Broadband near-infrared BaMSi3O9:Cr3+ (M = Zr, Sn, Hf) phosphors for light-emitting diode applications

A series of Cr3+-doped BaMSi3O9 (M = Zr, Sn, Hf) near-infrared emitting phosphors with tunable luminescence properties have been successfully synthesized by using a simple solid-state reaction method. The developed BaMSi3O9:Cr3+ phosphors show a broad near-infrared emission band ranging from 650 nm to 1200 nm with a peak wavelength longer than 800 nm and a full width at half maximum (FWHM) of more than 155 nm upon blue light excitation. The optimized phosphor also demonstrates good thermal stability, whose emission intensity at 150 °C can retain about 59% of its initial intensity at room temperature. The near-infrared LED prototypes constructed by combining the BaMSi3O9:Cr3+ phosphor with a blue LED chip give a maximum output power of 12.19 mW at a drive current of 320 mA. By using the fabricated near-infrared LED device as a lighting source, night-vision lighting and blood vessel imaging of human fingers and arms are successfully realized, demonstrating the great potential of BaMSi3O9:Cr3+ phosphors for near-infrared LED applications.