基于噻吩基异靛青给受体型共轭聚合物的设计合成及其热电性能研究

Doping donor-acceptor type(D-A) conjugated polymers with high mobility has become an important approach to develop organic thermoelectric materials. Currently, P type D-A conjugated polymers used as thermoelectric materials has the problem of low doping efficiency due to their low-lying highest occupied molecular orbit (HOMO) levels as well as their D-A alternate structures, which prevent further improvement of their thermoelectric performance. So the aim of this project is to develop new thermoelectric polymers based on thienoisoindigo electron accepting unit which possesses highly planar structure. D-A type conjugated polymers with high lying HOMO levels and ordered structure will be designed and synthesized by introducing electron donating unit groups with different donating abilities, different side chains and different geometries. With synergistic polymer molecular structure design and doping condition optimization, high performance thermoelectric polymer materials will be developed. Furthermore, the effect of polymer structure on its energy levels, solid state structures, oxidation doping efficiency and thermoelectric properties will be studied. The structure-property relationship for thienoisoindigo based D-A conjugated polymers as thermoelectric materials will be explored, which will pave the way for developing high performance polymer thermoelectric materials.

掺杂给受体型（D-A）高迁移率共轭聚合物逐渐成为开发有机热电材料的重要途径。但目前报道的P型D-A共轭聚合物热电材料由于其较低的HOMO能级及给受体单元交替结构，使其氧化掺杂效率较低，不利于此类聚合物热电性能的提升。本项目拟开发基于噻吩基异靛青的高HOMO能级D-A共轭聚合物热电材料，利用噻吩基异靛青单元的缺电子和共平面性，通过分子设计选取具有不同给电子能力、含有不同侧链和具有不同几何形状的给电子单元与其构筑D-A共轭聚合物，合成系列分子平面性好且HOMO能级高的D-A共轭聚合物材料，协同优化其氧化掺杂条件，提升D-A共轭聚合物材料的热电性能。系统研究D-A共轭聚合物的分子结构对材料能级、聚集态结构、氧化掺杂效率和热电性能的影响规律，揭示其分子结构与热电性能之间的关联，为高性能共轭聚合物热电材料的设计提供新思路。

化学掺杂高迁移率共轭聚合物是开发有机热电材料的重要途径。本项目围绕共轭聚合物热电材料的分子结构设计及其掺杂导电和热电性能研究，设计合成了一系列基于噻吩基异靛青单元及其类似结构吡咯并吡咯二酮的D-A共轭聚合物，采用三氯化铁及F4TCNQ等掺杂剂对聚合物薄膜进行氧化掺杂，系统研究不同给电子单元及其侧链对聚合物能级结构及氧化掺杂后电荷传输和热电性能的影响。引入富电子3,4-乙烯二氧噻吩（EDOT）单元部分代替其共轭主链中的噻吩单元，提升聚合物HOMO能级同时构建聚合物分子内非共价O···S相互作用，使D-A共轭聚合物更容易在较低掺杂剂浓度下获得更高的电导率和塞贝克系数，最终提升D-A共轭聚合物的热电转化性能，基于EDOT的D-A共轭聚合物热电功率因子可达298 μW m-1 K-2，在D-A共轭聚合物热电材料体系中处于较高水平。通过本项目的实施，揭示了D-A共轭聚合物分子结构与其能级、氧化掺杂效率及热电性能之间的关联，为设计高性能D-A共轭聚合物热电材料提供新的思路和途径。