title: Luminescence and upconversion from thulium(III) species in solution.
abstract: Thulium salts and complexes are shown to be emissive from three states in the excited state manifold of Tm(3+). Formation of the (1)D(2) state can result in luminescence, or in energy transfer to the lower energy (1)G(4) and (3)H(4) emissive states. Where chromophores are present in the ligand structure, emission is restricted to thulium centred emissive states that are lower in energy than the chromophore centred donor state. We have also observed direct multi-photon excitation of the thulium excited state manifold. Furthermore, additional transitions are observed in the multi-photon excitation spectra that are consistent with upconversion as a consequence of sequential single photon absorption and relaxation processes within the thulium excited state manifold.
authors.affiliation: Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
authors.forename: Octavia A
authors.initials: OA
authors.lastname: Blackburn
authors.forename: Manuel
authors.initials: M
authors.lastname: Tropiano
authors.forename: Thomas Just
authors.initials: TJ
authors.lastname: Sørensen
authors.forename: James
authors.initials: J
authors.lastname: Thom
authors.forename: Andrew
authors.initials: A
authors.lastname: Beeby
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Bushby
authors.forename: David
authors.initials: D
authors.lastname: Parker
authors.forename: Louise S
authors.initials: LS
authors.lastname: Natrajan
authors.forename: Stephen
authors.initials: S
authors.lastname: Faulkner