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

Abstract 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 (Ba_3‐mSr_mSc₄O₉: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 (λ_em = 820 nm) and broader full width at half maximum (FWHM≈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.