Luminescence of Tb-based materials doped with Eu³⁺: case studies for energy transfer processes

This review addresses the energy transfer processes involving lanthanide ions, analysing in particular the case of the Tb³⁺→Eu³⁺ energy transfer processes in terbium-based materials containing Eu³⁺ as a dopant. These examples are used as case studies for the processes and mechanisms concerning energy transfer generally involving Ln³⁺ ions, pointing out the differences caused by the structural characteristics of the host. The review introduces the theoretical background of the energy transfer processes, providing a brief description of the possible regimes for the donor–acceptor transfer depending on the donor concentration, together with the general considerations on the specific case of Tb³⁺→Eu³⁺ transfer. The review is completed by a brief survey of the literature published on this topic from the 60 s to date, including some of the most recent papers.