Highly Efficient and Stable Near‐Infrared Broadband Garnet Phosphor for Multifunctional Phosphor‐Converted Light‐Emitting Diodes

Abstract Broadband near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LED) are ideal light sources to meet the next generation of NIR spectroscopy. However, NIR phosphors have numerous problems such as low quantum yields (QY) and low thermal stability. In this work, a series of Gd₃Y_xIn_xGa_5‐2xO₁₂:Cr³⁺ NIR broadband phosphors with high internal quantum yields (IQYs) and high thermal stability are discovered by uniquely replacing GaO₆ in Gd₃Ga₅O₁₂ with Y³⁺ and In³⁺ in a co‐doped manner through cation modulation. Under 449 nm excitation, Gd₃Y_0.5In_0.5Ga₄O₁₂ (GYIG):yCr³⁺ depicts emission from 650 to 1050 nm with a full‐width at half maximum (FWHM) of 134 nm. The emission intensity reaches its optimum value at y = 6%, while the IQY reaches an impressive 81.8% and, at 375 K, the emission intensity remains at room temperature of 94.1%. Excitingly, the obtained phosphors are made into pc‐LEDs. At 0.28 W output power and 0.1 A output current, NIR pc‐LED has a NIR photoelectricity conversion efficiency of 15%; more promising is that when the output power is increased to 2.247 W, the pc‐LED photoelectric conversion efficiency can still maintain at 8.5%, which can be applied in different fields such as plant lighting, night vision, biological tissue penetration, and object detection.