High thermally Sm3+-activated SrBi2Ta2O9 orange-red phosphor: Preparation, characterization, and optical properties

Highlights: • SrBi₂Ta₂O₉:Sm³⁺ phosphors can be synthesized via solid-state reaction. • The phosphor emits intense red light at 403 nm excitation. • The phosphor possesses excellent thermal stability. • (4) The fabricated w-LED exhibits high color rending index and good correlated color temperature. -- Abstract: A new orange-red SrBi₂Ta₂O₉:Sm³⁺ phosphor is prepared via high-temperature solid-state route in air atmosphere. The phase purity of phosphor is characterized using X-ray diffraction (XRD). The phosphor shows the intense excitation peak at 403 nm and emits bright orange-red light at 564, 600, 647, and 701 nm in photoluminescence (PL) spectrum. Among them, the strongest peak is located at 600 nm due to ⁴G_5/2 – ⁶H_7/2 transition of Sm³⁺. The critical transfer distance of Sm³⁺ is calculated as 26.31 Å. The optimal doping concentration is determined to be about 2 mol%. The temperature dependent emission spectra exhibit excellent thermal stability. The Commission International de L'Eclairage (CIE) coordinates of the SrBi₂Ta₂O₉:xSm³⁺ (0.005 ≤ x ≤ 0.30) are located in the reddish orange region. These results indicate that the orange-red emitting SrBi₂Ta₂O₉:Sm³⁺ phosphor can be used as potential substitute red phosphors for white light emitting diodes (w-LEDs).