Portal de Periódicos da CAPES

Artigo Acesso aberto Produção Nacional Revisado por pares

BIBTEX RIS

Persistent luminescence behavior of materials doped with Eu^2+ and Tb^3+

2012; Optica Publishing Group; Volume: 2; Issue: 4 Linguagem: Inglês

10.1364/ome.2.000382

2159-3930

Lucas Carvalho Veloso Rodrigues, Hermi F. Brito, Jorma Hölsä, Mika Lastusaari,

Perovskite Materials and Applications

In this work, the persistent luminescence mechanisms of Tb3+ (in CdSiO3) and Eu2+ (in BaAl2O4) based on solid experimental data are compared. The photoluminescence spectroscopy shows the different nature of the inter- and intraconfigurational transitions for Eu2+ and Tb3+, respectively. The electron is the charge carrier in both mechanisms, implying the presence of electron acceptor defects. The preliminary structural analysis shows a free space in CdSiO3 able to accommodate interstitial oxide ions needed by charge compensation during the initial preparation. The subsequent annealing removes this oxide leaving behind an electron trap. Despite the low band gap energy for CdSiO3, determined with synchrotron radiation UV-VUV excitation spectroscopy of Tb3+, the persistent luminescence from Tb3+ is observed only with UV irradiation. The need of high excitation energy is due to the position of 7F6 level deep below the bottom of the conduction band, as determined with the 4f8→4f75d1 and the ligand-to-metal charge-transfer transitions. Finally, the persistent luminescence mechanisms are constructed and, despite the differences, the mechanisms for Tb3+ and Eu2+ proved to be rather similar. This similarity confirms the solidity of the interpretation of experimental data for the Eu2+ doped persistent luminescence materials and encourages the use of similar models for other persistent luminescence materials.