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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Characterization of a Perylenediimide Self-Assembled Monolayer on Indium Tin Oxide Electrodes Using Electrochemical Impedance Spectroscopy

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Author(s):
Silva, Barbara P. G. [1] ; de Florio, Daniel Z. [1] ; Brochsztain, Sergio [1]
Total Authors: 3
Affiliation:
[1] Univ Fed ABC, Ctr Engn Modelagem & Ciencias Sociais Aplicadas, BR-09210580 Santo Andre, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Journal of Physical Chemistry C; v. 118, n. 8, p. 4103-4112, FEB 27 2014.
Web of Science Citations: 19
Abstract

Self-assembled monolayers (SAMs) of N,N'-bis(2-phosphonoethyl)-3,4,9,10-perylenediimide (PPDI), a perylene dye substituted with phosphonic acid groups, were deposited on indium tin oxide (ITO) substrates. Dye deposition was confirmed by UV-visible absorption spectroscopy and by electrochemical methods. Electrochemical characterization of the SAM was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Two reversible redox waves were observed by CV for the PPDI monolayer, corresponding to E-1/2 = -0.49 V (radical anion formation) and E-1/2 = -0.90 V (dianion formation). The effect of applied bias on the EIS response was studied, comparing a region where PPDI was not reduced (applied bias = 0 V) with a region within the redox window of the imide (applied bias = -0.6 V). The EIS results Were analyzed using, either impedance (Nyquist and Bode) or capacitance (Cole-Cole) diagrams. Capacitance plots were shown to be by far more sensitive to study the faradaic activity of the SAM, allowing the determination of both the pseudocapacitance (C-pc) for charging the monolayer and the heterogeneous electron transfer rate constant (ice) from the electrode to the SAM. A molecular coverage of 7 X 10(-11) mol/cm(2) was calculated for the SAM from the pseudocapacitance. A value of k(et) = 41 s(-1) was obtained, consistent with literature data for similar systems. (AU)

FAPESP's process: 12/16358-9 - Synthesis and characterization of functional materials containing aromatic imides
Grantee:Sergio Brochsztain
Support Opportunities: Regular Research Grants