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The discovery of highly efficient broadband near infrared (NIR) emission material is urgent and crucial for constructing NIR lighting sources and emerging applications. Herein, a series of NIR emission hexafluorides A2BMF6:Cr3+ (A = Na, K, Rb, Cs; B = Li, Na, K, Cs; M = Al, Ga, Sc, In) peaking at ≈733–801 nm with a full width at half maximum (FWHM) of ≈98–115 nm are synthesized by a general ammonium salt assisted synthesis strategy. Benefiting from the pre‐ammoniation of the trivalent metal sources, the Cr3+ can be more efficiently doped into the A2BMF6 and simultaneously prevent the generation of the competitive phase. Particularly, Na3ScF6:Cr3+ (λem = 774 nm, FWHM ≈ 108 nm) with optimal Cr3+‐doping concentration of 35.96% shows a high internal quantum efficiency of 91.5% and an external quantum efficiency of ≈40.82%. A lighting emitting diode (LED) device with a NIR output power of ≈291.05 mW at 100 mA driven current and high photoelectric conversion efficiency of 20.94% is fabricated. The general synthesis strategy opens up new avenues for the exploration of Cr3+‐doped high efficiency phosphors, and the as‐obtained record NIR output power demonstrates for NIR LED lighting sources applications. [ABSTRACT FROM AUTHOR]

The development of highly efficient and thermally stable broadband near‐infrared (NIR) luminescence materials is a great challenge to advance the next‐generation smart NIR light source. Benefitting from the low phonon energy and relatively weak electron phonon coupling effect of the fluoride, K2NaScF6:Cr3+ phosphor is designed and obtained, which demonstrates a full width at half maximum of 100 nm peaking at ≈765 nm. Upon blue light excitation, the phosphor exhibits a high quantum efficiency of 74% and its emission intensity at 150 °C can keep 89.6% of the initial value at 25 °C. An NIR output power of 159.72 mW (input electric power, 1094 mW) with a high photoelectric conversion efficiency of ≈14.60%, light‐emitting diode (LED) device is presented based on this K2NaScF6:Cr3+ phosphor. Furthermore, applying the high‐power NIR phosphor‐converted LED device as lighting source, clear and quick veins imaging and recognition in fingers, palm, wrist, and arm of the human hand are first realized, suggesting K2NaScF6:Cr3+ phosphor has high promise in practical applications. [ABSTRACT FROM AUTHOR]

The development of highly efficient and thermally stable broadband near‐infrared (NIR) luminescence materials is a great challenge to advance the next‐generation smart NIR light source. Benefitting from the low phonon energy and relatively weak electron phonon coupling effect of the fluoride, K2NaScF6:Cr3+ phosphor is designed and obtained, which demonstrates a full width at half maximum of 100 nm peaking at ≈765 nm. Upon blue light excitation, the phosphor exhibits a high quantum efficiency of 74% and its emission intensity at 150 °C can keep 89.6% of the initial value at 25 °C. An NIR output power of 159.72 mW (input electric power, 1094 mW) with a high photoelectric conversion efficiency of ≈14.60%, light‐emitting diode (LED) device is presented based on this K2NaScF6:Cr3+ phosphor. Furthermore, applying the high‐power NIR phosphor‐converted LED device as lighting source, clear and quick veins imaging and recognition in fingers, palm, wrist, and arm of the human hand are first realized, suggesting K2NaScF6:Cr3+ phosphor has high promise in practical applications. [ABSTRACT FROM AUTHOR]