Na Replaces Rb towards High‐Performance Narrow‐Band Green Phosphors for Backlight Display Applications

Abstract The improvement of high‐performance narrow‐band green phosphors in backlight display applications is still a major challenge. Based on the UCr 4 C 4 type of oxide phosphor, the high‐performance narrow‐band green phosphors Rb 3 M(Li 3 SiO 4 ) 4 :Eu 2+ (M = Rb or Na) are studied in different luminous positions. Benefiting from the replacement of Rb by Na, the change of the local environment in the crystal structure of Rb 3 Na(Li 3 SiO 4 ) 4 :Eu 2+ (R 3 NLSO:Eu 2+ ) leads to the decrease of Stokes shift, which improves the quantum efficiency. Moreover, change in the local environment enhances the structural rigidity, which makes the thermal and chemical stability better. The R 3 NLSO:8%Eu 2+ phosphor presents a narrow‐band green emission centered at 527 nm, excellent thermal stability (102% @150 ° C of the integrated emission intensity at room temperature), and high internal/external quantum efficiency (85.3%/40.4%). The white light‐emitting diode (wLED) using R 3 NLSO:8%Eu 2+ phosphor presents a superior luminous efficiency of 128.3 lm W ‐1 and a wide color gamut. All the results indicate that R 3 NLSO:8%Eu 2+ green phosphor has great application prospects in the field of liquid crystal display. This work also provides important guiding significance for the optimization of alkali metal element type of phosphors.