Enhancement of Optical and Electrochemical Properties via Bottom-Up Assembly of Binary Oligomer System

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• 作者：Prakash Chandra Mondal ; Megha Chhatwal ; Yekkoni Lakshmanan Jeyachandran ; Michael Zharnikov
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 8, 2014
• 年：2014
• 卷：118
• 期：18
• 页码：9578-9587
• 全文大小：458K
• 年卷期：v.118,no.18(May 8, 2014)
• ISSN：1932-7455

文摘

Heterometallic, coordination-based, binary oligomer films were fabricated on SiO_x-based solid substrates using successive layer-by-layer assembly of optically rich and redox-active polypyridyl complexes, Ru(pytpy)₂路2PF₆ (Ru-PT) and Os(pytpy)₂路2PF₆ (Os-PT) (where pytpy = 4鈥?pyridyl-2,2鈥?6鈥?2鈥?terpyridyl). The individual oligomer chains comprised alternating Ru-PT and Os-PT units connected via Cu²⁺, Pd²⁺, Ag⁺, Fe²⁺, Co²⁺, or Zn²⁺ metallo-linkers. The growth and properties of the oligomer films were monitored in detail by UV鈥搗is spectroscopy and cyclic voltammetry. The films exhibited a linear growth upon addition of the successive building blocks, with a joint grafting density of 3.9鈥?.0 脳 10¹⁴ metallo-ligands/cm² for the final oligomer films (10 layers), corresponding to a characteristic area of 2.0鈥?.5 nm²/oligomer. The only exception was the Pd²⁺-linked film on glass that showed an exponential growth, which, however, could also be changed to the linear mode by the introduction of a conductive substrate. The combination of two different functional molecular units in the oligomer chains resulted in enhancement of the optical window and in an increase in the number of the available redox states as compared to the analogous single component assemblies.