Tailoring Ultra-Wide Visible-NIR Luminescence by Ce³⁺/Cr³⁺/Yb³⁺-alloying Sc-Based Oxides for Multifunctional Optical Applications

Visible-to-near-infrared (VIS-NIR) luminescent materials are in great demand in the field of non-destructive testing such as component determination and hyperspectral imaging. Although Cr3+-activated phosphors are widely reported, controllable tailoring ultra-wide VIS-NIR luminescence excited by blue light is still a challenge. The strategies of cationic substitution and energy transfers are effective for adjusting the luminescence of Cr3+-activated phosphors. In this work, a series of Cr3+-doped Sc-based solid solution phosphors (Ba3-mSrmSc4O9:Cr3+) are reported. Under the excitation of blue light, these phosphors exhibit broadband emission due to the different luminescence centers induced by Cr3+ occupying different cationic sites. Because of the weaker crystal field strength, Cr3+ realizes a broadband emission with a longer peak position (lambda(em) = 820 nm) and broader full width at half maximum (FWHM approximate to 182 nm) in Ba2SrSc4O9. Furthermore, Ce3+/Yb3+ ions are introduced into Ba2SrSc4O9:Cr3+, achieving an ultra-wide VIS-NIR luminescence (460-1200 nm) by the Ce3+-> Cr3+-> Yb3+ multiple energy transfers. Designing energy transfers is beneficial to improve the quantum efficiency and weaken the thermal quenching. Finally, the NIR phosphor-converted light-emitting diode (pc-LED) fabricated by Ba2SrSc4O9:Cr3+ demonstrates great potential in night-vision and water component detection. This work provides an effective design idea for controllable tailoring ultra-wide VIS-NIR luminescence by chemical substitution and energy transfer.