title: Upconversion from aqueous phase lanthanide chelates.
abstract: We have prepared and characterized several lanthanide ion complexes of multidentate ligands or chelates in an effort to develop new upconverting luminescent labels that can be immune to autofluorescence and photobleaching. This study has involved the characterization of various chelates of Nd, Er, and Tm with respect to relative luminescent efficiency and excited-state lifetimes and explored various two-photon stepwise excitation mechanisms. Using peak laser powers near 100 kW, the upconversion emissions of Nd in Nd(EDTA)2(5-) at 386 nm, Er in Er(DPA)3(3-) at 550 nm, and Tm in Tm(DPA)3(3-) at 480 nm, at levels of approximately 10(-12) moles can be detected.
authors.affiliation: Molecular Physics Laboratory, SRI International, 333 Ravenswood Avenue, Menlo Park, California 94025, USA.
authors.forename: Xudong
authors.initials: X
authors.lastname: Xiao
authors.forename: Jeanne P
authors.initials: JP
authors.lastname: Haushalter
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Faris
mesh_terms: D002614:Chelating Agents / Q000737:chemistry / Q000528:radiation effects; D005456:Fluorescent Dyes; D028581:Lanthanoid Series Elements / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008163:Luminescent Measurements / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods*; D044367:Phase Transition; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D005456:Fluorescent Dyes; D028581:Lanthanoid Series Elements; D014867:Water