Tunable Electrochemical Switches Based on Ultrathin Organic Films

Fave, Claire; Leroux, Yann R.; Trippé, Gaëlle; Randriamahazaka, Hyacinte; Noël, Vincent; Lacroix, Jean‐Christophe

doi:10.1021/ja068143u

Cited by 75 publications

(109 citation statements)

References 16 publications

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“…Chemically modified surfaces were already the subject of many studies in the last decades since they find application in numerous areas including electrocatalysis, [114] [115] corrosion protection, [116] molecular electronics, [117] [118] integrated circuits, [119] [120] information storage, [120]- [122] sensing [123] [124] and many others.…”

Section: Surface Modificationmentioning

confidence: 99%

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Shape‐Switchable Azo‐Macrocycles

et al. 2009

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The synthesis of four shape‐switchable macrocycles comprising different peripheral substituents is described. The macrocycles 1–4 consist of m‐terphenyl semicircles interlinked by two azo joints. These macrocycles were assembled from nitro‐functionalized m‐terphenyl moieties through reductive dimerization. The semicircles were assembled through Suzuki cross‐coupling reactions. The molecular weights of the macrocycles were determined by vapour pressure osmometry, because mass spectrometry failed in the cases of 2 and 3. The E → Z photoisomerization reactions were analysed by UV/Vis spectroscopy complemented by 1H NMR studies. A very slow thermal back‐reaction indicated considerable stabilization of the Z isomer. The reduced efficiency of the thermal back‐reaction probably arises from the reduced degree of freedom due to the mechanical interlinking of the two azo groups. The photostationary state consisted of all‐Z (85 %) and all‐E isomers (15 %). The E → Z transformation induced by irradiation displayed simple exponential kinetics, which indicates pairwise switching of the two azo groups in a macrocycle, at least on the timescale under investigation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Surface Modificationmentioning

confidence: 99%

“…Due to the increasing importance of modified electrodes for numerous applications including molecular electronics, [117][118] bioelectronics and sensors, [114][115][123] [124] there is a need to find ways to chemically deposit suitable molecular films onto electrodes.…”

Section: Platinum Electrode Modificationmentioning

confidence: 99%

Shape‐Switchable Azo‐Macrocycles

et al. 2009

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“…Reduction of a diazonium reagent of bis-thienylbenzene (BTB) (25)(26)(27)(28)(29) on carbon surfaces permits formation of molecular films of controlled thickness consisting of conjugated oligomers, and the electronic junction is completed by electron-beam deposition of carbon and gold (30). Such grafted oligo(BTB) layers can be easily p-doped and switched from insulating to conductive states in electrochemical conditions (25)(26)(27)(28). Previous transport measurements in planar Au junctions containing a 7-nm-thick BTB molecular layer were explained with a mixed-transport mechanism combining a conducting molecular region with a tunnel barrier (31).…”

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confidence: 99%

Activationless charge transport across 4.5 to 22 nm in molecular electronic junctions

Yan

Bergren

McCreery

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

156

259

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In this work, we bridge the gap between short-range tunneling in molecular junctions and activated hopping in bulk organic films, and greatly extend the distance range of charge transport in molecular electronic devices. Three distinct transport mechanisms were observed for 4.5-22-nm-thick oligo(thiophene) layers between carbon contacts, with tunneling operative when d < 8 nm, activated hopping when d > 16 nm for high temperatures and low bias, and a third mechanism consistent with field-induced ionization of highest occupied molecular orbitals or interface states to generate charge carriers when d = 8-22 nm. Transport in the 8-22-nm range is weakly temperature dependent, with a field-dependent activation barrier that becomes negligible at moderate bias. We thus report here a unique, activationless transport mechanism, operative over 8-22-nm distances without involving hopping, which severely limits carrier mobility and device lifetime in organic semiconductors. Charge transport in molecular electronic junctions can thus be effective for transport distances significantly greater than the 1-5 nm associated with quantum-mechanical tunneling.all-carbon molecular junction | attenuation coefficient | field ionization | strong electronic coupling C harge transport mechanisms in organic and molecular electronics underlie the ultimate functionality of a new generation of electronic devices. Understanding, controlling, and designing molecular devices for use as practical components requires an intimate knowledge of the system energy levels and operative transport mechanisms, and how key variables such as molecule length, identity, temperature, etc., affect device performance parameters. Especially interesting in this context is the relationship between organic electronic devices, which typically have active layer thicknesses of tens to hundreds of nanometers, and molecular electronic devices reported to date, in which at least one dimension for charge propagation is below 10 nm. Indeed, many types of functional organic electronic devices have been demonstrated, including thinfilm transistors, organic light-emitting diodes, and memory cells (1, 2). Bridging the gap between organic and molecular devices may therefore reveal pathways for improving the performance of such devices, or even lead to new types of devices based on alternative transport mechanisms.The great majority of molecular electronic devices investigated to date have transport distances of <5 nm between the contacts, where the prevalent transport mechanism is quantum-mechanical tunneling. For this distance range, there is general agreement that the conductance scales exponentially with length, with an attenuation coefficient (β), defined as the slope of ln J vs. thickness (d), equal to 8 to 9 nm −1 for aliphatic molecules (3-6) and 2-3 nm −1 for aromatic molecules (7)(8)(9)(10)(11)(12)(13)(14). A few molecular electronic systems have been investigated beyond 5 nm (15, 16), some of which exhibit a decrease in β to less than 1 nm −1 . Such small values of β ar...

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“…This family of bithiophenes could allow simple access to electronic devices or materials. [30] The C4-arylation of thiopheness ubstituted in the 3-position was also investigated. 3-Chlorothiophene reactedp oorly with 4-nitrobenzenesulfonyl chloridet og ive the arylated product 40 in al ow yield of 35 %.…”

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confidence: 99%

Eco‐Friendly Solvents for Palladium‐Catalyzed Desulfitative CH Bond Arylation of Heteroarenes

et al. 2015

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Herein, we report the Pd-catalyzed regioselective direct arylation of heteroarenes in which benzenesulfonyl chlorides are used as coupling partners through a desulfitative cross-coupling that can be performed in diethyl carbonate (DEC) or cyclopentyl methyl ether (CPME) as green and renewable solvents or even in neat conditions instead of dioxane or dimethylacetamide (DMA). Under these solvent conditions, the reaction proceeds with a wide range of heteroarenes. C2- or C5-arylated products were obtained with furan and pyrrole derivatives. Benzofuran was also arylated regioselectively at the C2-position, whereas the reaction proceeds selectively at the C3- or C4-positions if thiophenes and benzothiophenes are used. Moreover, in some cases, especially with 1-methylindole, solvent-free conditions afforded better regioselectivities and/or yields than the reaction performed in the presence of solvents.

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Tunable Electrochemical Switches Based on Ultrathin Organic Films

Cited by 75 publications

References 16 publications

Shape‐Switchable Azo‐Macrocycles

Shape‐Switchable Azo‐Macrocycles

Activationless charge transport across 4.5 to 22 nm in molecular electronic junctions

Eco‐Friendly Solvents for Palladium‐Catalyzed Desulfitative CH Bond Arylation of Heteroarenes

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