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Exploring Wholly Doped Conjugated Polymer Films Based on Hybrid Doping: Strategic Approach for Optimizing Electrical Conductivity and Related Thermoelectric Properties
Author(s) -
Yoon Sang Eun,
Kang Yeongkwon,
Jeon Gyeong G.,
Jeon Dohyeon,
Lee Sang Yeon,
Ko SeoJin,
Kim Taekyeong,
Seo Hyungtak,
Kim BongGi,
Kim Jong H.
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202004598
Subject(s) - materials science , doping , dopant , thermoelectric effect , seebeck coefficient , electrical resistivity and conductivity , amorphous solid , thermoelectric materials , polymer , conductivity , optoelectronics , nanotechnology , chemical engineering , composite material , thermal conductivity , chemistry , organic chemistry , electrical engineering , thermodynamics , physics , engineering
Conventional chemical doping processes for conjugated polymers (CPs) often degrade the film morphology or cause unsatisfactory doping efficiency owing to the aggregation formation between charged species or insufficient dopant diffusion. In this work, a new strategic doping method, “hybrid doping,” is suggested for maximizing the doping efficiency of CPs without hampering the surface morphology of the CP films. The advantage of hybrid doping is that it combines mixture blending and sequential soaking processes. Based on systemic characterizations including spectroscopic, structural, and electrical analyses, it is revealed that hybrid doping enables whole area doping for the crystalline and amorphous regions of CP films, and thus an unprecedentedly high electrical conductivity of up to 81.5 and 639.1 S cm −1 , for poly(3‐hexylthiophene) P3HT and poly (2‐([2,2′‐bithiophen]‐5‐yl)‐3,8‐difluoro‐5,10‐bis(5‐octylpentadecyl)‐5,10‐dihydroindolo [3,2‐b]indole) (PIDF‐BT), respectively, is achieved. Furthermore, the exceptional electrical conductivity compensates a reduced Seebeck coefficient, resulting in excellent power factors up to 26.8 and 76.1 μW m −1 K −2 for thermoelectric devices based on doped‐P3HT and PIDF‐BT films, respectively, which is among the highest levels for semiconducting CPs. Hybrid doping is a strategic approach for the simultaneous optimization of electrical conductivity and thermoelectric properties of various CPs.