title: Taming Lanthanide-Centered Upconversion at the Molecular Level.
abstract: Considered at the beginning of the 21th century as being incompatible with the presence of closely bound high-energy oscillators, lanthanide-centered superexcitation, which is the raising of an already excited electron to an even higher level by excited-state energy absorption, is therefore a very active topic strictly limited to the statistical doping of low-phonon bulk solids and nanoparticles. We show here that molecular lanthanide-containing coordination complexes may be judiciously tuned to overcome these limitations and to induce near-infrared (NIR)-to-visible (VIS)-light upconversion via the successive absorption of two low-energy photons using linear-optical responses. Whereas single-ion-centered excited-state absorption mechanisms remain difficult to implement in lanthanide complexes, the skillful design of intramolecular intermetallic energy-transfer processes operating in multimetallic architectures is at the origin of the recent programming of erbium-centered molecular upconversion.
authors.forename: Yan
authors.initials: Y
authors.lastname: Suffren
authors.forename: Bahman
authors.initials: B
authors.lastname: Golesorkhi
authors.forename: Davood
authors.initials: D
authors.lastname: Zare
authors.forename: Laure
authors.initials: L
authors.lastname: Guénée
authors.forename: Homayoun
authors.initials: H
authors.lastname: Nozary
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR 4301 , Rue Charles Sadron, F-45071 Orléans Cedex 2, France.
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Eliseeva
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR 4301 , Rue Charles Sadron, F-45071 Orléans Cedex 2, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Petoud
authors.forename: Andreas
authors.initials: A
authors.lastname: Hauser
authors.forename: Claude
authors.initials: C
authors.lastname: Piguet