Semi-metallic polymers

Bubnova, Olga; Khan, Zia Ullah; Wang, Hui; Braun, Slawomir; Evans, Drew; Fabretto, Manrico; Hojati-Talemi, Pejman; Dagnelund, Daniel; Arlin, Jean-Baptiste; Geerts, Yves; Desbief, Simon; Breiby, Dag W.; Andreasen, Jens Wenzel; Lazzaroni, Roberto; Chen, Weimin; Zozoulenko, Igor; Fahlman, Mats; Murphy, Peter; Berggren, Magnus; Crispin, Xavier

doi:10.1038/nmat3824

Cited by 750 publications

(860 citation statements)

References 49 publications

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“…For both materials the temperature-dependent electrical resistivity together with the thermopower and the thermal conductivity is displayed in Figure 3a-c in a temperature regime between 20 K and 300 K. The TTT2I3 p-type conductivity of RT = 2.1 ⋅ 10 5 S m ⁄ at RT is among the highest 6 reported for organic solids exceeding values obtained in the organic polymer PEDOT:Tos [5] . With RT = 10 5 S/m the conductivity of DCNQI2Cu also achieves an extraordinary high value for an ntype organic conductor.…”

Section: Low-cost and Sustainable Organic Thermoelectrics Based On Lomentioning

confidence: 91%

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Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

et al. 2017

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 1 DOI: 10.1002/((please add manuscript number)) Article type: Communication Low-Cost and Sustainable Organic Thermoelectrics Based on LowDimensional Molecular MetalsBy Florian Huewe*, Alexander Steeger*, Kalina Kostova, Laurence Burroughs, Irene Bauer, Peter Strohriegl, Vladimir Dimitrov, Simon Woodward and Jens Pflaum* F. Huewe [ †] , A. Steeger [ †] The dimensionless figure of merit measures a material's thermoelectric performancewhere electrical conductivity (resistivity ), Seebeck coefficient/thermopower , and thermal conductivity provide the power factor = 2 . Materials with high electrical conductivity and thermopower but low thermal conductivity are desirable to maximize and hence, the thermoelectric conversion efficiency. Approximately, is inversely proportional to which in turn is related to the electronic thermal conductivity el = via the Wiedemann-Franz (WF) law.Advances in have been achieved by tuning the doping of semiconductors to maximize the [6] together with reducing the phononic contribution to thermal conduction by means of nanostructured superlattice architectures [7,8] . To overcome the inherent limitations of ordinary materials, a dimensionality reduction of the electronic system has been proposed [9] . This can lead to a violation of the WF law [10,11] and to phonon drag contributions to the thermopower [12] . Complex crystal structures, e.g. Zintl compounds [13] and skutterudites [14] , have been evaluated as good thermoelectric 3 candidates due to reduced lattice thermal conductivity and electronic band structure tunability. These optimization strategies, together with the ability for low-cost production and low-temperature processibility, have recently raised interest in organic polymers [15] , such as PEDOT:Tos, reaching = 0.25 at room temperature (RT) [4] and thus advancing the value of = 1.2 obtained for Bi2Te3 (the best RT thermoelectric material to date [7] ). Herein, quasi-1D organic conductors based on small molecules constitute a new, sustainable approach towards organic thermoelectrics that provide many of the desired electrical and thermal properties described above. Additionally, they are lightweight and thermodynamically stable allowing for portable device manufacturing and long-term usage. In comparison to organic polymers the availability of electrically high-performing p-and ntype organic conductors facilitates the construction of all-organic thermoelectric devices.As a starting point we chose two of the best p-and n-type conducting radical ion salts, TTT2I3 (TTT = Tetrathiotetracene) and (DMe-DCNQI)2Cu (DMe-DCNQI = Dimethyl-Dicyanoquinonediimine).They form macroscopic needle-like sin...

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Section: Low-cost and Sustainable Organic Thermoelectrics Based On Lomentioning

confidence: 91%

“…been proposed as potential candidates to meet these challenges showing appreciable low-temperature thermoelectric performance, but unfortunately suffering from low electrical conductivity due to inherent disorder [2][3][4][5] . Herein …”

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Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

et al. 2017

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“…[ 12,13 ] Interestingly, the thermal conductivity of bulk polymers as well as conjugated macromolecules can be tuned by controlling molecular orientation. [14][15][16] In order to increase the modest electrical conductivity of polymers, a number of strategies have been proposed, including careful doping, [ 4,11,[17][18][19][20][21] making composites of polymers with conductive fi llers such as CNTs, [22][23][24] or fabricating multilayer composite A broad range of organic electronic applications rely on the availability of both p-and n-type organic semiconductors, and the possibility to deposit them as sequential layers or to form spatial patterns. Examples include transport layers in diodes (OLEDs, photovoltaics, etc.…”

Section: Doi: 101002/adma201505521mentioning

confidence: 99%

Photoinduced p‐ to n‐type Switching in Thermoelectric Polymer‐Carbon Nanotube Composites

et al. 2016

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“…However, such PSS-based processes also experience difficulties with performance optimization. For example, the insulating PSS lamellas remain in the polymer matrix, 20,21 resulting in an amorphous polymer 22 with limited σ and S. 5,9 Compared to PEDOT:PSS, PEDOT doped with smallsized anions (S-PEDOTs), such as tosylate (OTs) or triflate (OTf), have greater potential for electrical applications because of their compact and ordered polycrystalline structure 23 that leads to higher σ and S. 22,[24][25][26] S-PEDOTs often exhibit large S 2 σ that can be further optimized by tuning the oxidation level. [27][28][29] However, these high quality films are hard to obtain due to their poor reaction controllability and difficult to put into practical use because of their limited film thickness.…”

Section: Introductionmentioning

confidence: 99%

“…30 However, the unequal evaporation of pyridine leads to uneven polymerization and a severe deterioration of σ when fabricating thicker films. 31 In addition to pyridine, copolymer inhibitors, such as poly(ethylene glycol)-blockpoly(propylene glycol)-block-poly(ethylene glycol) (PEPG), are also commonly used to reduce the oxidant reactivity through steric effects and suppress the crystallization of oxidants, 22,[26][27][28][32][33][34][35] but the copolymer phase remaining inside PEDOT causes the deterioration of σ. 33 For both applications as TE devices and electrode materials, PEDOT films with a reasonable thickness are required.…”

Section: Introductionmentioning

confidence: 99%

Micron-thick highly conductive PEDOT films synthesized via self-inhibited polymerization: roles of anions

Shi

Qin

et al. 2017

NPG Asia Mater

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The inhibitor-dependent poly(3,4-ethylenedioxythiophene) (PEDOT) fabrication suffers major problems in the areas of controllability and film thickness. In this work, we found that anions play a key role in both the polymerization and the structure of PEDOT. As a precursor, anions greatly influence the reaction rate and oxidant solubility. In its role as a counter-ion, the anions also affect chain conductance and crystal growth. With these behaviors in mind, a self-inhibited polymerization approach using novel oxidants with appropriate anions was successfully developed to facilitate the fabrication of high quality in situ polymerized PEDOT films and solve the thickness limitation problem. Inhibitor-free heavy oxidative solutions with weakly basic anions enable the spin-coating of thick and homogeneous oxidant layers and also effectively inhibit both the crystallization of the oxidant and H + formation throughout the polymerization process. PEDOT: dodecylbenzenesulfonate (PEDOT:DBSA) exhibits the highest performance among all candidates due to its appropriate anion basicity and low steric effect. An extremely high doping level of 42.9% is achieved, and an electrical conductivity of~1100 S cm − 1 is successfully maintained for film thicknesses between 310 nm and 1.79 μm. In addition, the thermoelectric power factor (RT) for pristine films was improved to 77.2 μW mK − 2 from 69.6 μW mK − 2 by the dedoping treatment. This study provides a new approach for fabricating high performance PEDOT thick films using anion-based design. NPG Asia Materials (2017) 9, e405; doi:10.1038/am.2017.107; published online 14 July 2017 INTRODUCTION Thermoelectric (TE) materials realize direct conversion between heat and electricity, which can be used in refrigeration and power generation. The performance of TE materials is characterized by the ZT value (S 2 σT/κ) or power factor (S 2 σ), where S, σ, T and κ are the Seebeck coefficient, electrical conductivity, absolute temperature and thermal conductivity, respectively. Conducting polymer TE materials possess the advantages of low κ, good flexibility and low cost in comparison with inorganic materials. 1-4 Among them, commercially available PEDOT:polystyrenesulfonate (PEDOT:PSS) has received the most attention due to its excellent water processability and high σ ( refs 5-11 ) and is also widely used as an electrode or conductive adhesive material in applications including solar cells, 12,13 organic light-emitting diodes (OLEDs), 14,15 supercapacitors, 16,17 sensors 18,19 and so on. The PSS polyanion enables the formation of aqueous PEDOT:PSS solutions, which benefits both film printing and the synthesis of hybrid materials. However, such PSS-based processes also experience difficulties with performance optimization. For example, the insulating PSS lamellas remain in the polymer matrix, 20,21 resulting in an amorphous polymer 22 with limited σ and S. 5,9 Compared to PEDOT:PSS, PEDOT doped with smallsized anions (S-PEDOTs), such as tosylate (OTs) or triflate (OTf), have greater potential...

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Semi-metallic polymers

Cited by 750 publications

References 49 publications

Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

Low‐Cost and Sustainable Organic Thermoelectrics Based on Low‐Dimensional Molecular Metals

Photoinduced p‐ to n‐type Switching in Thermoelectric Polymer‐Carbon Nanotube Composites

Micron-thick highly conductive PEDOT films synthesized via self-inhibited polymerization: roles of anions

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