A novel Ba₂SrWO₆:Mn⁴⁺/Dy³⁺ red phosphors for warm WLED applications

A novel non-rare-earth red-emitting phosphor of Ba₂SrWO₆:Mn⁴⁺ with a double-perovskite structure was synthesized via a solid-state reaction method at high temperatures, and the mechanism of structural formation was systematically investigated. Moreover, Dy³⁺co-dopant ions were exploited to develop a white-light phosphor of Ba₂SrWO₆:Mn⁴⁺/Dy³⁺. Excitation spectra of Ba₂SrWO₆:Mn⁴⁺ and Ba₂SrWO₆:Mn⁴⁺/Dy³⁺ were both in a wavelength range of 250–550 nm. Under 325 nm excitation, the Ba₂SrWO₆:Mn⁴⁺ phosphors showed a red emission with a peak at 693 nm because of the ²E → ⁴A₂ transition of Mn⁴⁺ ions. The Mn⁴⁺ ion concentration in the Ba₂SrWO₆:Mn⁴⁺ phosphors was optimized at 0.6 mol%, and the corresponding CIE (Commission International de I'Edairage) chromaticity coordinate was determined at about (0.7238, 0.2762), locating in the deep-red-light region. Meanwhile, the white-light Ba₂SrWO₆:Mn⁴⁺/Dy³⁺ phosphors displayed a wide emission band, including a blue emission at 492 nm (attributed to ⁴F_9/2 → ⁶H_15/2), a yellow emission at 582 nm (owing to ⁴F_9/2 → ⁶H_13/2), and the red emission at 693 nm. By varying the Dy³⁺ ion concentration, the emission color of the co-doped phosphors can be tuned from white light (0.3365, 0.3493) to warm white-light (0.4263, 0.3778), qualifying the phosphorous materials as a potential candidate for white-light- or warm white-light-emitting diode applications.