Wydział Chemii

Małgorzata Puchalska

Eugeniusz Zych

Adam Watras

2017

Journal of Luminescence

183

185-192

10.1016/j.jlumin.2016.11.022

Naukowa

Angielski

Artykuł

A detailed analysis of the luminescence behaviour of Yb³⁺-doped and Yb³⁺-Tb³⁺ co-doped strontium aluminates powders: Sr_1-xYb_xAl₄O₇ (x=0.002–0.07) and Sr_1-x-yYb_xTb_yAl₄O₇ (x=0.03; y=0.002–0.02) were performed. The studies of singly doped samples show that direct excitation of Yb³⁺ by means of ²F_7/2-²F_5/2 absorption at 900–980 nm leads to Stokes Yb³⁺ emission in the range of 970–1130 nm as well as bluish-green Yb³⁺ cooperative luminescence (CL) whose energy doubles that of the NIR one. The effect of activator concentration and charge compensation through Na⁺ co-doping on both Yb³⁺ emissions were also studied. It was found that Na⁺ addition enhanced Stokes Yb³⁺ photoluminescence brightness, while the cooperative emission intensity appeared to be lower. In doubly Yb³⁺-Tb³⁺ doped materials excitation at 980 nm led to cooperative sensitization of the Tb^{3+ 5}D₄ level giving rise to its green ⁵D₄→⁷F_J (J=⁷F₆-⁷F₃) up-conversion luminescence with the dominant component around 542 nm. The cooperative energy transfer (CET) mechanism was proposed basing on the results obtained from emission and absorption spectra, decay kinetics as well as the dependence of UC luminescence intensity on NIR excitation power.

optical materials, Yb3+ luminescence, Tb3+ luminescence, defects, energy transfer

http://dx.doi.org/10.1016/j.jlumin.2016.11.022

http://www.elsevier.com