Wydział Chemii

K. A. Prokop

M. Guzik

G. Boulon

Y. Guyot

A.- V. Mudring

J. Cybińska

2024

Journal of Luminescence

275

120777/1-120777/8

10.1016/j.jlumin.2024.120777

Naukowa

Angielski

Artykuł

Yb³⁺-doped inorganic materials are constantly in demand due to a strong interest in fundamental and applied research. The simplicity of the 4f¹³ electronic structure minimizes de-excitation processes and enables a quasi-three-level laser emission scheme at 1 μm employed for IR laser devices.

In this work, we present an unusual simultaneous emission from two of the lowest levels of the ²F_5/2 excited state observed at 77 K, measured for the first time and confirmed by the barycenter law for Yb³⁺-doped tetragonal LuPO₄ revealing the lowest crystal field among Yb³⁺ ion-activated oxide crystals.

Three series of tetragonal lutetium orthophosphate powders, containing various concentrations of Yb³⁺ ions (0.5–5 mol %), were analyzed in nano and micro-crystalline forms. The ionic liquid-assisted (IL) hydrothermal (HT) method was used for the nano-powders' preparation. This route enabled the fabrication of fine nano-powders with particle sizes of 15 nm in an ethylene glycol (GE) reaction medium and 30 nm in a water (W) medium, each exhibiting the desired well-crystallized single-phase phosphate. For comparative studies, the micro-crystalline samples were synthesized via reaction in the solid phase at a relatively high temperature.

The Yb³⁺ ion also served as a structural probe, its spectroscopy i.e., absorption at 4.2 K, selectively excited luminescence at 77 K, and fluorescence decays were used to assign Yb³⁺ energy levels in only one D_2d center precisely. This assignment was based on exceptional features due to the unique emissions observed from the two lowest levels of the ²F_5/2 excited state, split only by 27 cm⁻¹, confirmed by calculation of the crystal field parameters from Zeeman spectra.

Nano/micro-powders, Ionic liquid-assisted hydrothermal methods, Unusual Yb3+ emission, D2d center, LuPO4

CC-BY

http://dx.doi.org/10.1016/j.jlumin.2024.120777

http://www.elsevier.com