Unlocking Cr 3+ –Cr 3+ Coupling in Spinel: Ultrabroadband Near-Infrared Emission beyond 900 nm with High Efficiency and Thermal Stability

作者：Geng Chen, Yahong Jin, Lifang Yuan, Bo Wang, Jiansheng Huo, Hao Suo, Haoyi Wu, Yihua Hu, Feng Wang · 发表于：ACS Applied Materials & Interfaces · 年份：2024 · DOI：10.1021/acsami.4c03419 · 被引用次数：104 · 研究领域：Luminescence Properties of Advanced Materials、Perovskite Materials and Applications、Advanced Photocatalysis Techniques

Broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) hold promising potential as next-generation compact, portable, and intelligent NIR light sources. Nonetheless, the lack of high-performance broadband NIR phosphors with an emission peak beyond 900 nm has severely hindered the development and widespread application of NIR pc-LEDs. This study presents a strategy for precise control of energy-state coupling in spinel solid solutions composed of Mg x Zn 1– x Ga 2 O 4 to tune the NIR emissions of Cr 3+ activators. By combining crystal field engineering and heavy doping, the Cr 3+ –Cr 3+ ion pair emission from the 4 T 2 state is unlocked, giving rise to unusual broadband NIR emission spanning 650 and 1400 nm with an emission maximum of 913 nm and a full width at half-maximum (fwhm) of 213 nm. Under an optimal Mg/Zn ratio of 4:1, the sample achieves record-breaking performance, including high internal and external quantum efficiency (IQE = 83.9% and EQE = 35.7%) and excellent thermal stability ( I 423 K / I 298 K = 75.8%). Encapsulating the as-obtained phosphors into prototype pc-LEDs yields an overwhelming NIR output power of 124.2 mW at a driving current of 840 mA and a photoelectric conversion efficiency (PCE) of 10.5% at 30 mA, rendering high performance in NIR imaging applications.