Fe³⁺/Yb³⁺ Co‐Activated MgGa₂O₄ Phosphor as Widely Near‐Infrared Lighting for Night‐Vision, Non‐Destructive Imaging, and Plant Cultivation

Abstract Fe 3+ as an activator for Near‐infrared (NIR) phosphors has the advantages over Cr 3+ and Ni 2+ due to its abundant resource, low cost, nontoxic, and eco‐friendly features, making it a luminescence activator candidate with huge commercial potential. However, most reported Fe 3+ ‐activated phosphors have relatively narrow NIR emission of 600–950 nm and may limit their applications. Here, a new strategy is reported to expand the emission bandwidth of Fe 3+ ‐activated phosphors by co‐doping with Yb 3+ in MgGa 2 O 4 phosphor exhibited a broadband NIR emission that covering 600–950 nm, attributed to the transition of Fe 3+ : 4 T 1 (4G)→ 6 A 1 (6S), and a sharp emission band of 950–1100 nm due to the transition of Yb 3+ : 2 F 5/2 → 2 F 7/2 , which extended the NIR emission range by nearly ≈ 150 nm compared with an Fe 3+ ‐activated phosphor, while energy transfer between Fe 3+ and Yb 3+ is demonstrated. It has an internal quantum efficiency of ≈ 48.9%, and a thermal stability with a measured NIR emission intensity at 423 K that is ≈ 69.57% of that measured at 293 K. An NIR pc‐LED device is prepared as NIR lighting source in night‐vision, non‐destructive imaging, and plant cultivation are demonstrated. This study provides a new strategy to extend the emission wavelength of nontoxic and eco‐friendly Fe 3+ ‐activated NIR phosphors.