Synthesis of Polyphenylene Molecular Wires by Surface‐Confined Polymerization

Lipton‐Duffin, Josh; Ivasenko, Oleksandr; Perepichka, Dmitrii F.; Rosei, Federico

doi:10.1002/smll.200801943

Cited by 320 publications

(368 citation statements)

References 43 publications

(24 reference statements)

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“…Dosing DIEDOT on a Cu(110) surface held at 200°C produces a sparse array of lines oriented along the [1][2][3][4][5][6][7][8][9][10] direction of the Cu lattice, separated by the Cuð110Þ-ð1 × 1Þ lattice, as shown in the STM micrograph displayed in Fig. 1A.…”

Section: Resultsmentioning

confidence: 99%

Step-by-step growth of epitaxially aligned polythiophene by surface-confined reaction

Lipton‐Duffin

Miwa

Kondratenko

et al. 2010

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

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116

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One of the great challenges in surface chemistry is to assemble aromatic building blocks into ordered structures that are mechanically robust and electronically interlinked-i.e., are held together by covalent bonds. We demonstrate the surface-confined growth of ordered arrays of poly(3,4-ethylenedioxythiophene) (PEDOT) chains, by using the substrate (the 110 facet of copper) simultaneously as template and catalyst for polymerization. Copper acts as promoter for the Ullmann coupling reaction, whereas the inherent anisotropy of the fcc 110 facet confines growth to a single dimension. High resolution scanning tunneling microscopy performed under ultrahigh vacuum conditions allows us to simultaneously image PEDOT oligomers and the copper lattice with atomic resolution. Density functional theory calculations confirm an unexpected adsorption geometry of the PEDOToligomers, which stand on the sulfur atom of the thiophene ring rather than lying flat. This polymerization approach can be extended to many other halogen-terminated molecules to produce epitaxially aligned conjugated polymers. Such systems might be of central importance to develop future electronic and optoelectronic devices with high quality active materials, besides representing model systems for basic science investigations.metal-catalyzed coupling reaction | molecular wires | cis-polythiophene | scanning probe microscopy | polymerization mechanism T he tunability and diversity of the structural and electronic properties of π-conjugated organic polymers have spurred a wide interest in these materials as wires and semiconductors for future electronic devices (1, 2), although significant optimization is required for real breakthrough performance. Conventional organic synthesis can create conjugated polymers of practically any length and structure (3), yet their controlled positioning and ordering on a surface remains nontrivial. This supramolecular ordering ultimately controls properties such as the charge mobility and recombination, which are critical for any application, including nanoelectronics and light harvesting. The approach presented here proposes a way to precisely control the long-range order in conducting polymers by performing synthesis of these materials, in an epitaxial way, directly on crystalline substrates. Although electrochemical polymerization on conducting surfaces has long been used to prepare films of conjugated polymers such as polythiophene (4), the techniques for preparation and characterization of aligned arrays of polymers have only recently been developed. Promising results were obtained by using UV irradiation (5) or scanning probe microscope tip pulsing (6) to form polydiacetylenes and surface-catalyzed coupling to form polyphenylene (7). However, these polymers are not good conductors due to a very large bond length alternation in their conjugated acetylene structures. (8). Conductive ordered polythiophene wires have been prepared by pulsed electrooxidative polymerization of substituted thiophenes (9, 10). The symmetry of the...

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Section: Resultsmentioning

confidence: 99%

Step-by-step growth of epitaxially aligned polythiophene by surface-confined reaction

Lipton‐Duffin

Miwa

Kondratenko

et al. 2010

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

Self Cite

116

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“…15,[36][37][38] This leads in general to a second reaction step, the intermolecular Ullmann carbon-carbon coupling. 15,16,22,36,[39][40][41][42][43][44][45] Here, our initial aim was to utilize an on-surface chemical reaction to produce covalently bonded linear polymers. In order to characterize the structure of the unreacted monomer units, the I 2 TMTP molecule was deposited onto an Au(111) sample held at a temperature of approximately 30K with the C-I bond expected to remain intact upon molecular adsorption, due to the low temperature.…”

Section: Resultsmentioning

confidence: 99%

Manipulating the Conformation of Single Organometallic Chains on Au(111)

et al. 2013

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The conformations of organometallic polymers formed via the bottom-up assembly of monomer units on a metal surface are investigated, and the relationship between the adsorption geometry of the individual monomer units, the conformational structure of the chain, and the overall shape of the polymer is explored. Iodine-functionalized monomer units deposited onto a Au (111) substrate are found to form linear chain structures, where each monomer is linked to its neighbors via an Au adatom. Lateral manipulation of the linear chains using a scanning tunneling microscope allows the structure of the chain to be converted from a linear geometry to a curved one, and it is shown that a transformation of the overall shape of the chain is coupled to a conformational re-arrangement of the chain structure as well as a change in the adsorption geometry of the monomer units within the chain. The observed conformational structure of the curved chain is well ordered and distinct from that of the linear chains. The structures of both the linear and curved chains are investigated by a combination of scanning tunneling microscopy measurements and theoretical calculations.

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“…According to this method an appropriate polyphenylene precursor, e.g. produced by Ullmann coupling, undergo cyclodehydrogenation on a Cu surface to form a polycyclic aromatic hydrocarbon (PAH) [47][48][49][50] , that in our case should include the dopant atom. When appropriately functionalized the PAHs can then polymerize on the metal surface to form graphene domains up to a nanometer scale as recently shown for the synthesis of the atomically precise nanoribbons 20 .…”

Section: Supporting Informationmentioning

confidence: 99%

Band Engineering in Graphene with Superlattices of Substitutional Defects

2011

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We investigate graphene superlattices of nitrogen and boron substitutional defects and by using symmetry arguments and electronic structure calculations we show how such superlattices can be used to modify graphene band structure. Specifically, depending on the superlattice symmetry, the structures considered here can either preserve the Dirac cones (D 6h superlattices) or open a band gap (D 3h ). Relevant band parameters (carriers effective masses, group velocities and gaps, when present) are found to depend on the superlattice constant n as 1/n p where p is in the range 1 − 2, depending on the case considered. Overall, the results presented here show how one can tune the graphene band structure to a great extent by modifying few superlattice parameters.

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Synthesis of Polyphenylene Molecular Wires by Surface‐Confined Polymerization

Cited by 320 publications

References 43 publications

Step-by-step growth of epitaxially aligned polythiophene by surface-confined reaction

Step-by-step growth of epitaxially aligned polythiophene by surface-confined reaction

Manipulating the Conformation of Single Organometallic Chains on Au(111)

Band Engineering in Graphene with Superlattices of Substitutional Defects

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