Broadband‐Emitting NaGdSiO ₄ :Eu 2+/3+ Phosphor for White Light‐Emitting Diodes

White light‐emitting diodes (LEDs) demand phosphors with efficient near‐ultraviolet (NUV) excitation and high color rendering. Herein, NaGdSiO 4 :Eu 2+/3+ phosphors were synthesized via a high‐temperature solid‐state method. Under 365/396 nm NUV excitation, they exhibit a broadband yellow emission (470–740 nm, 545 nm peak, a full‐width at half maximum (FWHM) of 140 nm) from Eu 2+ occupying Na + and Gd 3+ sites, complemented by Eu 3 + ’s red sharp peaks. The phosphors show homogeneous elemental distribution. Introduction of Li 2 CO 3 as flux enhances emission intensity and thermal stability, obviously. A prototype pc‐LED device (365 nm chip + NaGdSiO 4 :Eu 2+/3+ + BAM:Eu 2+ ) achieves a high color‐rendering index (CRI = 91.7), outperforming commercial Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ )‐based LEDs (CRI = 74.6). These results demonstrate NaGdSiO 4 :Eu 2+/3+ ’s potential as a high‐CRI phosphor for high‐quality white LEDs.