Optical investigation of Eu3+:PbF2 ceramics and transparent glass–ceramics

Abstract This paper reports an optical investigation of glass–ceramics formed by annealing glasses with compositions 50 GeO 2 –40 PbO–10 PbF 2 – x EuF 3 , x  = [0.5; 1; 1.5; 2] and polycrystalline ceramics with composition 100 PbF 2 , y EuF 3 , with y  = 5, 10, 15 and 20. For each material, the photoluminescence spectrum and the photoluminescence lifetimes of the 5 D 0 , 5 D 1 and 5 D 2 Eu 3+ levels are measured. Occurrence of Eu 3+ :β-PbF 2 nanocrystallites in the glass–ceramics is confirmed and total ceramisation requires more than 10% of EuF 3 with respect to PbF 2 in the starting glass. In the Eu 3+ :β-PbF 2 ceramics and glass–ceramics, Eu 3+ ions replace Pb 2+ in their regular cubic site, but they interact together to form dimers and higher nuclearity clusters. These two species are easily distinguished according to their photoluminescence decay rate. For the EuF 3 rates investigated here, there are no isolated Eu 3+ ions in the PbF 2 lattice. A preliminary investigation of the optical properties of co-doped Gd 3+ :Eu 3+ :β-PbF 2 ceramics was also performed. It shows that mixed Gd 3+ –Eu 3+ dimers and clusters are formed, and that efficient Gd 3+  → Eu 3+ energy transfer occurs in these ceramics. The Pb 2+ ions of the lattice may also be involved in the energy transfer process.