Rapid Nondestructive Detection Enabled by an Ultra-Broadband NIR pc-LED

The rapid development of near-infrared (NIR) spectroscopic techniques has greatly stimulated the discovery of novel broadband NIR-emitting phosphors as advanced light sources. Herein, a novel double-perovskite phosphor La₂MgHfO₆:Cr³⁺/Yb³⁺ that displays ultra-broadband NIR emissions with a full-width at half maximum (FWHM) of 333 nm is reported. The remarkable luminescence property stems from the multiple crystallographic sites, relatively weak crystal field, and efficient Cr³-to-Yb³⁺ energy transfer (ET). The site occupation of Cr³⁺ is elaborately verified by the Rietveld refinement and first-principles calculation. By controlling the ET process, the internal/external quantum efficiency (IQE/EQE), bandwidth, and thermal stability of NIR emissions are substantially improved. The as-prepared phosphors are further integrated into a miniaturized NIR light-emitting diode (LED) package, demonstrating superior performance in rapid nondestructive detection of structural failure in thin electronic cables. The results described here provide a novel pointcut for designing broadband NIR-emitting phosphors with desired optical properties toward applications in industrial inspection and medical diagnosis.