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 (λem = 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. Controllable luminescence tailoring and ultra‐broadband Visible‐to‐near‐infrared (VIS‐NIR) luminescence with a spectral range of 460–1200 nm is achieved by the introduction of Ce3+/Yb3+ into Ba3‐mSrmSc4O9:Cr3+ using strategies of crystal field regulation and energy transfer. By co‐doping Ce3+ and Yb3+, the absorption, quantum efficiency, and thermal stability of Cr3+ are enhanced based on the Ce3+→Cr3+→Yb3+ multiple energy transfer processes.