Wydział Chemii

Małgorzata Puchalska

Eugeniusz Zych

Marcin Sobczyk

Adam Watras

P. Deren

2015

Materials Chemistry and Physics

156

220-226

10.1016/j.matchemphys.2015.03.004

Naukowa

Angielski

Artykuł

Tb³⁺ and Yb³⁺ co-doped calcium aluminate powders: Ca_1−x−yYb_xTb_yAl₄O₇ (x = 0.02–0.06; y = 0.02), Ca_1−x−yYb_xTb_yAl₄O₇ (x = 0.03, y = 0.01–0.07), Ca_1−x−yYb_xTb_yAl₄O₇ (x = 0.01–0.05, y = 0.01) were synthesized by a modified Pechini citrate process and their optical properties were investigated. Upon excitation at 245 nm all studied samples yielded relatively strong Tb³⁺ luminescence corresponding to the ⁵D₄ → ⁷F_J and ⁵D₃ → ⁷F_J transitions with the dominant component around 542 nm. The direct excitation of two Yb³⁺ ions at 980 nm led to cooperative sensitization of the Tb^{3+ 5}D₄ level giving rise to its green up-conversion luminescence. The up-conversion emission was also observed from higher ⁵D₃ level of Tb³⁺, which is rather rare in high phonon frequency host materials. The effect of activator concentration and charge compensation by co-doping with Na⁺ ions on luminescence properties were studied. It was found that Na⁺ addition lowers disturbance/distribution of activator ions local symmetries and enhanced Stokes Tb³⁺ photoluminescence brightness, while the up-conversion emission intensity does not appear to change noticeably then.

optical materials, oxides, luminescence, Electronic structure, Defects

http://dx.doi.org/10.1016/j.matchemphys.2015.03.004

http://www.elsevier.com