Efficient and thermal stable broadband near-infrared emitting Gd2CaAl3GaZrO12:Cr3+ garnet phosphor: structure, luminescence, and pc-LED application

To meet the diverse requirements of the near-infrared (NIR) phosphor-converted light-emitting-diodes (NIR pc-LEDs) in various fields, high-performance broadband NIR-emitting phosphors are attracting growing interest. A novel garnet-type Gd 2 CaAl 3‒ y GaZrO 12 : y Cr 3+ (GCAGZ: y Cr) NIR phosphor with satisfactory luminescence efficiency and thermal stability was discovered in this work. The typical GCAGZ:0.04Cr phosphor exhibited highly efficient (IQE = 93.3 %, EQE = 20.0 %) broadband NIR emission with peaking at ∼748 nm (full-width at half-maximum ∼102 nm) and excellent thermal stability (88.3 %@423 K) under 450 nm light excitation, owing to the wide band gap of the garnet host, the relatively weak crystal field environment, and the exceedingly weak electron-phonon coupling effect. The NIR pc-LED device constructed by coating this GCAGZ:0.04Cr phosphor on a 450 nm blue LED chip presented outstanding NIR output power (∼44.8 mW) and photoelectric conversion efficiency (19.8 %) under a driving current of 100 mA, showing that this phosphor has huge potential utilized in the construction of NIR pc-LED applied in plant growth lighting, night vision, and non-invasive medical diagnosis.