Portal de Periódicos da CAPES

Artigo Acesso aberto Produção Nacional Revisado por pares

BIBTEX RIS

Energy transfer between terbium and europium ions in barium orthosilicate phosphors obtained from sol-gel route

2018; Elsevier BV; Volume: 199; Linguagem: Inglês

10.1016/j.jlumin.2018.03.057

1872-7883

Airton G. Bispo‐Jr, S.A.M. Lima, Ana Maria Pires,

Radioactive element chemistry and processing

The present paper reports on the energy transfer mechanism between Eu3+ and Tb3+ in barium orthosilicate obtained from the sol-gel route, when both activators concentration is varied. The synthetic methodology was adjusted to provide high crystalline and monophasic Ba2SiO4. In the emission spectra under 250 nm excitation, both Eu3+ (5D0→7FJ) and Tb3+ (5D3→7FJ and 5D4→7FJ) transitions can be observed at low Eu3+ doping concentrations with an unexpected and intense blue emission from Tb3+. However, when the Eu3+ content is higher than that of the Tb3+, just the Eu3+ emission is noticed. Also, it is possible to tune the phosphor emission from red to pink by varying the Eu3+ and Tb3+ content. From the excitation spectra, we inferred that energy transfer (ET) from Tb3+ to Eu3+ occurs at any doping situation, nonetheless, the opposite process happens just when both activators amount is similar. An approach using the Tb3+ and Eu3+ lifetimes and the Eu3+ quantum efficiency confirms this observation, indicating that not only the matrix act as sensitizer to the Eu3+ ions, but also Tb3+ ions contribute by increasing the Eu3+ quantum efficiency in up to 20%. Finally, by using the Van Uitert theory, it was found for this system that the ET between the two rare-earth ions is dominated by the dipole-dipole mechanism.