Ultra-broadband near-infrared emission in the double-perovskite Ca2InTaO6:Cr3+phosphor for light-emitting-diode applications

Broadband near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have extensive applications basing on spectroscopy technology, which promote the exploration of broadband NIR phosphors. However, there are still lack of efficient ultra-broadband NIR phosphors with peak emission wavelength over 850 nm. In this work, a series of double-perovskite-type Ca2InTaO6:Cr3+ NIR phosphors were successfully prepared through a conventional high-temperature solid-state reaction process. Optimizing the Cr3+ doping concentration, the ob-tained phosphor exhibits an ultra-broadband emission covering 700-1300 nm with peak wavelength located at 880 nm. The full width at half maximum (FWHM) of this phosphor reaches 200 nm ascribing to the two crys-tallographic sites in this compound that are available for Cr3+ substitution. Upon 480 nm excitation, the pho-toluminescence quantum yield (PLQY) and absorption efficiency are determined to be 33.6% and 30.6%, respectively, indicating an excellent efficiency within this emission range among ultra-broadband NIR phos-phors. Thus, this work provides an alternative Cr3+-activated ultra-broadband and long-wavelength NIR phos-phor Ca2InTaO6:Cr3+ for the upcoming smart spectroscopy applications.