title: Photoactive Langmuir-Blodgett, Freely Suspended and Free Standing Films of Carboxylate Ligand-Coated ZnO Nanocrystals.
abstract: A new possibility for the formation of macroscopic and photoactive structures from zinc oxide nanocrystals is described. Photoactive freely suspended and free-standing films of macroscopic area (up to few square millimeters) and submicrometer thickness (up to several hundreds of nanometers) composed of carboxylate ligand-coated zinc oxide nanocrystallites (RCO2-ZnO NCs) of diameter less than 5 nm are prepared according to a modified Langmuir-Schaefer method. First, the suspension of RCO2-ZnO NCs is applied onto the air/water interface. Upon compression, the films become turbid and elastic. The integrity of such structures is ensured by interdigitation of ligands stabilizing ZnO NCs. Great elasticity allows transfer of the films onto a metal frame as a freely suspended film. Such membranes are afterward extracted from the supporting frame to form free-standing films of macroscopic area. Because the integrity of the films is maintained by ligands, no abolishment of quantum confinement occurs, and films retain spectroscopic properties of initial RCO2-ZnO NCs. The mechanism of formation of thin films of RCO2-ZnO NCs at the air/water interface is discussed in detail.
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Paczesny
authors.affiliation: Faculty of Chemistry, Warsaw University of Technology , Noakowskiego 3, 00-664 Warsaw, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Wolska-Pietkiewicz
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Ilona
authors.initials: I
authors.lastname: Binkiewicz
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Wadowska
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Wróbel
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Kinga
authors.initials: K
authors.lastname: Matuła
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Nogala
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.|Faculty of Chemistry, Warsaw University of Technology , Noakowskiego 3, 00-664 Warsaw, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Lewiński
authors.affiliation: Institute of Physical Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Robert
authors.initials: R
authors.lastname: Hołyst
keywords: aggregation; capping ligand; interdigitation; nanoparticles; self-assembly; self-supported films; zinc oxide