Charge transport and structure in semimetallic polymers

Rudd, Sam; Franco-González, Juan Felipe; Singh, Sandeep Kumar; Khan, Zia Ullah; Crispin, Xavier; Andreasen, Jens Wenzel; Zozoulenko, Igor; Evans, Drew

doi:10.1002/polb.24530

Cited by 63 publications

(82 citation statements)

References 49 publications

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“…The different PEDOT:Tos morphologies studied in this work were generated by molecular dynamics simulations (MD) following the methodology developed in previous works [42][43][44]. The initial systems are mixtures of positively charged PEDOT oligomers, Tosylate anions and water molecules; the system has a neutral charge when the total positive charge carried by the PEDOT oligomers exactly compensate the Tosylate anionic charge.…”

Section: A From Morphology To Resistive Networkmentioning

confidence: 99%

Understanding morphology-mobility dependence in PEDOT:Tos

Rolland

Franco-González

Volpi

et al. 2018

Phys. Rev. Materials

105

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The potential of conjugated polymers to compete with inorganic materials in the field of semiconductor is conditional on fine-tuning of the charge carriers mobility. The latter is closely related to the material morphology, and various studies have shown that the bottleneck for charge transport is the connectivity between well-ordered crystallites, with a high degree of π -π stacking, dispersed into a disordered matrix. However, at this time there is a lack of theoretical descriptions accounting for this link between morphology and mobility, hindering the development of systematic material designs. Here we propose a computational model to predict charge carriers mobility in conducting polymer PEDOT depending on the physicochemical properties of the system. We start by calculating the morphology using molecular dynamics simulations. Based on the calculated morphology we perform quantum mechanical calculation of the transfer integrals between states in polymer chains and calculate corresponding hopping rates using the Miller-Abrahams formalism. We then construct a transport resistive network, calculate the mobility using a mean-field approach, and analyze the calculated mobility in terms of transfer integrals distributions and percolation thresholds. Our results provide theoretical support for the recent study [Noriega et al., Nat. Mater. 12, 1038] explaining why the mobility in polymers rapidly increases as the chain length is increased and then saturates for sufficiently long chains. Our study also provides the answer to the long-standing question whether the enhancement of the crystallinity is the key to designing high-mobility polymers. We demonstrate, that it is the effective π -π stacking, not the long-range order that is essential for the material design for the enhanced electrical performance. This generic model can compare the mobility of a polymer thin film with different solvent contents, solvent additives, dopant species or polymer characteristics, providing a general framework to design new high mobility conjugated polymer materials.

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Section: A From Morphology To Resistive Networkmentioning

confidence: 99%

Understanding morphology-mobility dependence in PEDOT:Tos

Rolland

Franco-González

Volpi

et al. 2018

Phys. Rev. Materials

105

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“…[28][29][30] Recent All Atomistic (AA) Molecular Dynamics (MD) calculations for PEDOT doped with different molecular counterions (including Tos) reveal a complex morphology where small crystallites consisting of several p-p stacking PEDOT chains are embedded in a polymer matrix including PEDOT chains, Tos counterions and water molecules. 16,31 Because of computational limitations, AA MD simulations do not always allow one to reach a lengthscale needed to study the morphology of a realistic material. For example, a formation of PEDOT-rich and PSS-rich phases in PEDOT:PSS that happens on the scale of B20-30 nm 32 is beyond the reach of AA MD.…”

Section: Introductionmentioning

confidence: 99%

Morphology and ion diffusion in PEDOT:Tos. A coarse grained molecular dynamics simulation

Modarresi

Franco-González

Zozoulenko

2018

Phys. Chem. Chem. Phys.

Self Cite

126

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A Martini coarse-grained Molecular Dynamics (MD) model for the doped conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is developed. The morphology of PEDOT:Tos (i.e. PEDOT doped with molecular tosylate) and its crystallization in aqueous solution for different oxidation levels were calculated using the developed method and compared with corresponding all atomistic MD simulations. The diffusion coefficients of Na+ and Cl- ions in PEDOT:Tos are studied using the developed coarse-grained MD approach. It is shown that the diffusion coefficients decrease exponentially as the hydration level is reduced. It is also predicted that the diffusion coefficients decrease when the doping level of PEDOT is increased. The observed behavior is related to the evolution of water clusters and trapping of ions around the polymer matrix as the hydration level changes. The predicted behavior of the ionic diffusion coefficients can be tested experimentally, and we believe that molecular picture of ionic diffusion in PEDOT unraveled in the present study is instrumental for the design of polymeric materials and devices for better and enhanced performance.

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“…We thus observe the same speed increase if the cells are in a CP environment in a redox state. Moreover, vapor‐phase polymerized PEDOT:TOS CP is known to have a bulk conductivity as high as 100–1000 S cm −1 . In our case, the bulk conductivity of the PEDOT:PSS microstripes is decreased by one order of magnitude after plasma oxygen processing.…”

Section: Resultsmentioning

confidence: 58%

Electrically controlled cellular migration on a periodically micropatterned PEDOT:PSS conducting polymer platform

ElMahmoudy

Curto

Ferro

et al. 2018

J of Applied Polymer Sci

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In the field of tissue engineering, the study of cellular adhesion and migration is of crucial interest. Conducting polymers such as poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) provide an outstanding interface with biology due to their soft nature, which is closer to the mechanical, chemical, and morphological properties of biological systems. In this work, periodically micropatterned PEDOT:PSS thin films are used as a platform to investigate cellular migration. Human cerebral microvascular endothelial cells (hCMEC) show alignment and linear motion along PEDOT:PSS microstripes of varying widths (10-30 μm). In addition, an electrochemical gradient is created on the PEDOT:PSS film along these microstripes to influence the cell behavior. hCMEC cells linearly change their velocities depending on the redox state of the conducting polymer film. This work demonstrates the potential of such conducting polymer platforms to combine, at the same time, several key physicochemical factors for controlling cellular migration. In the future, we envision that these conducting polymer platforms will deliver tools for tissue regeneration and lead to new opportunities in regenerative medicine.the soft nature of CPs is closer to the mechanical and morphological properties of the tissues, therefore developing less foreign interactions. This is in addition to the ability to tailor the chemical structure and to fit the electrical and mechanical properties of these polymers. 22 Another advantage of CPs is the mixed ionic and electronic conduction, which provides enhanced communication between cells and devices. [23][24][25] Wong et al. have shown that the shape and the growth of cells can be controlled noninvasively using CPs by applying an electrical bias and changing the redox state of the polymer film. 26 In their investigation, they used the polypyrrole CP and observed that aortic endothelial cells adhered and functioned differently on the reduced and the oxidized films. This study has paved the way for several others research groups focusing on the effect of the electrochemical state of conducing polymers on cell growth and stimulation. 27,28 Adjacent cells attach to each other or to a surface with the use of anchoring molecules (integrins, proteins, and actins). The surface chemistry thus affects the adsorption of these molecules and varies their spatial density. 29 Salto et al. have demonstrated the use of PEDOT doped with p-toluenesulfonate Additional Supporting Information may be found in the online version of this article.

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Charge transport and structure in semimetallic polymers

Cited by 63 publications

References 49 publications

Understanding morphology-mobility dependence in PEDOT:Tos

Understanding morphology-mobility dependence in PEDOT:Tos

Morphology and ion diffusion in PEDOT:Tos. A coarse grained molecular dynamics simulation

Electrically controlled cellular migration on a periodically micropatterned PEDOT:PSS conducting polymer platform

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