High Efficiency and Narrow‐Band Green Emission in Eu²⁺ and Mn²⁺ Co‐Doped Na₂MgAl₁₀O₁₇ Phosphor for Backlight Display Application

Wide color gamut display has become a new generation of display technology because of its good color saturation. However, the low quantum efficiency and wide half peak width of narrow-band green phosphors are still the main barriers in their development and application. This work addresses these challenges by using Mn²⁺ as the luminescent center and constructing efficient Eu²⁺ → Mn²⁺ energy transfer in Na₂MgAl₁₀O₁₇ (NMAO) matrix. The NMAO:0.15Eu²⁺, 0.30Mn²⁺ phosphor presents a single-band emission peaking at 513 nm with a full width at half maximum (FWHM) of only 33 nm under the excitation of 365 nm LED chip. In addition, under the excitation wavelength of 365 nm, the energy transfer efficiency reaches 74%. Compared with the NMAO:0.30Mn²⁺, the intensity of the NMAO:0.15Eu²⁺, 0.30Mn²⁺ increases by 5.5 times and the internal quantum efficiency is up to 61.82%. A white LED device with the CIE coordinates of (0.2871, 0.3472) and a color gamut area of 94% NTSC has been assembled successfully by combining 365 nm LED chips with NMAO:0.15Eu²⁺, 0.30Mn²⁺, BaMgAl₁₀O₁₇:Eu²⁺, and K₂SiF₆:Mn⁴⁺ as green, blue, and red component. This work enriches the relevant content of Mn²⁺-doped phosphors and provides a constructive insight into improving luminescent performance through energy transfer.