Zero-Disturbance Sensitization Strategy for Ultra-High- Efficiency Cr3+ Near-Infrared Phosphors

<title>Abstract</title> <p> Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) are in urgent demand for high-efficiency NIR phosphors, and Cr ³⁺ -activated garnet-type materials have emerged as promising candidates. In this work, a novel zero-disturbance sensitization strategy was proposed to significantly enhance the luminescence performance of Cr ³⁺ -doped Ca ₃ Gd ₂ Ga ₂ Ge ₂ O ₁₂ (CGGGO) NIR phosphors by introducing Tb ³⁺ as an efficient energy transfer mediator. Tb ³⁺ co-doping further boosts the emission intensity by 28% under 260 nm excitation and 14% under 450 nm excitation, raising the IQE to 97% without altering the emission peak position, spectral shape, or fluorescence lifetime, fully verifying the zero-disturbance nature of the sensitization effect. A dual-pathway energy transfer mechanism was proposed to elucidate the enhanced energy utilization efficiency, and crystal-field analysis confirmed the moderate crystal field environment of Cr ³⁺ favorable for broadband NIR emission. Finally, a NIR pc-LED device fabricated with the optimal co-doped phosphor demonstrates stable electroluminescence, high output power, and excellent night-vision imaging performance. This work not only develops a high-performance Cr ³⁺ -activated NIR phosphor but also provides a universal zero-disturbance sensitization strategy for designing efficient luminescent materials for advanced NIR optoelectronic applications. </p>