Voltammetric, spectroscopic, and microscopic investigations of electrocrystallized forms of semiconducting AgTCNQ (TCNQ = 7,7,8,8- tetracyanoquinodimethane) exhibiting different morphologies and colors

Harris, A, Nafady, A, O'Mullane, A and Bond, A 2007, 'Voltammetric, spectroscopic, and microscopic investigations of electrocrystallized forms of semiconducting AgTCNQ (TCNQ = 7,7,8,8- tetracyanoquinodimethane) exhibiting different morphologies and colors', Chemistry of Materials, vol. 19, no. 23, pp. 5499-5509.


Document type: Journal Article
Collection: Journal Articles

Title Voltammetric, spectroscopic, and microscopic investigations of electrocrystallized forms of semiconducting AgTCNQ (TCNQ = 7,7,8,8- tetracyanoquinodimethane) exhibiting different morphologies and colors
Author(s) Harris, A
Nafady, A
O'Mullane, A
Bond, A
Year 2007
Journal name Chemistry of Materials
Volume number 19
Issue number 23
Start page 5499
End page 5509
Total pages 11
Publisher American Chemical Society
Abstract Chemically synthesized AgTCNQ exists in two forms that differ in their morphologies (needles and microcrystals) and colors (red and blue). It is now shown that both forms exhibit essentially indistinguishable X-ray diffraction, spectroscopic, and thermochemical data, implying that they are not separate phases, as implied in some literature. Electrochemical reduction of TCNQ (MeCN) in the presence of Ag(MeCN)+ generates both red and blue AgTCNQ. On glassy carbon, platinum, or indium tin oxide electrodes and at relatively positive deposition potentials, slow growth of high aspect ratio, red needle AgTCNQ crystals occurs. After longer times and at more negative deposition potentials, blue microcrystalline AgTCNQ thin films are favored. Blue AgTCNQ is postulated to be generated via reduction of a Ag +[(TCNQ.-)(TCNQ)](MeCN) intermediate. At even more negative potentials, Ag(metal) formation inhibits further growth of AgTCNQ. On a gold electrode, Ag(metal) deposition occurs at more positive potentials than on the other electrode materials examined. However, surface plasmon resonance data indicate that a small potential region is available between the stripping of Ag(metal) and the oxidation of TCNQ(MeCN).- back to TCNQ(MeCN) where AgTCNQ may form. AgTCNQ in both the red and blue forms also can be prepared electrochemically on a TCNQ(s) modified electrode in 0.1 M AgNO 3(aq) where deposition of Ag(metal) onto the TCNQ (s) crystals allows a charge transfer process to occur. However, the morphology formed in this solid-solid phase transformation is more difficult to control. © 2007 American Chemical Society.
Subject Chemical Engineering not elsewhere classified
DOI - identifier 10.1021/cm070780b
Copyright notice © 2007 American Chemical Society.
ISSN 0897-4756
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