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 obtained 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 crystallographic sites in this compound that are available for Cr3+ substitution. Upon 480 nm excitation, the photoluminescence 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 phosphors. Thus, this work provides an alternative Cr3+-activated ultra-broadband and long-wavelength NIR phosphor Ca2InTaO6:Cr3+ for the upcoming smart spectroscopy applications.