Two-stage ultra-broadband luminescence of Cr3+-doped multisite layered phosphor Sr3Ga2Ge4O14 and its application in pc-LEDs

Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have enormous potential for all kinds of applications, both non-destructive testing and biological applications. The development of broadband NIR phosphors with good thermal stability for a wide range of applications remains a challenge. This work successfully synthesized a layered structure ultra-broadband NIR phosphor Sr3Ga2Ge4O14:Cr3+ (SGGO:Cr3+) under 431 nm excitation and achieved a spectrum adjusted from 750 nm to 900 nm in a two-stage ultra-broadband emission with a full width at half maximum (FWHM) varying between 257 and 336 nm by controlling the Cr3+ concentration. In particular, SGGO:0.15Cr3+ has a FWHM of 257 nm and the internal quantum efficiency (IQE) of 36.67%, while the emission intensity at 423 K remained at 76% of room temperature. Finally, SGGO:0.03Cr3+ and SGGO:0.15Cr3+ phosphors were used with 430 nm blue light chips to produce NIR pc-LEDs devices and applied to night vision and human palm penetration, as well as plant illumination, revealing the potential of SGGO:Cr3+ for multiple applications. The potential of SGGO:Cr3+ for a variety of applications was demonstrated.