Li Qikai, Zhou Qing, Xu Wangping, Wen Long, Li Jun, Deng Biao, Zhang Jiajia, Xu Hu, Liu Weishu
Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China.
Shenzhen Engineering Research Center for Novel Electronic Information Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China.
ACS Appl Mater Interfaces. 2022 Jun 22;14(24):27911-27921. doi: 10.1021/acsami.2c05591. Epub 2022 Jun 7.
Poly(3,4-ethylene dioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) thermoelectric thin films have attracted significant interest due to their solution-processable manufacturing. However, molecular-level tuning or doping is still a challenge to synergistically boost their thermoelectric performance and mechanically stretchable capabilities. In this work, we report a counterion exchange between ionic liquid bis(-fluorosulfonyl) amide lithium (Li:FSI, = 1, 3, 5) with different sizes of anions and a PEDOT:PSS-induced bipolaron network, which significantly boosted the thermoelectric power factor from 0.8 to 157 μW m K at 235 °C and the maximum tensile strain from 3% to over 30%. The π-π* stacking of the PEDOT polymer chains was fine-tuned by the hydrophobic anions of FSI, providing a technical route for constructing a bipolaron network and inducing the transition from hopping transport to band-like transport. Furthermore, we found that the stretchable capabilities, that is, ε, were connected to the gelation time of the PEDOT:PSS-Li:FSI aqueous solution. Thus, more fluorine-containing groups resulted in longer gelation times and higher ε values, which significantly improved the processability of the solution-derived films.
聚（3,4 - 乙烯二氧噻吩）：聚（苯乙烯磺酸）（PEDOT:PSS）热电薄膜因其可溶液加工制造而备受关注。然而，在分子水平上进行调控或掺杂，以协同提高其热电性能和机械拉伸能力，仍然是一项挑战。在这项工作中，我们报道了不同尺寸阴离子的离子液体双（氟磺酰）酰胺锂（Li:FSI， = 1, 3, 5）与PEDOT:PSS诱导的双极化子网络之间的抗衡离子交换，这显著提高了热电功率因子，在235°C时从0.8提高到157 μW m K，最大拉伸应变从3%提高到超过30%。FSI的疏水阴离子对PEDOT聚合物链的π-π*堆积进行了微调，为构建双极化子网络和诱导从跳跃传输到带状传输的转变提供了一条技术路线。此外，我们发现可拉伸能力，即ε，与PEDOT:PSS-Li:FSI水溶液的凝胶化时间有关。因此，更多的含氟基团导致更长的凝胶化时间和更高的ε值，这显著提高了溶液衍生薄膜的加工性能。
