Premium
Highly Conducting Polythiophene Thin Films with Less Ordered Microstructure Displaying Excellent Thermoelectric Performance
Author(s) -
Zhang Jiajia,
Song Guangjie,
Qiu Lin,
Feng Yanhui,
Chen Jie,
Yan Jie,
Liu Liyao,
Huang Xing,
Cui Yutao,
Sun Yimeng,
Xu Wei,
Zhu Daoben
Publication year - 2018
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201800283
Subject(s) - materials science , polythiophene , raman spectroscopy , thermoelectric effect , amorphous solid , thin film , microstructure , thermal conductivity , conductive polymer , doping , polymerization , analytical chemistry (journal) , polymer , chemical engineering , composite material , nanotechnology , organic chemistry , optoelectronics , optics , thermodynamics , chemistry , physics , engineering
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 −1 for films obtained under an optimized current density of 1 mA cm −2 . 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 −9 W Ω K −2 and low lattice thermal conductivity of 0.21 W m −1 K −1 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.