Screening of Broadband Near-Infrared Cr3+-Activated Phosphors Using Ce3+ as a Probe

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are ideal miniaturized NIR light sources, but it is still difficult to find broadband-emitting NIR phosphors due to the lack of appropriate material design principles. In this work, we propose a method to find hosts yielding broadband NIR Cr 3+ emission by screening Ce 3+ -doped phosphor hosts for which both Ce 3+ and Cr 3+ can occupy the same crystallographic site. A NIR phosphor Ba 3 Sc 4 O 9:Cr 3+ (BSO:Cr 3+ ) with an emission peak at 835 nm and a full width at half-maximum (FWHM) of 188 nm is obtained, where Ce 3+ or Cr 3+ is accommodated at the same Sc 3+ site. The BSO:Cr 3+ ceramic is demonstrated to produce a NIR emitter with an output power of 14.56 mW when driven by a blue laser diode at 5.0 V/100 mA. By following the proposed method, two broadband NIR phosphors composed of Li 3 Sc 2 (PO 4 ) 3:Cr 3+ (λ em = 1000 nm, FWHM = 223 nm) and Na 3 Sc 2 (PO 4 ) 3:Cr 3+ (λ em = 895 nm, FWHM = 184 nm) are further discovered.