Broadband, Enhanced, and Antithermally Quenched Near-Infrared Phosphors via a Cosubstitution Approach.

Wearable biosensing and food safety inspection devices with high thermal stability, high brightness, and broad near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) could accelerate the next-generation NIR light applications. In this work, NIR LaGdGaGeO:Cr ( = 0 to 1.5) phosphors were successfully fabricated by a high-temperature solid-state method. Here, by doping Gd ions into the La sites in the LaGaGeO matrix, a 7.9-fold increase in the photoluminescence (PL) intensity of the Cr ions, as well as a remarkably broadened full width at half-maximum (FWHM) of the corresponding PL spectra, is achieved. The enhancements in the PL, PLE intensity, and FWHM are attributed to the suppression of the nonradiative transition process of Cr when Gd ions are doped into the host, which can be demonstrated by the decay curves. Moreover, the LaGdGaGeO:Cr phosphor displays an abnormally negative thermal phenomenon that the integral PL intensity reaches 131% of the initial intensity when the ambient temperature increases to 160 °C. Finally, the broadband NIR pc-LED was fabricated based on the as-explored LaGdGaGeO:Cr phosphors combined with a 460 nm chip, and the potential applications for the broadband NIR pc-LEDs were discussed in detail.