How to Achieve Excellent Luminescence Properties of Cr Ion‐Doped Near‐Infrared Phosphors

Abstract

Transition metal chromium (Cr) ion‐doped inorganic materials exhibit distinct tunable broadband near‐infrared luminescence, and they have promising applications including nondestructive composition analysis, night vision, biomedicine, plant illumination, and afterglow anticounterfeiting. Currently, the most critical issue is to optimize their full width at half maxima, thermal stability, and internal/external quantum efficiency. This review systematically summarizes strategies to effectively improve the photoluminescence performance of near‐infrared‐emitting materials with transition metal chromium ions. Key examples of the design and preparation of Cr ion‐doped luminescence with different transition modes, a detailed discussion of strategies to effectively improve the photoluminescence properties of near‐infrared luminescent materials, and a summary of generic strategies to help explore novel and efficient Cr‐doped phosphor materials are provided. Next, the latest developments and trends in these Cr ion‐doped phosphor materials are presented for a variety of application scenarios. Finally, future research directions and new challenges faced are also discussed.

Simultaneous NIR photoluminescence and mechanoluminescence from Cr3+ activated MgGa2O4 phosphors with multifunctions for optical sensing

“…24 Considering that the doping process follows the principle of similar ionic radii, Cr 3+ ( r = 0.615 Å) is more inclined to occupy the Ga 3+ ( r = 0.662 Å) site. 25–29 We conjecture the presence of [CrO 6 ] octahedra within the MGO:Cr 3+ phosphor. The crystal structure diagram illustrates the sequential coordination of Ga 3+ ions with Ga–O, Ga–Ga, and Ga–Mg shells.…”

Remarkable near-infrared emission enhancement of Cr3+-activated BaGe4O9: the role of lithium ions

“…Among the transition metal ions, Cr 3+ possesses outstanding luminescent properties, featuring high photoluminescence quantum yield, large emission bandwidth and blue-light excitability. 4,5 Additionally, the emission of Cr 3+ can be remarkably tuned, as it is sensitive to the surrounding ligand environment. Therefore, host materials are vital for Cr 3+ emission.…”

Hydrothermal synthesis of ZnGa2O4 nanophosphors with high internal quantum efficiency for near-infrared pc-LEDs

“…9–13 It means near-infrared light has better application prospects in the field of optical imaging. 14,15 Although the near-infrared light sources used most widely are tungsten halogen lamps and ultra-continuous lasers, 16 they are limited in many applications, due to their low energy efficiency and large size. 17 Combining high-power LED chips with fluorescent nanomaterials, which down-shifts light conversion to produce infrared light, has the advantages of convenience, small size, high efficiency, long life and low cost.…”