A NIR phosphor with ultra-broadband emission enabled by dual energy transfer within two Cr3+ emitters and Cr3+ → Yb3+

Abstract

Broadband near-infrared phosphors have received unprecedented attention in areas such as non-destructive food testing, plant growth light sources, night vision lighting, and medical diagnostics. It is challenging to design phosphors with significant full-width at half-maximum (FWHM) width variations. In this work, Sr₃SiAl₁₀O₂₀:Cr³⁺ (SSAO:Cr³⁺) has two emission centers and achieves an interesting change of emission peaks from the ultra-narrow band (FWHM = 37 nm) to ultra-wideband (FWHM = 225 nm) with increasing Cr³⁺ doping concentration. Photoluminescence decay lifetime fitting confirms the existence of energy transfer in two emission centers. The emission intensity and thermal stability of the phosphor after 950 nm were extended by introducing Yb³⁺ ions. A NIR phosphor-converted LED was fabricated using SSAO:Cr³⁺,Yb³⁺ and a 410 nm LED chip, which shows great potential in the fields of night vision illumination, non-destructive monitoring, and information encryption.