A high-thermal-stability orange-red phosphor Sr3TaGa3Si2O14: Sm3+ for optical thermometry and white light emitting diodes

The advancement of White light emitting diodes (WLEDs) drives the demand for efficient red-emitting phosphors with superior thermal stability. In this paper, a series of Sr 3 TaGa 3 Si 2 O 14 : Sm 3+ phosphors with excellent thermal properties were successfully synthesized via high-temperature solid-phase method. The crystal structure, luminescent properties and thermal stability of the samples were systematically investigated. Under 402 nm near-ultraviolet excitation, the fluorescence emission spectra of Sr 3 TaGa 3 Si 2 O 14 : Sm 3+ with different doping concentrations were obtained, and the optimal Sm 3+ doping concentration was found to be 0.03 mol. Co-doping with M ( M = Li + , Na + , and K + ) as charge compensation ions can improve the luminescent performance of Sr 3 TaGa 3 Si 2 O 14 : Sm 3+ . Furthermore, the luminescent intensity ( 4 G 5/2 → 6 H 7/2 ) of this phosphor at 420 K remains at 74.2 % of its initial temperatures (300 K), demonstrating excellently thermal stability. The temperature sensing characteristics based on Fluorescence Intensity Ratio (FIR) technique was investigated and the maximum absolute and maximum relative sensitivities of the Sr 3 TaGa 3 Si 2 O 14 : 3 mol% Sm 3+ samples were 6.52 % and 0.80 %, respectively. In addition, the quantum yield of Sr 3 TaGa 3 Si 2 O 14 : 3 mol% Sm 3+ , 3 mol% Na + was measured to be 44.0 %, and the WLEDs fabricated with it could emit bright white light with CIE chromaticity coordinates of (0.28, 0.33). Therefore, the synthesized phosphors have great potential for applications in optical temperature measurement and solid-state lighting.