Modeling of self-assembled monolayers (SAMs) of Octadecanethiol and Hexadecanethiol on gold (Au) and silver (Ag)

• Published in: Results in physics 2017, Vol.7, p.2289-2295
• Main Authors: Jalal Uddin, M., Khalid Hossain, M., Hossain, Mohammad I., Qarony, Wayesh, Tayyaba, S., Mia, M.N.H., Pervez, M.F., Hossen, S.
• Format: Article
• Language: English
• Subjects: Capacitance of the SAM (CSAM); Hexadecanethiol (HDT; Impedance; Octadecanethiol (ODT); Resistance of the SAM (RSAM); Self-assembled monolayers (SAMs)
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2017.06.055

[Display omitted] •SAMs of ODT and HDT on Au and Ag surface using PET substrate have been fabricated.•The leaky behavior of the monolayers has been studied and modeled using EIS.•The leakage defect has been studied demonstrating a simplified RRC electrical model.•Matlab simulation was done suggesting a low frequency to analyze defective SAMs.•Developed model provided capacitance, resistance and thickness of monolayer to characterize defective SAMs. This work proposes a modeling of self-assembled monolayers (SAMs) to assess the quality of SAM layers in terms of their leaky behavior. In the modeling, electrochemical impedance spectroscopy (EIS) and a conceptual and simplified resistance-resistance-capacitance (RRC) electrical model from an electrochemical setup were demonstrated. Based on the model, Matlab-based simulation was carried out to find out the suggestive low frequency measurement for analyzing the defective monolayers. Finally, the developed electrical model facilitated the interpretation of the EIS spectra measured in the range of 10Hz to 100kHz and provided the capacitance, resistance and thickness of the monolayer. Thus the proposed model could be considered as a powerful tool to characterize the defective SAMs, which was very specific to determine the resistive behavior of the self-assembled monolayers prepared for shorter adsorption time.