Wydział Chemii

Małgorzata Guzik

Elżbieta Tomaszewicz

Yannick Guyot

Janina Legendziewicz

Georges Boulon

2016

Journal of Luminescence

169

755-764

10.1016/j.jlumin.2015.02.043

Naukowa

Angielski

Artykuł

A series of micro-crystalline Yb³⁺-doped vacancied Cd_1−3xYb_2x□_xMoO₄ solid solutions has been prepared by a high-temperature solid state reaction method. The structural studies performed by X-ray powder diffraction measurements have shown that the samples are monophasic and crystallize in the tetragonal scheelite-type structure (the space group I4₁/a, with point symmetry close to D_2d) when the x parameter is greater than 0 and does not reach 0.1430 (33.36 mol% of Yb³⁺ ions). The substitution of divalent Cd²⁺ by trivalent Yb³⁺ cations leads to the formation of cationic vacancies in the framework (which are denoted in the chemical formula as □), due to the charge compensation: 3Cd²⁺→2Yb³⁺+□ vacancy. Direct excitation of Yb³⁺ by means of²F_7/2→²F_5/2 absorption at 940–980 nm leads to reversed ²F_5/2→²F_7/2 transitions giving Yb³⁺ emission in the range of 970–1130 nm. The intense and broad emission lines of Yb³⁺ ions, which are also used as a structural probe at 77 K have been observed. The existence of more than one component of the 0-phonon line at 975 nm and 976.6 nm indicate two Yb³⁺ distribution sites, which is in agreement with results obtained for the Nd³⁺ ion. Basing on the absorption and emission spectra the Yb³⁺ electronic energy levels have been proposed. The effect of dopant concentration had an influence on luminescent properties but had no influence on the powder morphology. Yb³⁺concentration dependences of the ²F_5/2 experimental decay time were analyzed in order to attempt the understanding of the concentration quenching mechanism and estimate the main parameters useful for a theoretical approach of laser potential.

Yb3+ dopant, Cadmium molybdate, Vacancied micro-powders, photoluminescence, Concentration quenching, Self-trapping

http://dx.doi.org/10.1016/j.jlumin.2015.02.043

http://www.elsevier.com