Structured Layer of Rhenium Dye on SiO2 and TiO2 Surfaces by Langmuir鈥揃lodgett Technique

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• 作者：Yongho Joo ; Josef W. Spalenka ; Kyle M. McElhinny ; Samantha K. Schmitt ; Paul G. Evans ; Padma Gopalan
• 刊名：Langmuir
• 出版年：2014
• 出版时间：June 3, 2014
• 年：2014
• 卷：30
• 期：21
• 页码：6104-6113
• 全文大小：594K
• 年卷期：v.30,no.21(June 3, 2014)
• ISSN：1520-5827

文摘

We demonstrate the Langmuir鈥揃lodgett assembly of two rhenium鈥揵ipyridine complexes containing a flexible or an aromatic bridge, and transfer of the monolayer to SiO₂ and single crystal TiO₂ substrates. Both of the complexes (ReEC and Re2TC) have a hydrophilic carboxylic acid group, which preferentially anchors into the water subphase, and forms stable monolayers at surface pressures up to 40 mN/m. The optimum conditions for the formation of complete monolayers of both ReEC and Re2TC were identified through characterization of the morphology by atomic force microscopy (AFM), the thickness by ellipsometry, and the surface coverage by X-ray photoelectron spectroscopy (XPS). X-ray reflectivity measurements (XRR) are consistent with the orientation of the molecules normal to the substrate, and their extension to close to their calculated maximum length. Parameters derived from XRR analysis show that there is a higher packing density for Re2TC monolayers than for ReEC monolayers, attributable to the more rigid bridge in the Re2TC molecule.