Mn2+ doped aluminum-rich spinel transparent ceramic phosphor with higher performance for wide color-gamut backlight display

Due to the great potential of narrow-band green-emitting phosphors for wide color-gamut white light-emitting diodes (WLED) backlight displays, there is great interest in finding host materials with the desired luminescent properties and high quantum efficiency. Herein, a series of Mg _0.98-xAl _2(1+x/3)O ₄: 0.02Mn ²⁺ ( x = 0, 0.125, 0.25) powders were synthesized using high-temperature solid-phase reactions, followed by a combination of pressureless sintering and hot isostatic pressure sintering to fabricate transparent ceramic phosphors. The crystal structure refinement, NMR spectroscopy, and photoluminescence results show tetrahedral coordination of Mn ²⁺ ions and an increase in cation vacancies and disorder with increasing x. These transparent ceramics exhibit narrow-band green emission, which shifts from 523 to 520 nm with increasing x. The Mg _0.855Al _2.08O ₄: 0.02Mn ²⁺ ceramic sample has an in-line transmittance of over 80 % above 500 nm and internal quantum efficiencies as high as 96.2 %. The luminous intensity of the Mg _0.855Al _2.08O ₄: 0.02Mn ²⁺ ceramic remains above 88.6 % at 425 K compared to room temperature, with a thermal conductivity of 12.4 W·m ⁻¹·K ⁻¹. A WLED device fabricated using the Mg _0.855Al _2.08O ₄: 0.02Mn ²⁺ ceramic, K ₂SiF ₆:Mn ⁴⁺ phosphors, and a blue chip show a wide color gamut of 126 % National Television System Committee standard. The results show that Mn ²⁺-doped aluminum-rich spinel transparent ceramics have great potential for application in wide color gamut WLED backlight devices.