for Laser,Plasma and Radiation Physics,Solid State Quantum Electronics Laboratory,409 Atomistilor Street,P.O.Box MG-36,Magurele,077125,Ilfov,Romania

出　　处：《Journal of Rare Earths》2022年第9期1445-1453,I0004,共10页稀土学报（英文版）

基　　金：Project supported by the Romanian Ministry of Research and Innovation under grant agreement no.16N/2019 within Program NUCLEULAPLASⅥ(PN-Ⅲ-P1-1.1-PD-2019-0665,PN-Ⅲ-P4-ID-PCE-2020-2203)。

摘　　要：In this work,calcium niobium gallium garnet(Ca_(3)Nb_(1.6875)Ga_(3.1875)O_(12)-CNGG)ceramic samples singledoped with Tb^(3+)and co-doped with Tb^(3+)and Yb^(3+)ions were sintered by the solid-state reaction method.The structural characterization of the samples was carried out by X-ray diffraction measurements.The optimal concentration of Tb^(3+)ions corresponding to the maximum luminescence in the green spectral range in CNGG:x at%Tb(x=0.1,0.5,1,2,3,4,and 5)was determined to be 4 at%.The timeresolved luminescence of the^(5)D_(4)level(Tb^(3+))in the CNGG:x at%Tb samples was analysed to explore the quenching mechanisms involved in the Tb^(3+)green emission.Co-doped CNGG:4 at%Tb,y at%Yb(y=0.5,2,4,6,8,and 10)ceramics were prepared and investigated.It is shown that CNGG:4 at%Tb,y at%Yb phosphors exhibit intense green luminescence under ultra-violet(UV),visible(VIS),and near-infrared(NIR)excitation,thus demonstrating the presence of simultaneous down-conversion(DC)and upconversion(UC)processes.The dependence of the UC luminescence intensity on the diode laser pumping power was measured and the results indicate a two-photon process based on cooperative energy transfer(CET).Under UV excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level slowly increases with increase of Yb^(3+)concentration,suggesting the energy transfer from Yb^(3+)to Tb^(3+)ions,while under NIR excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level decreases with increase of Yb^(3+)ions concentration,indicating the presence of a strong energy transfer from Tb^(3+)to Yb^(3+)ions.The highest energy transfer efficiency ofη_(ET)≈42%was determined for the CNGG:4 at%Tb,10 at%Yb sample.The obtained results indicate that CNGG:(Tb^(3+),Yb^(3+))could be efficient new yellowish-green-emitting phosphors.

关 键 词：PHOSPHORS Tb^(3+)and Tb^(3+)-Yb^(3+)luminescence properties UP-CONVERSION DOWN-CONVERSION Quantum cutting process Rare earths 

分 类 号：TQ422[化学工程]