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The development of conjugated polymers with structures that are suitable for efficient molecular doping and charge transport is a key challenge in the construction of high‐performance conjugated polymer‐based thermoelectric devices. In this study, three novel conjugated polymers based on dithienopyrrole (DTP) are synthesized and their thermoelectric properties are compared. When doped with p‐dopant, a donor–acceptor type copolymer, DPP‐MeDTP, exhibits higher electrical conductivity and thermoelectric power factor compared to the other donor–donor type copolymers. The high electrical conductivity of DPP‐MeDTP compared to the other polymers originates from the high degree of backbone planarity and molecular order, which contributes to its high charge carrier mobility. In addition, the highly crystalline structure of DPP‐MeDTP is well maintained upon doping, while the crystalline order of the other polymers decreases significantly upon doping. The findings of this work not only provide insights into the design of DTP‐based conjugated polymers for thermoelectric use but also demonstrate the significance of a high degree of molecular order and structural robustness upon doping to achieve high thermoelectric performance. [ABSTRACT FROM AUTHOR]

Abstract: A polyoxadiazole containing the 4-hydroxypyridine group, introduced to enhance the intermolecular interaction between polymer chains as well as for photosensitization, was synthesized from a corresponding precursor polyhydrazide. The absorption and emission spectra of the polymer film exhibited red-shifted maxima compared to those of the polyoxadiazole in chloroform solution, indicative of the presence of significant intermolecular interactions. The synthesized polymer showed a unique fluorescence enhancement upon UV irradiation in solution as well as in the film, presumably due to the photosensitized oxidation of hydroxypyridine groups to produce pyridone structures having different intermolecular interactions. Thus, this phenomenon enabled us to obtain a stable patterned image with enhanced fluorescence intensity in the UV-exposed area of the polymer film without any subsequent processes such as baking or etching. [Copyright &y& Elsevier]

[Display omitted] • Thermoelectric properties of novel isoindio-based conjugated copolymers are compared. • A high thermoelectric power factor of 212 µW m−1 K−2 is attained. • Interchain molecular docking of polymer enables high thermoelectric performance. The development of organic materials with high thermoelectric performance requires the exploration of organic molecules having various structures and a deep understanding of the relationship between their structure and thermoelectric properties. In this study, a series of donor–acceptor-type conjugated copolymers with an isoindigo (IID) unit as a building block are synthesized and compared to investigate the effect of the molecular structure of the IID-based conjugated polymers on the microstructure and thermoelectric properties of polymer films. The crystallinity and molecular packing of the polymers change significantly depending on the symmetry of the donor unit copolymerized with the IID unit, resulting in considerable differences in the doping and charge transport characteristics of the polymers. Importantly, the polymer with high crystallinity and fibril-like crystalline network shows excellent thermoelectric performance, exhibiting a high power factor of 212 µW m−1 K−2 upon doping; this is attributed to the high electrical conductivity and high Seebeck coefficient, which result from its highly ordered structure. This study not only demonstrates the potential of the IID unit as a promising building block for high-performance conjugated polymers for thermoelectric applications but also provides important guidelines for the design of IID-based polymers having high thermoelectric performance. [ABSTRACT FROM AUTHOR]