On the thermal conductivity of conjugated polymers for thermoelectrics
The thermal conductivity (κ) governs how heat propagates in a material, and thus is a key parameter that constrains the lifetime of optoelectronic devices and the performance of thermoelectrics (TEs). In organic electronics, understanding what determines κ has been elusive and experimentally challen...
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
25 June 2024
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| In: |
Advanced energy materials
Year: 2024, Volume: 14, Issue: 35, Pages: 1-15 |
| ISSN: | 1614-6840 |
| DOI: | 10.1002/aenm.202401705 |
| Online Access: | Verlag, kostenfrei, Volltext: https://doi.org/10.1002/aenm.202401705 Verlag, kostenfrei, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202401705 
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| Author Notes: | Xabier Rodríguez-Martínez, Fernan Saiz, Bernhard Dörling, Sara Marina, Jiali Guo, Kai Xu, Hu Chen, Jaime Martin, Iain McCulloch, Riccardo Rurali, Juan Sebastian Reparaz, and Mariano Campoy-Quiles |
| Summary: | The thermal conductivity (κ) governs how heat propagates in a material, and thus is a key parameter that constrains the lifetime of optoelectronic devices and the performance of thermoelectrics (TEs). In organic electronics, understanding what determines κ has been elusive and experimentally challenging. Here, by measuring κ in 17 π-conjugated materials over different spatial directions, it is statistically shown how microstructure unlocks two markedly different thermal transport regimes. κ in long-range ordered polymers follows standard thermal transport theories: improved ordering implies higher κ and increased anisotropy. κ increases with stiffer backbones, higher molecular weights and heavier repeat units. Therein, charge and thermal transport go hand-in-hand and can be decoupled solely via the film texture, as supported by molecular dynamics simulations. In largely amorphous polymers, however, κ correlates negatively with the persistence length and the mass of the repeat unit, and thus an anomalous, albeit useful, behavior is found. Importantly, it is shown that for quasi-amorphous co-polymers (e.g., IDT-BT) κ decreases with increasing charge mobility, yielding a 10-fold enhancement of the TE figure-of-merit ZT compared to semi-crystalline counterparts (under comparable electrical conductivities). Finally, specific material design rules for high and low κ in organic semiconductors are provided. |
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| Item Description: | Gesehen am 17.02.2025 |
| Physical Description: | Online Resource |
| ISSN: | 1614-6840 |
| DOI: | 10.1002/aenm.202401705 |