Photoactive Langmuir–Blodgett, Freely Suspended and Free Standing Films of Carboxylate Ligand-Coated ZnO Nanocrystals

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• 作者：Jan Paczesny ; Małgorzata Wolska-Pietkiewicz ; Ilona Binkiewicz ; Monika Wadowska ; Zbigniew Wróbel ; Kinga Matuła ; Wojciech Nogala ; Janusz Lewiński ; Robert Hołyst
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：June 1, 2016
• 年：2016
• 卷：8
• 期：21
• 页码：13532-13541
• 全文大小：625K
• 年卷期：0
• ISSN：1944-8252

文摘

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.