Odd鈥揈ven Effects in Charge Transport across n-Alkanethiolate-Based SAMs

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• 作者：Mostafa Baghbanzadeh ; Felice C. Simeone ; Carleen M. Bowers ; Kung-Ching Liao ; Martin Thuo ; Mahdi Baghbanzadeh ; Michael S. Miller ; Tricia Breen Carmichael ; George M. Whitesides
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：December 3, 2014
• 年：2014
• 卷：136
• 期：48
• 页码：16919-16925
• 全文大小：410K
• ISSN：1520-5126

文摘

This paper compares rates of charge transport across self-assembled monolayers (SAMs) of n-alkanethiolates having odd and even numbers of carbon atoms (n_odd and n_even) using junctions with the structure M^TS/SAM//Ga₂O₃/EGaIn (M = Au or Ag). Measurements of current density, J(V), across SAMs of n-alkanethiolates on Au^TS and Ag^TS demonstrated a statistically significant odd鈥揺ven effect on Au^TS, but not on Ag^TS, that could be detected using this technique. Statistical analysis showed the values of tunneling current density across SAMs of n-alkanethiolates on Au^TS with n_odd and n_even belonging to two separate sets, and while there is a significant difference between the values of injection current density, J₀, for these two series (log|J_0Au,even| = 4.0 卤 0.3 and log|J_0Au,odd| = 4.5 卤 0.3), the values of tunneling decay constant, 尾, for n_odd and n_even alkyl chains are indistinguishable (尾_Au,even = 0.73 卤 0.02 脜^鈥?, and 尾_Au,odd= 0.74 卤 0.02 脜^鈥?). A comparison of electrical characteristics across junctions of n-alkanethiolate SAMs on gold and silver electrodes yields indistinguishable values of 尾 and J₀ and indicates that a change that substantially alters the tilt angle of the alkyl chain (and, therefore, the thickness of the SAM) has no influence on the injection current density across SAMs of n-alkanethiolates.