Coadsorption of Dye Molecules at TiO2 Surfaces: A Photoelectron Spectroscopy Study

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• 作者：Johan Oscarsson ; Maria Hahlin ; Erik M. J. Johansson ; Susanna K. Eriksson ; Rebecka Lindblad ; Anna I. K. Eriksson ; Azhar Zia ; Hans Siegbahn ; Håkan Rensmo
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：June 16, 2016
• 年：2016
• 卷：120
• 期：23
• 页码：12484-12494
• 全文大小：717K
• 年卷期：0
• ISSN：1932-7455

文摘

The effects of coadsorbing the amphiphilic ruthenium-based dye Z907 (cis-bis(isothiocyanato)(2,20-bipyridyl-4,40-dicarboxylato)(4,40-dinonyl-20-bipyridyl)ruthenium(II)) with the coadsorbent DPA (n-decylphosphonic acid) and with the organic dye D35 ((E)-3-(5-(4-(bis(2′,4′-dibutoxybiphenyl-4-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid) on mesoporous TiO₂ were investigated using photoelectron spectroscopy (PES). Z907 is expected to adsorb to the TiO₂ surface via the carboxylic acid groups. However, Z907 also shows signs of interacting with the TiO₂ via the sulfur of the thiocyanate groups, and this interaction is affected by both the addition of DPA and D35. DPA, when added, exchanges with Z907 at the TiO₂ surface, and each Z907 is replaced by six DPA molecules, but it does not affect the energy level alignment between Z907 and TiO₂ substantially. Adding D35 to Z907 induces changes in the adsorption configuration of Z907 by the means of suppressing the interaction of the thiocyanate ligands and the TiO₂ surface. The HOMO level of Z907 is shifted by the addition of D35. Coadsorbing Z907 with D35 thus gives changes at a molecular level, meaning that this is an example of collaborative sensitization.