Distorted octahedral site occupation-induced high-efficiency broadband near-infrared emission in LiScGe2O6:Cr3+ phosphor

Abstract

The discovery of high-efficiency broadband near-infrared (NIR) emission phosphors for light-emitting diodes (pc-LEDs) is of importance for optoelectronic devices and their emerging applications. Herein, a highly efficient broadband NIR emission phosphor LiScGe₂O₆:Cr³⁺ peaking at 886 nm with a full width at half maximum (FWHM) of 160 nm (∼2230 cm⁻¹) is developed via a distorted octahedral site occupation strategy. Upon 480 nm blue-light excitation, the optimal phosphor composition LiSc_0.93Ge₂O₆:0.07Cr³⁺ presents an internal quantum efficiency (IQE) of 72.6% and high external quantum efficiency (EQE) of 39.9%. A NIR LED is fabricated based on this phosphor and a blue InGaN chip, which shows a maximum NIR output power of 407.3 mW at 300 mA driving current with a photoelectric conversion efficiency of ∼8.9%, suggesting its high promise for night-vision applications. This work provides a new strategy for achieving high-efficiency Cr³⁺-doped NIR emission phosphors.