A novel Mn⁴⁺ -activated far-red Sr₂ MgWO₆ phosphor: synthesis, luminescence enhancement, and application prospect

A novel far-red emitting phosphor Sr₂ MgWO₆ : Mn⁴⁺ was fabricated using high-temperature solid-state reaction. X-ray diffraction patterns, scanning electron microscopy images, and photoluminescence excitation and photoluminescence spectra for this phosphor were analyzed in detail. The analysis revealed that its emission ranged from 600 to 800 nm and peaked at 699 nm, which was attributed to the ² E_g →⁴ A_2g transition of Mn⁴⁺ under 314 nm excitation. Moreover, we introduced rare-earth Yb³⁺ ions into the Sr₂ MgWO₆ :Mn⁴⁺ to improve its far-red emitting intensity. The photoluminescence (PL) intensity of the Yb³⁺ co-doped phosphor was three times higher than that of the single-doped phosphor. Therefore charge compensation is an efficient approach to improving PL intensity. The phosphor emitted a far-red light that resembled the pigments essential for plant growth in terms of the absorption spectrum. Therefore, the obtained phosphor, Sr₂ MgWO₆ :0.006Mn⁴⁺ ,0.2Yb³⁺ , had the potential to be a new type of far-red luminescent powder for indoor plant growth LEDs.