n-type charge transport in heavily p-doped polymers
| Autor: | Xuyi Luo, Ashkan Abtahi, Jacob L. Hempel, Chad Risko, Douglas R. Strachan, Uma Shantini Ramasamy, Kenneth R. Graham, Zhiming Liang, Hyun Ho Choi, Tuo Liu, Kyle N. Baustert, Armin Ansary, J. Andrew Hitron, Jianguo Mei, Alex M. Boehm, Vitaly Podzorov |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
02 engineering and technology 010402 general chemistry 01 natural sciences Condensed Matter::Materials Science Delocalized electron Hall effect Condensed Matter::Superconductivity Seebeck coefficient General Materials Science chemistry.chemical_classification Dopant Mechanical Engineering Doping technology industry and agriculture General Chemistry Electron acceptor 021001 nanoscience & nanotechnology Condensed Matter Physics Thermoelectric materials 0104 chemical sciences chemistry Mechanics of Materials Chemical physics Condensed Matter::Strongly Correlated Electrons Charge carrier 0210 nano-technology |
| Zdroj: | Nature materials. 20(4) |
| ISSN: | 1476-4660 |
| Popis: | It is commonly assumed that charge-carrier transport in doped π-conjugated polymers is dominated by one type of charge carrier, either holes or electrons, as determined by the chemistry of the dopant. Here, through Seebeck coefficient and Hall effect measurements, we show that mobile electrons contribute substantially to charge-carrier transport in π-conjugated polymers that are heavily p-doped with strong electron acceptors. Specifically, the Seebeck coefficient of several p-doped polymers changes sign from positive to negative as the concentration of the oxidizing agents FeCl3 or NOBF4 increase, and Hall effect measurements for the same p-doped polymers reveal that electrons become the dominant delocalized charge carriers. Ultraviolet and inverse photoelectron spectroscopy measurements show that doping with oxidizing agents results in elimination of the transport gap at high doping concentrations. This approach of heavy p-type doping is demonstrated to provide a promising route to high-performance n-type organic thermoelectric materials. A broad range of characterization techniques is used to understand the dominant electron conduction in various p-type doped π-conjugated polymers, which show p-type and n-type thermoelectric power factors depending on the dopant concentration. |
| Databáze: | OpenAIRE |
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