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Journal ArticleDOI: 10.1021/ACSAMI.1C01059

Synergistically Boosting Thermoelectric Performance of PEDOT:PSS/SWCNT Composites via the Ion-Exchange Effect and Promoting SWCNT Dispersion by the Ionic Liquid.

05 Mar 2021-ACS Applied Materials & Interfaces (American Chemical Society)-Vol. 13, Iss: 10, pp 12131-12140
Abstract: Poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is perhaps the most successful polymer material for thermoelectric (TE) applications. So far, treatments by high-boiling solvents, acid or base, or mixing with the carbon nanotube (CNT) are the main ways to improve its TE performance. Herein, we report the synergistically boosting TE properties of PEDOT:PSS/single-walled CNT (SWCNT) composites by the ionic liquid (IL). The composites are prepared by physically mixing the SWCNT dispersion containing the IL with PEDOT:PSS solution and subsequent vacuum filtration. The IL additive has two major functions, that is, inducing the phase separation of PEDOT:PSS and a linear quinoid conformation of PEDOT and promoting the SWCNT dispersion. The maximum power factor at room temperature reaches 182.7 ± 9.2 μW m-1 K-2 (the corresponding electrical conductivity and Seebeck coefficient are 1602.6 ± 103.0 S cm-1 and 33.4 ± 0.4 μV K-1, respectively) for the free-standing flexible film of the PEDOT:PSS/SWCNT composites with the IL, which is much higher than those of the pristine PEDOT:PSS, the IL-free PEDOT:PSS/SWCNT, and the SWCNT films. The high TE performance of composites can be ascribed to synergistic roles of the ion-exchange effect and promotion of SWCNT dispersion by the IL. This work demonstrates the dual roles for the IL in regulating each component of the PEDOT:PSS/SWCNT composite that synergistically boosts the TE performance.

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13 results found

Journal ArticleDOI: 10.1016/J.COCO.2021.100869
Xiaoyin Cao1, Mao Zhang1, Yan Yang1, Hua Deng1  +1 moreInstitutions (1)
Abstract: PEDOT:PSS has been a major area of interest in the field of thermoelectrics in recent years. Extensive research has shown that doping or various post-washing treatment can effectively improve the conductivity . This article proposes PEDOT:PSS sheet as the building block to fabricate functional polymer composites based on PEDOT:PSS, thus, expand the contact area between PEDOT:PSS and secondary treatment agent to improve the efficiency of doping or post-treatment. On this basis, single wall carbon nanotubes (SWCNT) was added to optimize the comprehensive thermoelectric performance of the composites. With a rather low SWCNT content of 30 wt%, PEDOT:PSS sheet/SWCNT composite film with layered structure achieves conductivity of 3085.4 S cm −1 and PF value of 224 μW m−1 K−2. The preparation of such sheet PEDOT:PSS provides a new possibility for the preparation of functional polymer composites.

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Topics: PEDOT:PSS (66%)

6 Citations

Journal ArticleDOI: 10.1016/J.COMPSCITECH.2021.108797
Hui Li1, Yuan Liang1, Yalong Liu1, Siqi Liu2  +3 moreInstitutions (3)
Abstract: Thermoelectric (TE) properties of pure polyaniline (PANI) have been extensively investigated and significant progress has been achieved with proper modulation of doping level, there is however few reports to illustrate the crucial role of doping level in modulating the microstructure and optimizing the TE performance of carbon nanotubes (CNTs)/PANI composites. Herein, a series of CNTs/PANI composites with varied CNTs loadings are doped with various amount of camphorsulfonic acid to control doping level of PANI. As the doping level decreases, PANI chains are transformed from extended coil with delocaliztion polarons to compact with polarons localized. All the CNTs/PANI composites exhibit increased Seebeck coefficient, while show less deteriorated conductivity compared with pure PANI film. With high CNTs loading more than 69 wt%, greatly enhanced power factor of 321 ± 24 μW m−1 K−2 could be achieved at low doping level, ascribing to not only strong π-π interaction and doping effect of CNTs which promote PANI chains ordered stacking, but also intrinsic conductive CNTs network which provides extra pathways to facilitate carrier transport. This work demonstrates the effective strategy of precise tuning doping level to improve TE properties of CNTs/PANI composites.

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Topics: Polyaniline (50%), Doping (50%)

3 Citations

Journal ArticleDOI: 10.1016/J.COCO.2021.100822
Xinyang He1, Jia Shi1, Yunna Hao1, Liming Wang1  +2 moreInstitutions (1)
Abstract: Conducting polymer/carbon nanotube (CNT) based thermoelectric (TE) composites, such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/CNT composites, have demonstrated great potential in wearable electronics. However, the lack of stretchability for currently reported PEDOT:PSS/CNT composites hinders their practical applications. In this work, PEDOT:PSS/CNT composites based ultra-stretchable TE films were fabricated by filtrating PEDOT:PSS/CNT onto electrospun nanofiber substrate, in which polyurethane (PU) nanofiber film acted as elastic skeleton and polycaprolactone (PCL) nanofibers were used as binders between PEDOT:PSS/CNT composites and PU nanofiber substrate. The optimal electrical conductivity and Seebeck coefficient of the composite films can reach 1581 S m −1 and 35 μV K−1 at room temperature, respectively. More importantly, the fabricated PEDOT:PSS/CNT composite films exhibit superior stretchability with an extremely high fracture strain of more than 400%. In addition, PEDOT:PSS/CNT composites based strain sensors are successfully designed for detecting human motions. Our fabrication strategy promotes the design and fabrication of stretchable TE composites.

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Topics: PEDOT:PSS (62%), Conductive polymer (53%)

2 Citations

Journal ArticleDOI: 10.1039/D1TA04698E
Jiaqian Zhou1, Peng Peng1, Zhao Li2, Lirong Liang3  +4 moreInstitutions (3)
Abstract: Organic polymer thermoelectrics (TEs) that can realize direct heat-to-electricity conversion hold great potential in flexible and wearable applications and thus are receiving tremendous attention. Constructing polymer-based nanocomposites represents an effective approach in achieving high TE performance, while current studies on the underlying mechanisms for the improvement of TE properties in aspects of interfacial nanostructures are insufficient. In this work, flexible ternary nanocomposite films with unique interfacial architectures are developed by sequential electrochemical polymerization of conducting polymers and subsequent anion treatment. The optimized interfacial architectures contribute to enhanced π electron conjugation, which facilitates interfacial charge transfer and favours large-area charge transport. The anion treatment further enables the molecular chains to arrange in a more ordered configuration, leading to improved carrier mobility. As a result, the nanocomposites exhibit high power factors of more than 500 μW m−1 K−2 that outperform most of the literature-reported peer composites. The feasible interfacial architecting and anion treatment methods proposed in this study demonstrate high potential in designing high-performance TE nanocomposites.

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Topics: Polymer nanocomposite (52%)

2 Citations


52 results found

Journal ArticleDOI: 10.1126/SCIENCE.1082289
27 Jun 2003-Science
Abstract: When mixed with imidazolium ion-based room-temperature ionic liquid, pristine single-walled carbon nanotubes formed gels after being ground. The heavily entangled nanotube bundles were found to untangle within the gel to form much finer bundles. Phase transition and rheological properties suggest that the gels are formed by physical cross-linking of the nanotube bundles, mediated by local molecular ordering of the ionic liquids rather than by entanglement of the nanotubes. The gels were thermally stable and did not shrivel, even under reduced pressure resulting from the nonvolatility of the ionic liquids, but they would readily undergo a gel-to-solid transition on absorbent materials. The use of a polymerizable ionic liquid as the gelling medium allows for the fabrication of a highly electroconductive polymer/nanotube composite material, which showed a substantial enhancement in dynamic hardness.

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Topics: Ionic liquid (60%), Nanotube (59%), Carbon nanotube (58%) ... show more

1,186 Citations

Journal ArticleDOI: 10.1038/NMAT3635
Gun-Ho Kim1, Lei Shao1, Kejia Zhang1, Kevin P. Pipe1Institutions (1)
01 Aug 2013-Nature Materials
Abstract: The conversion efficiency of heat to electricity in thermoelectric materials depends on both their thermopower and electrical conductivity. It is now reported that, unlike their inorganic counterparts, organic thermoelectric materials show an improvement in both these parameters when the volume of dopant elements is minimized; furthermore, a high conversion efficiency is achieved in PEDOT:PSS blends.

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Topics: Thermoelectric materials (64%), Seebeck coefficient (57%), Energy conversion efficiency (55%) ... show more

1,163 Citations

Journal ArticleDOI: 10.1016/J.POLYMER.2004.10.001
Jianyong Ouyang1, Qianfei Xu1, Chi-Wei Chu1, Yang Yang1  +2 moreInstitutions (2)
01 Nov 2004-Polymer
Abstract: The conductivity of a poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) film is enhanced by more than 100-folds on adding some organic compounds into PEDOT:PSS aqueous solutions or by treating the PEDOT:PSS film with organic solvents, such as ethylene glycol (EG), 2-nitroethanol, methyl sulfoxide or 1-methyl-2-pyrrolidinone. The mechanism for this conductivity enhancement was studied through various chemical and physical characterizations. The PEDOT:PSS film which is soluble in water becomes insoluble after treatment with EG. This strongly suggests an increased interchain interaction among the PEDOT chains. Raman spectroscopy indicates that this increased interchain interaction results from conformational changes of the PEDOT chains, which change from a coil to linear or expanded-coil structure. The increased interchain interaction and conformation changes are further confirmed by the temperature dependence of conductivity and the electron spin resonance (ESR). It is found that EG treatment lowers the energy barrier for charge hopping among the PEDOT chains, lowers the polaron concentration in the PEDOT:PSS film by ∼50%, and increases the electrochemical activity of the PEDOT:PSS film in NaCl aqueous solution by ∼100%. Atomic force microscopy (AFM) and contact angle measurements show that the surface morphology of the PEDOT:PSS film changes as well after the EG treatment. Conductivity enhancement was also observed when other organic compounds were used, but it was strongly dependent on the chemical structure of the organic compounds, and observed only with organic compound with two or more polar groups. These experimental results support our proposal that the conductivity enhancement is due to the conformational change of the PEDOT chains and the driving force is the interaction between the dipoles of the organic compound and dipoles or charges on the PEDOT chains.

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1,066 Citations

Journal ArticleDOI: 10.1002/ADMA.201104795
Yijie Xia1, Kuan Sun1, Jianyong Ouyang1Institutions (1)
08 May 2012-Advanced Materials
Abstract: The conductivity of PEDOT:PSS films was significantly enhanced from 0.3 S cm(-1) to 3065 S cm(-1) through a treatment with dilute sulfuric acids. PEDOT:PSS films with a sheet resistance of 39 Ω sq(-1) and transparency of around 80% at 550 nm are obtained. These PEDOT:PSS films with conductivity and transparency comparable to ITO can replace ITO as the transparent electrode of optoelectronic devices.

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Topics: PEDOT:PSS (64%), Conductive polymer (54%), Sheet resistance (51%)

814 Citations

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