Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James Franck-Str. 1, Garching, 85748, Germany.
Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, AREA Science Park, Basovizza, 34149, Italy.
Macromol Rapid Commun. 2021 Oct;42(20):e2100397. doi: 10.1002/marc.202100397. Epub 2021 Sep 17.
Ionic liquid (IL) post-treatment of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) thin films with ethyl-3-methylimidazolium dicyanamide (EMIM DCA), allyl-3-methylimidazolium dicyanamide (AMIM DCA), and 1-ethyl-3-methylimidazolium tetracyanoborate (EMIM TCB) is compared. Doping level modifications of PEDOT are characterized using UV-Vis spectroscopy and directly correlate with the observed Seebeck coefficient enhancement. With conductive atomic force microscopy (c-AFM) the authors investigate changes in the topographic-current features of the PEDOT:PSS thin film surface due to IL treatment. Grazing incidence small-angle X-ray scattering (GISAXS) demonstrates the morphological rearrangement towards an optimized PEDOT domain distribution upon IL post-treatment, directly facilitating the interconductivity and causing an increased film conductivity. Based on these improvements in Seebeck coefficient and conductivity, the power factor is increased up to 236 µW m K . Subsequently, a model is developed indicating that ILs, which contain small, sterically unhindered ions with a strong localized charge, appear beneficial to boost the thermoelectric performance of post-treated PEDOT:PSS films.
离子液体（IL）后处理聚（3,4-亚乙基二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT：PSS）薄膜与乙基-3-甲基咪唑二氰胺（EMIM DCA）、烯丙基-3-甲基咪唑二氰胺（AMIM DCA）和 1-乙基-3-甲基咪唑四氰硼酸盐（EMIM TCB）进行了比较。使用紫外-可见光谱法对 PEDOT 的掺杂水平进行了表征，并与观察到的 Seebeck 系数增强直接相关。通过导电原子力显微镜（c-AFM），作者研究了 IL 处理后 PEDOT：PSS 薄膜表面形貌-电流特征的变化。掠入射小角 X 射线散射（GISAXS）表明，IL 后处理后，PEDOT 畴分布向优化方向进行形态重排，直接促进了互导电性，并导致薄膜电导率增加。基于 Seebeck 系数和电导率的这些提高，功率因数提高了 236 µW m K 。随后，开发了一个模型，表明含有小的、空间位阻较小且局部电荷较强的离子的 IL 似乎有利于提高后处理的 PEDOT：PSS 薄膜的热电性能。
