Seeking new, ultra-narrow-band blue emitting phosphors with high color purity for wide color gamut displays

Ultra-narrow-band phosphors have gained widespread applications in lighting and displays to enhance brightness and improve color saturation. Typical phosphor designs employ UCr4C4-type compounds and designing new narrow-band phosphors with high color purity is a major challenge. Here, we explore a Eu2+-doped Ba5GeO4Br6 phosphor, showing a narrow-band blue emission (λem = 436 nm) excitation at the near-ultraviolet light with a full width at half maximum of 30.7 nm and high color purity of 96.6%. In addition, attractive cathodoluminescence characteristics were systematically analyzed by varying filament current (30–70 mA) and accelerating voltage (3–7 eV). Robust anti-degradation behavior and color point stability under continuous electron beam bombardment were confirmed. Given its excellent performance in photoluminescence and cathodoluminescence, application in wide color gamut displays appears promising. Using commercial phosphors β-SiAlON:Eu2+ and K2SiF6:Mn4+ as green and red light converters respectively, and the title phosphor as the blue light converters, the fabricated w-LED exhibits a wide color gamut of 82% NTSC.