Polarons and Charge Carrier Solvation on Conjugated Carbon Chains: A Comparative Ab Initio Study

Mayo, Michael L.; Gartstein, Yuri N.

doi:10.1021/jp102771m

Cited by 3 publications

(3 citation statements)

References 41 publications

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“…To quantify the extent of hole delocalization, we have calculated the Kohn–Sham lowest singly unoccupied molecular orbital (LSUMO), the orbital resulting from the splitting of the HOMO upon removal of an electron from the molecule. Since, in the gas phase, the B3LYP exchange and correlation (XC) functional overestimates delocalization, − we have tested four additional hybrid and long-range XC functionals. That is, besides B3LYP, we considered BHandHLYP, a hybrid functional with 50% exact Hartree–Fock (HF) exchange, HSE1PBE, a hybrid functional with short-range HF exchange and long-range DFT exchange, CAM-B3LYP, a long-range corrected hybrid functional with 19% exchange at short-range and 65% exchange at long-range, and LC-wPBE, a long-range corrected functional with exchange from 0% to100%.…”

Section: Methodsmentioning

confidence: 99%

How Do Disorder, Reorganization, and Localization Influence the Hole Mobility in Conjugated Copolymers?

et al. 2013

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In order to unravel the intricate interplay between disorder effects, molecular reorganization, and charge carrier localization, a comprehensive study was conducted on hole transport in a series of conjugated alternating phenanthrene indenofluorene copolymers. Each polymer in the series contained one further comonomer comprising monoamines, diamines, or amine-free structures, whose influence on the electronic, optical, and charge transport properties was studied. The series covered a wide range of highest occupied molecular orbital (HOMO) energies as determined by cyclovoltammetry. The mobility, inferred from time-of-flight (ToF) experiments as a function of temperature and electric field, was found to depend exponentially on the HOMO energy. Since possible origins for this effect include energetic disorder, polaronic effects, and wave function localization, the relevant parameters were determined using a range of methods. Disorder and molecular reorganization were established first by an analysis of absorption and emission measurements and second by an analysis of the ToF measurements. In addition, density functional theory calculations were carried out to determine how localized or delocalized holes on a polymer chain are and to compare calculated reorganization energies with those that have been inferred from optical spectra. In summary, we conclude that molecular reorganization has little effect on the hole mobility in this system while both disorder effects and hole localization in systems with low-lying HOMOs are predominant. In particular, as the energetic disorder is comparable for the copolymers, the absolute value of the hole mobility at room temperature is determined by the hole localization associated with the triarylamine moieties.

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Section: Methodsmentioning

confidence: 99%

How Do Disorder, Reorganization, and Localization Influence the Hole Mobility in Conjugated Copolymers?

et al. 2013

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“…Conjugated oligoynes or polyynes constitute a class of quasi-one-dimensional conjugated carbon chains and have been extensively investigated as versatile scaffoldings for functional carbon-rich materials, owing to their rich optoelectronic and electromagnetic properties and unique solid-state reactivities. − For instance, the nonlinear optical susceptibilities of oligoynes were found to increase exponentially with increasing number of acetylenic repeat units, , while topochemical polymerization of oligoynes tended to result in highly conjugated polymer networks ,− and ordered carbon-based nanomaterials. − Moreover, the “wire-like” sp carbon chains (spCCs) of conjugated oligoynes or polyynes are the substructures of an intriguing carbon allotrope−carbyne, , while debates over the nature of electronic delocalization in spCCs have galvanized both experimental and theoretical investigations. − In particular, synthetic endeavors aiming at extension and functionalization of conjugated oligoynes have been actively undertaken in recent years in order to realize suitable models for unraveling the mystical characteristics of carbyne and related polyyne materials. − …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Properties of Conjugated Oligoyne-Centered π-Extended Tetrathiafulvalene Analogues and Related Macromolecular Systems

Chen

Mahmud

Daniels³

et al. 2011

J. Org. Chem.

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Alkynyl-substituted phenyldithiafulvenes have been found to act as versatile building blocks for the construction of π-conjugated molecular rods, shape-persistent macrocycles (SPMs), and conducting polymers. Through Cu(I)-catalyzed alkynyl homocoupling, a series of linear-shaped π-extended tetrathiafulvalene analogues (exTTFs) carrying conjugated oligoynes (ranging from diyne to hexayne) as the central π-bridge were readily prepared. The solid-state properties and reactivities of diyne- and tetrayne-centered exTTFs were characterized by X-ray crystallography and differential scanning calorimetry (DSC), while the electronic properties of the oligoyne-exTTFs were elucidated by UV-vis absorption spectroscopy and density functional theory (DFT) calculations. Cyclic voltammetric analysis showed that the terminal phenyldithiafulvene groups of the oligyne-exTTFs could undergo oxidative coupling to form tetrathiafulvalene vinylogue (TTFV)-linked polymer wires. Through a different synthetic route involving oxidative dimerization and Pd/Cu-catalyzed alkynyl homocoupling, the acetylenic phenyldithiafulvene precursors led to shape-persistent macrocycles where the formation of trimeric macrocycles was particularly favored due to the small ring strain incurred. Finally, spectroelectrochemical studies on these oligoyne and TTF hybrid materials disclosed electrochromic and molecular redox-controlled switching properties applicable to molecular electronic and optoelectronic devices.

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“…‡ 27 Since then the transport properties of these molecular wires in contact by various means with metallic (and more recently graphenic) electrodes have received increased attention, and several key aspects have been addressed. [28][29][30][31][32][33][34][35][36] However information is very scattered and a well-rounded perspective of the key aspects affecting electron transport in these systems is missing.…”

Section: Introductionmentioning

confidence: 99%

Electron transport in carbon wires in contact with Ag electrodes: a detailed first principles investigation

Bonardi

Achilli

Tantardini

et al. 2015

Phys. Chem. Chem. Phys.

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The structure and electronic properties of carbon atom chains Cn in contact with Ag electrodes are investigated in detail with first principles means. The ideal Ag(100) surface is used as a model for binding, and electron transport through the chains is studied as a function of their length, applied bias voltage, presence of capping atoms (Si, S) and adsorption site. It is found that the metal-molecule bond largely influences electronic coupling to the leads. Without capping atoms the quality of the electric contact improves when increasing the carbon atom coordination number to the metal (1, 2 and 4 for adsorption on a top, bridge and hollow position, respectively) and this finding translates almost unchanged in more realistic tip-like contacts which present one, two or four metal atoms at the contact. Current-voltage characteristics show Ohmic behaviour over a wide range of bias voltages and the resulting conductances change only weakly when increasing the wire length. The effect of a capping species is typically drastic, and either largely reduces (S) or largely increases (Si) the coupling of the wire to the electrodes. Comparison of our findings with recent experimental results highlights the limits of the adopted approach, which can be traced back to the known gap problem of density-functional-theory.

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Polarons and Charge Carrier Solvation on Conjugated Carbon Chains: A Comparative Ab Initio Study

Abstract: We study accommodation of an excess charge carrier on long even-N polyynic oligomers

Cited by 3 publications

References 41 publications

How Do Disorder, Reorganization, and Localization Influence the Hole Mobility in Conjugated Copolymers?

How Do Disorder, Reorganization, and Localization Influence the Hole Mobility in Conjugated Copolymers?

Synthesis and Properties of Conjugated Oligoyne-Centered π-Extended Tetrathiafulvalene Analogues and Related Macromolecular Systems

Electron transport in carbon wires in contact with Ag electrodes: a detailed first principles investigation

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