Cathodo- and Photoluminescence in the System Y2−xTbxSiO5: Eu3+ a Case with an Unusual Effective Energy Transfer in Cathodoluminescence

Abstract

Cathode ray excitation of X2–Y2SiO5:Eu3+ results in a moderate red emission. The efficiency is enhanced considerably (≈ 700%) by the simultaneous introduction of a high Tb3+ concentration (e.g. YTbSiO5:Eu3+). An enhancement of the photoluminescence emission is observed as well. The luminescence properties are studied as a function of the Tb3+ content. The mechanism of energy transfer in cathodo‐ and photoluminescence are discussed.

Energy Transfer Tb3+ → Eu3+ in Cathodoluminescence for Oxyorthosilicates of X1 and X2 Type. System Y2SiO5:Eu3+, Tb3+

“…However, the observed selection rules are in agreement with one Eu3+ of site C,. From that observation both Eu3+ sites in the X, type are deduced to be very similar; corresponding results are obtained from the fluorescence Raman spectra [8] and with site selective excited photoluminescence [ 111. Introduction of Tb3+ in X, -Y,SiO, : Eu;' does not influence the selection rules for the Eu3' transitions (e.g.…”

“…In PL in the system X, -Y,SiO, : Tb:+Eu;+ an energy transfer Tb3+ -+ Eu3+ is present as well [8]. Due to the differences in the transfer mechanism for CL and PL small Tb3+ concentrations are less effective in PL.…”

“…X, -Y,SiO, :Tb;,:Eu& in Fig. 1, curve 2 and [8]). However, pronounced differences are observed for the pure Tb compound Tb,SiO, : EU;, :' with XI structure ( Fig.…”

“…Eu3' activated phosphors of type X, -Y,SiO, : Eu:' yield a moderate brightness [8]. The emission is of type 'Do -+ 7F, (Fig.…”

“…Recently, we reported the enhancement of the red CL of Eu3+ by the simultaneous introduction of a high concentration of Tb3+ in the X, type of Y,SiO, (X, system Y, -,-,Tb,Eu,SiO, [8]). For higher Tb3+ concentrations the crystal structure changes from the X, to the X, type.…”