Enhancing Quantum Efficiency of Narrow Band Green Emitting Phosphor SrGa 2 S 4 :Eu 2+ via Solid Solution Engineering for Wide Color Gamut Display

ABSTRACT The pursuit of high‐performance narrow‐band green phosphors is crucial for wide color gamut displays including liquid crystal displays and laser‐driven displays. SrGa 2 S 4 :Eu 2+ is a well‐established narrow‐band green‐emitting phosphor, but its low external quantum efficiency (EQE) limits its practical application. Herein, Mg 2+ doping strategy is employed to enhance the EQE of SrGa 2 S 4 :Eu 2+ , significantly improving in its EQE from 33.1% to 53.1%. This improvement is attributed to enhanced lattice rigidity induced by Mg 2+ doping, which suppresses lattice vibrations, thereby reducing energy loss via phonon coupling and increasing the probability of radiative emission. This effect is corroborated by Raman spectroscopy, which reveals a shift in vibrational modes consistent with increased rigidity. To evaluate its practical applicability, we integrated the newly obtained narrow green‐emitting phosphor into liquid crystal displays (LCDs) and laser‐driven projection systems. Prototype tests demonstrate that displays utilizing (Sr,Mg)Ga 2 S 4 :Eu 2+ deliver significantly more vivid and color‐saturated images compared to those employing the conventional broad‐spectrum yellow‐emitting Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) phosphor. These results fully underscore the great potential of the modified phosphor for wide‐color‐gamut display applications.