Effects of Cationic Species in Salts on the Electrical Conductivity of Doped PEDOT:PSS Films

Li, Xin; Liu, Zhen; Zhou, Zekun; Gao, Haiyang; Liang, Guodong; Rauber, Daniel; Kay, Christopher W. M.; Zhang, Peng

doi:10.1021/acsapm.0c01084

Cited by 47 publications

(58 citation statements)

References 43 publications

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“…At first sight, it appears that cations are not very important because most of them are removed with PSS after an ion-exchange reaction with PEDOT:PSS. It is true that the influence of IL cations has rarely been explored, leading us to question whether EMIM is indeed the optimal cation for this purpose. The rare exploration of cations has been limited to aromatic EMIM-derivatives. , In particular, Kee and co-workers probed the influence of IL A + :TCB – on the mechanical properties of a PEDOT:PSS film by varying cation A + .…”

Section: Resultsmentioning

confidence: 99%

“…In fact, the ion-exchange-based design principles developed for anions in our previous studies ,, is naturally extended to propose hydrophilic cations since ion exchange between PEDOT:PSS and A:X would be optimal if hydrophilic cations A + promptly unbind from (i.e., weakly bind to) hydrophobic anions X – and strongly bind to hydrophilic SO 3 – groups of PSS – or stay in water, while hydrophobic anions X – strongly bind to hydrophobic PEDOT + clusters. The most representative hydrophilic cations would be H + (as in acid treatment, e.g., with H 2 SO 4 ) , and Li + (as in salt treatment, e.g., with Li:TFSI) . Indeed, acid treatments with H 2 SO 4 solutions have produced crystalline PEDOT:PSS with the highest conductivity (>4000 S cm –1 ). , Also, a significant conductivity enhancement has been achieved by vigorously mixing PEDOT:PSS solutions with IL A + :TFSI – by varying the cation A + from P2EOE (8 S cm –1 ), PEOE (16 S cm –1 ), and EMIM (220 S cm –1 ) to Li + (418 S cm –1 ) which is the most efficient among the series because of improved crystalline order and p-doping level of PEDOT .…”

Section: Resultsmentioning

confidence: 99%

“…The most representative hydrophilic cations would be H + (as in acid treatment, e.g., with H 2 SO 4 ) , and Li + (as in salt treatment, e.g., with Li:TFSI) . Indeed, acid treatments with H 2 SO 4 solutions have produced crystalline PEDOT:PSS with the highest conductivity (>4000 S cm –1 ). , Also, a significant conductivity enhancement has been achieved by vigorously mixing PEDOT:PSS solutions with IL A + :TFSI – by varying the cation A + from P2EOE (8 S cm –1 ), PEOE (16 S cm –1 ), and EMIM (220 S cm –1 ) to Li + (418 S cm –1 ) which is the most efficient among the series because of improved crystalline order and p-doping level of PEDOT . Indeed, small cations with fast mobility such as Li + combine more easily with the PSS chain to favor the interaction of TFSI anions with PEDOT.…”

Section: Resultsmentioning

confidence: 99%

“…Such observations lead us to propose non-EMIM-based new ILs (or salts) for efficient PEDOT:PSS treatment, containing nonplanar (aliphatic) and hydrophilic (protic or alkaline metallic) cations (such as N -alkylpyrrolidinium or Li + ) coupled to hydrophobic anions (TCM or TCB). Indeed, a recent experiment has shown that salts of Li cation coupled to hydrophobic TFSI anion lead to better PEDOT:PSS conductivity than EMIM:TFSI …”

Section: Discussionmentioning

confidence: 99%

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Molecular Dynamics of PEDOT:PSS Treated with Ionic Liquids. Origin of Anion Dependence Leading to Cation Design Principles

et al. 2021

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Conductivity enhancement of PEDOT:PSS via the morphological change of PEDOT-rich domains has been achieved by introducing a 1-ethyl-3-methylimidazolium (EMIM)-based ionic liquid (IL) into its aqueous solution, and the degree of such change varies drastically with the anion coupled to the EMIM cation constituting the IL. We carry out a series of molecular dynamics simulations on various simple model systems for the extremely complex mixtures of PEDOT:PSS and EMIM:X IL in water, varying the anion X, the IL concentration, the oligomer model of PEDOT:PSS, and the size of the model systems. The common characteristic found in all simulations is that although planar hydrophobic anions X are the most efficient for ion exchange between PEDOT:PSS and EMIM:X, they tend to bring together planar EMIM cations to PEDOT-rich domains, disrupting PEDOT π-stacks with PEDOT–X–EMIM intercalating layers. Nonplanar hydrophobic anions, which leave most of EMIM cations in water, are efficient for both ion exchange and the formation of extended PEDOT π-stacks, as observed in experiments. Based on such findings, we propose a design principle for new cations replacing EMIM; nonplanar hydrophilic cations combined with hydrophobic anions should improve IL efficiency for PEDOT:PSS treatment.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Molecular Dynamics of PEDOT:PSS Treated with Ionic Liquids. Origin of Anion Dependence Leading to Cation Design Principles

et al. 2021

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“…Apart from a treatment with solvent, treating PEDOT:PSS with aqueous or organic solution of a common salt like ZnCl 2 , CuCl 2 , InCl 3 , or methyl ammonium iodide (MAI) can also significantly enhance its conductivity 37,42–46 . The conductivity enhancement depends on the cations and anions of the salts.…”

Section: Icps As Flexible Transparent Electrode Of Optoelectronic Devicesmentioning

confidence: 99%

Application of intrinsically conducting polymers in flexible electronics

Ouyang

2021

SmartMat

108

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Intrinsically conducting polymers (ICPs), such as polyacetylene, polyaniline, polypyrrole, polythiophene, and poly(3,4‐ethylenedioxythiophene) (PEDOT), can have important application in flexible electronics owing to their unique merits including high conductivity, high mechanical flexibility, low cost, and good biocompatibility. The requirements for their application in flexible electronics include high conductivity and appropriate mechanical properties. The conductivity of some ICPs can be enhanced through a postpolymerization treatment, the so‐called “secondary doping.” A conducting polymer film with high conductivity can be used as flexible electrode and even as flexible transparent electrode of optoelectronic devices. The application of ICPs as stretchable electrode requires high mechanical stretchability. The mechanical stretchability of ICPs can be improved through blending with a soft polymer or plasticization. Because of their good biocompatibility, ICPs can be modified as dry electrode for biopotential monitoring and neural interface. In addition, ICPs can be used as the active material of strain sensors for healthcare monitoring, and they can be adopted to monitor food processing, such as the fermentation, steaming, storage, and refreshing of starch‐based food because of the resistance variation caused by the food volume change. All these applications of ICPs are covered in this review article.

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Ion‐Conducting Non‐Flammable Liquid Crystal–Polymer Composites for High‐Frequency Soft Actuators

Liu

Cao

Yoshio

2023

Adv Funct Materials

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High‐frequency actuators are reported based on non‐flammable lithium‐ion conducting phosphate liquid crystal–polymer composite electrolytes, which exhibit a bending response at frequencies up to 80 Hz under an AC voltage of 2 V, owing to its high ionic conductivity reaching 10−4 S cm−1 at room temperature. An equimolar complex of a phosphate‐containing mesogenic molecule and lithium bis(trifluoromethylsulfonyl)imide through the ion‐dipole interactions induced a room‐temperature smectic A liquid‐crystalline (LC) phase forming 2D ion‐transport pathways comprising the 2D array of the phosphate moieties. A blend of 80 wt% LC electrolyte and 20 wt% polymers (poly(vinyl chloride) and poly(vinylidene fluoride‐co‐hexafluoropropylene)) formed a flexible, mechanically robust LC–polymer composite film. Scanning electron microscopy and white light interference microscopy revealed a microphase‐segregated structure consisting of a continuous LC phase and a porous polymer matrix. In addition, the continuity of porous structure across the film is confirmed by permeation experiments of solvents thorough the membrane with a homemade filter in a dead‐end filtration mode. The LC–polymer composite film sandwiched between two poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonic acid) electrodes is found to simultaneously exhibit high bending strain (0.63%) and high output force (0.35 mN), owing to the high ion migration into the composite electrolyte and electrode.

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Effects of Cationic Species in Salts on the Electrical Conductivity of Doped PEDOT:PSS Films

Cited by 47 publications

References 43 publications

Molecular Dynamics of PEDOT:PSS Treated with Ionic Liquids. Origin of Anion Dependence Leading to Cation Design Principles

Molecular Dynamics of PEDOT:PSS Treated with Ionic Liquids. Origin of Anion Dependence Leading to Cation Design Principles

Application of intrinsically conducting polymers in flexible electronics

Ion‐Conducting Non‐Flammable Liquid Crystal–Polymer Composites for High‐Frequency Soft Actuators

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