White emitting GeO2PbO Bi2O3SrF2 glass and nano-glass ceramics co-doped with Eu3+, Tb3+ and Tm3+ ions

Abstract

Abstract The study is devoted to a luminescent glass and its devitrified counterpart (nano-glass ceramics) both triply co-doped with Eu 3+ , Tb 3+ and Tm 3+ ions. Besides for comparison glasses singly doped with Eu 3+ , Tb 3+ or Tm 3+ and a glass doubly co-doped with Eu 3+ and Tb 3+ were studied. The singly Tb 3+ doped glass did not exhibit cross-relaxation effect. In the case of the di-doped glass energy transfers Tb 3+ → Eu 3+ was certified. Then, for the tri-doped glass energy transfers Tb 3+ → Eu 3+ and in reverse Eu 3+ → Tb 3+ as well as Tm 3+ → Tb 3+ were observed. In the emission spectrum of the triply co-doped devitrified glass, similarly as in the other Eu 3+ doped glasses, band peaked at 612 nm ascribed to 5 D 0 → 7 F 2 transition in Eu 3+ was dominated above the 5 D 0 → 7 F 2 band. It suggests that the majority of Eu 3+ (and very probably also Tb 3+ and Tm 3+ ) ions were incorporated into the residual vitreous phase of the glass-ceramics. Reduced luminescence lifetimes τ 1 of the Tb 3+ and Tm 3+ dopants in the triply co-doped glass in comparison to τ values of these dopants singly embedded in the glasses additionally confirms presence of the energy transfer effects in the tri-doped material. Devitrification of the tri-doped glassy phosphor did not improve its white color emission.