Synthesis and luminescence properties of Eu2+/Ce3+, Ce3+/Tb3+ and Eu2+/Tb3+ co-doped AlONs

Abstract

Series of Eu2+/Ce3+, Ce3+/Tb3+ and Eu2+/Tb3+ co-doped aluminum oxynitrides Al5O6N were prepared using the standard sol-gel technique with following annealing in the flow of N2. In all the samples Al5O6N is a major phase, just traces of α-Al2O3 and AlN were found for some particular samples with high loading of rare-earth ions. According to pulsed cathodoluminescence and photoluminescence data a non-radiative energy transfer occurs from Ce3+ to Eu2+, from Ce3+ to Tb3+ and from Eu2+ to Tb3+. Also, it was shown that for Eu2+/Ce3+ co-doped Al5O6N the optimal contents of both REE ions are different compared to those for single doped Al5O6N (0.25 at% of Eu2+ and 0.04 at% of Ce3+). In case of Al5O6N:0.4%Tb3+,yCe3+ (y = 0.01…0.08%) the PCL and PL intensities increase in the whole range of Ce3+ content. Finally, for Al5O6N:0.4%Tb3+,yEu2+ (y = 0.1…0.8%) no pronounced dependence of luminescence caused by Tb3+ ions on the Eu2+ content is observed. Concentration quenching of Eu2+ caused luminescence is given at Eu2+ content above 0.3%. The chromaticity coordinates of prepared co-doped AlONs were calculated and three samples were found to give close to white emission.