Broadband near‐infrared emission enhancement in K ₂ Ga ₂ Sn ₆ O ₁₆ :Cr ³⁺ phosphor by electron‐lattice coupling regulation

Cr 3+ ‐doped phosphors have recently gained attention for their application in broadband near‐infrared phosphor‐converted light‐emitting diodes (pc‐LEDs), but generally exhibit low efficiency. In this work, K 2 Ga 2 Sn 6 O 16 :Cr 3+ (KGSO:Cr) phosphor was designed and synthesized. The experimental results show that the Cr 3+ ‐doped phosphor exhibited broadband emissivity in the range 650‐1300 nm, with a full width at half maximum (FWHM) of approximately 220‐230 nm excited by a wavelength of 450 nm. With the co‐doping of Gd 3+ ions, the internal quantum efficiency (IQE) of the KGSO:Cr phosphor increased from 34% to 48%. The Gd 3+ ions acted neither as activators nor sensitizers, but to justify the crystal field environment for efficient Cr 3+ ions broad emission. The Huang‐Rhys factor decreased as the co‐doping of Gd 3+ ions increased, demonstrating that the nonradiative transitions were suppressed. An efficient strategy for enhancing the luminescence properties of Cr 3+ ions is proposed for the first time. The Gd 3+ –co‐doped KGSO:Cr phosphor is a promising candidate for broadband NIR pc‐LEDs.