Synthesis and Thermoelectric Properties of Polycarbazole, Polyindolocarbazole, and Polydiindolocarbazole Derivatives
ABSTRACT In a quest for thermoelectric polymeric materials novel polycarbazole and polyindolocarbazole derivatives were synthesized. Alkyl side chains on the carbazole cycle and different side chains (alkyl or benzoyl) on the nitrogen atom of the backbone unit were introduced. Optical, electrochemical, electrical, and thermoelectric properties were investigated on these polymers and on two poly(diindolocarbazole)s. Band structure calculations were used to predict which polymers might be promising as thermoelectric materials. The best combination of Seebeck coefficient and conductivity (power factor) was around 10-7 W m-1 K-2 with copolymers comprising thiophene units alternating with carbazole or indolocarbazole. This family of polymers possesses good Seebeck coefficients, but there is still a need to improve the electrical conductivity, to produce useful thermoelectric materials.
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- "Different types of polymers have been used in thermoelectric devices, such as polyaniline (PANI)  , poly(p-phenylene vinylene) (PPV)  , polyacetylene (PA)  , poly(2,7-carbazolenevinylene)  , and poly(2,5-dimethoxy phenylenevinylene) (PMeOPV) . These polymers are chosen due to their conductive nature. "
ABSTRACT: Thermoelectricity, by converting heat energy directly into useable electricity, offers a promising technology to convert heat from solar energy and to recover waste heat from industrial sectors and automobile exhausts. In recent years, most of the efforts have been done on improving the thermoelectric efficiency using different approaches, that is, nanostructuring, doping, molecular rattling, and nanocomposite formation. The applications of thermoelectric polymers at low temperatures, especially conducting polymers, have shown various advantages such as easy and low cost of fabrication, light weight, and flexibility. In this review, we will focus on exploring new types of polymers and the effects of different structures, concentrations, and molecular weight on thermoelectric properties. Various strategies to improve the performance of thermoelectric materials will be discussed. In addition, a discussion on the fabrication of thermoelectric devices, especially suited to polymers, will also be given. Finally, we provide the challenge and the future of thermoelectric polymers, especially thermoelectric hybrid model.The Scientific World Journal 11/2013; 2013(3):713640. DOI:10.1155/2013/713640 · 1.73 Impact Factor
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ABSTRACT: Polythieno[3,2-b]thiophene (PTT) was electrosynthesized by facile anodic oxidation of thieno[3,2-b]thiophene (TT) in three systems: boron trifluoride diethyl etherate (BFEE), acetonitrile (ACN), and dichloromethane solutions. The onset oxidation potential of TT in BFEE was determined to be 0.62V vs. Ag/AgCl, which was much lower than those in ACN and dichloromethane solutions. PTT films exhibited excellent electrochemical property, high thermal stability, good redox activity, and stability. Free-standing PTT films with good mechanical property can be obtained from BFEE solution, whose structure and morphology were characterized by FT-IR, UV–visible spectra, and scanning electron microscopy. With an electrical conductivity of 1.5S cm−1 and a Seebeck coefficient of 85µVK−1 at 306K, the as-prepared free-standing PTT films showed a certain thermoelectric property. The dimensionless figure-of-merit of PTT films was estimated to be 2.3 × 10−3 at 306K, which was much higher than those of some organic thermoelectric materials reported previously. All these results indicated that PTT films may have potential applications in the thermoelectric field. KeywordsConducting polymers–Thieno[3,2-b]thiophene–Electrochemical polymerization–Thermoelectric property–PolythiopheneJournal of Solid State Electrochemistry 03/2010; 15(3):539-548. DOI:10.1007/s10008-010-1095-8 · 2.45 Impact Factor
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ABSTRACT: Significant enhancement of thermoelectric (TE) performance was observed for free-standing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) composite films obtained from a PEDOT:PSS aqueous solution by simultaneous addition of dimethyl sulfoxide (DMSO) and different concentrations of urea. The electrical conductivity was enhanced from 8.16 S cm−1 to over 400 S cm−1, and the maximum Seebeck coefficient reached a value of 18.81 μV K−1 at room temperature. The power factor of the PEDOT:PSS composite films reached 8.81 μW m−1 K−2. The highest thermoelectric figure of merit (ZT) in this study was 0.024 at room temperature, which is at least one order of magnitude higher than most polymers and bulk Si. These results indicate that the obtained composite films are a promising thermoelectric material for applications in thermoelectric refrigeration and thermoelectric microgeneration.Journal of Electronic Materials 09/2012; 41(9). DOI:10.1007/s11664-012-2162-y · 1.80 Impact Factor