White emitting GeO2-PbO-Bi2O3-SrF2 glass and nano-glass ceramics co-doped with Eu3+, Tb3+ and Tm3+ ions

• Published in: Journal of alloys and compounds 2017-05, Vol.705, p.539
• Main Authors: Kłonkowski, Andrzej M, Wiczk, Wiesław, Szczodrowski, Karol, Wileńska, Dorota, Górecka, Natalia, Szyszkowska, Małgorzata
• Format: Article
• Language: English
• Subjects: Ceramics; Devitrification; Dopants; Emission; Energy transfer; Europium; Glass; Glass ceramics; Lighting; Luminescence; Solid state physics; Terbium; Thulium
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.02.153

The study is devoted to a luminescent glass and its devitrified counterpart (nano-glass ceramics) both triply co-doped with Eu3+, Tb3+ and Tm3+ ions. Besides for comparison glasses singly doped with Eu3+ , Tb3+ or Tm3+ and a glass doubly co-doped with Eu3+ and Tb3+ were studied. The singly Tb3+ doped glass did not exhibit cross-relaxation effect. In the case of the di-doped glass energy transfers Tb3+ → Eu3+ was certified. Then, for the tri-doped glass energy transfers Tb 3+ → Eu3+ and in reverse Eu3+ → Tb3+ as well as Tm3+ → Tb3+ were observed. In the emission spectrum of the triply co-doped devitrified glass, similarly as in the other Eu3+ doped glasses, band peaked at 612 nm ascribed to 5D0 → 7F2 transition in Eu3+ was dominated above the 5D0 → 7F2 band. It suggests that the majority of Eu3+ (and very probably also Tb3+ and Tm3+ ) ions were incorporated into the residual vitreous phase of the glass-ceramics. Reduced luminescence lifetimes τ1 of the Tb3+ and Tm3+ 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.