Toward Optical Ceramics Based on Yb3+ Rare Earth Ion-Doped Mixed Molybdato-Tungstates: Part II - Spectroscopic Characterization

M. Bieza (1) , M. Guzik (1) , E. Tomaszewicz (2) , Y. Guyot (3) , Kheirreddine Lebbou (3) , Georges Boulon (3)

1 UWr - University of Wrocław [Poland]
2 West Pomeranian University of Technology Szczecin
3 ILM - Institut Lumière Matière [Villeurbanne]

Investigations of spectroscopic properties were performed for Yb³⁺-doped solid solutions of chemical formulas based on mixed La₂MoWO₉ molybdato-tungstate powders that crystallize in the cubic system with the space group P2₁3 (No. 198) and from which it was also possible to prepare the first translucent optical ceramics. Samples activated by the Yb³⁺ ion in a wide concentration range were synthesized by three various techniques: high-temperature solid-state reaction, the Pechini method, and the combustion method. The microcrystalline solid solutions obtained by the high-temperature solid-state reaction characterized by intense luminescence are useful for detailed fundamental analysis. The direct excitation of Yb³⁺ into ²F_7/2 → ²F_5/2 absorption at 940–980 nm leads to reversed ²F_5/2 → ²F_7/2 transitions giving Yb³⁺ emission lines in the 970–1100 nm range. The absorption and emission 0-phonon lines of Yb³⁺ ions were also used as structural probes at a low temperature, and the conjugation with SEM and TEM techniques was particularly useful here. The multisite character of Yb³⁺ was confirmed in high-resolution site-selective emission spectra. In the case of microcrystalline ceramics, the grains are characterized by a wide 0-phonon line around 976 nm and a high number of multisites and white points by another sharper line around 968 nm. Based on the absorption and emission spectra, the Yb³⁺ electronic energy level diagram was proposed for the main site. The effect of dopant concentration as well as the grain size influence on the luminescent properties and the decay times were analyzed in order to attempt to understand the concentration quenching mechanism and estimate the parameters useful for a theoretical approach to laser potential first with cubic single crystals and then with cubic transparent ceramics. This second part is related to the spectroscopic properties of powders and microceramic samples analyzed in the first part.

Mots clés: Luminescence; Ions; Ceramics; Absorption spectroscopy; Lasers

Domaines: Chimie; Physique [physics]; Sciences de l'ingénieur [physics]

M. Bieza, M. Guzik, E. Tomaszewicz, Y. Guyot, Kheirreddine Lebbou, et al.. Toward Optical Ceramics Based on Yb3+ Rare Earth Ion-Doped Mixed Molybdato-Tungstates: Part II - Spectroscopic Characterization. Journal of Physical Chemistry C, 2017, 121 (24), pp.13303-13313. ⟨10.1021/acs.jpcc.7b00747⟩. ⟨hal-02289390⟩