Hydrothermal Synthesis and Properties of Yb3+/Tm3+ Doped Sr2LaF7 Upconversion Nanoparticles

Abstract

We report the procedure for hydrothermal synthesis of ultrasmall Yb3+/Tm3+ co-doped Sr2LaF7 (SLF) upconversion phosphors. These phosphors were synthesized by varying the concentrations of Yb3+ (x = 10, 15, 20, and 25 mol%) and Tm3+ (y = 0.75, 1, 2, and 3 mol%) with the aim to analyze their emissions in the near IR spectral range. According to the detailed structural analysis, Yb3+ and Tm3+ occupy the La3+ sites in the SLF host. The addition of Yb3+/Tm3+ ions has a huge impact on the lattice constant, particle size, and PL emission properties of the synthesized SLF nanophosphor. The results show that the optimal dopant concentrations for upconversion luminescence of Yb3+/Tm3+ co-doped SLF are 20 mol% Yb3+ and 1 mol% Tm3+ with EDTA as the chelating agent. Under 980 nm light excitation, a strong upconversion emission of Tm3+ ions around 800 nm was achieved. In addition, the experimental photoluminescence lifetime of Tm3+ emission in the SLF host is reported. This study discovered that efficient near IR emission from ultrasmall Yb3+/Tm3+ co-doped SLF phosphors may have potential applications in the fields of fluorescent labels in bioimaging and security applications. © 2022 by the authors. --//-- Milićević B., Periša J., Ristić Z., Milenković K., Antić Ž., Smits K., Kemere M., Vitols K., Sarakovskis A., Dramićanin M.D., Hydrothermal Synthesis and Properties of Yb3+/Tm3+ Doped Sr2LaF7 Upconversion Nanoparticles, (2023) Nanomaterials, 13 (1), art. no. 30, DOI: 10.3390/nano13010030, https://www.scopus.com/inward/record.uri?eid=2-s2.0-85145824982&doi=10.3390%2fnano13010030&partnerID=40&md5=aaad8d348b12b86447784dd82261d5f7, published under the CC BY 4.0 license.