Tuning charge delocalization for high performance organic thermoelectrics
Understanding and optimizing charge delocalization is essential for enhancing charge transport and thermoelectric performance in conjugated polymers (CPs). However, a practical and generalized methodology to quantify charge delocalization remains lacking. Here, we investigate a series of fluorinated...
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| Autori principali: | , , , , , , , , , , , , |
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| Natura: | Article (Journal) |
| Lingua: | inglese |
| Pubblicazione: |
July 2026
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| In: |
Materials today
Year: 2026, Volume: 96, Pages: 1-12 |
| ISSN: | 1873-4103 |
| DOI: | 10.1016/j.mattod.2026.103330 |
| Accesso online: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.mattod.2026.103330 Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S1369702126001768 
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| Note sull'autore: | Xiaoran Wei, Guanlin Wang, Yong Cui, Yingguo Yang, Dorothea Scheunemann, Yuqian Liu, Wei Fu, Zelong Li, Jianhui Hou, Wanlu Zhang, Martijn Kemerink, Ruiqian Guo, Guangzheng Zuo |
| Riassunto: | Understanding and optimizing charge delocalization is essential for enhancing charge transport and thermoelectric performance in conjugated polymers (CPs). However, a practical and generalized methodology to quantify charge delocalization remains lacking. Here, we investigate a series of fluorinated CPs based on benzodithiophene (BDT) donor and thieno [3], [4], [5], [6], [7], [8], [9] thiophene (TT) acceptor units, systematically varying fluorine position to tune the degree of charge delocalization. Using the Efros-Shklovskii variable range hopping (ES-VRH) model, we experimentally analyze how the localization length (α) evolves with doping concentration and fluorination site. We find that fluorination induces charge localization, reducing α from ∼ 10 nm to ∼ 2 nm and increasing activation energy, which benefits the Seebeck coefficient (S). Importantly, α serves as a structural limit for the power factor (PF), with greater delocalization enabling superior performance. TT-side fluorination maintains a relatively long α (∼8 nm) and moderate activation energy, yielding a maximum PF of ∼ 230μW m−1K−2 for PBDTT-TT-1F. In contrast, BDT-side fluorination causes excessive aggregation and suppressed PF. Normalized S-σ curves reveal a universal charge transport mechanism, with the optimal PF occurring at the transition between conventional VRH and ES-VRH. This study provides valuable insights for designing efficient thermoelectric CPs through charge delocalization control and transport mechanism understanding. |
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| Descrizione del documento: | Gesehen am 19.06.2026 |
| Descrizione fisica: | Online Resource |
| ISSN: | 1873-4103 |
| DOI: | 10.1016/j.mattod.2026.103330 |