High Quantum Efficiency and Zero‐Thermal‐Quenching Blue‐Light‐Excited Near‐Infrared‐Emitting Y₃Ga₅O₁₂:Cr³⁺/Ni²⁺ Phosphors

Abstract Near‐infrared (NIR) phosphors that exhibit high quantum efficiency and excellent thermostability are of critical importance for the development of NIR light‐emitting diodes (LEDs) with substantial output power. In this work, Cr 3+ ‐Ni 2+ codoping Y 3 Ga 5 O 12 (YGAO) NIR phosphors with a high internal quantum efficiency (IQE), external quantum efficiency (EQE), and notable thermal stability are prepared via solid‐state reactions. When excited by blue light at 437 nm, YGAO:Cr 3+ /Ni 2+ phosphors demonstrate broad and intense NIR emission spanning 600–1100 nm and 1200–1650 nm. YGAO:3%Cr 3+ /0.01%Ni 2+ phosphors exhibit an IQE of 96.9% and an EQE of 37.5%, whereas the YGAO:6%Cr 3+ /0.01%Ni 2+ phosphors have an IQE of 76.2% and an EQE of 36.3%. The NIR luminescence intensities of Cr 3+ ions at 423 K show zero thermal quenching in YGAO:6%Cr 3+ /0.01%Ni 2+ and YGAO:3%Cr 3+ /0.01%Ni 2+ phosphors compared to those at 303 K, which is attributed to the thermal enhancement effect caused by the electron population between the Cr 3+ energy levels and trap‐supplemented luminescence. The NIR LED based on YGAO:3%Cr 3+ /0.01%Ni 2+ phosphors has a maximum output power of 197.79 mW under 1000 mA operating current. Furthermore, YGAO:Cr 3+ /Ni 2+ phosphors also exhibit promising potential for the detection of functional groups, night vision, and penetration.