Synthesis and optical properties of new red-emitting SrBi2Ta2O9:Eu3+ phosphor application for w-LEDs commercially based on InGaN

In the present work, a novel Eu³⁺-doped SrBi₂Ta₂O₉ red-emitting phosphor has been successfully synthesized by solid-state reaction. The X-ray diffraction (XRD) and luminescence properties of SrBi₂Ta₂O₉ have been investigated in detail. Under the excitation of λ = 395 nm and λ = 465 nm, the phosphor can emit bright red light at 615 nm due to ⁵D₀→⁷F₂ transition. The optimal doping concentration and the thermal stability are investigated. Compared with reported commercial Y₂O₂S:Eu³⁺, Y₂O₃:Eu³⁺, the Commission International de L'Eclairage (CIE) coordinates of the red phosphor SrBi₂Ta₂O₉:0.10Eu³⁺ are much closer to the standard of the National Television System Committee (NTSC). The value of color purity is 97%. The luminescence lifetime of SrBi₂Ta₂O₉:Eu³⁺ is measured. Moreover, the white light emitting diode (w-LED) can be manufactured on the basis of InGaN. The chromaticity coordinates of combined w-LED are (0.327, 0.350), which approximates the equal energy point (0.333, 0.333).