Control of upconversion luminescence by tailoring energy migration in doped perovskite superlattices

We describe an experimental investigation of photon upconversion (UC) in a series of perovskite BaTiO₃/SrTiO₃ superlattices doped with different lanthanide compositions. We show that UC emission can be effectively enhanced by precisely incorporating a set of lanthanide ions into separated layers rather than homogeneously distributing the dopant ions in the host lattice. The use of an inert layer in the superlattice can suppress deleterious energy cross-relaxation. Furthermore, UC emission can be rendered by controlling the energy migration mediated by the Yb-doped sublattice. These results demonstrate the opportunity to modulate energy migration and transfer processes through the rational design of superlattice structures.