Bifunctional application of La3BWO9:Bi3+,Sm3+ phosphors with strong orange-red emission and sensitive temperature sensing properties

Abstract

Through a solid-phase reaction technique, Sm³⁺ and Bi³⁺ co-doped La₃BWO₉ phosphors with high emission intensity and sensitive temperature sensing properties have been successfully synthesized. Based on XRD Rietveld refinement, the optimized crystal structure was used as the original model to calculate the band structure and partial density of states (PDOS) by density functional theory (DFT) calculations. The luminescence characteristics of Sm³⁺ and Bi³⁺ co-doped La₃BWO₉ phosphors were measured and analyzed. In addition, the optimal doping concentrations of Sm³⁺ and Bi³⁺ were investigated. The luminescence properties of Sm³⁺ doped phosphors were optimized by introducing Bi³⁺ ions. Efficient energy transfer from Bi³⁺ to Sm³⁺ ions was observed in La₃BWO₉:Sm³⁺, Bi³⁺ phosphors. An optical temperature sensor with high sensitivity was designed based on the different thermal quenching properties of Sm³⁺ and Bi³⁺ ions. In the temperature range of 293-498 K, the optimum absolute sensitivity (S_a) and maximum relative sensitivity (S_r) were 2.88 %K^-1 and 1.32 %K^-1, respectively. These results indicated that the prepared La₃BWO₉:Bi³⁺, Sm³⁺ phosphors have wide application prospects as solid state lighting materials and optical temperature sensors.