Narrow-Band Green-Emitting Magnetoplumbite-Structured CeZnAl11O19:Mn2+ Phosphor for Wide Color Gamut Backlighting

A novel magnetoplumbite-type narrow-band green-emitting phosphor, CeZnAl11O19:Mn2+, has been created by replacing the [La3+-Mg2+] pair in the prototype material LaMgAl11O19 with the [Ce3+-(Zn2+/Mn2+)] pair. When excited by blue light at 450 nm, optimized CeZnAl11O19:Mn2+, featuring a high Mn2+ doping content of 35%, emits a bright green light that peaks at 517 nm, with a full width at half maximum (fwhm) of 30 nm and internal/external quantum efficiencies of 75%/19%, respectively. Additionally, optimized CeZn0.65Al11O19:0.35Mn2+ demonstrates low thermal quenching, with only 29% reduction at 473 K compared to room temperature. Temperature-dependent fwhm analysis reveals weak electron-phonon coupling in the optimized CeZn0.65Al11O19:0.35Mn2+ phosphor. This is quantitatively supported by a Huang-Rhys factor (S) of 0.74 and a phonon energy of 62.8 meV, which collectively minimize thermal broadening of the emission band. A white LED device constructed using this newly developed green emitter exhibits a luminous efficiency of ∼50 lm/W and a wide color gamut of 117% of the National Television System Committee (NTSC) standard, positioning it as a highly promising candidate for wide color gamut white LED backlighting.