Qijie Xiong,Chun Liu,Wensheng Li,Zhenggang Zou,Yijian Sun,Jinsheng Liao,Herui Wen,Guoliang Gong
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.
The development of high-efficiency and thermally stable phosphors is crucial for improving the color rendering index (CRI) of near-ultraviolet (n-UV) pumped white light-emitting diodes (WLEDs). In this work, a novel orange-red emitting phosphor La 2 SrGa 4 Si 2 O 14 :Sm 3+ was successfully synthesized via a [Sr 2+ -Si 4+ ] co-substitution strategy to optimize the lattice of the traditional La 3 Ga 5 SiO 14 . Detailed structural analyses confirmed the successful substitution and phase purity. Excited by n-UV light at 402 nm, the phosphor exhibited a prominent emission peak at 600 nm, with an optimal doping concentration of 3 mol%. The material exhibits acceptable thermal stability, retaining 74% of its initial emission intensity at 423 K, together with an internal quantum efficiency of 32.3%, which is comparable to those of several reported Sm 3+ -activated silicate phosphors. When integrated into WLED devices with blue and green phosphors, it yielded high-quality warm white light with a low correlated color temperature of 4680 K and an exceptionally high CRI of 93.2, which represents a noticeable improvement compared with a commercial blue-chip + YAG:Ce WLED measured under identical experimental conditions. Furthermore, by utilizing the unique thermal response characteristics of Sm 3+ transitions, this material was explored for optical temperature sensing, achieving a maximum relative sensitivity of 2.06% K −1 . These results indicate that La 2 SrGa 4 Si 2 O 14 :Sm 3+ is a potential multifunctional material for high-CRI solid-state lighting and non-contact temperature sensing.
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