Chen, Kuan-ChunKuan-ChunChenChen, Shih-EnShih-EnChenTsao, Chuan-FangChuan-FangTsaoHuang, Yu-ChiehYu-ChiehHuangLiu, Ru-ShiRu-ShiLiu2025-10-302025-10-302026-03https://scholars.lib.ntu.edu.tw/handle/123456789/733271Near-infrared (NIR) phosphors have emerged as critical components for next-generation optoelectronic devices, spanning biological windows NIR-I (650–950 nm), NIR-II (1000–1350 nm), and NIR-III (1500–1850 nm). This review aims to provide the evolution of NIR phosphor structures, luminescence mechanisms, and applications from fundamental crystal field theory to cutting-edge intervalence charge transfer processes. We systematically analyze activator systems including rare earth elements and transition metals, elucidating structure–property relationships through site engineering, cation substitution, and energy transfer mechanisms. Recent breakthroughs achieving high internal quantum efficiency and broadband emission demonstrate remarkable progress, especially in the NIR-II phosphor research field. Applications encompass plant growth lighting, artificial intelligence image recognition, spectroscopic analysis, and optical communication. Machine learning-accelerated discovery approaches now enable good prediction accuracy for new phosphor systems. This review provides design principles for high-performance NIR phosphors while identifying future opportunities in high-power laser diode light sources and biomedical applications, establishing a roadmap for next-generation NIR phosphor materials.enEnergy transferLight-emitting diodesNear-infraredPhosphorRare earth elementsTransition metalsjournal article10.1016/j.pmatsci.2025.101588