Abstract
Tb3+ and Yb3+ co-doped calcium aluminate powders: Ca1−x−yYbxTbyAl4O7 (x = 0.02–0.06; y = 0.02), Ca1−x−yYbxTbyAl4O7 (x = 0.03, y = 0.01–0.07), Ca1−x−yYbxTbyAl4O7 (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 → 7FJ and 5D3 → 7FJ transitions with the dominant component around 542 nm. The direct excitation of two Yb3+ ions at 980 nm led to cooperative sensitization of the Tb3+5D4 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.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
