Resumo de eventos cient??ficos
Discovering new colors of luminescence in rare-earths doped CaTiO3 through co-doping
Registro en:
0000-0001-7028-0878
Autor
BEZZAN, OTAVIO P.
PEDROSO, CASSIO C.S.
CARVALHO, JOSE M.
FELINTO, MARIA C.F.C.
BRITO, HERMI F.
RODRIGUES, LUCAS C.V.
WORLD CHEMISTRY CONGRESS, 46th; ANNUAL MEETING OF THE BRAZILIAN CHEMICAL SOCIETY, 40th; IUPAC GENERAL ASSEMBLY, 49th
Resumen
The luminescence of CaTiO3:Pr3+ has been known since mid-90s [1] and its persistent
luminescence has been explained via InterValence Charge Transfer transitions [2]. However, the
trivalent dysprosium doped materials besides presenting white luminescence does not present
any persistent luminescence. On the other hand, the expected red emission on materials doped
with Eu3+ only occur when exciting in the forbidden 4f6-4f6 transitions. The objectives of this work
are to show the synthesis and luminescence properties of CaTiO3:Dy3+ and CaTiO3:Dy3+,R3+
prepared with the sol-gel method [3, 4]. The excitation spectra of single Eu3+ or Dy3+ doped
materials (Fig. left) show for Eu3+, only the 4f6-4f6 transitions while for Dy3+ both the 4f9-4f9
transitions as well as the O2-???TiIV charge transfer and the host absorption. The excitation
spectrum for the Dy3+,Eu3+ co-doped material monitoring the Eu3+ emission at 610 nm exhibit both
the Eu3+ intraconfigurational transitions as well as the O2-???TiIV charge transfer and the host
absorption. This result indicates that there is no direct energy transfer from Dy3+ to Eu3+, but Dy3+
acts as a sensitizer for Eu3+ to be excited by host transitions. Based on experimental data the
energy level diagram was constructed (Fig. right) showing that Eu3+ is deep inside the valence
band.