Smaller Stokes Shift Induced Highly Efficient Broadband Near Infrared Garnet Phosphor

Abstract Broadband near‐infrared (NIR) phosphor converted light emitting diodes (pc‐LEDs) are novel compact light sources that enable portable devices for substance detection. However, to achieve such efficient pc‐LEDs is still a challenge due to lack of efficient phosphors. In this paper, Stokes shift as an efficiency predictor is emphasized. In Cr 3+ activated Ca 2 LuZr 2 Al 3 O 12 (CLZA) garnet phosphor, Stokes shift decreases from 2990 to 2854 cm −1 upon substituting Ca‐Zr with Lu‐Al. As a result, electron–phonon coupling related nonradiative process is reduced. The external quantum efficiency is significantly enhanced to 47.4%, and the as fabricated NIR pc‐LED offers 33.7% @10 mA electro‐optical efficiency. The results can advance the development of efficient NIR phosphors.