Structural and Optical Properties of NIR Laser Excited Ho ³⁺ /Yb ³⁺ Doped Sr ₂ LaF ₇ UC Phosphor

This article reported the synthesis and upconversion luminescence properties of Ho³⁺/Yb³⁺ co-doped Sr₂LaF₇ phosphors. It has been synthesized by the wet chemical method. The structural and morphological properties of the prepared phosphor were studied by XRD, SEM, and HRTEM analysis. UCL of Sr₂LaF₇: Ho³⁺/Yb³⁺ nanophosphors was observed in the visible to NIR range under 980-nm laser excitation. Thus, it exhibits intense green upconversion at 542 nm, and doublet red emission bands were observed at 645 and 653 nm, respectively. The emission intensities were enhanced by increasing the concentration of Ho³⁺ ions. Hence, nanocrystalline Sr₂LaF₇: Ho³⁺/Yb³⁺ is a promising host for bioimaging applications.