Cr3+-doped borate phosphors for broadband near-infrared LED applications

Abstract

With the increase in near-infrared light-emission diode light sources, super broadband NIR phosphors have become a research hotspot. The study of single emitting center is of great significance for the development of super broadband NIR LED phosphors. Herein, a novel NIR phosphor K₆Li_0.9Na_0.1CaSc₂(B₅O₁₀)₃:Cr³⁺ (KLNCSBO:Cr³⁺) with a single emitting center has been successfully synthesized, which exhibits broadband emission in the range from 700 to 1200 nm, peaking at ∼825 nm with a full width at half maximum (FWHM) of ∼167 nm. By analyzing the relationship between the local coordination environment and the luminescence properties, such a broad NIR emission of KLNCSBO:Cr³⁺ phosphor originates from the Cr³⁺ preferential occupancy in the distorted [ScO₆] octahedron with a weak crystal field. The relative content of Li and Na was regulated to realize the perturbation effect on the crystal field structure and its influence on the luminescence properties was further explored. In addition, the effects of the crystal structure on the luminescence intensity and thermal stability were also discussed for the KLNCSBO:Cr³⁺ phosphor. This work may provide some design ideas and reference significance for the development of super broadband NIR phosphors.