Thin films of hydroxy-TEMPO-substituted TTF and of its charge-transfer complex with TCNQ

Casellas, Hélène; de, Dominique; Valade, Lydie; Fraxedas, Jordi

doi:10.1039/b111662m

Cited by 21 publications

(14 citation statements)

References 26 publications

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“…The peak at 163.8 eV is due to the component from the adsorbed H 2 Cat-BMT-TTF molecules. The binding energy is in good agreement with the reported values for TTF derivatives. − Therefore, it is concluded that the H 2 Cat-BMT-TTF molecules are adsorbed intact on the Im-SAM surface. From the intensity ratio of the S 2p signal for the Im-SAM sample to that for the H 2 Cat-BMT-TTF sample on Im-SAM, i.e., 1:3.45, the relative coverage is estimated.…”

Section: Results and Discussionsupporting

confidence: 88%

Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

et al. 2018

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Hydrogen-bonding heterogeneous bilayers on substrates have been studied as a base for new functions of molecular adlayers by means of atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRAS), and density functional theory (DFT) calculations. Here, we report the formation of the catechol-fused bis(methylthio)tetrathiafulvalene (HCat-BMT-TTF) adlayer hydrogen bonding with an imidazole-terminated alkanethiolate self-assembled monolayer (Im-SAM) on Au(111). The heterogeneous bilayer is realized by sequential two-step immersions in solutions for the individual Im-SAM and HCat-BMT-TTF adlayer formations. In the measurements by AFM, a grained HCat-BMT-TTF adlayer on Im-SAM is revealed. The coverage and the chemical states of HCat-BMT-TTF on Im-SAM are specified by XPS. On the vibrational spectrum measured by IRAS, the strong hydrogen bonds between HCat-BMT-TTF and Im-SAM are characterized by the remarkably red-shifted OH stretching mode at 3140 cm, which is much lower than that for hydrogen-bonding water (typically ∼3300 cm). The OH stretching mode frequency and the adsorption strength for the HCat-BMT-TTF molecule hydrogen bonding with imidazole groups are quantitatively examined on the basis of DFT calculations.

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Section: Results and Discussionsupporting

confidence: 88%

Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

et al. 2018

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“…33 The S(2p) and W(4d 5/2 ) lines are at 164.2 and 248.0 eV, respectively. The first peak position is in agreement with that of TTF derivatives 7,34 and the second line has a binding energy characteristic of W VI oxides. 35 SEM images shown in Fig.…”

Section: Thin Films Of [Ttf][tcnq]supporting

confidence: 80%

Tetrathiafulvalene-based conducting deposits on silicon substrates

Caillieux

Valade

et al. 2003

J. Mater. Chem.

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Tetrathiafulvalene-based molecular conductors, namely [TTF][TCNQ], (TTF) 6 [N(C 2 H 5 ) 4 ](HPM 12 O 40 ) (M ~W, Mo), and TTF[Ni(dmit) 2 ] 2 have been processed as thin films on microrough (001)-oriented silicon substrates using three different techniques. CVD-grown [TTF][TCNQ] deposits consist of platelets (10 6 5 mm) and filaments (diameter y1 mm). CN stretching modes in the infrared spectrum and CC stretching modes in the Raman spectrum are in agreement with a charge transfer of y0.6 from the TTF donor to the TCNQ acceptor. The N(1s) photoelectron spectrum confirms the presence of a reduced tetracyanoquinodimethane moiety. The films exhibit a semiconducting behaviour with a room-temperature conductivity of y0.4 S cm 21 . Deposits of (TTF) 6 [N(C 2 H 5 ) 4 ](HPW 12 O 40 ) are electrodeposited on microrough Si(001) at constant current from TTF and [N(C 2 H 5 ) 4 ] 3 (PW 12 O 40 ) in acetonitrile solution. The films are made of stacked sheets (5 v thickness v 25 mm). Vibrational spectra, conductivity measurements and magnetic susceptibility data are similar to those obtained on single crystals of (TTF) 6 [N(C 2 H 5 ) 4 ](HPW 12 O 40 ) grown on a platinum electrode. Thin films of TTF[Ni(dmit) 2 ] 2 are grown on microrough Si(001) by an adsorption process in organic solution. The deposits are characterized by Raman micro-probe and exhibit a pseudo-metallic behaviour with a room-temperature conductivity of about 2 S cm 21 .

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“…The most intense line, with a binding energy E of 163.5 eV, corresponds to C±S±C, as has already been reported for TTF derivatives. [14] We assign the 161.8 and 165.3 eV lines to C±S±Ni and CS, respectively, based on their relative intensities. In the nominal formula TTF[Ni-(dmit) 2 ] 2 there are 12 C±S±C, 8 C±S±Ni, and 4 CS bonds, which results in a ratio of 3:2:1.…”

Section: ±1mentioning

confidence: 99%

“…10 lm thick) electrically deposited (at 25 lA cm ±2 ) on Pt foil as the substrate exhibited a dendritic structure and have shown bistable electrical switching and memory phenomena. [13] Moreover, thin films of TTF derivatives, such as TTF±TCNQ (TCNQ = tetracyanoquinodimethane), [8c] [TTF±(OH)TEMPO]TCNQ (TEMPO = N,N,Ntrimethyl-1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl), [14] or TTF- [15] [15] Depending on the stirring conditions used, continuous films or agglomerates of nanowires are obtained with r RT~2 .5 S cm ±1 . Therefore, in our electrodeposited films, observation of spherical grains in close contact may seem surprising to some extent.…”

Section: ±1mentioning

confidence: 99%

Metallic Thin Films of TTF[Ni(dmit)₂]₂ by Electrodeposition on (001)‐Oriented Silicon Substrates

de¹,

Fraxedas

Faulmann

et al. 2004

Advanced Materials

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Dedicated to Patrick Cassoux to let him know that the dream of a TTF[Ni(dmit) 2 ] 2 -based device may come true!The preparation of thin films of crystalline molecular organic materials with specific physical properties (magnetic order, metallic behavior, superconductivity, etc.) is an active field boosted by the ever-increasing availability of remarkable new materials and their potential applications.[ , due to the high conduction activation barriers induced by grain boundaries.[2]Here, we present results on the preparation of metallic thin films of the molecular metal TTF[Ni(dmit) 2 ] 2 , where dmit 2± = 1,3-dithiole-2-thione-4,5-dithiolato, by electrocrystallization, using silicon wafers as electrodes. TTF[Ni(dmit) 2 ] 2 single crystals (obtained by a diffusion process) exhibit metallic behavior down to 3 K, with r RT~3 00 S cm ±1 and superconductivity is observed at T c = 1.6 K under application of a hydrostatic pressure of 7 kbar.[6] Our films exhibit metallic character down to ca. 12 K in spite of their polycrystalline morphology. Electrocrystallization is the most suitable technique to obtain charge transfer (CT) compounds. [7] The advantages of this technique over, e.g., vapor-phase deposition methods [8] include precise control of the concentration of solute at the interface, the ability to fabricate thin films on substrates with unusual geometries, and the fact that vapor-phase deposition is limited to sublimation/evaporation of neutral species. Although the electrocrystallization technique has been extensively used, the utilization of substrates as electrodes is rare. [9] On the other hand, there is great interest in characterizing hybrid organic±silicon structures. Molecular materials have been shown to be complementary to inorganic-based materials (organic light-emitting diodes, organic thinfilm transistors, etc.), and certain applications are receptive to their substitution because they can be processed as thin films at lower cost.[10]Electrodeposition of TTF[Ni(dmit) 2 ] 2 was carried out with intrinsic Si(001) as the anode and a platinum wire as the cathode. We have selected silicon single crystals as substrates in order to eliminate spurious effects associated with grain boundaries, avoiding, e.g., non-homogeneous current densities. The anodic oxidation of the TTF is performed at constant current density (1.5 lA cm ±2 ) at room temperature. Within 5 days, a black air-stable thin film is formed on the polished face of the (001) Si(001) wafers as anodes in an electrocrystallization process. Scanning electron microscopy (SEM) micrographs of a covered area show a dense film made of roughly spherical grains with sizes ranging from 0.6 to 1 lm (Fig. 1). The estimated thickness of the films is ca. 1 lm. Other works have reported quite different morphologies. Applying a low current density (< 5 lA cm ±2 ), Wang et al. reported electrodeposited films of (BEDT-TTF) 2 PF 6 as 100 lm long needles.[9] When the current density values were increased (> 10 lA cm ±2 ), they ob-

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Thin films of hydroxy-TEMPO-substituted TTF and of its charge-transfer complex with TCNQ

Cited by 21 publications

References 26 publications

Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

Tetrathiafulvalene-based conducting deposits on silicon substrates

Metallic Thin Films of TTF[Ni(dmit)₂]₂ by Electrodeposition on (001)‐Oriented Silicon Substrates

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Thin films of hydroxy-TEMPO-substituted TTF and of its charge-transfer complex with TCNQ

Cited by 21 publications

References 26 publications

Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

Strong Hydrogen Bonds at the Interface between Proton-Donating and -Accepting Self-Assembled Monolayers on Au(111)

Tetrathiafulvalene-based conducting deposits on silicon substrates

Metallic Thin Films of TTF[Ni(dmit)2]2 by Electrodeposition on (001)‐Oriented Silicon Substrates

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Metallic Thin Films of TTF[Ni(dmit)₂]₂ by Electrodeposition on (001)‐Oriented Silicon Substrates