Closing the Stability-Performance Gap in Organic Thermoelectrics by Adjusting the Partial to Integer Charge Transfer Ratio
| Autor: | Bernhard Dörling, Mariano Campoy-Quiles, Osnat Zapata-Arteaga, Jaime Martín, Aleksandr Perevedentsev, J. Sebastian Reparaz |
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| Přispěvatelé: | Ministerio de Economía, Industria y Competitividad (España), European Commission, Generalitat de Catalunya, Consejo Superior de Investigaciones Científicas (España), European Research Council, CSIC - Unidad de Recursos de Información Científica para la Investigación (URICI) |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Polymers and Plastics Polymers Analytical chemistry 02 engineering and technology Conductivity 010402 general chemistry 01 natural sciences Article Inorganic Chemistry Electrical resistivity and conductivity Seebeck coefficient Thermoelectric effect Materials Chemistry Electrical conductivity Doping Thermal stability Dopant Organic Chemistry 021001 nanoscience & nanotechnology Thermoelectric materials 0104 chemical sciences 0210 nano-technology Stability Impurities |
| Zdroj: | Macromolecules Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0024-9297 |
| Popis: | Two doping mechanisms are known for the well-studied materials poly(3-hexylthiophene) (P3HT) and poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT), namely, integer charge transfer (ICT) and charge transfer complex (CTC) formation. Yet, there is poor understanding of the effect of doping mechanism on thermal stability and the thermoelectric properties. In this work, we present a method to finely adjust the ICT to CTC ratio. Using it, we characterize electrical and thermal conductivities as well as the Seebeck coefficient and the long-term stability under thermal stress of P3HT and PBTTT of different ICT/CTC ratios. We establish that doping through the CTC results in more stable, yet lower conductivity samples compared to ICT doped films. Importantly, moderate CTC fractions of ∼33% are found to improve the long-term stability without a significant sacrifice in electrical conductivity. Through visible and IR spectroscopies, polarized optical microscopy, and grazing-incidence wide-angle X-ray scattering, we find that the CTC dopant molecule access sites within the polymer network are less prone to dedoping upon thermal exposure. We thank Dr. Martijn Kemerink for fruitful discussions at the early stages of this project. The authors acknowledge financial support from the Spanish Ministry of Economy, Industry, and Competitiveness through the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2015-0496), MAT2015-70850-P, PGC2018-095411-B-I00, and No. MAT2017-90024-P (TANGENTS)-EI/FEDER, UE projects; from the Generalitat de Catalunya through grants 2017SGR488 and AGAUR 2018 PROD 00191; from CSIC through project 201560I032; and from the European Research Council (ERC) under grant agreement no. 648901. O.Z.-A. acknowledges CONACYT-SENER for his Ph.D. scholarship (No. 472571). J.M. furthermore thanks MINECO for the Ramón y Cajal contract and the PGC2018-094620-A-I00 grant. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). |
| Databáze: | OpenAIRE |
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