Phosphor-converted light-emitting diodes (pc-LEDs) have great potential in near-infrared spectroscopy technology and near-infrared imaging technology. However, the development of novel broadband near-infrared phosphors remains a challenge. In this paper, a series of hexagonal phase structure Cs₂NaAlF₆∶Cr³⁺ near-infrared emission phosphors are prepared by an ammonium salt conversion method. Under 434 nm blue light excitation, the phosphors show a broadband near-infrared emission band peak at ~780 nm with full width at half maximum of 106 nm, and the luminescence intensity at 150 ℃ can maintain 68.4% of that at room temperature (25 ℃). Further, a broadband near-infrared pc-LED device is fabricated based on Cs₂NaAlF₆∶0.30Cr³⁺ phosphor and a blue LED chip. When the driving current is 1000 mA, a near-infrared output power of 226.49 mW is obtained in pc-LED device, and the corresponding energy conversion efficiency is 2.4%.The device may find application in veins imaging and other fields.