Boosting broadband short-wave infrared emission to achieve near-unity quantum efficiency via bridging Cr3+–Ni2+ in spinel solid-solutions towards light-emitting diode applications

Abstract

Recently, short-wave infrared (SWIR) phosphor-converted light-emitting diodes (pc-LEDs) have garnered increased attention due to their widespread applications in night vision, biological imaging, and non-destructive testing. Nevertheless, the currently used SWIR phosphors suffer from poor thermal stability and low quantum efficiency. In this study, a finely tuned spinel-based solid solution, Mg_0.5Zn_0.5Ga₂O₄, is prepared to host Ni²⁺ to induce SWIR emission. Cr³⁺ is codoped as a sensitizer to bridge Cr³⁺ and Ni²⁺ ions, significantly enhancing blue light absorption and facilitating energy transfer (ET) to Ni²⁺ ions. The champion SWIR phosphor exhibits a broadband emission centered at 1304 nm with a full width at half maximum (FWHM) of 250 nm, achieving a near-unity internal quantum efficiency (IQE = 97.7%) and a good thermal stability (70.7%@423 K). The fabricated SWIR pc-LED device delivers a high SWIR output power of 39.9 mW at 360 mA, enabling its application in non-destructive imaging and testing.