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 Cr 3+ -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 Cr 3+ -activated phosphors. In this work, a series of Cr 3+ -doped Sc-based solid solution phosphors (Ba 3-m Sr m Sc 4 O 9 :Cr 3+ ) are reported. Under the excitation of blue light, these phosphors exhibit broadband emission due to the different luminescence centers induced by Cr 3+ occupying different cationic sites. Because of the weaker crystal field strength, Cr 3+ realizes a broadband emission with a longer peak position (λ em = 820 nm) and broader full width at half maximum (FWHM≈182 nm) in Ba 2 SrSc 4 O 9 . Furthermore, Ce 3+ /Yb 3+ ions are introduced into Ba 2 SrSc 4 O 9 :Cr 3+ , achieving an ultra-wide VIS-NIR luminescence (460–1200 nm) by the Ce 3+ →Cr 3+ →Yb 3+ 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 Ba 2 SrSc 4 O 9 :Cr 3+ 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.