Structure analysis and fluorescence properties of Ce3+ activated La2SrGa4Si2O14 langasite phosphor

The La 3 Ga 5 SiO 14 is a representative electro-optical material (A 3 BC 3 D 2 O 14 , P 321) with disordered C and D sites. Theoretically, composition adjustment from La 3 Ga 5 SiO 14 to La 2 SrGa 4 Si 2 O 14 can achieve shifting the disordered parts from double Ga, Si sites to the sole La site. In this study, Ce 3+ doped isomorphic La 2 SrGa 4 Si 2 O 14 (LSGS) phosphors with a more compact and ordered lattice than La 3 Ga 5 SiO 14 are prepared. The LSGS:Ce 3+ samples show narrow purple-blue emission around 395 nm with higher quantum efficiency than that of the La 3 Ga 5 SiO 14 :Ce 3+ . The LSGS:1.2 %Ce 3+ exhibits highest fluorescence intensity with decaying lifetime of sub-10 ns The large Stokes shift reduces the overlap of the absorption and emission bands. The structural defects reflected by X-ray induced fluorescence is discussed. The potential of LSGS:Ce 3+ as a kind of scintillator is preliminarily evaluated.