Broadband near-infrared phosphor BaMgAl10O17:Cr3+ realized by crystallographic site engineering

Near infrared (NIR) light sources play vital roles in bioimaging, medical treatments, food analysis and machine vision. Herein, we report unusual broadband NIR emission in BaMgAl10O17:Cr3+ (BAM:Cr3+) via site engineering. Both the emission maximum and spectral bandwidth of BAM:Cr3+ can be tailored by controlling the site occupancy of Cr3+ on two different Al sites. The optimal BAM:0.2Cr3+ phosphor exhibits both a sharp line spectrum (λem = 696 nm) and a broadband emission centered at 762 nm, having an internal quantum efficiency (IQE) of ~ 94%. A prototype NIR light source was demonstrated by combining a blue laser diode with BAM:Cr3+ phosphor-in-glass (PiG) and revealed an NIR light output power of 3.4 mW when driven by a 100 mW blue laser diode.