Broadband near-infrared CaHf4(PO4)6: Cr3+ phosphor for multi-functional applications in light-emitting diodes

Broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have garnered widespread research interest. The development of broadband NIR phosphors remains hindered by significant challenges, restricting their potential applications. In this work, a novel broadband NIR emitting CaHf 4 (PO 4 ) 6 : Cr 3+ (CHPO: Cr 3+ ) phosphor was synthesized. Under 472 nm excitation, the phosphor demonstrated a broadband emission centered at 925 nm with a full width at half maximum (FWHM) of 181 nm. The emission spectrum effectively encompassed the third-order frequency-doubling absorption band of C-H bonds and the second-order frequency-doubling absorption band of O-H bonds. A pc-LED was fabricated by combining CHPO: Cr 3+ phosphor with a 470 nm blue LED chip, achieving a near-infrared output power of 25.5 mW and an impressive photoelectric conversion efficiency of 6.4 % at a driving current of 120 mA. Finally, studies on night-vision, non-destructive testing, and solution concentration detection demonstrate the potential of the synthesized NIR phosphor for advancing broadband NIR pc-LED applications.