High‐Efficiency Short‐Wave Near‐Infrared Emission Enabled by Energy Transfer Engineering of Cr ³⁺ ‐to‐Ni ²⁺ in Gd ₃ Ga ₅ O ₁₂ :Cr ³⁺ ,Ni ²⁺ Phosphor

ABSTRACT Phosphor‐converted shortwave infrared light‐emitting diodes (pc‐SWIR LEDs, 900−1700 nm) are highly promising next‐generation portable light sources. Cr 3+ →Ni 2+ energy transfer is an effective strategy to improve the blue‐light excitation efficiency of Ni 2+ ‐doped SWIR phosphors, yet enhancing the energy transfer efficiency is quite challenging. A Cr 3+ ‐Ni 2+ energy transfer engineering based on the synergistic effect of multiple tactics (optimizing doping concentration, heterovalent doping, and two‐step sintering) is proposed and successfully applied to Gd 3 Ga 5 O 12 :Cr 3+ ,Ni 2+ phosphors. Benefiting from energy transfer engineering, Cr 3+ →Ni 2+ energy transfer efficiency is enhanced from 20.6% to 75.8%, and the Ni 2+ emission intensity under blue light excitation is 37‐fold higher than that of the Ni 2+ ‐monodoped counterpart. The Gd 3 Ga 5 O 12 :Cr 3+ ,Ni 2+ phosphor achieves broadband SWIR emission centered at 1475 nm and an external quantum efficiency of 31.1% for Ni 2+ emission. Furthermore, a SWIR pc‐LED device fabricated by integrating the Gd 3 Ga 5 O 12 :Cr 3+ ,Ni 2+ phosphor with a 450 nm blue LED chip exhibits a high output power of 24.62 mW at a driving current of 320 mA. The application potential of the SWIR pc‐LED has been verified in medical and night vision. The proposed energy transfer engineering based on multi‐dimensional synergistic optimization strategy provides valuable insights for the design and development of high‐performance SWIR phosphors.