Enhanced near‐infrared luminescence of Gd _2‐ <i> _x </i> La <i> _x </i> GaSbO ₇ :Cr ³⁺ phosphors by crystal field engineering

Abstract Near‐infrared phosphor‐converted light‐emitting diodes (NIR pc‐LEDs) are considered intriguing light sources for various applications, leveraging their broadband emission, compact size, and high output power. The key to preparing high‐performance NIR pc‐LEDs lies in the rational design of phosphors. Herein, a bunch of Gd 2− x La x GaSbO 7 (G 2− x L x GSO):Cr 3+ phosphors was successfully designed. By modulating the crystal field strength of Cr 3+ through substitution of Gd 3+ with La 3+ and adjusting Cr 3+ concentration, significant spectral redshift and improved broadband NIR luminescence of G 2− x L x GSO:Cr 3+ under 468 nm excitation are achieved. The resultant sample owns good thermal stability and high quantum efficiency. Moreover, the representative G 1.4 L 0.6 GSO:2%Cr 3+ phosphor was integrated with a commercial 470 nm blue chip to fabricate a NIR pc‐LED. The fabricated device was validated for nondestructive examination, bio‐imaging, and night vision. The above results indicate that the prepared pc‐LED has bright application prospects as NIR light sources.