title: Calcination-free micromolding in capillaries for nanopatterning of inorganic upconversion luminescent layers on flexible plastic sheets.
abstract: We report calcination-free micromolding in capillaries for the nanopatterning of inorganic upconversion luminescent layers on flexible plastic sheets. We prepared Er(3+)- and Yb(3+)-codoped NaYF4 nanoparticles modified with a cationic polymer to improve dispersion stability of aqueous dispersion of the NaYF4 nanoparticles. We controlled the line width and density of nanoparticles in the NaYF4 nanoparticle films on flexible plastic sheets by adjusting the concentrations of the NaYF4 nanoparticle dispersion and the channel sizes of silicone stamps, resulting in the formation of nanopatterned NaYF4 nanoparticle films at the line width of the nanoparticle size (50 nm). Visible upconversion luminescence and near-infrared fluorescence appeared from the NaYF4 nanoparticle films excited with a near-infrared laser beam. These results demonstrate that calcination free micromolding in capillaries using aqueous dispersion of NaYF4 nanoparticles modified with a cationic polymer allows for the nanopatterning of inorganic upconversion luminescent layers on flexible plastic sheets.
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan. Electronic address: watasato@rs.noda.tus.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Asanuma
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hyodo
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Soga
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Mutsuyoshi
authors.initials: M
authors.lastname: Matsumoto
keywords: Flexible device; Micromolding in capillaries; Nanopatterning; Rare-earth-ion-doped nanoparticle; Upconversion luminescence