DataVXAdvanced Electronic MaterialsPaper
journal article·2026-05Open access

Side‐Chain Branching Dictates the σ–S Coupling in Conjugated Polymer Thermoelectrics

Yingyao Zhang, So‐Huei Kang, Po Chen, Huadeng Xie, Qinfang Zhang, Seoyoung Kim, Donghoo Won, Zilong Zhang, Chi Li, Liang Liu, Qi Zhu, Feiyan Wu, Lie Chen, Reza Keshavarzia, Changduk Yang, Peng Gao

Advanced Electronic Materials· Volume 12· Issue 10
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Abstract

ABSTRACT Understanding the intrinsic coupling between electrical conductivity (σ) and the Seebeck coefficient (S) remains a central challenge in organic thermoelectrics, where energetic disorder and charge transport are highly sensitive to molecular design. Here, we show that precise control over the side‐chain branching position provides an effective structural lever to tune the σ–S relationship in conjugated polymers. Two DPP–selenophene copolymers with identical backbones but branched at distinct positions exhibit markedly different molecular packing, charge‐carrier delocalization, and density‐of‐states (DOS) widths. Polymers with more distant branching points form tighter π–π stacks, yielding enhanced carrier mobility and a narrower DOS that collectively boost σ to 129.3 S cm − 1 . In contrast, closer branching induces greater energetic disorder and broader DOS distributions, resulting in a substantially higher S of 160 µV K − 1 . Despite their contrasting transport characteristics, both polymers deliver similar peak power factors owing to complementary changes in σ and S. These results identify side‐chain branching as a previously underappreciated design parameter that mechanistically governs the coupling between conductivity and Seebeck coefficient in organic thermoelectric materials.
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Research context

Polymers

OpenAlex topics: Organic Electronics and Photovoltaics · Advanced Thermoelectric Materials and Devices · Covalent Organic Framework Applications

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou Fujian China

Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth Materials Chinese Academy of Sciences Xiamen China

Fujian College University of Chinese Academy of Sciences Fuzhou China

Department of Energy Engineering School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST) 50 UNIST‐gil Ulju‐gun Ulsan Republic of Korea

UNIST InnoCORE AI‐Space Solar Initiative Ulsan National Institute of Science and Technology (UNIST) Ulsan Republic of Korea

Department of Chemistry McGill University Quebec Canada

College of Chemistry Nanchang University Nanchang China

Department of Chemistry University of Isfahan Isfahan Iran

Graduate School of Carbon Neutrality Ulsan National Institute of Science and Technology (UNIST) 50 UNIST‐gil Ulju‐gun Ulsan South Korea

Funding

Iran National Science Foundation · National Research Foundation of Korea · Ministry of Science and ICT, South Korea · State Key Laboratory of Structural Chemistry

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