Influence of the Crystal Structure on the Energy Transfer Tb3+ → Eu3+ in Oxyorthosilicates Ln2SiO5: TbxEUy

Luminescence of the System (Y, Gd, Tb)2, SiO5 :Eu3+

“…For higher Tb3+ (x > 1.0) and Eu3+ concentrations (y > 0.05) the Eu emission is increasingly quenched. The largest enhancement of the Eu luminescence to Sre, = 840 is observed for the couple x = 0.51~ = 0.05 with an efficiency of the energy transfer qET of more than 90% [3]. The persistence of the Tb3+ emission is strongly influenced by the simultaneous presence of Eu3+ and the decay from ,D3 as well as 5D, becomes considerably faster, reaching the experimental limit of our instrumentation for x z 1.0.…”

“…Correspondingly, even for small Tb3+ concentrations an energy transfer Tb3+ + Eu3+ is already working Table 2). With increasing x and y the conditions for the energy transfer are improved up to x x 0.5 and y = 0.05, whereas for higher values concentration quenching takes place (Table 1 and [3]). In contrast with the X, series in the coactivated XI system Gd,SiOs : Tb,Eu, an energy transfer Tb3+ + Eu3+ is absent.…”

“…The optical absorption edge of the yttrium host X,-Y,SiO, is situated at energies higher than 200 nm (experimental limit of our instrumentation). The diffuse reflectance spectrum Diffuse reflectance spectra of (1) X,-Gd2Si05, (2) X,-GdzSi05 : Eu, (for clarity spectrum ( 3 ) is shifted along the y-axis)…”