Tunable broadband near-infrared emission in LiScO2:Cr3+ phosphor induced by the variation of chromium ion concentration

Broadband near-infrared (NIR) spectroscopy within 700–1100 nm generated by phosphor-converted light-emitting diode has multifunctional applications in night vision, bioimaging, and food quality analysis. To ensure the spectral coverage and saturability in this region, developing broadband NIR phosphors with tunable emission is desired. Herein, in this work, a tunable broadband NIR phosphor LiScO2:Cr3+ was reported, which has a full width at half maximum (FWHM) of 165 nm, and an emission peak ranging from 807 to 870 nm depending on the Cr3+ concentration varying from 0.5% to 5% when excited by 450 nm. Obviously, the significant red-shift of emission spectrum induced by the increase of Cr3+ concentration is not derived from the weakening of crystal field, because the smaller Cr3+ substituting larger Sc3+ will cause lattice's shrink and enhancement of crystal field. To understand the mechanism of tunable emission induced by Cr3+ concentration, the electronic properties, site occupation, local structure, and behavior of Cr3+ ions were investigated in detailed. Thus, this work provides a valuable reference for the developing of tunable NIR phosphor based on the control of chromium ion concentration. •A broadband near-infrared LiScO2: Cr3+ phosphor was reported.•A tunable NIR emission from 807 to 870 nm was achieved via Cr3+ concentration variation.•The specific mechanism for the tunable emission was explored.