Narrow-band green nitride phosphor for wide color gamut backlighting

β-Sialon:Eu 2+ (Si 6-z Al z O z N 8-z :Eu 2+ , 0 < z ≤ 4.2) has been recognized as an excellent narrow-band green phosphor for wide-color-gamut backlights, but it is quite difficult to realize high quantum efficiency when further reducing the bandwidth of β-Sialon:Eu 2+ to achieve high color purity. Herein, we propose an ingenious sintering method to minimize the trade-off between color purity and luminescence intensity of β-Sialon:Eu 2+ , and finally obtain ultra-narrow band β-Sialon:Eu 2+ with an emission maximum of 527 nm, a full width at half maximum of 44.9 nm and an external quantum efficiency of 37.3 % when z is reduced to 0.03. Structural analyses indicate that β-Sialon:Eu 2+ shows higher structural ordering and rigidity with decreasing the Al-O substitution ( i.e. , z value). By combining β-Sialon:Eu 2+ (z = 0.03), a red phosphor K 2 SiF 6 :Mn 4+ with a blue InGaN LED chip, white light-emitting diodes with a luminous efficacy of 93.91 lm W −1 and a color gamut as high as 101.2 % National Television System Committee standard were demonstrated, which are superior to those in color gamut (4.3–16.8 % up) by using commercial β-Sialon:Eu 2+ .