Near-infrared (NIR) phosphors with capability for blue light to 850 nm broadband NIR emission conversion are highly desirable for security-monitoring LEDs. Targeted phosphor LaSc 2.93-y Ga y B 4 O 12 (LSGB): 0.07Cr 3+ (y = 0.6) is designed from the initial model of LaSc 2.93 B 4 O 12 (LSB): 0.07Cr 3+ by chemical composition modification. The correlations among crystal-field environment, structural evolution, and luminescence properties of LSGB: 0.07Cr 3+ (0 ≤ y ≤ 1.5) are elucidated by the Dq/B values, decay curves, and polyhedron distortion. The substitution of Sc 3+ by Ga 3+ in LSGB: Cr 3+ (0 ≤ y ≤ 1.5) leads to decreasing structural polyhedron distortion and strengthened crystal field, consequently resulting in the blue-shift of broadband emission and enhanced thermal stability of LSGB: 0.07Cr 3+ (y = 0.6) compared to that of LSB: 0.07Cr 3+ . The above results demonstrate that the superiority of blue-shift and enhanced thermal stability of LSGB: 0.07Cr 3+ (y = 0.6) make it more suitable for the blue-pumped securitymonitoring LEDs.

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