Highly efficient and thermally stable far-red-emitting phosphors for plant-growth lighting

Far-red phosphor-converted light-emitting diodes (pc-LEDs) are potential efficient and cost-effective light sources for regulating the photomorphogenesis of plants, but it still lacks ideal far-red phosphors with right excitation and emission bands, high quantum efficiency and high thermal stability. Here, we developed an excellent far-red phosphor Gd3Al2Ga3O12:Cr3+ (GAGG: Cr3+). Upon blue light excitation, GAGG: Cr3+ exhibits efficient far-red emission peaking at 720 nm with internal quantum efficiency as high as 94.1% and zero thermal quenching even at 150 °C. Moreover, a high-performance pc-LED device was fabricated by using the optimized GAGG: Cr3+ as the color converter, which can radiate 61.03 mW far-red light at 100 mA with a record photoelectric conversion efficiency of 20.6%. The results indicate that GAGG: Cr3+ holds great promise for plant-growth lighting and other LED applications.