Research progress on Fe3+-activated near-infrared phosphor

Fe3+-activated near-infrared (NIR) luminescent materials have attracted widespread attention due to their tunable emission wavelength and extensive applications in various fields such as plant growth, food analysis, biomedical imaging, and night vision. Many excellent NIR materials have been developed by introducing non-toxic and environmentally friendly Fe3+ ions into different inorganic hosts. This article elucidates the luminescent properties of Fe3+ ions by combining the Tanabe–Sugano energy level diagram and the configuration coordinate model. The latest research progress on Fe3+-doped NIR luminescent materials is outlined, summarizing the luminescent characteristics of various Fe3+-doped materials, including emission wavelength, emission bandwidth, quantum efficiency, and thermal stability. Particularly, a detailed summary and analysis of the application areas of Fe3+-doped NIR luminescent materials are provided. Finally, the future prospects and challenges faced by Fe3+-doped NIR luminescent materials are presented. This review contributes to a deeper understanding of the luminescence mechanism of Fe3+ and the research progress of iron ion-doped luminescent materials, aiming to develop advanced Fe3+-activated NIR luminescent materials with enhanced performance and explore new application fields.