Ultrawide near-infrared SrHfO3:Cr3+ phosphor with dual emission bands

Near-infrared phosphor-converted light-emitting diodes (NIR-pc-LEDs) are superior to traditional NIR-LEDs in spectral modulation, volume, and cost, and their optoelectronic properties are dominantly controlled by the NIR phosphors, which thus boosts the search for high efficiency and broadband NIR phosphors. In this work, we attempt to realize ultra-broadband NIR phosphors by doping Cr3+ in self-emitting SrHfO3 with a weak crystal field. Dual emission bands centered at 770 (host) and 1000 nm (Cr3+) are observed, leading to a wide spectral range of 700-1400 nm. The Cr3+ ions enter the HfO6 octahedron and thus produce an NIR emission with a full width at half maximum of 190 nm and an internal quantum efficiency of 24% under 460 nm excitation. A prototype NIR-pc-LED surface light is demonstrated for machine vision by using NIR-pc-LEDs that combine the blue LED with SrHfO3:Cr. The work paves an avenue for designing super-broadband NIR phosphors by doping Cr3+ or other ions into hosts with self-trapped exciton emission (e.g., halide perovskites).