Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic Liquids
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is one of the most popular conducting polymers and widely used as polymer thermoelectric materials, and its thermoelectric performance could be improved by a variety of post-treatment processes. This paper reported two series of pos...
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Frontiers Media S.A.
2020-01-01
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Online Access: | https://www.frontiersin.org/article/10.3389/fchem.2019.00870/full |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Temesgen Atnafu Yemata Temesgen Atnafu Yemata Yun Zheng Aung Ko Ko Kyaw Aung Ko Ko Kyaw Xizu Wang Jing Song Wee Shong Chin Jianwei Xu Jianwei Xu |
spellingShingle |
Temesgen Atnafu Yemata Temesgen Atnafu Yemata Yun Zheng Aung Ko Ko Kyaw Aung Ko Ko Kyaw Xizu Wang Jing Song Wee Shong Chin Jianwei Xu Jianwei Xu Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic Liquids Frontiers in Chemistry conducting polymer PEDOT:PSS thermoelectric ionic liquids environmental stability |
author_facet |
Temesgen Atnafu Yemata Temesgen Atnafu Yemata Yun Zheng Aung Ko Ko Kyaw Aung Ko Ko Kyaw Xizu Wang Jing Song Wee Shong Chin Jianwei Xu Jianwei Xu |
author_sort |
Temesgen Atnafu Yemata |
title |
Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic Liquids |
title_short |
Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic Liquids |
title_full |
Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic Liquids |
title_fullStr |
Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic Liquids |
title_full_unstemmed |
Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic Liquids |
title_sort |
improved thermoelectric properties and environmental stability of conducting pedot:pss films post-treated with imidazolium ionic liquids |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Chemistry |
issn |
2296-2646 |
publishDate |
2020-01-01 |
description |
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is one of the most popular conducting polymers and widely used as polymer thermoelectric materials, and its thermoelectric performance could be improved by a variety of post-treatment processes. This paper reported two series of post-treatment methods to enhance the thermoelectric performance. The first series method included pre-treatment of PEDOT:PSS film with formamide, followed by imidazolium-based ionic liquids. The second series method included pre-treatment of PEDOT:PSS film with formamide, followed by sodium formaldehyde sulfoxylate, and finally imidazolium-based ionic liquids. Two series of post-treatment methods significantly improved the power factor of PEDOT:PSS when compared to that of PEDOT:PSS treated with formamide only. For example, using the first series post-treatment method with 40 vol.% ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide, the Seebeck coefficient of the PEDOT:PSS film increased from 14.9 to 28.5 μV/K although the electrical conductivity reduced from 2,873 to 1,701 S/cm, resulting in a substantial improvement in the overall power factor from 63.6 to 137.8 μW/K2m. The electrical conductivity enhancement in the formamide-treatment process was in part ascribed to the removal of the insulating PSS component. Further treatment of PEDOT:PSS film with ionic liquid caused dedoping of PEDOT and hence increased in Seebeck coefficient. In contrast, second series post-treatment method led to the reduction in electrical conductivity from 2,873 to 641 S/cm but a big improvement in the Seebeck coefficient from 14.9 to 61.1 μV/K and thus the overall power factor reached up to ~239.2 μW/K2m. Apart from the improvement in electrical conductivity, the increase in Seebeck coefficient is on account of the substantial dedoping of PEDOT polymer to its neutral form and thus leads to the big improvement of its Seebeck coefficient. The environmental stability of ionic liquid-treated PEDOT:PSS films were examined. It was found that the ionic liquid treated PEDOT:PSS retained more than 70% Seebeck coefficient and electrical conductivity at 75% RH humidity and 70°C for 480 h. The improved long-term TE stability is attributed to the strong ionic interaction between sulfonate anions and bulky imidazolium cations that effectively block the penetration of water and lessen the tendency to take up water from the air. |
topic |
conducting polymer PEDOT:PSS thermoelectric ionic liquids environmental stability |
url |
https://www.frontiersin.org/article/10.3389/fchem.2019.00870/full |
work_keys_str_mv |
AT temesgenatnafuyemata improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT temesgenatnafuyemata improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT yunzheng improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT aungkokokyaw improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT aungkokokyaw improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT xizuwang improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT jingsong improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT weeshongchin improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT jianweixu improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids AT jianweixu improvedthermoelectricpropertiesandenvironmentalstabilityofconductingpedotpssfilmsposttreatedwithimidazoliumionicliquids |
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doaj-feae4efbb6404755a8088ce3272fc05c2020-11-25T02:22:12ZengFrontiers Media S.A.Frontiers in Chemistry2296-26462020-01-01710.3389/fchem.2019.00870484977Improved Thermoelectric Properties and Environmental Stability of Conducting PEDOT:PSS Films Post-treated With Imidazolium Ionic LiquidsTemesgen Atnafu Yemata0Temesgen Atnafu Yemata1Yun Zheng2Aung Ko Ko Kyaw3Aung Ko Ko Kyaw4Xizu Wang5Jing Song6Wee Shong Chin7Jianwei Xu8Jianwei Xu9Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), Singapore, SingaporeDepartment of Chemistry, National University of Singapore, Singapore, SingaporeInstitute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), Singapore, SingaporeInstitute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), Singapore, SingaporeDepartment of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, ChinaInstitute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), Singapore, SingaporeInstitute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), Singapore, SingaporeDepartment of Chemistry, National University of Singapore, Singapore, SingaporeInstitute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), Singapore, SingaporeDepartment of Chemistry, National University of Singapore, Singapore, SingaporePoly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is one of the most popular conducting polymers and widely used as polymer thermoelectric materials, and its thermoelectric performance could be improved by a variety of post-treatment processes. This paper reported two series of post-treatment methods to enhance the thermoelectric performance. The first series method included pre-treatment of PEDOT:PSS film with formamide, followed by imidazolium-based ionic liquids. The second series method included pre-treatment of PEDOT:PSS film with formamide, followed by sodium formaldehyde sulfoxylate, and finally imidazolium-based ionic liquids. Two series of post-treatment methods significantly improved the power factor of PEDOT:PSS when compared to that of PEDOT:PSS treated with formamide only. For example, using the first series post-treatment method with 40 vol.% ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide, the Seebeck coefficient of the PEDOT:PSS film increased from 14.9 to 28.5 μV/K although the electrical conductivity reduced from 2,873 to 1,701 S/cm, resulting in a substantial improvement in the overall power factor from 63.6 to 137.8 μW/K2m. The electrical conductivity enhancement in the formamide-treatment process was in part ascribed to the removal of the insulating PSS component. Further treatment of PEDOT:PSS film with ionic liquid caused dedoping of PEDOT and hence increased in Seebeck coefficient. In contrast, second series post-treatment method led to the reduction in electrical conductivity from 2,873 to 641 S/cm but a big improvement in the Seebeck coefficient from 14.9 to 61.1 μV/K and thus the overall power factor reached up to ~239.2 μW/K2m. Apart from the improvement in electrical conductivity, the increase in Seebeck coefficient is on account of the substantial dedoping of PEDOT polymer to its neutral form and thus leads to the big improvement of its Seebeck coefficient. The environmental stability of ionic liquid-treated PEDOT:PSS films were examined. It was found that the ionic liquid treated PEDOT:PSS retained more than 70% Seebeck coefficient and electrical conductivity at 75% RH humidity and 70°C for 480 h. The improved long-term TE stability is attributed to the strong ionic interaction between sulfonate anions and bulky imidazolium cations that effectively block the penetration of water and lessen the tendency to take up water from the air.https://www.frontiersin.org/article/10.3389/fchem.2019.00870/fullconducting polymerPEDOT:PSSthermoelectricionic liquidsenvironmental stability |