Structural characterization and luminescence properties of Cr³⁺ activated ZnMgTiO₄ far-red emitting phosphor

Cr³⁺doped ZnMgTiO₄ phosphors were successfully prepared with a high-temperature solid-state reaction method. The Cr³⁺ doped ZnMgTiO₄ phosphor exhibits a near-infrared emission around 620–870 nm with a peak at 720 nm under UV 325 nm excitation. The emission peak at around 720 nm is related to the ²E → ⁴A₂ transition of Cr³⁺, which matches the absorption spectra of phytochrome P_FR. The structure and crystal field environment were studied and discussed. The Cr concentration and temperature dependent photoluminescence properties of ZnMgTiO₄: Cr³⁺ were also investigated. This study indicates that ZnMgTiO₄: Cr³⁺ phosphor has a promising potential for plant cultivation.