title: Defect structure and up-conversion luminescence properties of ZrO2:Yb3+,Er3+ nanomaterials.
abstract: The up-converting ZrO2:Yb3+,Er3+ nanomaterials were prepared with the combustion and sol-gel methods. FT-IR spectroscopy was used for analyzing the impurities. The crystal structures were characterized with X-ray powder diffraction and the mean crystallite sizes were estimated with the Scherrer formula. Up-conversion luminescence measurements were made at room temperature with IR-laser excitation at 977 nm. The IR spectra revealed the conventional NO3- and OH- impurities for the combustion synthesis products. The structure of the ZrO2:Yb3+, Er3+ nanomaterials was cubic except for the minor monoclinic and tetragonal impurities obtained with the sol-gel method. The materials showed red (650-700 nm) and green (520-560 nm) up-conversion luminescence due to the 4F9/2-->4I15/2 and (2H11/2, 4S3/2)-->4I15/2 transitions of Er3+, respectively. The products obtained with the combustion synthesis exhibited the most intense luminescence intensity and showed considerable afterglow.
authors.affiliation: Department of Chemistry, University of Turku, FI-20014, Turku, Finland.
authors.forename: Iko
authors.initials: I
authors.lastname: Hyppänen
authors.forename: Jorma
authors.initials: J
authors.lastname: Hölsä
authors.forename: Jouko
authors.initials: J
authors.lastname: Kankare
authors.forename: Mika
authors.initials: M
authors.lastname: Lastusaari
authors.forename: Laura
authors.initials: L
authors.lastname: Pihlgren
authors.forename: Tero
authors.initials: T
authors.lastname: Soukka
mesh_terms: D003460:Crystallization; D005063:Europium / Q000737:chemistry*; D049449:Luminescence; D049329:Nanostructures / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D014961:X-Ray Diffraction; D015018:Ytterbium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D005063:Europium; D015040:Zirconium; D015018:Ytterbium