Redox-Active 蟺-Conjugated Organometallic Monolayers: Pronounced Coulomb Blockade Characteristic at Room Temperature

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• 作者：Chiao-Pei Chen ; Wan-Rou Luo ; Chen-Ni Chen ; Shin-Mou Wu ; Shuchen Hsieh ; Chao-Ming Chiang ; Teng-Yuan Dong
• 刊名：Langmuir
• 出版年：2013
• 出版时间：March 5, 2013
• 年：2013
• 卷：29
• 期：9
• 页码：3106-3115
• 全文大小：531K
• 年卷期：v.29,no.9(March 5, 2013)
• ISSN：1520-5827

文摘

We report the electrical transport characteristics of a series of molecular wires, fc-C鈮鈥擟₆H₄鈥擲Ac (fc = ferrocenyl; Ac = acetyl) and AcS-C₆H₄鈥擟鈮-(fc)_n-C鈮鈥擟₆H₄鈥擲Ac (n = 2, 3), consisting of multiple redox-active ferrocenyl centers. The self-assembled monolayers of these molecular wires on Au surfaces were comprehensively characterized by electrochemistry and conductive atomic force microscopy techniques. Characterization of the wires revealed that electron transport is made extremely efficient by the organometallic redox states. There is a strong electronic coupling between ferrocenyl moieties, and superior electron-transport ability exists through these semirigid molecular wires. Standard rate constants for the electron transfer between the electrode and the ferrocenyl moieties were measured for the monolayers by a potential-step chronoamperometry technique. The electron conduction through the molecular wires was estimated using the monolayers as a bridge from the Au(111) metal surface to the gold tip of a conductive atomic force microscope (CAFM). Using the CAFM, Coulomb blockade behavior arising from the capacitive charging of the multinuclear redox-active molecules was observed at room temperature. The conductance switching was mediated by the presence of various ferrocenyl redox states and each current step corresponded to a specific redox state.