Zhang Jiajia, Song Guangjie, Qiu Lin, Feng Yanhui, Chen Jie, Yan Jie, Liu Liyao, Huang Xing, Cui Yutao, Sun Yimeng, Xu Wei, Zhu Daoben
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Macromol Rapid Commun. 2018 Jul 5:e1800283. doi: 10.1002/marc.201800283.
Polythiophene (PTh) with highly regular molecular structure is synthesized as nearly amorphous thin films by electrochemical methods in a BFEE/DTBP mixed medium (BFEE = boron fluoride ethyl ether; DTBP = 2,6-di-tert-butypyridine). The doping level and film morphology of PTh are modulated through adjusting the current density applied during the polymerization process. A combined analysis with solid-state NMR, FT-IR, and Raman spectra reveals the molecular structural regularity of the resulted PTh films, which leads to the highest electrical conductivity up to 700 S cm for films obtained under an optimized current density of 1 mA cm . By applying the self-heating 3ω-method, thermal conductivities are measured along the in-plane direction. A highly reduced Lorenz number of 6.49 × 10 W Ω K and low lattice thermal conductivity of 0.21 W m K were extracted based on the analyses of the electrical and thermal conductivities according to the Wiedemann-Franz Law; the former is about one-third of the Sommerfeld value. Finally, the maximized ZT value can reach up to 0.10 under room temperature, which shows that the highly conducting polymers with less ordered structure is the practical direction for developing organic thermoelectric materials.
通过电化学方法在BFEE/DTBP混合介质（BFEE = 氟化硼乙醚；DTBP = 2,6 - 二叔丁基吡啶）中合成具有高度规则分子结构的聚噻吩（PTh），形成近乎非晶态的薄膜。通过调节聚合过程中施加的电流密度来调控PTh的掺杂水平和薄膜形态。结合固态核磁共振、傅里叶变换红外光谱和拉曼光谱分析揭示了所得PTh薄膜的分子结构规则性，这使得在1 mA cm²的优化电流密度下获得的薄膜具有高达700 S cm⁻¹的最高电导率。通过应用自热3ω方法，沿面内方向测量热导率。根据维德曼 - 夫兰兹定律，基于电导率和热导率的分析，提取出6.49×10⁻⁸ W Ω⁻¹ K⁻²的高度降低的洛伦兹数和0.21 W m⁻¹ K⁻¹的低晶格热导率；前者约为索末菲值的三分之一。最后，在室温下最大化的ZT值可达0.10，这表明结构无序程度较低的高导电聚合物是开发有机热电材料的实际方向。
