Influence of crystal structure on the luminescence properties of bismuth(III), europium(III) and dysprosium(III) in Y2SiO5

Abstract

The luminescence properties of Bi3+, Eu3+, Dy3+ and energy transfer from Bi3+ to Dy3+ and Eu3+ have been studied in two modifications of Y2SiO5(low-temperature X1 type and high-temperature X2 type) and discussed in relation to their crystal structures. The Bi3+ ion luminesces in the blue region of the spectrum in X1-Y2SiO5 but in the UV region in X2-Y2SiO5. Two obviously different luminescent centres have been observed for Bi3+ and Eu3+ in X1-Y2SiO5, but only one has been seen in X2-Y2SiO5. The Stokes shift (9200 cm–1) for Bi3+ in X1-Y2SiO5 is much larger than that (5000 cm–1) in X2-Y2SiO5. This suggests that the host lattice is more rigid in X2-Y2SiO5 than in X1-Y2SiO5. As a result, the Bi3+, Eu3+ ions show higher emission intensity in the former than in the latter type. X1-Y2SiO5 is more suitable for Bi3+→ Eu3+ energy transfer and X2-Y2SiO5 is more suitable for Bi3+→ Dy3+ energy transfer.