LiGaP2O7:Cr3+, Yb3+ phosphors for broadband NIR LEDs toward multiple applications

Abstract

Developing high-performance broadband near-infrared (NIR) phosphors for NIR phosphor-converted light-emitting diodes (pc-LEDs) is still a challenge. Co-doping is an effective strategy to enhance performances of the NIR phosphors. Herein, we explore a novel NIR phosphor by co-doping Yb3+ into LiGaP2O7:Cr3+ (LGAP:Cr3+) and systematically analyse its microtopography. Under 450 nm excitation, LGAP:Cr3+,Yb3+ emits a broad NIR band from 700 to 1100 nm. Due to the energy transfer from Cr3+ to Yb3+, the Yb3+ emission is strengthened more than 8 times and the external quantum efficiency reaches 25.5%. The addition of Yb3+ suppresses the thermal quenching compared with the Cr3+ single-doped specimen. The LGAP:Cr3+,Yb3+ phosphors and commercial blue chips are used to fabricate the NIR pc-LED. At 100 mA, the NIR pc-LED manifests an output NIR power of 24.86 mW and a photoelectric conversion efficiency of 8.30%, demonstrating possible applications in night version and bioimaging.